Agilent 34420A User's Guide

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The 34420A is a 71/2 digit, high performance nanovolt, micro-ohm
meter. Its combination of bench-top and system features makes this
meter a versatile solution for your testing requirements now and in the
future.

Convenient bench-top features
• Built-in math operations including thermistor, thermocouple and
RTD temperature measurements
• Two channel input allows ratio and difference functions for voltage
measurements
• Highly visible vacuum-fluorescent display
• Portable, ruggedized case with non-skid feet
Flexible system features
• HP-IB
GPIB (IEEE-488) interface and RS-232 interface are standard
• SCPI (Standard Commands for Programmable Instruments) and
Keithley 181 compatibility
• Readings at up to 250 per second

Agilent
34420A
HP
34420A
Nano Volt/Micro Ohm Meter

The Front-Panel at a Glance

1
2
3
4

Input channel select
Measurement function keys
Math operation keys
Filter select key

5
6
7
8

Menu operation keys
Range/number of digits displayed keys
Single trigger/autotrigger/auto hold key
Shift / local key

The Front-Panel Menu at a Glance
The menu is organized in a top-down tree structure with three levels.
To turn on menu press:
To move left/right

To move up/down

To enter a command press:

A: MEASurement MENU
1: DIG FILTER

B: TEMPerature MENU

1: PROBE TYPE

2: UNITS

C: MATH MENU
1: STATS

2: INTEGRATE

2: NULL VALUE

Ø
Ø

3: RTD TYPE

2: TRIG DELAY

E: SYStem MENU

ØØ

1: RDGS STORE
7: CHART NULL

4: LOW POWER Ω

4:RTD Ro

2: INTERFACE

ØØ

[1: SECURED]
6: CAL COUNT

5: T/C TYPE

5: LOW VOLT Ω

6: LoV LIMIT Ω

6: COLD JUNCT

7: JUNCT TEMP

4: SCALE OFST

ØØ

3: BAUD RATE

Ø
Ø

3: N SAMPLES

Ø Ø

G: CALibration MENU
1: UNSECURED
[5: INJECTED I]

ØØ

2: SAVED RDGS
3: ERROR
4: TEST
8: DISPLAY
9: COMMA
10: PRESET

F: Input/Output MENU
1: HP-IB ADDR

3: SCALE GAIN

D: TRIGger MENU
1: READ HOLD

3: OCOMP Ω

[2: CALIBRATE]
7: MESSAGE

4: PARITY

5: CHART OUT
11: REVISION

6: CHART SPAN

5: LANGUAGE

[3: CHART ZERO]

[4: CHART GAIN]

NOTE: The commands enclosed in square brackets ([ ]) in the CAL MENU are "hidden" unless the meter is UNSECURED for calibration.

Display Annunciators

*Adrs
Rmt
Man
Trig
OC Off
Null
Stats
Scale
ERROR
Shift
Ch1
Ch2
Ch1 - Ch2
Ch1 / Ch2

Turns on during a measurement.
Meter is addressed to listen or talk over the HP-IB interface.
Meter is in remote mode (using remote interface).
Meter is using manual ranging (autorange is disabled).
Meter is waiting for a single trigger or external trigger.
Offset compensation is turned off.
A null value is being used.
Math statistics operations are being used.
Math scaling operations are being used.
Hardware or remote interface command error(s) detected.
"Shift" key has been pressed.
Meter input is on Channel 1.
Meter input is on Channel 2.
Meter is indicating the difference between inputs on channel 1 and channel 2.
Meter is indicating the ratio of the inputs on channel 1 and channel 2.

Ω
LP
2W
LoV
Hold
Filt
Mem

Meter is measuring resistance (Ohms).
Meter is using low power Ohms.
Meter is using 2-wire Ohms (annunciator off indicates a 4-wire measurement).
Meter is using voltage limited Ohms.
Automatic reading hold is enabled.
The analog and/or the digital filter is enabled.
Turns on when reading memory is enabled.

To review the display annunciators, hold down the Shift key as you
turn on the meter.

The Rear Panel at a Glance

1
2
3
4

Chassis ground
Power-line fuse-holder assembly
Power-line voltage setting
Chart recorder output terminal
(Analog out)

5
6
7
8

Voltmeter complete output terminal
External trigger input terminal
GPIB (IEEE-488) interface connector
RS-232 interface connector

Use the front-panel Input / Output Menu to:

• Select the GPIB or RS-232 interface
• Set the GPIB bus address
• Set the RS-232 baud rate and parity

In This Book
Quick Start Chapter 1 prepares the meter for use and helps you get
familiar with a few of its front-panel features.
Front-Panel Operation Chapter 2 introduces you to the front-panel menu
and describes some of the meter’s menu features.
Features and Functions Chapter 3 gives a detailed description of the
meter’s capabilities and operation. You will find this chapter useful
whether you are operating the meter from the front panel or from a
remote interface.
Remote Interface Reference Chapter 4 contains reference
information to help you program the meter using a remote interface.
Error Messages Chapter 5 lists the error messages that may appear as
you are working with the meter. Each listing contains enough
information to help you diagnose and solve the problem.
Application Programs Chapter 6 contains several remote interface
application programs to help you develop programs for your
measurement application.
Measurement Tutorial Chapter 7 discusses measurement
considerations and techniques to help you obtain the best accuracy and
reduce sources of measurement error.
Specifications Chapter 8 lists the meter’s specifications and describes
how to interpret these specifications.

If you have questions relating to the operation of the meter, call
1-800-452-4844 in the United States, or contact your nearest
Agilent Technologies Sales Office.

Contents
Chapter 1 Quick Start
To Prepare the Meter For Use 13
If the Meter Does Not Turn On 14
To Adjust the Carrying Handle 16
To Make Input Connections 17
To Measure Voltage 19
To Measure Resistance 20
To Measure Temperature With Thermistors 21
To Measure Temperature With RTDs 21
To Measure Temperature With Thermocouples 22
To Select a Range 23
To Set the Number of Digits 24
To Set the Integration Time 25
Front-Panel Display Formats 26
To Rack Mount the Meter 27
Chapter 2 Front-Panel Operation
Front-Panel Menu Reference 31
A Front-Panel Menu Tutorial 33
To Select an Input Channel 41
To Select a Range 42
To Set or Change the Number of Digits 43
To Set the Integration Time 44
To Make Null (Relative) Measurements 45
To Store Minimum and Maximum Readings (Stats) 46
To Trigger the Meter 47
To Use Reading Hold 48
To Make Voltage Ratio and Difference Measurements 49
To Use Reading Memory 50

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Chapter 3 Features and Functions
General Measurement Configuration 55
Input Filters 55
Integration Time 58
Reducing Measurement Noise 60
Number of Digits Displayed 62
Ranging 64
Overload Detection 65
Voltage Measurement Configuration 66
Input Channels 66
Resistance Measurement Configuration 68
Temperature Measurement Configuration 71
Measurement Units 71
RTD Measurements 72
Thermistor Measurements 72
Thermocouple Measurements 73

Contents

Chapter 3 Features and Functions (continued)
Math Operations 74
Null (Relative) Operation 77
Reading Hold 79
Triggering 80
Trigger Source Choices 82
The Wait-for-Trigger State 85
Halting a Measurement in Progress 85
Number of Samples 86
Number of Triggers 86
Trigger Delay 87
Automatic Trigger Delays 89
System-Related Operations 90
Reading Memory 90
Error Conditions 92
Self-Test 93
Display Control 94
Comma Separators 95
Firmware Revision Query 95
SCPI Language Version 96
Voltmeter Complete Terminal 97
External Trigger Terminal 97
Chart Output (Analog Output) 98
Chart Rollover 100
Remote Interface Configuration 101
Remote Interface Selection 101
GPIB Address 102
HP-IB
Baud Rate Selection (RS-232) 103
Parity Selection (RS-232) 104
Programming Language Selection 105
Connection to a Terminal or Printer (RS-232) 106
Calibration 107
Calibration Security 107
Calibration Count 110
Calibration Message 111
Defaults, Power-On and Reset States 112
Chapter 4 Remote Interface Reference
Command Summary 117
Simplified Programming Sequence 126
Using the MEASure? Command 128
Using the CONFigure Command 128
Using the range and resolution Parameters 129
Using the READ? Command 130
Using the INITiate and FETCh? Commands 131
The MEASure? and CONFigure Commands 134
Setting the Function, Range, and Resolution 137
Selecting the Input Channel 140
Special Resistance Measurement Commands 141
Temperature Measurement Commands 142

Contents

Chapter 4 Remote Interface Reference (continued)
Null (Relative) Commands 145
Input Filter Commands 146
Math Operation Commands 148
Statistics operation commands (AVERage) 149
Scale operation commands 150
Triggering 151
The Wait-for-Trigger State 153
Triggering Commands 154
Chart Output (Analog Out) Commands 156
System-Related Commands 157
The SCPI Status Model 159
What is an Event Register? 159
What is an Enable Register? 159
What is a Condition Register? 159
SCPI Status System 160
The Status Byte 161
Using Service Request (SRQ) and Serial POLL 162
Using *STB? to Read the Status Byte 163
To Interrupt Your Bus Controller Using SRQ 163
To Determine When a Command Sequence is Completed 163
How to Use the Message Available Bit (MAV) 164
Using *OPC to Signal When Data is in the Output Buffer 164
The Standard Event Register 165
The Questionable Data Register 167
The Operational Status and Condition Registers 169
Status Reporting Commands 171
Calibration Commands 174
RS-232 Interface Configuration 176
RS-232 Configuration Overview 176
RS-232 Data Frame Format 177
Connection to a Computer or Terminal 177
Connection to a Printer 179
DTR / DSR Handshake Protocol 179
RS-232 Troubleshooting 181
RS-232 Interface Commands 182
An Introduction to the SCPI Language 183
SCPI Data Types 185
Input Message Terminators 186
Output Data Formats 186
Using Device Clear to Halt Measurements 187
TALK ONLY for Printers 187
GPIB Address 188
To Set the HP-IB
To Select the Remote Interface 189
To Set the Baud Rate 190
To Set the Parity 191
To Select the Programming Language 192
Alternate Programming Language Compatibility 193
Specific Issues 193
SCPI Compliance Information 194
IEEE-488 Compliance Information 197

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Contents

Chapter 5 Error Messages
Execution Errors 201
Self-Test Errors 208
Calibration Errors 210
Chapter 6 ApplicationPrograms
HP BASIC Language Programs 215
GPIB Program Example 1 215
HP BASIC / HP-IB
GPIB Program Example 2 216
HP BASIC / HP-IB
HP BASIC / HP-IB
GPIB Program Example 3 218
GPIB Program Example 4 221
HP BASIC / HP-IB
RS-232 Operations with QuickBASIC 223
Microsoft® Visual Basic Language Program 224
C Language Programs 231
Compiling and Linking a C Program 231
C / HP-IB
GPIB Example 1 233
C / HP-IB
GPIB Example 2 235
GPIB Program Example 3 239
C / HP-IB
Microsoft® Excel Macro Example 243
Macro Comments 244
Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error 249
Voltage Measurements 249
Resistance Measurements 258
Temperature Measurements 263
Cleaning the Connector Contacts 271
Input Connector 272
Obtaining Parts For the Input Connector 273
Chapter 8 Specifications
Accuracy Specifications
Measurement Characteristics
Operating Characteristics
Dimensions
To Calculate Total Measurement Error 281
Interpreting Meter Specifications 285
Number of Digits and Overrange 285
Sensitivity 285
Resolution 286
Accuracy 286
24-Hour Accuracy 287
90-Day and 1-Year Accuracy 287
Temperature Coefficients 287
Configuring for Highest Accuracy Measurements 287
Index 289
Declaration of Conformity 295

Quick Start

Quick Start
This chapter helps you prepare the meter for use and contains exercises
designed to get you started with the meter, its menus, and the front
panel.
The front panel has two rows of keys to select various functions and
operations. Most keys have a shifted function printed in blue above
the key. To perform a shifted function, press Shift (the Shift display
annunciator will turn on). Then, press the key that has the desired label
above it. For example, to select the temperature measurement function,
press Shift DCV .
If you accidentally press Shift , just press it again to turn off the Shift
annunciator.
The rear cover of this book is a fold-out Quick Reference Guide. On this
cover you will find a quick summary of various meter features. Inside
the rear cover is a diagram of the front panel menu options.

Chapter 1 Quick Start
To Prepare the Meter For Use

To Prepare the Meter For Use
The following steps help you verify that the meter is ready for use.
1

Check the list of supplied items.
Verify that you have received the following items with your meter. If any
item is missing, contact your nearest Hewlett-Packard
Sales
Office.
Agilent Technologies
Sales
Office.
One low thermal input cable.
One low thermal four-wire shorting plug.
One power cord.
This User’s Guide.
One Service Guide.
One folded Quick Reference card.
Certificate of Calibration with removeable calibration label.
One bottle of DeoxIT contact cleaner.

Connect the power cord and turn the meter on.
The front panel display will light up while the meter performs its
power-on self-test. The GPIB
HP-IB bus address is displayed. The meter is left
in 61/2 digit resolution, channel 1 input, and digital filter on.
To view the display with all annunciators turned on,
hold down Shift as you turn on the meter.

Perform a complete self-test.
The complete self-test performs a more extensive series of tests than
those performed at power-on. Hold down Shift as you press the
power switch to turn on the meter; continue to hold Shift for more than
5 seconds. The self-test will begin when you release the key.
If the self-test is successful, "PASS" is displayed on the front panel. If the
test is not successful, "FAIL" is displayed and the ERROR annunciator
turns on. See the Service Guide for instructions on returning the meter to
Hewlett-Packard
for service.
Agilent for service.

DeoxIT is a trademark of CAIG Laboratories, Inc., San Diego, California.

Chapter 1 Quick Start
If the Meter Does Not Turn On

If the Meter Does Not Turn On
Use the following steps to help solve problems you might experience
when turning on the meter. If you need more help, see the Service Guide
Agilent for service.
for instructions on returning the meter to Hewlett-Packard
for service.
1

Verify there is ac power to the meter.
First verify that the meter’s power switch is in the "On" position. Make
sure the power cord is firmly plugged into the power module on the
meter’s rear panel. Verify that the power source is energized.

Verify the power-line voltage setting.
The line voltage is set to the proper value for your country when the
meter is shipped from the factory. Change the voltage setting if it is not
correct. The settings are: 100, 120, 220, or 240 Vac (for 230 Vac operation,
use the 220 Vac setting).
See the diagram on the next page to verify or change the setting.
To replace the 250 mAT 250 V fuse, order part number 2110-0817.
This fuse is used for all power line voltage settings.

Chapter 1 Quick Start
If the Meter Does Not Turn On

1 Remove the power cord. Remove
the fuse holder assembly from the rear

2 Install the fuse. Remove the
line-voltage selector from the assembly.

250 mAT fuse
(250V)

3 Rotate the line-voltage selector until
the correct voltage appears in the window.

4 Replace the fuse-holder assembly in the
rear panel.

100, 120, 220 (230), or 240 Vac

Install the correct fuse and verify that the correct line voltage appears in the window.

Chapter 1 Quick Start
To Adjust the Carrying Handle

To Adjust the Carrying Handle
To adjust the position, grasp the handle by the sides and pull outward.
Then, rotate the handle to the desired position.

Bench-top viewing positions

Carrying Position

Chapter 1 Quick Start
To Make Input Connections

To Make Input Connections
Using the Cable Provided
Align the front panel connector and cable conductors, press in.
Tighten coupling nut.

RED

Torque to 20 in-lb
maximum

CH1

BLACK

HI
CH2

GREEN
WHITE
LO

The connector and cable are an integral part of the measurement system.
For the highest accuracy, use the copper cable and connectors supplied
Agilent Technologies.
by Hewlett-Packard.
The conductors may require occasional cleaning to remove oxides.
Cleaning the conductors is described on page 271.

Warning

The connector body and cable shield are connected to earth ground.

Chapter 1 Quick Start
To Make Input Connections

Using a Custom Cable
Channel 1

DCV
4-WireΩ
2-WireΩ
Thermistor

+
Source +
Source and Sense +
Source and Sense +

–
Source –
Source and Sense –
Source and Sense –

Earth Ground (shell)

Channel 2

DCV
4-WireΩ
Thermocouple

+
Sense +
+

–
Sense –
–

Refer to page 272 for additional information about building custom input
cables.

Chapter 1 Quick Start
To Measure Voltage

To Measure Voltage
Channel 1 Ranges: 1 mV, 10 mV, 100 mV, 1 V, 10 V, 100 V
Maximum resolution: 0.1 nV (on 1 mV range)
Channel 2 Ranges: 1 mV, 10 mV, 100 mV, 1 V, 10 V
Maximum resolution: 0.1 nV (on 1 mV range)
Independent NULL for each channel
Channel 1 LO to Channel 2 LO isolated to 150 Vpeak.

RED
DC Voltage
BLACK
CH1

CH2

GREEN

DC Voltage

WHITE

DIFFERENCE
RATIO

VOLTAGE
TOGGLES MEASUREMENT CHANNEL
(SCAN) ALTERNATING MEASUREMENT CHANNELS

Scan mode alternates between input channels every 3 seconds or every
measurement, whichever is longer.

Chapter 1 Quick Start
To Measure Resistance

To Measure Resistance
Ranges: 1 Ω , 10 Ω , 100 Ω , 1 kΩ , 10 kΩ , 100 kΩ , 1 MΩ
Maximum resolution: 0.1 µ Ω (on 1 ohm range)
See also Resistance Measurements on page 68.

RED
(SOURCE)
CH1

GREEN

CH2
(SENSE)

WHITED

4-WIRE

BLACK

OR
4-WIRE
RED
2-WIRE
SOURCE
BLACK

GREEN

NOT CONNECTED
WHITE

Resistance measurements use offset compensation. Offset compensation
can be disabled if desired (see page 69).

2-WIRE

Chapter 1 Quick Start
To Measure Temperature With Thermistors

To Measure Temperature With Thermistors
Thermistor type: 5 kΩ
RED

CH1

BLACK

GREEN

OPEN

WHITE

To Measure Temperature With RTDs
4-wire, type: α = .00385 (DIN/IEC 751) or α = .00391
R0 = 4.9 Ω to 2.1 kΩ

RED
(SOURCE)
CH1

GREEN

CH2
(SENSE)

WHITE

BLACK

Chapter 1 Quick Start
To Measure Temperature With Thermocouples

To Measure Temperature With Thermocouples
Thermocouple types: B, E, J, K, N, R, S, T
Reference: external thermistor, external fixed value, or internal thermistor.
Channel 2 only.
ISOTHERMAL BLOCK
RED

CH1

REFERENCE
THERMISTOR

BLACK

GREEN
CH2

EXTERNAL

WHITE

RED
CH1

OPEN
BLACK

OR
FIXED VALUE

GREEN

OR
INTERNAL

CH2
WHITE

CH2
ICE BATH

When using the internal thermistor as the temperature reference, you
should make a custom cable to connect the thermocouple wire directly
to the input terminals (see page 272).

Chapter 1 Quick Start
To Select a Range

To Select a Range
You can let the meter automatically select the range using autoranging
or you can select a fixed range using manual ranging.

Toggles between autoranging
and manual ranging
Selects a higher range
and disables autoranging
Selects a lower range
and disables autoranging

Man annunciator is on when
manual range is enables

• Autoranging is selected at power-on and after a remote interface reset.
• Autorange thresholds:
Down range at <10% of range
Up range at >120% of range
• If the input signal is greater than the present range can measure, the
meter will give an overload indication ("OVLD").
• When making difference or ratio measurements, an overload on either
channel will give an overload indication ("OVLD").
For voltage measurements, ranging is local to the selected channel. This
means that you can select the ranging method (auto or manual) for each
channel independently. When manually ranging, the selected range is
local to the active channel; the meter remembers the range when you
switch between channels.

Chapter 1 Quick Start
To Set the Number of Digits

To Set the Number of Digits
You can set the display to show 41⁄2 , 51⁄2 , 61⁄2 , or 71⁄2 digits. In this
book, the most significant digit (leftmost on the display) is referred to as
the “1⁄2” digit, since it can only be a “0” or “1”. The number of digits
displayed also depends upon the integration time set, see page 25.

Selects 71⁄2 digits
(100 PLC)

Press the Shift key

Selects 61⁄2 digits
(10 PLC)
Selects 51⁄2 digits
(1 PLC)

• The number of digits is set to 61⁄2 digits at power-on and after a
remote interface reset.
• The number of digits shown is dependent upon integration time and
filter settings. The meter will not allow you to show more digits than
the practical measurement capability of the meter. You can, however,
reduce the number of digits shown.
Fewer
Digits

More
Digits

Chapter 1 Quick Start
To Set the Integration Time

To Set the Integration Time
Integration time is specified in Number of Power Line Cycles (NPLC).
You can set the NPLC to 0.02, 0.2, 1, 2, 10, 20, 100, or 200.
• You can set the integration time to one of three fixed values by
choosing the number of digits displayed, see page 24.
• You can set the integration time in the MEASure menu using the
INTEGRATE command.
• The Integration Time is directly related to the maximum number of
digits the meter will display.

NPLC

Filter Off
Max Digits Shown

Filter On
Max Digits Shown

0.02

41⁄2

51⁄2

0.2

51⁄2

61⁄2

71⁄2

61⁄2

71⁄2

61⁄2

71⁄2

100

71⁄2

200

71⁄2

• You can always show fewer digits than the maximum allowed
(the minimum number of digits shown is 41⁄2).
Integration Time is local to the selected function. This means that you
can select the integration time for each function independently. The
meter remembers integration time when you switch between functions.

Chapter 1 Quick Start
Front-Panel Display Formats

Front-Panel Display Formats
-H.DDD,DDD,D EFF
Front-panel display format.

H
D
E
F

Negative sign or blank (positive)
"1/2" digit (0 or 1)
Numeric Digits
Exponent (m,k,M)
Measurement units

6 digits
V

This is the 1 V range,
61⁄2 digits are displayed.

This is the 100 mV range,
51⁄2 digits are displayed.

1.021,651

"1/2" digit

5 digits

-045.230
"1/2" digit

7 digits
0.133,256,7

Ω

This is the 1 ohm range,
71⁄2 digits are displayed.

"1/2" digit

O.VLD

This is an overload indication on the 1 mV range.
26

Chapter 1 Quick Start
To Rack Mount the Meter

To Rack Mount the Meter
You can mount the meter in a standard 19-inch rack cabinet using one of
three optional kits available. Instructions and mounting hardware are
included with each rack-mounting kit. Any System II instrument of the
same size can be rack-mounted beside the 34420A meter.
Remove the carrying handle, and the front and rear rubber bumpers,
before rack-mounting the meter.

To remove the handle, rotate it to the vertical position and pull the ends outward.

To remove the rubber bumper, stretch a corner and then slide it off.

Chapter 1 Quick Start
To Rack Mount the Meter

To rack mount a single instrument, order adapter kit 5063-9240.

To rack mount two instruments side-by-side, order lock-link kit 5061-9694
and flange kit 5063-9212.

To install one or two instruments in a sliding support shelf,
order shelf 5063-9255, and slide kit 1494-0015 (for a single instrument,
also order filler panel 5002-3999).

Front-Panel Operation

Front-Panel Operation
This chapter assumes you are familiar with the meter and menu
operations. You should also understand how to make connections for the
various types of measurements. If you are not familiar with this
information, please read chapter 1, "Quick Start", starting on page 11.
This chapter does not give a detailed description of every front-panel key
or menu operation. It does, however, give you a good overview of the
front-panel menu and the most common front-panel operations. See
chapter 3 “Features and Functions,” starting on page 53, for a complete
discussion of the meter’s capabilities and operation.

Chapter 2 Front-Panel Operation
Front-Panel Menu Reference

Front-Panel Menu Reference
A: MEASurement MENU
1: DIG FILTER Ø 2: INTEGRATE Ø 3: OCOMP Ω Ø 4: LOW POWER Ω Ø 5: LOW VOLT Ω Ø 6: LoV LIMIT Ω
1: DIG FILTER
2: INTEGRATE
3: OCOMP Ω
4: LOW POWER Ω
5: LOW VOLT Ω
6: LoV LIMIT Ω

Selects the digital filter speed. Can be set to FAST, MEDIUM, or SLOW.
Sets the measurement integration time.
Enables or disables offset compensation for resistance measurements.
Enables or disables low power ohms measurements.
Enables or disables voltage limited resistance measurements.
Sets the voltage limit for voltage limited resistance measurements.

B: TEMPerature MENU
1:PROBE TYPE Ø 2: UNITS Ø 3: RTD TYPE Ø 4:RTD Ro Ø 5:T/C TYPE Ø 6: COLD JUNCT Ø 7:JUNCT TEMP
1: PROBE TYPE
2: UNITS
3: RTD TYPE
4: RTD Ro
5: T/C TYPE
6: COLD JUNCT
7: JUNCT TEMP

Selects thermocouples, thermistors, or RTDs as the temperature probe.
Sets the measurement units to either °C, °F, or Kelvins.
Sets the type of RTD in use.
Sets the nominal (0°C) value for the RTD in use.
Selects the type of thermocouple in use.
Sets the source of the temperature reference junction.
Allows direct entry of reference junction temperature.

C: MATH MENU
1: STATS Ø 2: NULL VALUE Ø 3: SCALE GAIN Ø 4 : SCALE OFST
1:STATS
2: NULL VALUE
3: SCALE GAIN
4: SCALE OFST

Recalls the values of minimum, maximum, standard deviation, average,
peak-to-peak, and number of readings.
Selects independent null settings for voltage on channels 1 and 2, resistance,
and temperature functions.
Sets the gain for linear scaling of the data.
Sets the offset for linear scaling of data.

D: TRIGger MENU
1: READ HOLD Ø 2: TRIG DELAY Ø 3: N SAMPLES
1: READ HOLD
2: TRIG DELAY
3: N SAMPLES

Selects the reading hold sensitivity band.
Specifies a time delay between the trigger and the start of the measurement.
Sets the number of samples taken per trigger.

Chapter 2 Front-Panel Operation
Front-Panel Menu Reference

E: SYStem MENU
1: RDGS STOREØ2: SAVED RDGS Ø3: ERRORØ4: TESTØ5: CHART OUT Ø6: CHART SPANØ
7: CHART NULLØ8: DISPLAYØ9: COMMAØ10: PRESETØ11: REVISION
1: RDGS STORE
2: SAVED RDGS
3: ERROR
4: TEST
5: CHART OUT
6: CHART SPAN
7: CHART NULL
8: DISPLAY
9: COMMA
10: PRESET
11: REVISION

Enables or disables reading memory.
Recalls readings stored in memory (up to 1024 readings).
Retrieves errors from the error queue (up to 20 errors).
Performs a complete self-test or individual self-tests.
Enables or disables the chart recorder output (Analog Out).
Sets the chart recorder output range (Analog Out).
Sets the chart recorder output offset (Analog Out).
Enables or disables the front panel display.
Enables or disables a comma separator between digits in the display.
Returns the meter to factory default settings.
Displays the meter’s firmware revision code.

F: Input / Output MENU
1: HPIB ADDR Ø 2: INTERFACE Ø 3: BAUD RATE Ø 4: PARITY Ø 5: LANGUAGE
1: HP-IB ADDR
2: INTERFACE
3: BAUD RATE
4: PARITY
5: LANGUAGE

Sets the GPIB bus address (0 to 30, default 22).
Selects either the GPIB or RS-232 remote interface.
Sets the baud rate for RS-232 operation.
Selects even, odd, or no parity for RS-232 operation.
Selects interface language, either SCPI or Keithley 181.

G: CALibration MENU *
1: SECURED Ø [1: UNSECURED] Ø [2:CALIBRATE] Ø [3: CHART ZERO] Ø [4 : CHART GAIN] Ø
[5: INJECTED I] Ø6:CAL COUNT Ø 7:MESSAGE
1: SECURED
1: UNSECURED
2: CALIBRATE
3: CHART ZERO
4: CHART GAIN
5: INJECTED I
6: CAL COUNT
7: MESSAGE

The meter is secured against calibration; enter code to unsecure.
The meter is unsecured for calibration; enter code to secure.
Performs a calibration of meter; must be UNSECURED.
Performs a calibration of the chart recorder output zero level.
Performs a calibration of the chart recorder output gain.
Performs a calibration to minimize the injected current.
Reads the total number of times the meter has been calibrated.
Reads the first 11 characters of a calibration string, if any,
entered from the remote interface.

* The commands enclosed in square brackets ( [ ] ) are "hidden" unless the meter is UNSECURED for calibration.

Chapter 2 Front-Panel Operation
A Front-Panel Menu Tutorial

A Front-Panel Menu Tutorial
This section is a step-by-step tutorial which shows how to use the
front-panel menu. We recommend that you spend a few minutes with this
tutorial to get comfortable with the structure and operation of the menu.
The menu is organized in a top-down tree structure with three levels
(menus, commands, and parameters). You move down ∨ or up ∧
the menu tree to get from one level to the next. Each of the three levels
has several horizontal choices which you can view by moving left < or
right > .

Menus

Commands

Parameters

• To turn on the menu, press Shift

(Menu On/Off).

• To turn off the menu, press Shift < (Menu On/Off), or press any of
the function or math keys on the top row of front-panel keys.
• To execute a menu command, press Auto/Man .
• To recall the last menu command that was executed, press Shift
(Menu Recall).

• To turn off the menu at any time without saving changes, press any
function key
If you become confused or get lost at any point during the tutorial, simply
turn off the menu and start over again with step 1 for that example.

Chapter 2 Front-Panel Operation
A Front-Panel Menu Tutorial

Messages Displayed During Menu Use
TOP OF MENU -You pressed ∧ while on the menus level; this is
the top level of the menu and you cannot go any higher.

To turn off the menu, press Shift < (Menu On/Off). To move across
the choices on a level, press < or > . To move down a level, press ∨ .
MENUS - You are on the menus level. Press < or > view the choices.
COMMANDS - You are on the commands level. Press < or > to view
the command choices within the selected menu group.
PARAMETER - You are on the parameter level. Press < or > to view
and edit the parameter for the selected command.
MENU BOTTOM - You pressed ∨ while on the parameter level; this is
the bottom level of the menu and you cannot go any lower.

To turn off the menu, press Shift
press ∧ .

< (Menu On/Off). To move up a level,

ENTERED - The change made on the parameter level is saved. This is
displayed after you press Auto/Man (Menu Enter) to execute the command.
MIN VALUE - The value you specified on the parameter level is too small for the
selected command. The minimum value allowed is displayed for you to edit.
MAX VALUE - The value you specified on the parameter level is too large for the
selected command. The maximum value allowed is displayed for you to edit.
EXITING - You will see this message if you turn off the menu by
pressing Auto/Man (Menu On/Off) or a front-panel function/math key. You
did not edit any values on the parameter level and changes were NOT saved.
NOT ENTERED - You will see this message if you turn off the menu by
pressing Shift < (Menu On/Off) or a front-panel function/math key.
You did some editing of parameters but the changes were NOT saved.
Press Auto/Man (Menu Enter) to save changes made on the parameter
level.
VOLTS ONLY - The requested function is only available for voltage
measurements.
UNAVAILABLE - The action requested is NOT allowed in the present configuration.

Chapter 2 Front-Panel Operation
A Front-Panel Menu Tutorial

The following steps show you how to turn on the menu, move up or down
between levels, move across the choices on each level, and turn off the
menu.
In this example, you will turn off the display comma separator.

Menu Example 1

The meter can display readings on the front panel with or without a
comma separator. The following steps show how to disable the comma.
- 0.824,153

With comma separator
(factory setting)

- 0.824153

Without comma separator

On/Off
Shift

Turn on the menu.
You enter the menu on the menus level. The MEAS MENU is your first
choice on this level.
A: MEAS MENU

Move across to the SYS MENU choice on this level.
There are six menu group choices available on the menus level. Each choice
has a letter prefix for easy identification (A: , B: , etc.).
E: SYS MENU

∨

Move down to the commands level within the SYS MENU.
The RDGS STORE command is your first choice on this level.
1: RDGS STORE

Chapter 2 Front-Panel Operation
A Front-Panel Menu Tutorial

Move across to the COMMA command on the commands level.
There are eleven command choices available in the SYS MENU. Each choice
on this level has a number prefix for easy identification (1: , 2: , etc.).
9: COMMA

∨

Move down a level to the COMMA parameter choices.
The first parameter choice is ON for the COMMA command (the comma
setting is stored in non-volatile memory and ON is the factory setting).
ON

Move across to the OFF choice.
There are two parameter choices for COMMA.
OFF

Auto/Man

ENTER

Save the change and turn off the menu.
The meter beeps and displays a message to show that the change is now in
effect. You are then exited from the menu. The meter will no longer show
commas in the display.
ENTERED

Chapter 2 Front-Panel Operation
A Front-Panel Menu Tutorial

The following exercise demonstrates how to use the menu recall feature
as a shortcut to set the COMMA command back to its original setting.
You must perform the steps in Menu Example 1 before you start this
example.

Menu Example 2

Recall
Shift

Use menu recall to return to the COMMA command.

This returns you to the COMMA command, which was the last command
used before you exited the menu in the Example 1.
9: COMMA

Move down to the COMMA parameter choices.
The first parameter choice is OFF (the current setting from Example 1).
OFF

Move across to the ON choice.
Set the parameter back to its original value.
ON

Auto/Man

ENTER

Save the change and turn off the menu.
The meter beeps and displays a message to show that the change is now in
effect. You are then exited from the menu.
ENTERED

Chapter 2 Front-Panel Operation
A Front-Panel Menu Tutorial

Some commands in the menu require that you enter a numeric
parameter value. The following steps show you how to enter a number in
the menu. For this example, you will set the null value for channel 1 to
–30 millivolts.

Menu Example 3

Make sure the meter has channel 1 selected, is in the dc voltage function,
and has 61⁄2 digits displayed. Connect the four-wire short to the meter
input.
On/Off
Shift

Turn on the menu.
You enter the menu on the menus level. The MEAS MENU is your first
choice on this level.
A: MEAS MENU

Move across to the MATH MENU choice on this level.
There are six menu group choices available on this level.
C: MATH MENU

Move down to the commands level within the MATH MENU.
The STATS command is your first choice on this level.
1: STATS

Move across to the NULL VALUE command.
2: NULL VALUE

Chapter 2 Front-Panel Operation
A Front-Panel Menu Tutorial

Move down to edit the NULL VALUE parameter.
The null value should be 0.000000 V when you come to this point in the
menu for the first time. For this example, you will first set the null value
to –0.300000 volts.

Ù0.000,000,0

When you see the flashing “∧” on the left side of the display, you can abort
the edit and return to the “commands” level by pressing ∧ .
v

Make the number negative.
The left most character on the display toggles between +, – , and ^.
– 0.000,000,0

Move the flashing cursor over to edit the second digit.
Notice that the digit to the right of the decimal point is flashing.
– 0.000,000,0

Increment the digit until “3” is displayed.
You decrement or increment each digit independently. Neighboring digits
are not affected.
– 0.300,000,0

Chapter 2 Front-Panel Operation
A Front-Panel Menu Tutorial

Move the flashing cursor over to the units location.
Notice that the units are flashing on the right side of the display.
– 0.300,000,0

10 Decrease the displayed number by a factor of 10.

Notice that the position of the decimal point changes and the displayed
number increases by a factor of 10 and the mV annunciator is on.
– 030.000,00

Auto/Man

ENTER

11 Save the change and turn off the menu.
The meter beeps and displays a message to show that the change is now
in effect. You are then exited from the menu.
ENTERED

You will be returned to the normal measurement display, and, if you
have installed the four-wire short, the display will show a positive
measurement in the approximate amount of the null value just entered.
The Null annunciator is on in the display.
Keep in mind that null is turned on and - 0.03 volts is used as the null
value for measurements. To clear the null value, press Null .
Hint

You can use the menu recall feature to save steps when entering the null
value. First, press Null on the front panel and then press Shift >
(Menu Recall). The meter will jump to the 2:NULL VALUE command.
Press v . The null value in the display is the first reading taken after
you turned NULL on. You can then edit this number as described.

This is the end of the front-panel menu tutorial. The remainder of the
chapter discusses several of the most common front-panel operations.

Chapter 2 Front-Panel Operation
To Select an Input Channel

To Select an Input Channel
For voltage measurements, you have two independent input channels.

RED
DC Voltage

Channel 1
BLACK
GREEN

DC Voltage

Channel 2

WHITE

TOGGLES MEASUREMENT CHANNEL

(SCAN) ALTERNATING MEASUREMENT CHANNELS

• Pressing Channel toggles the display between Channel 1 and
Channel 2.
• Pressing Shift Channel (Scan) creates an alternating Channel 1 and
Channel 2 display. Press Channel again to cancel.

Scan mode alternates between input channels every 3 seconds or every
measurement, whichever is longer. If you are using the scan mode, turn
off all the input filters (both digital and analog), see page 55.

Chapter 2 Front-Panel Operation
To Select a Range

To Select a Range
You can let the meter automatically select the range using autoranging
or you can select a fixed range using manual ranging.

Toggles between autoranging
and manual ranging
Selects a higher range
and disables autoranging
Selects a lower range
and disables autoranging

Man annunciator is on when
manual range is enables

For voltage measurements, ranging is local to the selected channel. This
means that you can select the ranging method (auto or manual) for each
channel independently. When manually ranging, the selected range is
local to the active channel; the meter remembers the range when you
switch between channels.

Chapter 2 Front-Panel Operation
To Set or Change the Number of Digits

To Set or Change the Number of Digits
You can set the display to show 41⁄2 , 51⁄2 , 61⁄2 , or 71⁄2 digits. In this
book, the most significant digit (leftmost on the display) is referred to as
the “1⁄2” digit, since it can only be a “0” or “1”. The number of digits
displayed also depends upon the integration time set, see page 25.

Press the Shift key

Selects 71⁄2 digits
(100 PLC)
Selects 61⁄2 digits
(10 PLC)
Selects 51⁄2 digits
(1 PLC)

More
Digits

Chapter 2 Front-Panel Operation
To Set the Integration Time

To Set the Integration Time
Integration time is specified in Number of Power Line Cycles (NPLC).
You can set the NPLC to 0.02, 0.2, 1, 2, 10, 20, 100, or 200. Also see
"Integration Time" on page 58.
• You can set the integration time to one of three fixed values by
choosing the number of digits displayed, see page 43.
• You can set the integration time in the MEASure menu using the
INTEGRATE command.
• The Integration Time is directly related to the maximum number of
digits the meter will display.

NPLC

Digital Filter Off
Max Digits Shown

Digital Filter On
Max Digits Shown

0.02

41⁄2

51⁄2

0.2

51⁄2

61⁄2

71⁄2

61⁄2

71⁄2

61⁄2

71⁄2

100

71⁄2

200

71⁄2

• You can always select to show fewer digits than the maximum allowed
(the minimum number of digits shown is 41⁄2 ).
Integration Time is local to the selected function. This means that you
can select the integration time for each function independently. The
meter remembers integration time when you switch between functions.

Chapter 2 Front-Panel Operation
To Make Null (Relative) Measurements

To Make Null (Relative) Measurements
Each null measurement, also called relative, is the difference between a
stored null value and the input signal. See page 77.

Enables null operation;
Press again to disable

Null annunciator is on when
null operation is enabled

Reading = measurement – null value
• You can make null measurements on any function or channel. You can
set a null for each channel and function independently. The meter
remembers the null value when you switch between input channels or
functions.
• To null the test lead resistance for more accurate two-wire ohms
measurements, short the ends of the test leads together and then
press Null .
• The first reading taken after you press Null is stored as the null value
in the Null Register. Any previously stored value is replaced with the
new value.
• After enabling null, you can edit the stored null value by
pressing Shift > (Menu Recall). This takes you to the “NULL
VALUE” command in the MATH MENU (only if null is enabled). Go
down to the “parameter” level, and then edit the displayed value.

Chapter 2 Front-Panel Operation
To Store Minimum and Maximum Readings (Stats)

To Store Minimum and Maximum Readings (Stats)
You can store the minimum and maximum readings during a series of
measurements. The following discussion shows how to read the minimum,
maximum, average, peak-to-peak, standard deviation, and reading count.

Enables stats operation;
Press again to disable

Stats annunciator is on when
stats operation is enabled

• You can use stats with any function. When you change functions, stats
operation is disabled.
• Changing input channels or selecting Scan does not disable stats. The
stored readings, however, are not marked as to the input channel.
• After enabling stats, you can read the stored minimum, maximum,
average, standard deviation, peak-to-peak, and count by pressing
Shift > (Menu Recall). This takes you to the “STATS” command in
the MATH MENU (only if stats is enabled). Go down to the
“parameter” level ∨ , and then read the values by
pressing < or > .
• After reading the stored value, pressing Shift < (Menu On/Off)
returns to the measurement display and continues stats operations.
• The stored values are cleared when you turn stats on, turn off the
power, or perform either a remote interface reset or preset.
• The average and standard deviation are of all readings taken since
stats was enabled (not just the average of the stored minimum and
maximum). The count is the total number of readings taken since
stats was enabled.

Chapter 2 Front-Panel Operation
To Trigger the Meter

To Trigger the Meter
You can trigger the meter from the front panel using single trigger
or autotrigger.

Toggles between autotrigger
and reading hold

Enables single trigger
and triggers the meter

Trig annunciator is on when the meter
is waiting for single
trigger (autotrigger disabled)

(sample) annunciator is on
during each measurement

• Autotriggering is enabled when you turn on the meter. Notice that the
* (sample) annunciator turns on during each measurement.
• Single triggering takes one reading each time you press Single and
then waits for the next trigger. Continue pressing this key to trigger
the meter.

Using an External Trigger
The external trigger mode is also enabled by pressing Single .
It is like the single trigger mode except that you apply a trigger pulse
to the rear-panel Ext Trig terminal. The meter is triggered on the
negative edge of a TTL pulse.
The front-panel Single key is disabled when in remote.

Chapter 2 Front-Panel Operation
To Use Reading Hold

To Use Reading Hold
The reading hold feature allows you to capture and hold a stable reading
on the display. When a stable reading is detected, the meter emits a beep
and holds the value on the display.

Toggles between autotrigger
and reading hold

* (sample) annunciator is on
during each measurement

• Reading hold has an adjustable sensitivity band to allow you to select
which readings are considered stable enough to be displayed. The
band is expressed as a percent of reading on the selected range. The
meter will capture and display a new value only after three
consecutive readings are within the band.
• The default band is 0.10% of reading. After enabling reading hold,
you can choose a different band by pressing Shift > (Menu Recall).
This takes you to the “READ HOLD” command in the TRIG MENU
(only if reading hold is enabled).
Go down to the “parameter” level, and then select a value: 0.01%,
0.10%, 1.00%, or 10.00% of reading.
• The sensitivity band is stored in volatile memory; the meter sets the
band to 0.10% of reading when power has been off or after a remote
interface reset.

Chapter 2 Front-Panel Operation
To Make Voltage Ratio and Difference Measurements

To Make Voltage Ratio and Difference Measurements
To calculate a voltage ratio, the meter measures the voltages applied
to the Channel 1 input terminals and Channel 2 input terminals. The
calculation is as follows:
Difference = ((Ch 1 voltage − Ch 1 Null ) − (Ch 2 voltage − Ch 2 Null )) − Null *
Ratio =

(Ch 1 voltage − Ch 1 Null )
(Ch 2 voltage − Ch 2 Null )
RED
DC Voltage
CH1

BLACK

CH2

GREEN
DC Voltage
WHITE

DIFFERENCE
RATIO

• Maximum input signal on Channel 1 is 120 Vdc, the meter will
autorange on the actual input or can be manually set.
• Maximum input signal on Channel 2 is 12 Vdc, the meter will
autorange on the actual input or can be manually set.
• Maximum voltage difference between Channel 1 LO and
Channel 2 LO is 150 Vdc.
• Null, if used, is independent for each channel. An additional null* of
the difference can also be made. If null is used on either input channel,
the ‘Null’ annunciator will flash when the difference function is
selected. If you null the difference, the ‘Null’ annunciator will be
steady.

*The difference null is only available from the front panel.

Chapter 2 Front-Panel Operation
To Use Reading Memory

To Use Reading Memory
The meter can store up to 1024 readings in internal memory. The
following steps demonstrate how to store readings and retrieve them.
1

Select the function.
Select any measurement function. You can change the function at any
time during reading memory.

Single

Select the single trigger mode.
Notice that the Trig annunciator turns on. When reading memory is
enabled, readings are stored when you trigger the meter.
For this example, single triggering is used to store readings. You can also
use auto triggering or reading hold.

On/Off
Shift

Turn on the menu.
A: MEAS MENU

Move across to the SYS MENU choice on this level.
E: SYS MENU

Move down to a level to the RDGS STORE command.
1: RDGS STORE

Chapter 2 Front-Panel Operation
To Use Reading Memory

Move down a level and then across to the “ON” choice.
ON

Auto/Man

ENTER

Save the change and exit the menu.
Notice that the Mem (memory) annunciator turns on to indicate that the
meter is ready to store readings. Up to 1024 readings can be stored in
first-in-first-out (FIFO) order. When memory is full, the Mem
annunciator will turn off.
Readings are preserved until you re-enable reading memory at another
time, turn off the power, or perform a remote interface reset.

Single
Single

Single

Trigger the meter three times.
This stores three readings in memory.

Recall
Shift

Use menu recall to retrieve the stored readings.
This takes you to the “SAVED RDGS” command in the SYS MENU.
2: SAVED RDGS

Chapter 2 Front-Panel Operation
To Use Reading Memory

10 Move down a level to view the first stored reading.

Reading memory is automatically turned off when you go to the
“parameter” level in the menu.
The first reading displayed is the first reading that was stored (FIFO). If no
readings are stored in memory, “EMPTY” is displayed. The first five
digits of the reading and the reading number are displayed. After a brief
pause, the reading number is removed and all reading digits are shown.
The stored readings are displayed with their units ( µ, m, k, etc.) when
appropriate. For example:
Reading
number
10.31607K: 11

Units
10.316076

11 Move across to view the two remaining stored readings.

The readings are stored horizontally on the “parameter” level.
If you press < when you first get to the “parameter” level, you will see the
last reading and you will know how many readings were stored.
On/Off
Shift

12 Turn off the menu.
EXITING

Features and Functions

Features and Functions
You will find that this chapter makes it easy to look up all the details
about a particular feature of the meter. Whether you are operating the
meter from the front panel or from the remote interface, this chapter will
be useful.
This chapter is divided into the following sections:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

General Measurement Configuration, page 55
Voltage Measurement Configuration, page 66
Resistance Measurement Configuration, page 68
Temperature Measurement Configuration, page 71
Math Operations, page 74
Null (Relative) Operation, page 77
Reading Hold, page 79
Triggering, page 80
System-Related Operations, page 90
Voltmeter Complete Terminal, page 97
External Trigger Terminal, page 97
Chart Output (Analog Output) Operation, page 98
Remote Interface Configuration, page 101
Calibration, page 107
Defaults, Power-On and Reset States, page 112

Some knowledge of the front-panel menu will be helpful before you read this
chapter. If you have not already read chapter 2, “Front-Panel Menu
Operation,” starting on page 29, you may want to read it now. Chapter 4,
“Remote Interface Reference,” starting on page 115, lists the syntax for the
SCPI (Standard Commands for Programmable Instruments) commands
available to program the meter.

Throughout this manual, the following conventions are used for SCPI
command syntax. Square brackets ( [] ) indicate optional keywords or
parameters. Braces ( {} ) enclose a list of parameters separated with a
vertical bar (|), use only one of the values . Triangle brackets ( <> )
indicate that you must substitute a value for the enclosed parameter.
The actual command string you send to the meter should not include
any of the conventions indicated above.

Chapter 3 Features and Functions
General Measurement Configuration

General Measurement Configuration
This section contains information to help you configure the meter for
making measurements. You may never have to change any of the
measurement parameters discussed here, yet they are provided to give
you the flexibility you might need.

Input Filters
Two input filters are available; a digital filter and an analog filter. You
can enable the digital filter, the analog filter, or both. The digital filter
may be used for any measurement type. The analog filter is only
available for thermocouple temperature measurements and voltage
measurements on the 1 mV, 10 mV, or 100 mV ranges.

TURN FILTERS ON OR OFF

DIGITAL Ø ANALOG Ø ANA + DIG

Chapter 3 Features and Functions
General Measurement Configuration

• Front Panel operation: Press Shift Filter and scroll to
one of DIGITAL, ANALOG, or ANA + DIG . Press Enter to enable the
filter type. Press the Filter key to turn the filter on or off.
To set the digital filter averaging, use the MEASurement menu
1: DIG FILTER command.
• Remote operation: the following commands turn the filters off, on,
set the digital filter count, :
INPut:FILTer
:STATe {OFF|ON}
:TYPE {ANAlog | DIGital | BOTH}
:DIGital:RESPonse {SLOW|MEDium|FAST}
:DIGital:PRECharge {ON | OFF}
Using the filters in remote operation is not recommended. Use:
INPut:FILTer:STATe OFF
to disable the filters. The digital filter is also disabled following a
remote reset (*RST) or preset (SYStem:PREset).
Use the math operation (AVERage) commands to obtain a single
reading that is the average of a number of readings (see page 148). An
example program is shown on page 221 in chapter 6.
If you attempt to use the digital filter in remote operations, be aware
of the following special conditions:
The digital filter requires a number of readings to settle (10, 50 or
100). The digital filter readings only occur when the meter is triggered
to take a reading. In remote operation a reading is only taken when
requested. For example, if you have set the digital filter to MEDIUM
(50 readings), you will need to request (trigger) 50 readings from the
remote interface before the filter can settle. It is also possible that
after 50 readings the digital filter will still not be settled as described
in the next paragraph.
The STATus:OPERational:CONDition register contains a bit that
indicates the settled/unsettled state of the digital filter on a per
reading basis. See page 169 in Chapter 4. You should check the state
of this bit for each reading to ensure the digital filter count has not
reset (filter reset operation is described in the next section).

Chapter 3 Features and Functions
General Measurement Configuration

Digital Filter
• The digital filter is a moving average (boxcar) filter. Equal weighting
is applied to all readings to calculate the displayed reading.
• Three digital filters are available:
SLOW (average last 100 readings),
MEDIUM (average last 50 readings), or
FAST (average last 10 readings)
• When the digital filter is enabled, the ‘Filt’ annunciator flashes until
the required number of readings are obtained. The measurement
displayed before the ‘Filt’ annunciator is steady is the average of the
number of readings taken so far. For example, with the filter set to
MEDIUM (average of 50 readings), the measurement displayed after
20 readings will be the average those 20 readings. The ‘Filt’
annunciator will flash until 50 readings have been taken.
• The filter count resets (and the ‘Filt’ annunciator will flash) if the
function, range, integration time, or channel is changed.
• The filter count resets if a reading is outside a set range of the
average. The amount of input reading change required to reset the
filter count is:

FAST
MEDIUM
SLOW

1mV Range

All Other Ranges

± 400 ppm of range
± 700 ppm of range
± 2000 ppm of range

± 100 ppm of range
± 300 ppm of range
± 1000 ppm of range

Analog Filter
The analog filter is an 11 Hz, two-pole low pass filter. Use this filter to remove
line frequency noise from the input measurement.
• The filter requires approximately 300 milliseconds after the input is
present to settle. Using the filter, therefore, slows the measurement
rate significantly.
• Use the analog filter only when line power noise (50/60 Hz) is causing
an overload (OVLD) condition. See page 65.
• The analog filter is available for voltage and thermocouple
temperature measurements. The analog filter is not available for
resistance measurements.
• The analog filter is available for the 1 mV, 10 mV, and 100 mV ranges.
57

Chapter 3 Features and Functions
General Measurement Configuration

Integration Time
Integration time is the period during which the meter’s analog-to-digital
(A/D) converter samples the input signal for a measurement. Integration
time affects the measurement resolution (for better resolution, use a
longer integration time), and measurement speed (for faster
measurements, use a shorter integration time).
• Integration time is specified in number of power line cycles (NPLCs).
The choices are 0.02, 0.2, 1, 2, 10, 20, 100, or 200 power line cycles.
The default is 10 NPLCs.
• The integration time is stored in volatile memory; the meter selects 10
NPLC when power has been off or after an interface reset.
• Only the integer number of power line cycles (1, 2, 10, 20, 100 or 200
NPLC) provide normal mode (line frequency noise) rejection.
• Integration time is related to the maximum number of digits the
meter will display. You can always choose to show fewer digits than
the maximum allowed (the minimum number of digits shown is 41⁄2).

NPLC

Digital Filter Off
Max Digits Shown

Digital Filter On
Max Digits Shown

0.02

41⁄2

51⁄2

0.2

51⁄2

61⁄2

71⁄2

61⁄2

71⁄2

61⁄2

71⁄2

100

71⁄2

200

71⁄2

Chapter 3 Features and Functions
General Measurement Configuration

• Front Panel operation: Integration time can be set indirectly when
you select the number of digits (See page 43).
You can also set the integration time in the MEASurement menu with
the 2: INTEGRATE command.
• Remote operation: Refer to the table on page 129. Use one of the
following commands:
[SENSe:]
VOLT:DC:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}
FRES|RES
:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}
TEMP:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}

Integration time and resolution are related. The CONFigure and
MEASure? commands can also set the integration time, see page 129.
Integration Time is local to the selected function. This means that you
can select the integration time for each function independently. The
meter remembers the integration time when you switch between
functions.

Chapter 3 Features and Functions
General Measurement Configuration

Reducing Measurement Noise
At high resolutions and low measurement levels, measurement noise can
become an important factor in the accuracy of your measurements. One
possible source of measurement noise is the wiring and cabling in the test
setup. These noise sources and their effects are discussed in Chapter 7,
"Measurement Tutorial". A smaller level of noise is also inherent in the
meter itself.
To minimize the effects of noise on your measurements, use the highest
possible integration time (NPLC) and average the readings. Faster
reading rates are more susceptible to noise. Choosing the best NPLC and
averaging method for your measurement requires a tradeoff between the
reading rate and the level of acceptable noise in the resulting
measurement.
The Integration Time (NPLC) and averaging can be multiplied to create
an equivalent NPLC. The equivalent NPLC defines the reading rate and
characterizes the expected noise level. Averaging can be performed in the
meter by using either the digital filter or by using the statistics (Stats) mode
of operation.
Measurement noise characteristics of the meter closely match theoretical
gaussian noise distributions. The graph on the next page shows typical
input noise measurements for the 1 mV range with the low thermal
shorting plug applied to the input terminals. Other functions and ranges
will exhibit similar noise reduction characteristics versus NPLC.
For example, if you set the NPLC to 20 and enable the digital filter
set to FAST (10 reading average), the equivalent NPLC is 200. At an
equivalent NPLC of 200, the reading rate is approximately 6 readings per
minute (digital filter fully settled) and the typical noise level expected is
1.6 nVrms.
Alternately, if you take readings every 5 minutes, you can set an
equivalent NPLC of 5000 to minimize the noise in the measurement.
An equivalent NPLC of 5000 could be obtained by setting the integration
time to 100 NPLC and enabling the digital filter set to MEDIUM (50
reading average). At this equivalent NPLC, a typical noise level
of 0.35 nVrms can be expected.

Chapter 3 Features and Functions
General Measurement Configuration

30 minute measurement, ±0.5° C, zero input, rms noise (typical)

nV rms Noise

3
Equivalent NPLC

Readings per second

Readings per minute

Approximate
Reading Rate
Minutes per reading

• Front Panel operation: Integration time can be set indirectly when
you select the number of digits (See page 43).
You can also set the integration time in the MEASurement menu with
the 2: INTEGRATE command.
Enable the digital filter and set the filter reading average as described
on page 55.
• Remote operation: Set the integration time for the measurement
function. If possible, use NPLC 200. If you use the CONFigure or
MEASure commands, refer to the table on page 129.
Use the math operations (AVERage) to average the readings or
average the readings in your program. An example program that uses
the math operations to average readings is shown on page 221 in
Chapter 6. Do not use the digital filter to average readings, see page 56.

Chapter 3 Features and Functions
General Measurement Configuration

Number of Digits Displayed
Front Panel operation only. See also “Integration Time,” on page 58.
• You can set the number of digits shown in the display to 4, 5, 6, or 7
full digits, plus a “1⁄2” digit which can only be a “0” or “1”.
• You can set both the number of digits displayed and the Integration
Time in a single operation by pressing digits keys (see page 43).
• You can change the number of digits displayed without disturbing
the Integration Time settings by pressing the < or > keys
(see page 43).
• The number of digits is set to 61⁄2 digits at power-on and after either a
remote interface reset or preset.
• The number of digits shown is dependent upon integration time and
filter settings. The meter will not allow you to show more digits than
the practical measurement capability of the meter. You can, however,
reduce the number of digits shown. The minimum number of digits
available is 41⁄2. (See the table on page 58).

Chapter 3 Features and Functions
General Measurement Configuration

7 digits
Ω

0.003,256,4

This is the 1 ohm range,
71⁄2 digits are displayed.

"1⁄2" digit

6 digits
0.216,569

This is the 1 mV range,
61⁄2 digits are displayed.

"1⁄2" digit

5 digits

-045.231

This is the 100 mV range,
51⁄2 digits are displayed.

"1⁄2"digit

Chapter 3 Features and Functions
General Measurement Configuration

Ranging
You can let the meter automatically select the range using autoranging
or you can select a fixed range using manual ranging. Autoranging is
convenient because the meter automatically selects the appropriate
range for each measurement. However, you can use manual ranging for
faster measurements since the meter does not have to determine which
range to use for each measurement.
• The selected mode (auto or manual range) is stored in volatile
memory; the meter returns to autoranging when power has been off or
after a remote interface reset.
• Autorange thresholds:
Down range at <10% of range
Up range at >120% of range
• If the input signal is greater than the present range can measure, the
meter gives an overload indication: “OVLD” from the front panel or
“9.90000000E+37” from the remote interface.
• For ratio and difference measurements, the specified range is
independent for both Channel 1 and Channel 2.
^

Auto/ Man

• Front Panel operation: Press a front-panel RANGE key to set
manual ranging and to up or down range. Press the Auto/Man key to
return to autoranging. See also “To Select a Range,” on page 42.
• Remote operation: Range is set with parameters in the MEASure
and CONFigure subsystems. For example:
CONF:VOLT:DC

10.0

Sets the 10 Volt DC range

Range can be set directly with the SENSe subsystem. For example:
SENS:VOLT:DC:RANGe 0.001
SENS:RES:RANGE:AUTO

Sets the 1 mV DC range
Sets auto ranging on
2-wire resistance
measurements

Chapter 3 Features and Functions
General Measurement Configuration

Overload Detection
The 34420A uses both an analog and digital method to generate an
overload condition and display the OVLD message. An understanding of
the cause of the overload can help you make more accurate
measurements.
Digital Overload Detection
The digital overload detect occurs when the magnitude of the
measurement is greater than 120% of the Range. For example,
on the 1 volt Range, signal levels of greater than ± 1.2 volts will cause
an OVLD in the display.

Analog Overload Detection
Another type of overload can result in measurement errors that are hard
to identify. For example if an overload signal only occurs for a portion of
the measurement period, the input amplifier could become non-linear
resulting in an inaccurate reading. The displayed result may appear to be
correct because the overload signal only occurred during a small portion
of the measurement cycle. The 34420A detects this problem by
providing comparators on the input amplifier. If signals large enough to
overload the input amplifier are detected, the display will read OVLD.
The comparators detect signals greater than 140% of the range setting.
If an overload occurs, two solutions are possible.
• Setting the meter to the next higher range will provide 10 times
improvement in the overload signal handling capability. For
example,if you are measuring on the 1 mV range and have 2 mV rms
of power line (50 or 60 Hz) pickup, the noise overload comparators
would sense the peaks of the signals and an OVLD message would be
displayed. If you set the range to 10 mV, the resolution (with 7 digits)
is still 1 nanovolt, and the reading rate is faster than if ANALOG
FILTER had been turned on. Additionally, the 10 mV range noise is
almost as low as the 1 mV range.
• Alternately, if using the 1 mV, 10 mV, or 100 mV ranges, turn on the
ANALOG FILTER. The reading rate slows down with the filter on. In
the case of a larger overloads (for example, 20 mV rms noise on the
1 mV range) using the ANALOG FILTER would give a lower noise
result than changing to the 100 mV range.

Chapter 3 Features and Functions
Voltage Measurement Configuration

Voltage Measurement Configuration
Input Channels
The meter has two independent input channels for measuring dc Volts.
You can make measurements on either or both channels, measure the
difference between the channels, or measure the ratio between the
channels. Each channel has an independent settings for null and range.
The figure on page 19 shows connections for two input channels.
• Channel 1 is the default input channel. Both channels use the same
integration time setting.
• The maximum measurable input on Channel 1 is 120V, on
Channel 2 is 12 V.
• For two channel operation, the maximum voltage difference between
Channel 1 LO and Channel 2 LO is ±150 V.
• For either channel, the maximum non-destructive input is ±150 V.

Channel

• If you enable input filters, the filters are active for both input
channels. Switching between the channels will reset the digital filter
reading count (see page 57).
• Front Panel operation: Toggle the input channel by pressing the
Channel key on the front panel. The CH1 or CH2 annunciator will
light in the display. The meter keeps range and null settings
independently for each channel.

Scan
Shift

Choose the scan mode to alternately show the CH1 and CH2 readings.
Disable the digital filter when using the scan mode. In scan mode, the
meter alternates between the CH1 and CH2 readings every 3 seconds
or for each measurement (whichever is longer).

Channel

Chapter 3 Features and Functions
Voltage Measurement Configuration

• Remote operation: The CONFigure and MEASure subsystems use
an optional parameter to specify the input channel as either 1 or 2:
CONF:VOLT:DC DEF, DEF,(@FRONTl)
CONF:VOLT:DC DEF, DEF,(@FRONT2)

Channel 1 operation
Channel 2 operation

The SENSe subsystem uses a keyword modification to indicate the
channel:
SENS1:VOLT:DC:RANG:AUTO
SENS2:VOLT:DC:RANG:AUTO

Ch1 - Ch2

Channel 1 operation
Channel 2 operation

Two Channel Measurements
• Difference measurements: First, set the range and null value for
each input channel. Then, select difference measurements.

Difference = ((Ch 1 voltage − Ch 1 Null ) − (Ch 2 voltage − Ch 2 Null )) − Null*

Shift

Ch1- Ch2

• Ratio measurements: First, set the range and null value for each
input channel. Then, select ratio measurements.
Ratio =

(Ch 1 voltage − Ch 1 Null )
(Ch 2 voltage − Ch 2 Null )

• Remote operation: use the following commands to measure or
configure a difference or ratio measurement. Set each channel to the
appropriate range and null conditions using:
[SENSe1: | SENSe2:]
VOLTage:DC
:RANGE
:NULL:STATe {OFF | ON}
:NULL:VALue { | MIN | MAX}
Then use the following commands to measure the ratio or difference:
MEASure:VOLTage:DC
:RATIO?
:DIFFerence?
CONFigure:VOLTage:DC
:RATIO
:DIFFerence
[SENSe:]FUNCtion "VOLTage:RATio"
[SENSe:]FUNCtion "VOLTage:DIFFerence"
*Difference Null is only available from the Front Panel.

Chapter 3 Features and Functions
Resistance Measurement Configuration

Resistance Measurement Configuration
The meter can make 2-wire or 4-wire ohms measurements. The meter
can compensate for voltages in the resistive circuit being measured using
offset compensation. You can also choose to either limit the power applied
or limit the open circuit voltage applied during a resistance
measurement.
The test current sourced by the meter depends upon the range and
conditions as shown below:

Range

Test current
2-wire or 4-wire
measurements

1Ω
10 Ω
100 Ω
1 kΩ
10 kΩ
100 kΩ*
1 MΩ*

10 mA
10 mA
10 mA
1 mA
100 µA
10 µA
5 µA

4-wire measurements
Low Power

Voltage Limited

10 mA
10 mA
1 mA

Not Available
1 mA

100 µA
10 µA
5 µA
5 µA

100 µA
Not Available
Not Available
Not Available
Not Available

* Offset Compensation is not applied to measurements on these ranges

Chapter 3 Features and Functions
Resistance Measurement Configuration

Offset Compensated Measurements
Offset compensation removes the effect of any voltages in the circuit
being measured. The technique involves taking two measurements, one
with the current source turned on, and one with the current source
turned off and computing the difference. A description of this operation is
given on page 259.
• Front Panel operation: Offset compensation is on at power on.
Turn offset compensation off under the 3: OCOMP Ω command in
the MEASure menu.
• Remote operation: Offset compensation is off following a remote
reset or preset. Use the following command to change the state of
offset compensation:

SENSe:
FRESistance:OCOMpensated {OFF|ON}
RESistance:OCOMpensated {OFF|ON}
Low Power Measurements
Low Power measurements use a reduced output measurement current to
limit the power dissipation in the circuit being measured.
• Low Power measurements apply only to 4-wire ohms measurements.
• When the low power measurement mode is enabled, the ‘LP’
annunciator is on in the display.
• Setting the Voltage Limited measurement mode will cancel the
Low Power mode.
• Front Panel operation: set low power mode under the
4: LOW POWER Ω command in the MEASure menu.
• Remote operation: use the following command to set the low power
ohms mode:
SENSe:FRESistance:POWer:LIMit {OFF|ON}

Chapter 3 Features and Functions
Resistance Measurement Configuration

Voltage Limited Measurements
Voltage limited resistance measurements clamp the open circuit voltage
to predefined limits.
• Voltage limits apply only to 4-wire ohms measurements.
• Voltage limited resistance measurements are only available on
the 10 Ω and 100 Ω ranges. If a manual range is selected in either
2-wire or 4-wire ohms, and then Voltage Limited measurements are
enabled, the range will be set to the highest valid range (either 10 Ω
or 100 Ω ).
• The open circuit voltage can be limited to 20 mV, 100 mV, or 500 mV.
• Setting the Low Power measurement mode will cancel the
Voltage Limited mode.
• Front panel operation: Enable or disable the voltage limit under the
5: LOW VOLT Ω command in the MEASure menu.
Set the voltage limit under the 6: LoV LIMIT Ω command in the
MEASure menu.
• Remote operation: the following command enables or disable the
low voltage limit mode:
SENSe:FRESistance:VOLTage:LIMit {OFF|ON}
Set the limit with the following command:
SENSe:FRESistance:VOLTage:LIMit:VALue {|MIN|MAX}

Chapter 3 Features and Functions
Temperature Measurement Configuration

Temperature Measurement Configuration
This section contains information to help you configure the meter for
making temperature measurements. To measure temperature, you will
need a temperature transducer. Transducer descriptions and specific
comments about their usage are given on page 263. The meter supports
three general categories of transducer:
• RTD (Resistive Temperature Device)
• THERM (Thermistor)
• T/C (Thermocouple)

The meter supports specific types of transducers in each category:

RTD’s
R0 = 4.9 Ω to 2.1 kΩ
α = 0.00385 (DIN/IEC 751)
α = 0.00391

Thermistor

Thermocouples

5k Ω

B, E, J, K, N, R, S, T

Once you set the measurement units, probe type, and transducer type,
the setting is stored in non-volatile memory. This makes the last probe
type used the default probe type.

Measurement Units
• The meter can report temperature in °C (Celsius), °F (Fahrenheit),
or K (Kelvins).
• The measurement units set are stored in non-volatile memory.
• Front Panel Operation: Set the units under the 2: UNITS command
in the TEMPerature menu.
• Remote operation: Set the units using the following command:
UNIT:TEMPerature {C|F|K}

Chapter 3 Features and Functions
Temperature Measurement Configuration

RTD Measurements
• The meter supports RTDs with α = 0.00385 (DIN/IEC 751) or
α = 0.00391. The nominal value of the RTD (R0) must be in the range
of 4.9 Ω to 2.1 kΩ. RTD Connections are shown on page 21.
• The meter makes a 4-wire measurement for RTD’s. All four input
leads must be connected.
• Front Panel operation: Set RTD as the probe type under the
1: PROBE TYPE command in the TEMPerature menu.
Select the RTD type under the 3: RTD TYPE command in the
TEMPerature menu.
Enter the 0° C resistance of the RTD (R0) in the 4: RTD R0 command
in the TEMPerature menu.
• Remote operation: Use the following commands for temperature
measurements with RTD’s:
CONFigure:TEMPerature FRTD,{85|91}[,1,]
MEASure:TEMPerature? FRTD, {85|91}[,1,]
SENSe:FUNCtion "TEMPerature"
SENSe:TEMPerature:TRANsducer:TYPE FRTD
SENSe:TEMPerature:TRANsducer:FRTD:TYPE {85|91}
SENSe:TEMPerature:TRANsducer:FRTD:RESistance

Thermistor Measurements
• Only the 5 kΩ thermistor type is supported. Thermistor connections
are shown on page 21.
• The thermistor must be connected to the Channel 1 inputs.
• Front Panel operation: Set THERM as the transducer type under
the 1: PROBE TYPE command in the TEMPerature menu.
• Remote operation: use the following commands for temperature
measurements with a thermistor:
CONFigure:TEMPerature THER, DEF,[,1,]
MEASure:TEMPerature? THER, DEF,[,1,]
SENSe:FUNCtion "TEMPerature"
SENSe:TEMPerature:TRANsducer:TYPE THER

Chapter 3 Features and Functions
Temperature Measurement Configuration

Thermocouple Measurements
• The thermocouple must be connected to the Channel 2 inputs. Be sure
to observe the correct polarity. Thermocouple connections are shown on
page 22.
• Thermocouple measurements require a reference junction
temperature. You can input a known fixed junction temperature, use
an external thermistor temperature, or use the internal thermistor
temperature as the reference junction temperature.
The accuracy of the measurement is very dependent upon the
thermocouple connections and the reference junction temperature.
Use a fixed temperature reference for highest accuracy measurements.
The internal thermistor reference produces the lowest accuracy
measurements. See page 265 for a discussion of the reference junction
temperature measurements.

• Front Panel operation: Set T/C as the probe type under the
1: PROBE TYPE command in the TEMPerature menu.
Select the thermocouple type under the 4: T/C TYPE command in the
Temperature menu.
Set the reference junction temperature source under the
5: COLD JUNCT command in the TEMPerature menu.
If you used a FIXed reference junction temperature, set the reference
temperature under the 6: JUNCT TEMP command in the TEMPerature
menu. The number entered must be in the range of –1° C to 55° C.
• Remote operation: use the following commands for temperature
measurements using thermocouples:
CONFigure:TEMPerature TC,{B|E|J|K|N|R|S|T}[,1,]
MEASure:TEMPerature? TC,{B|E|J|K|N|R|S|T}[,1,]
SENSe:
FUNCtion "TEMPerature"
TEMPerature:TRANsducer
:TYPE TC
:TCouple
:TYPE {B|E|J|K|N|R|S|T}
:RJUNction:TYPE {FIXed|INTernal|THERmistor}
:RJUNction {|MIN|MAX}
73

Chapter 3 Features and Functions
Math Operations

Math Operations
There are two math operations available, only one of which can be
enabled at a time. You can choose to either scale the readings as they are
taken, or keep statistics on a group of readings. The selected math
operation remains in effect until you disable it, change functions, turn off
the power, or perform a remote interface reset.
Scaling
• The scaling is applied as:
reading = gain ∗ (measurement − offset)
Scale
Shift

Stats

• Front Panel operation: Set the values of gain and offset in the
MATH menu. Enable scaling by pressing the scale key. The Stats
annunciator will light in the display.
• Remote operation: the math operations and registers are controlled
using commands within the CALCulate command subsystem. First,
select the math operation you want to use
CALCulate:FUNCtion SCALe
Then, set the values for gain and offset.
CALCulate:SCALe:GAIN
CALCulate:SCALe:OFFSet
Finally, enable the selected math function by turning the math state on:
CALCulate:STATe ON

Chapter 3 Features and Functions
Math Operations

Statistics
• After you enable statistics, the first reading that the meter takes is
stored as both the minimum and maximum value. The minimum is
replaced with any subsequent value that is less. The maximum is
replaced with any subsequent value that is greater.
• All values are stored in volatile memory; the meter clears the values
when stats is turned on, when power has been off, or after a remote
interface reset or preset.
• When enabled, the following statistics are available:
MIN
MAX
AVER
STD DEV
PEAK – PEAK
COUNT

minimum reading
maximum reading
arithmetic average of all readings
standard deviation of all readings
peak to peak value of minimum and maximum
the total number of readings

• Front Panel operation: Enable the statistics by pressing
the Stats key. Read the statistics gathered in the MATH menu
under the STATS command.
After reading the stored statistics, press Shift < (Menu On/Off) to
return to the measurement and continue taking statistics.

Chapter 3 Features and Functions
Math Operations

• Remote operation: the math operations and registers are controlled
using math operation commands. First, select the math operation you
want to use
CALCulate:FUNCtion AVERage
Then, enable the selected math function by turning the math state on:
CALCulate:STATe ON
When you have finished collecting readings, obtain the desired statistics:
CALCulate:AVERage
:MINimum?
:MAXimum?
:AVERage?
:SDEViation?
:PTPeak?
:COUNt?
After reading the statistics, supply another trigger to continue taking
measurements and collecting statistics. Measurements are not taken
while reading the results.
If you are interested in the statistics on a number of readings, but not
the readings themselves, you can use the following command:
DATA:FEED

RDG_STORE, ""

The null value parameter in the command tells the meter not to store
the individual readings. The meter does, however, accumulate
statistics on the readings. This method removes the 1024 reading
limitation and you can calculate statistics on any number of readings.
See page 150 for more information.

Chapter 3 Features and Functions
Null (Relative) Operation

Null (Relative) Operation
When making null measurements, also called relative, each reading is the
difference between the input signal and a stored null value. You could,
for example, make a more accurate two-wire ohms measurement by
shorting the test leads and pressing Null to remove the test lead
resistance. See also “To Make Null (Relative) Measurements,” on page 45.
Reading = measurement – null value
• The null value is adjustable and you can set it to any value between
0 and ± 120% of the highest range, for the present function.
• The null value is stored in volatile memory; the value is cleared when
power has been off or after a remote interface reset.
• Each function and channel has an independent null value. For voltage
measurements, each input channel has an independant null.
Temperature measurement null is applied to all temperature
measurements (if you change the probe type, null is still enabled and
applied). The null for resistance measurements applies to both 2-wire
and 4-wire measurements.
• The null value is stored in the meter’s Null Register. There are two
ways you can specify the null value. First, you can enter a specific
number into the register from the front-panel menu or from the remote
interface. Any previously stored value is replaced with the new value.
If you are operating the meter from the front panel, entering a null
value also turns on the null function.
The second way to enter the null value is to let the meter store the
first reading in the register. Press the Null key to make the
displayed measurement the null value and enable the Null operation.
After you enable null, the first reading displayed will be zero. If you
entered a number into the register, as described in the paragraph
above, the first reading does not overwrite the stored value.
• Since an independent null value is stored for each input channel,
difference or ratio functions also use these null values. Additionally,
when using the difference function, an additional difference null can
be applied (the difference null is only available from the front panel).
See page 67 for a description of how null is applied to difference and
ratio functions.

Chapter 3 Features and Functions
Null (Relative) Operation

• Front-panel operation: After enabling null, you can edit the stored
null value by pressing Shift > (Menu Recall). Any previously stored
value is replaced with the new value. Turning on the menu does not
disable the null operation; the meter will resume taking
measurements when you turn off the menu.
When null is enabled, the Null annunciator lights in the display. For
ratio or difference measurement, if either input channel has a null
enabled, the Null annunciator will flash. If you apply the difference
null, the Null annunciator will light (not flash).
• Remote interface operation: You can use the following commands
to make null measurements. Null must be enabled before you can store
a value in the Null Register.
SENSe1 | SENSe2
:VOLTage:DC
:NULL {OFF|ON}
:NULL {|MIN|MAX}
[SENSe:]
FRESistance | RESistance
:NULL { OFF | ON }
:NULL {|MIN|MAX}
TEMPerature
:NULL { OFF | ON }
:NULL {|MIN|MAX}
To enable null and set a null value (0.10) for the 2-wire resistance
function execute the following commands in the order shown.
SENS:RES:NULL ON
SENS:RES:NULL 0.10
You can use the first reading as a null value from the remote interface
by first setting the function, range, and resolution and then executing
the following command:
[SENSe:]NULL [{OFF | ON | ONCE}]

Chapter 3 Features and Functions
Reading Hold

Reading Hold
The reading hold feature allows you to capture and hold a stable reading
on the front-panel display. This is especially useful in situations where
you want to take a reading, remove the test probes, and have the reading
remain on the display. When a stable reading is detected, the meter
beeps and holds the reading on the display.
The reading hold feature is available only from the front panel. If you go
to remote when reading hold is enabled, the meter ignores it; when you
return to local (front panel), reading hold is enabled again.
• Reading hold has an adjustable sensitivity band (adjustable only from
the front panel) to allow you to select which readings are considered
stable enough to be displayed. The band is expressed as a percent of
reading, on the selected range. The meter will capture and display a
new value only after three consecutive readings are within the band.
Select one of these values: 0.01%, 0.10% (default), 1.00%, or 10.0%
of reading.
For example, assume that the 1.00% band is selected and a 5 volt
signal is applied to the meter. If three consecutive readings are
between 4.95 volts and 5.05 volts, the meter will beep and display a
new reading.
• The sensitivity band is stored in volatile memory; the meter sets the
band to 0.10% when power has been off or after an interface reset.
• If the meter is in autorange when you enable reading hold, it will
autorange to the correct range. If the meter is in the manual range
mode, the same fixed range will be used for reading hold.
• For certain applications, it may be useful to use reading hold with
reading memory. See also “Reading Memory,” on page 90.
• Front Panel operation: After enabling reading hold, you can select
a different sensitivity band by pressing Shift > (Menu Recall).

1: READ HOLD

Chapter 3 Features and Functions
Triggering

Triggering
The meter’s triggering system allows you to generate triggers either
manually or automatically, take multiple readings per trigger, and insert
a delay before each reading. Normally, the meter will take one reading
each time it receives a trigger, but you can specify multiple readings (up
to 50,000) per trigger.
• You can trigger the meter from the front panel, with an external
trigger, or use autotriggering. Single triggering takes one reading each
time you press the Single key. External triggering is like single
triggering, but the meter waits for a pulse on the rear-panel Ext Trig
(external trigger) terminal before taking a reading. Autotriggering
takes continuous readings at the fastest rate possible for the present
configuration. See also “To Trigger the Meter,” on page 47.
• Press Shift

Auto/Hold

to return the meter to auto triggering.

Triggering the meter from the remote interface is a multi-step process
that offers triggering flexibility.
• First, you must configure the meter for the measurement by selecting
the function, range, integration time, etc.
• Then, you must specify the source from which the meter will accept
the trigger. The meter will accept a software (bus) trigger from the
remote interface, a hardware trigger from the Ext Trig terminal, or an
immediate internal trigger.
• Then, you must make sure that the meter is ready to accept a trigger
from the specified trigger source (this is called the wait-for-trigger
state).
• Finally, to make the measurement, you must provide an INITiate,
READ?, or MEASure command.
The diagram on the next page shows the meter’s triggering system.

Chapter 3 Features and Functions
Triggering

Initiate Triggering
MEASure?
READ?
INITiate

Trigger Source
TRIGger:SOURce IMMediate
TRIGger:SOURce EXTernal
TRIGger:SOURce BUS
front-panel "Single" key

Idle
State

Wait-forTrigger
State

3
Trigger Delay
TRIGger:DELay
Delay

Sample (*)
Annunciator

Measurement
Sample

Yes

Sample
Count >1

Triggering the meter is a multi-step process.

Trigger
Count >1
No

Chapter 3 Features and Functions
Triggering

Trigger Source Choices
You must specify the source from which the meter will accept a trigger.
• The trigger source is stored in volatile memory; the source is set to
autotrigger (front panel) or immediate (remote interface) when power
has been off or after a remote interface reset.
• Front Panel operation: the meter will accept a either a front panel
single trigger or a hardware trigger from the Ext Trig terminal, or
continuously take readings using autotrigger. At power-on,
autotriggering is used.
• Remote operation: the meter will accept a software (bus) trigger, a
hardware trigger from the Ext Trig terminal, or an immediate internal
trigger. See "Triggering" on page 80 for more information.
Autotriggering In the autotrigger mode (front panel only), the meter
continuously takes readings at the fastest rate possible for the present
configuration. This is the power-on trigger source for front-panel
operation.
Single Triggering In the single trigger mode (front panel only), you
can manually trigger the meter by pressing Single . The meter takes one
reading, or the specified number of readings (sample count), each time
you press the key. The ‘Trig’ annunciator turns on when the meter is
waiting for a trigger.
Pressing the Single key also allows the meter to accept triggers on the
Ext Trig terminal.
The front-panel Single key is disabled when in remote.

Chapter 3 Features and Functions
Triggering

External Triggering In the external trigger mode, the meter will
accept a hardware trigger applied to the Ext Trig terminal. The meter
takes one reading, or the specified number of readings (sample count),
each time Ext Trig receives a low-true pulse.
See also “External Trigger Terminal,” on page 97.
• The meter buffers one external trigger. This means that if the meter is
taking a reading and another external trigger occurs, that trigger is
accepted (a “Trigger ignored” error is not reported). After the reading
in progress is complete, the stored trigger satisfies the trigger source
and then the trigger is issued.
• Front-panel operation: The external trigger mode is like the single
trigger mode except that you apply the trigger to the Ext Trig
terminal. Pressing Single to enable the single trigger mode also
enables the external trigger mode. The ‘Trig’ annunciator turns on
when the meter is waiting for an external trigger.
The front-panel Single key is disabled when in remote.
• Remote operation: Use the following command to enable external
trigger.
TRIGger:SOURce EXTernal

Chapter 3 Features and Functions
Triggering

Internal Triggering In the internal trigger mode (remote interface
only), the trigger signal is always present. When you place the meter in
the wait-for-trigger state, the trigger is issued immediately. This is the
power-on trigger source for remote interface operation.
To select the internal trigger source, send the following command. The
CONFigure and MEASure? commands automatically set the trigger
source to IMMediate.
TRIGger:SOURce IMMediate
After setting the source to IMMediate, an INITitate or a READ?
command will trigger the measurement.
Software (Bus) Triggering The bus trigger mode is available only
from the remote interface. This mode is similar to the single trigger mode
from the front panel, but you trigger the meter by sending a bus trigger
command.
• To select the bus trigger source, send the following command.
TRIGger:SOURce BUS

GPIB or RS-232),
• To trigger the meter from the remote interface (HP-IB
send the *TRG (trigger) command. The *TRG command will not be
accepted unless the meter is in the wait-for-trigger state.
HP-IB interface by sending the
• You can also trigger the meter from the GPIB
IEEE-488 Group Execute Trigger (GET) message. The meter must be
in the wait-for-trigger state. The following statement shows how to
send a GET from a Hewlett-Packard controller.

TRIGGER 722

(group execute trigger)

Chapter 3 Features and Functions
Triggering

The Wait-for-Trigger State
After you have configured the meter and selected a trigger source,
you must place the meter in the wait-for-trigger state. A trigger will not
be accepted until the meter is in this state. If a trigger signal is present,
and if meter is in the “wait-for-trigger” state, the measurement sequence
begins and readings are taken.
The “wait-for-trigger” state is a term used primarily for remote interface
operation. From the front panel, the meter is always in the “wait-fortrigger” state and will accept triggers at any time, unless a measurement
is already in progress.
You can place the meter in the “wait-for-trigger” state by executing any of
the following commands from the remote interface.
MEASure?
READ?
INITiate

Halting a Measurement in Progress
You can send a device clear at any time to halt a measurement in
progress and place the meter in the “idle state.” The following statement
shows how to send a device clear from a Hewlett-Packard controller if you
are using the HP-IB
GPIB interface. See also page 187.
CLEAR 722

(device clear)

For operation with the RS-232, you must establish a means to send a
device clear (for example, by pressing ^C (Control C)).
A device clear does not affect the configuration of the triggering system.
The trigger source, sample count, trigger delay, and number of triggers
are not changed.
If you have set the meter to infinite sampling (TRIGger:COUNt
INFinity), the device clear is the only way to halt the measurements.

Chapter 3 Features and Functions
Triggering

Number of Samples
Normally, the meter takes one reading (or sample) each time it receives
a trigger from the selected trigger source (if the meter is in the
wait-for-trigger state). You can, however, instruct the meter to take
multiple readings for each trigger received.
• Number of samples: 1 to 50,000. The default is 1 sample per trigger.
• The sample count is stored in volatile memory; the meter sets the
sample count to 1 when power has been off or after a remote interface
reset. The CONFigure and MEASure? commands automatically set
the sample count to 1.
• Front Panel operation: set the number of samples per trigger in the
3: N SAMPLES command under the TRIGger menu.
• Remote operation: use the following command:
SAMPle:COUNt {|MIN|MAX}

Number of Triggers
Normally, the meter will accept only one trigger before returning to the
“idle” trigger state. You can, however, instruct the meter to accept
multiple triggers.
This feature is available only from the remote interface. If you set the
trigger count and then go to local (front panel), the meter ignores the
trigger count setting; when you return to remote, the trigger count returns
to the value you selected.
• The selected number of triggers is stored in volatile memory; the
meter sets the trigger count to 1 when power has been off or after a
remote interface reset or preset. The CONFigure and MEASure?
commands automatically set the trigger count to 1.
• The number of triggers can be set to any number between 1 (MIN) and
50000 (MAX) or can be set to be INFinity. When the trigger count is
set to be infinite, use the READ? command to collect the readings.
Send a device clear to stop the measurements. See page 187 for
information about device clear.
TRIGger:COUNt {|MIN|MAX|INFinity}

Chapter 3 Features and Functions
Triggering

Trigger Delay
You can insert a delay between the trigger signal and each sample that
follows. This may be useful in applications where you want to allow the
input to settle before taking a reading, or for pacing a burst of readings.
If you do not specify a trigger delay, the meter automatically selects a
delay for you.
• Delay range: 0 to 3600 seconds. The default trigger delay is
automatic; the delay is determined by function, range, and integration
time (see also “Automatic Trigger Delays,” on page 89).
• The trigger delay is stored in volatile memory; the meter selects an
automatic trigger delay when power has been off or after a remote
interface reset. The CONFigure and MEASure? commands set the
trigger delay to automatic.

• If you specify a delay other than automatic, that same delay is used for
all functions and ranges.
• If you have configured the meter to take more than one reading per
trigger (sample count > 1), the specified trigger delay is inserted
between the trigger and each reading.
• Front Panel operation: You can use an automatic trigger delay or
you can specify a delay in seconds. Set the delay time in the
2: TRIG DELAY command of the TRIGger menu.
If an automatic trigger delay is enabled, “AUTO” is displayed
momentarily before the actual number of seconds is displayed.
AUTO

Chapter 3 Features and Functions
Triggering

• Front Panel operation (continued)
To set the delay to 0 seconds, select the “parameter” level of the
TRIG DELAY command. Move the flashing cursor to the “units”
location on the right side of the display. Press ∨ until
ZERO DELAY is reached, then press Enter .

ZERO

DELAY

• To select the automatic trigger delay, select the “parameter” level of
the TRIG DELAY command. Move the flashing cursor to the “units”
location on the right side of the display. Press ∨ until
AUTO DELAY is reached, then press Enter .

AUTO

DELAY

• Remote operation:
You can use the following command to set the trigger delay.
TRIGger:DELay {|MIN|MAX}
You can use the following command to set an automatic trigger delay.
TRIGger:DELay:AUTO {OFF|ON}

Chapter 3 Features and Functions
Triggering

Automatic Trigger Delays
If you do not specify a trigger delay, the meter selects an automatic delay
for you. The delay is determined by function, range, and integration time.
• DC voltage :
Range

NPLC < 1
Trigger Delay

NPLC ³ 1
Trigger Delay

1 mV
10 mV to 120 V

15 ms
1.0 ms

15 ms
1.5 ms

• Resistance (2-wire and 4-wire):
Range

NPLC < 1
Trigger Delay

NPLC ³ 1
Trigger Delay

1Ω
10 Ω
100 Ω
1 kΩ
10 kΩ
100 kΩ
1 MΩ

1.0 ms
1.0 ms
1.0 ms
1.0 ms
1.0 ms
4 ms
40 ms

1.5 ms
1.5 ms
1.5 ms
1.5 ms
1.5 ms
6 ms
60 ms

NPLC < 1
Trigger Delay

NPLC ³ 1
Trigger Delay

1.0 ms
1.0 ms
1.0 ms

1.5 ms
1.5 ms
1.5 ms

• Temperature:

RTD
THERmistor
ThermoCouple

Chapter 3 Features and Functions
System-Related Operations

System-Related Operations
This section gives information on topics such as reading memory, errors,
self-test, and front-panel display control. This information is not directly
related to making measurements but is an important part of operating
the meter.

Reading Memory
The meter can store up to 1024 readings in internal memory. Readings
are stored in first-in-first-out (FIFO) order. The first reading returned is
the first reading stored. See also “To Use Reading Memory,” on page 50.
• You can use reading memory with all functions, math operations, and
also reading hold. After you have enabled reading memory, you can
change the function or input channel. Be aware, however, that the
function labels and channel labels (V, OHM, etc.) are not stored with the
reading.
• Readings taken while reading memory is enabled are stored in volatile
memory; the meter clears the stored readings when reading memory is
turned on again, when power has been off, after a self-test, or after a
remote interface reset.
• You can use reading memory with autotrigger, single trigger, external
trigger, and reading hold. If you configure the meter for multiple
readings per trigger, the specified number of readings are stored in
memory each time a trigger is received.

Chapter 3 Features and Functions
System-Related Operations

• Front-panel operation: enable readings storage under the
1: RDGS STORE command in the SYStem menu. The ‘Mem’
annunciator lights in the display.
Recall the stored readings under the 2: SAVED RDGS command in the
SYStem menu. Press Shift > (Menu Recall) after enabling reading
memory to quickly go to the Saved Readings command.
Reading memory is automatically turned off when you go to the
“parameter” level in the menu to recall the readings.
• Remote interface operation: The INITiate command uses reading
memory to store readings prior to a FETCh? command. You can query
the number of stored readings in memory by sending the
DATA:POINts? command from the remote interface.

Chapter 3 Features and Functions
System-Related Operations

Error Conditions
When the front-panel ‘ERROR’ annunciator turns on, one or more
command syntax or hardware errors have been detected. A record of up
to 20 errors is stored in the meter’s error queue. See chapter 5, “Error
Messages,” for a complete listing of the errors.
• Errors are retrieved in first-in-first-out (FIFO) order. The first error
returned is the first error that was stored. When you have read all
errors from the queue, the ERROR annunciator turns off. The meter
beeps once for each error generated.
• If more than 20 errors have occurred, the last error stored in the
queue (the most recent error) is replaced with –350 “Queue Overflow”.
No additional errors are stored until you remove errors from the
queue. If no errors have occurred and you read the error queue, the
meter responds with +0, “No error”.
• The error queue is cleared when power has been off or after a *CLS
(clear status) command has been executed.
• Front-panel operation: read the errors under the 3: ERROR
command in the SYStem menu.
If the ERROR annunciator is on, press Shift > (Menu Recall) to read
the errors stored in the queue. The errors are listed horizontally on the
“parameter” level. The error queue is cleared when you go to the
“parameter” level and then turn off the menu.
ERR 1:

-113

First error in queue

Error code

• Remote interface operation: use the following command to read
the errors.
SYSTem:ERRor?
Errors have the following format (the error string may contain up to
80 characters).
–113,

"Undefined header"

Chapter 3 Features and Functions
System-Related Operations

Self-Test
A power-on self-test occurs automatically when you turn on the
multimeter. This limited test assures you that the meter is operational.
This self-test does not perform the extensive set of tests that are included
as part of the complete self-test described below.
A complete self-test runs a series of tests and takes approximately
15 seconds to execute. If all tests pass, you can have a high confidence
that the meter is operational.
• The results of the complete self-test are stored in internal reading
memory (see page 50). Memory is cleared as the self-test stores this
information. Other than clearing memory, the complete self-test
does not alter the state of the meter.

• If the complete self-test is successful, “PASS” is displayed on the front
panel. If the self-test fails, “FAIL” is displayed and the ERROR
annunciator turns on. See the 34420A Service Guide for
Agilent for service.
instructions on returning the meter to Hewlett-Packard
for service.
• Front Panel operation: You can perform some of the tests
individually or you can perform all tests together at once. Scroll
through the parameters under the 4: TEST command in the SYStem
menu.
Another way to perform the complete self-test from the front panel is
as follows: Hold down Shift as you press the Power switch to turn on
the meter; hold down the key for more than 5 seconds. The self-test will
begin when you release the key.
• Remote operation: use the following command to initiate a self-test
and return the results:
*TST?
Returns “0” if the self-test is successful, or “1” if it fails.

Chapter 3 Features and Functions
System-Related Operations

Display Control
To speed up your measurement rate, or for security reasons, you may
want to turn off the front-panel display. From the remote interface, you
can also display a 11-character message on the front panel. See page 43
for information about the number of digits displayed.
• When the display is turned off, readings are not sent to the display
and all display annunciators except ‘ERROR’ and ‘Shift’ are disabled.
Front-panel operation is otherwise unaffected by turning off the
display.
• The display state is stored in volatile memory; the display is enabled
when power has been off or after a remote interface reset.
• You can display a message on the front panel by sending a command
from the remote interface. The meter can display up to 11 characters
of the message on the front panel; any additional characters are
truncated. Commas, periods, and semicolons share a display space
with the preceding character, and are not considered individual
characters. When a message is displayed, readings are not sent to the
display.
• Sending a message to the display from the remote interface overrides
the display state; this means that you can display a message even if
the display is turned off.
• Front-panel operation: set the display state under the 5: DISPLAY
command in the SYStem menu.
The display always turns on for menu operation; this means that even
when the display is turned off, you can still operate the menu.
• Remote operation: use the following commands to control the
display:
DISPlay {OFF|ON}
DISPlay:TEXT
DISPlay:TEXT:CLEar

disable/enable the display
display the string
enclosed in quotes
clear the message in the
display

The following statement shows how to display a message on the front
panel from a Hewlett-Packard controller.
OUTPUT 722; "DISP:TEXT ’HELLO’"

Chapter 3 Features and Functions
System-Related Operations

Comma Separators
The meter can display readings on the front panel with or without a
comma separator. This feature is available only from the front panel. See
“Menu Example 1” on page 35.
08.241,53

With comma separator
(factory setting)

08.24153

Without comma separator

• The display format is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset. The
comma separator is enabled when the meter is shipped from the
factory.
• Front-panel operation: change the state of the comma display under
the 9: COMMA command in the SYStem menu.

Firmware Revision Query
The meter has three microprocessors for control of various internal
systems. You can query the meter to determine which revision of
firmware is installed for each microprocessor.
• The meter returns three numbers. The first number is the firmware
revision number for the measurement processor; the second is for the
input/output processor; and the third is for the front-panel processor.
• Front-panel operation: read the revisions under the 11: REVISION
command in the SYStem menu.
X.X-X.X-X.X
• Remote operation: use the following command to read the revision:
*IDN?

returns “HEWLETT-PACKARD,34420A,0,X.X-X.X-X.X”

Be sure to dimension a string variable with at least 40 characters.

Chapter 3 Features and Functions
System-Related Operations

SCPI Language Version
The meter complies with the rules and regulations of the present version
of SCPI (Standard Commands for Programmable Instruments). You can
determine the SCPI version with which the meter is in compliance by
sending a command from the remote interface.
You cannot query the SCPI version from the front panel.
• The following command returns the SCPI version.
SYSTem:VERSion?
Returns a string in the form “YYYY.V” where the “Y’s” represent the year
of the version, and the “V” represents a version number for that year
(for example, 1994.0).

Chapter 3 Features and Functions
Voltmeter Complete Terminal

Voltmeter Complete Terminal
The rear-panel VM Comp (voltmeter complete) terminal provides a low-true
pulse after the completion of each measurement. Voltmeter complete and
external trigger (see below) implement a standard hardware handshake
sequence between measurement and switching devices.
Output

Approximately 2µs

External Trigger Terminal
You can trigger the meter by applying a low-true pulse to the rear-panel
Ext Trig (external trigger) terminal. To use this terminal from the remote
interface, you must select the external trigger source
(TRIGger:SOURce EXTernal).
Input

>1µs

You can use a simple switch to generate an external trigger using the
Ext Trig input as shown below.

Chapter 3 Features and Functions
Chart Output (Analog Output)

Chart Output (Analog Output)
You can use the Chart Output (Analog Output) connector on the rear
panel to run a strip chart recorder or similar instrument. The connector
provides an output voltage proportional to the measured voltage.
• The output can range from –3.00 V to +3.00 V.
• When chart output is disabled (Off), the output is set to 0 V.
• The output impedance is 1 kΩ.
• The output voltage is related to the input signal as follows:
(reading − chart null)
= chart output voltage
span

Note that reading includes the results of measurement unit
conversion, filtering, null, and any math operation performed on the
measurement.
• The chart output state (including the span and null values) is stored
in non-volatile memory.
• span cannot have a negative value.
• The chart output has a voltage "rollover" to prevent the loss of data,
see page 100.
Examples:
See page 38 for a menu procedure to enter a number.
1) To set the chart span so that a ±1 mV input signal produces a ±1.0
Volt chart output:
(0.001 − 0.0)
= 1.00
span
span =

0.001
= 0.001
1.00

When chart null is set to 0, the value
chart output = gain ∗ reading.

1
can be considered the gain and
span

Chapter 3 Features and Functions
Chart Output (Analog Output)

2) To set the chart output voltage to ±3.0 V to correspond to an input
temperature range of 5° C to 45° C with a mid temperature of 25° C
(chart output is 0 V at 25° C).
(25 − chart null )
= 0
span

chart null = 25

and
(45 − 25)

span

= 3.0

span =

3.0

= 6.66

• Front Panel operation: Enable the chart output under the
5: CHART OUT command in the SYStem menu.
Set the chart span under the 6: CHART SPAN command in the
SYStem menu.
Set the chart offset under the 7: CHART NULL command in the
SYStem menu.
You can also press Shift Null (Chart Null) to null the chart output
voltage based upon the displayed reading. This action places a null
value in the Chart Offset register. Pressing Shift > (Menu Recall)
will take you to the 7: CHART NULL command where you can manually
edit the null value.
• Remote operation: use the following commands to enable and set
the chart output values.
OUTPut {OFF|ON}
OUTPut:REFerence
:OFFSet {|MIN|MAX}
:OFFSet:NULL
:SPAN { |MIN|MAX}
:SPAN?
:VALue {|MIN|MAX}
:GAIN?

Chapter 3 Features and Functions
Chart Output (Analog Output)

Chart Rollover
To prevent the loss of data, the chart output will "rollover" if a
measurement would cause the chart output to exceed the limits (± 3 V).
This feature is especially useful with strip chart recorders.
Rollover can be used to increase the resolution of the chart since smaller
values of span can be specified. As smaller values of span are used, chart
rollover will occur more frequently.
Rollover occurs when a chart limit is exceeded. The chart output voltage
rolls over to the opposite limit. The result, on a strip chart, is a step from
one limit to the opposite limit, effectively shifting the chart range and
center values. By counting the steps and noting their direction, the
actual measurement values can be deduced.
Example:
The chart output voltage is set to ± 3 V to correspond to an input
temperature range of 5° C to 45° C with the 0 V output at 25° C,
span = 6.66 and chart null = 25.
If the actual measured temperatures ranged from 20° C to 100° C, a strip
chart recorder might look like the one shown. The actual measurements
recorded could be reconstructed by cutting and pasting the chart between
the rollovers.

chart range
5° C to 45° C
chart center
25° C

100

chart range
45° C to 85° C
chart center
65° C

chart range
85° C to 125° C
chart center
105° C

chart range
45° C to 85° C
chart center
65° C

Chapter 3 Features and Functions
Remote Interface Configuration

Remote Interface Configuration
This section gives information on configuring the remote interface. For
programming information, see Chapter 4, “Remote Interface Reference,”
starting on page 115.

Remote Interface Selection
The meter is shipped with both a HP-IB
GPIB (IEEE-488) interface and an
RS-232 interface. Only one interface can be enabled at a time. The GPIB
HP-IB
interface is selected when the meter is shipped from the factory.
The remote interface can be set only from the front-panel.
• The interface selection is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset.
• If you select the HP-IB
GPIB interface, you must select a unique address for
the meter. The HP-IB
GPIB address is displayed when you turn on the
meter.
• If you select the RS-232 interface, you must set the baud rate and
parity for the meter. “RS-232” is displayed when you turn on the
meter.
• If you select the RS-232 interface and then set the HP-IB
GPIB address to
the talk only address (31), the meter will send readings over the
RS-232 interface when in the local mode.
• There are certain restrictions to be aware of when you are selecting
the remote interface (see also “Programming Language Selection,”
on page 105). The only programming language supported on RS-232
is SCPI.
Front Panel operation: set the interface under the 2: INTERFACE
command in the I/O menu.
See also “To Select the Remote Interface,” on page 189.

101

Chapter 3 Features and Functions
Remote Interface Configuration

GPIB Address
HP-IB
Each device on the HP-IB
GPIB (IEEE-488) interface must have a unique
address. You can set the meter’s address to any value between 0 and 31.
The address is set to “22” when the meter is shipped from the factory.
HP-IB address is displayed when you turn on the meter.
The GPIB
The HP-IB
GPIB address can be set only from the front-panel.
• The address is stored in non-volatile memory, and does not change
when power has been off or after a remote interface reset.
• You can set the address to “31” which is the talk only mode. In this
mode, the meter can output readings directly to a printer without
being addressed by a bus controller. Address 31 is not a valid address
HP-IB interface with a
if you are operating the multimeter from the GPIB
bus controller.
HP-IB address to the
• If you select the RS-232 interface and then set the GPIB
talk only address (31), the meter will send readings over the RS-232
interface when in the local mode.

• Your HP-IB
GPIB bus controller has its own address. Be sure to avoid using
the bus controller’s address for any instrument on the interface bus.
Hewlett-Packard controllers generally use address “21”.
• Front Panel operation: set the address under the 1: HP–IB ADDR
command in the I/O menu.
See also “To Set the HP-IB
GPIB Address,” on page 188.

102

Chapter 3 Features and Functions
Remote Interface Configuration

Baud Rate Selection (RS-232)
You can select one of six baud rates for RS-232 operation. The rate is set
to 9600 baud when the meter is shipped from the factory.
• Select one of the following: 300, 600, 1200, 2400, 4800, or 9600 baud
(factory setting).
• The baud rate selection is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset.
• Front Panel operation: set the baud rate under the 3: BAUD RATE
command in the I/O menu.

See also “To Set the Baud Rate,” on page 190.
• Remote operation: use the following commands to set the baud rate:
SYStem:COMMunicate:SERial:BAUD
If you change the baud rate over the remote interface, you may lose control
of the meter.

103

Chapter 3 Features and Functions
Remote Interface Configuration

Parity Selection (RS-232)
You can select the parity for RS-232 operation. The meter is configured for
even parity with 7 data bits when shipped from the factory.
• Select one of the following: None (8 data bits), Even (7 data bits), or
Odd (7 data bits). When you set the parity, you are indirectly setting
the number of data bits.
• The parity selection is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset.
• Front Panel operation: set the parity under the 4: PARITY
command in the I/O menu.
See also “To Set the Parity,” on page 191.
• Remote operation: use the following commands to set the parity:
SYStem:COMMunicate:SERial:PARity {EVEN|ODD|NONE}
If you change the parity over the remote interface, you may lose control of
the meter.

104

Chapter 3 Features and Functions
Remote Interface Configuration

Programming Language Selection
You can select one of two languages to program the meter from the
selected remote interface. The programming language is SCPI when
the meter is shipped from the factory.
• Select one of the following: SCPI or 181 (Keithley).
• The language selection is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset.
• There are certain restrictions to be aware of when you are selecting
the interface language (see also “Remote Interface Selection,” on
page 101). The Keithley 181 language is not supported on the RS-232
interface.
• Front Panel operation: set the programming language under the
5: LANGUAGE command in the I/O menu.
See also “To Select The Programming Language,” on page 192.
• Remote operation: use the following command to set the language:
SYStem:LANGuage

105

Chapter 3 Features and Functions
Remote Interface Configuration

Connection to a Terminal or Printer (RS-232)
The RS-232 connector on the meter’s rear panel is a 9-pin connector
(DB-9, male connector). You can connect the meter to any terminal or
printer with a properly configured DTE connector (DB-25). You can use a
standard serial interface cable and the 34399A Adapter Kit to make
connections. Additional information about the interface is given on
page 176.

Pin Number
1
2
3
4
5
6
9

Input/Output

Input
Output
Output
Input

Description

Receive Data (RxD)
Transmit Data (RxD)
Data Terminal Ready(DTR)
Signal Ground (SG)
Data Set Ready (DSR)

If you are using the RS-232 interface for connection to a printer, you may
wish to use the Talk Only mode. This mode is enabled by setting the
GPIB address to 31. See page 187 for more information.
HP-IB

106

Chapter 3 Features and Functions
Calibration

Calibration
This section gives a brief introduction to the calibration features of the
meter. For a more detailed discussion of the calibration procedures, see
Chapter 4 in the Service Guide.

Calibration Security
This feature allows you to enter a security code to prevent accidental or
unauthorized calibrations of the meter. When you first receive your
meter, it is secured. Before you can calibrate the meter, you must
unsecure it by entering the correct security code.
• The security code is set to “HP034420” when the meter is shipped from
the factory. The security code is stored in non-volatile memory, and
does not change when power has been off or after a remote interface
reset.
• To secure the meter from the remote interface, the security code may
contain up to 11 alphanumeric characters as shown below. The first
character must be a letter, but the remaining characters can be letters
or numbers. You do not have to use all 11 characters but the first
character must always be a letter.
A _ _ _ _ _ _ _ _ _ _ _

(11 characters)

• To secure the meter from the remote interface so that it can be
unsecured from the front panel, use the eight-character format shown
below. The first two characters must be “HP” and the remaining
characters must be numbers. Only the last six characters are
recognized from the front panel, but all eight characters are required.
(To unsecure the meter from the front panel, omit the “HP” and enter
the remaining numbers as shown on the following pages.)
HP _ _ _ _ _ _

(8 characters)

If you secure the meter from the remote interface and the secure code you
use does not have the first two characters "HP" and the next 6 characters
as digits, you cannot unsecure the meter from the front panel.

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Chapter 3 Features and Functions
Calibration

To Unsecure for Calibration You can unsecure the meter for
calibration either from the front panel or remote interface. The meter is
secured when shipped from the factory, and the security code is set to
“HP034420”.
• Front-panel operation:
1: SECURED

If the meter is secured, you will see the above command when you go
into the CAL MENU. (If you move across the “commands” level in the
menu, you will notice that the “2: CALIBRATE” command is “hidden”
if the meter is secured.) To unsecure the meter, select the “parameter”
level of the SECURED command, enter the security code, then press
Enter.
∧ 000000

CODE

When you go to the “commands” level in the CAL MENU again, you
will notice that the meter is unsecured. Notice also that the
2: CALIBRATE command is no longer hidden and you can perform a
calibration.
1:

UNSECURED

• Remote operation: use the following command:
CALibration:SECure:STATe {OFF|ON},
To unsecure the meter, send the above command with the same code
used to secure. For example,
CAL:SEC:STAT OFF, HP034420

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Chapter 3 Features and Functions
Calibration

To Secure Against Calibration You can secure the meter against
calibration either from the front panel or remote interface. The meter is
secured when shipped from the factory, and the security code is set to
“HP034420”.
Be sure to read the security code rules on page 107 before attempting to
secure the meter.
• Front-panel operation:
1: UNSECURED

If the meter is unsecured, you will see the above command when you
go into the CAL MENU. To secure the meter, select the “parameter”
level of the UNSECURED command, enter the security code, then
press Menu Enter.
∧ 000000

CODE

• When you go to the “commands” level in the CAL MENU again, you
will notice that the meter is secured. Notice also that the
2: CALIBRATE command is now hidden and you cannot perform a
calibration.
1:

UNSECURED

• Remote interface operation:
CALibration:SECure:STATe {OFF|ON},
To secure the meter, send the above command with the same code as
used to unsecure. For example,
CAL:SEC:STAT ON, HP034420

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Chapter 3 Features and Functions
Calibration

To Change the Security Code To change the security code, you must
first unsecure the meter, and then enter a new code. Make sure you have
read the security code rules on page 107 before attempting to secure the
meter.
• Front-Panel operation: To change the security code, first make
sure that the meter is unsecured. Select the “parameter” level of the
UNSECURED command, enter the new security code, then press
Menu Enter. Changing the code from the front panel also changes the
code as seen from the remote interface.
• Remote interface operation:
CALibration:SECure:CODE
To change the security code, first unsecure the meter using the old
security code. Then, enter the new code. For example,
CAL:SEC:STAT OFF, HP034420
CAL:SEC:CODE HP010495

unsecure with old code
enter new code

Calibration Count
You can determine the number of times that your meter has been
calibrated. Since the value increments by one for each calibration point, a
complete calibration increases the value by several counts.
• The calibration count is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset. Your
meter was calibrated before it left the factory. When you receive your
meter, read the count to determine its initial value.
• The calibration count increments up to a maximum of 32,767 after
which it wraps-around to 0.
• Front-Panel operation: read the calibration count under the
3: CAL COUNT command in the CALibrate menu.
• Remote operation: use the following command:
CALibration:COUNt?

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Chapter 3 Features and Functions
Calibration

Calibration Message
You can use the calibration message feature to record calibration
information about your meter. For example, you can store such
information as the last calibration date, the next calibration due date,
the meter’s serial number, or even the name and phone number of the
person to contact for a new calibration.
You can record information in the calibration message only from the
remote interface. You can read the message from either the front-panel
menu or the remote interface.
• The calibration message may contain up to 40 characters. The meter
can display up to 11 characters of the message on the front panel; any
additional characters are truncated.
• The calibration message is stored in non-volatile memory, and does
not change when power has been off or after a remote interface reset.
• Front Panel operation: read the calibration message (if any) under
the 4: MESSAGE command in the CALibrate menu.
• Remote operation: use the following command to store a calibration
message:
CALibration:STRing
The following statement shows how to store a calibration message from a
Hewlett-Packard controller.
OUTPUT 722; "CAL:STR ’CAL 9-1-94’"

111

Chapter 3 Features and Functions
Defaults, Power-On and Reset States

Defaults, Power-On and Reset States
The meter stores settings in either volatile or non-volatile memory.
Settings stored in volatile memory are returned to default settings at
power-on or after a remote reset. Settings stored in non-volatile memory
are not changed by power-on or a remote reset (*RST), CONFigure, or
MEASure command.
• Volatile memory settings and their defaults:
Setting
Function
Input Channel
Digital Filter
Analog Filter
Offset Compensation
N Samples
Display (On or Off)
Trigger
Math
Readings Hold
Readings Store
Trigger Delay
Integration Time (NPLC) 3
Null 3
Range 3

Front Panel Default

Remote Default 1

DCV
Channel 1
On (50 rdgs)
Off
On
1
On
Autotrigger
Off
Off
Off
Auto
(10 plc)
Off
Autorange

DCV
Channel 1
Off2
Off
Off
1
On
Autotrigger
Off
Off
Off
Auto
(10 plc)
Off
Autorange

Remote defaults are used following reset (*RST), preset (SYSTem:PRESet), CONFigure,
or MEASure commands.

You should ensure the digital filter is turned off when using the remote interface. See page 57.

Integration Time, Null, and Range are independent in each function. CONFigure or MEASure
commands will only affect the Integration Time, Null, or Range for the function used.

112

Chapter 3 Features and Functions
Defaults, Power-On and Reset States

• Non-volatile memory settings can be returned to their factory defaults.
Front Panel operation: return the settings to factory defaults under
the 11: PRESET command in the SYStem menu.
Remote operation: use the SYStem:PRESet command to return the
meter to the factory defaults.
Non-volatile memory settings and their factory defaults:
Setting

Factory Default
1

Digital Filter
Digital Filter Precharge
Low Power Ω
Low Volt Ω
LoV Limit Ω
Probe Type
RTD Type
RTD R0
Temperature Units
Chart Out
Chart Span
Chart Offset
Comma
1

MEDium 50 rdgs
On
Off
Off
20 mV
RTD
α = .00385
100 Ω
°C
Off
1 mV
0.00 V
On

The digital filter is ON following a Front Panel PRESET.
The digital filter is OFF following a Remote Interface PRESET.

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Chapter 3 Features and Functions
Defaults, Power-On and Reset States

• Independent vs. common settings: Some settings are independent to
the channel or function being used and some are common to multiple
channels or functions:

Voltage
Channel 1

Resistance
2-Wire Ω

Channel 2

Null (On/Off)
Null (On/Off)
Range
Range
Integration Time
Number of Digits

4-Wire Ω

Null (On/Off)
Range 1
Integration Time
Number of Digits
Math (Stats or Scale)
Digital Filter (On /Off)
Analog Filter (On/Off) 2
Trigger
Readings Hold
Readings Store

Temperature
Null (On/Off)
Range
Integration Time
Number of Digits

The meter may change the set resistance measurement range when voltage limited measurements
are enabled.

Analog filter available for voltage and thermocouple measurements on the 1 mV, 10 mV, and
100 mV ranges.

114

Remote Interface Reference

Remote Interface Reference
This chapter is divided into the following sections:

➡

•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

Command Summary, page 117
Simplified Programming Sequence, page 126
The MEASure? and CONFigure Commands, page 134
Setting the Function, Range, and Resolution, page 137
Selecting the Input Channel, page 140
Special Resistance Measurement Commands, page 141
Temperature Measurement Commands, page 142
Null (Relative) Commands, page 145
Input Filter Commands, page 146
Math Operation Commands, page 148
Triggering, page 151
Triggering Commands, page 154
Chart Output (Analog Output) Commands, page 156
System-Related Commands, page 157
The SCPI Status Model, page 159
Status Reporting Commands, page 171
Calibration Commands, page 174
RS-232 Interface Configuration, page 176
RS-232 Interface Commands, page 182
An Introduction to the SCPI Language, page 183
Input Message Terminators, page 186
Output Data Formats, page 186
Using Device Clear to Halt Measurements, page 187
TALK ONLY for Printers, page 187
To Set the GPIB
HP-IB Address, page 188
To Select the Remote Interface, page 189
To Set the Baud Rate, page 190
To Set the Parity, page 104
To Select the Programming Language, page 192
Alternate Programming Language Compatibility, page 193
SCPI Compliance Information, page 194
IEEE-488 Compliance Information, page 197

If you are a first-time user of the SCPI language, refer to these sections to
become familiar with the language before attempting to program the meter.
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Chapter 4 Remote Interface Reference
Command Summary

Command Summary
This section summarizes the SCPI (Standard Commands for
Programmable Instruments) commands available to program the meter.
Refer to the later sections in this chapter for more complete details on
each command.
Throughout this manual, the following conventions are used for SCPI
command syntax. Square brackets ( [] ) indicate optional keywords or
parameters. Braces ( {} ) enclose a list of parameters separated with a
vertical bar ( | ), use only one of the values. Triangle brackets ( <> )
indicate that you must substitute a value for the enclosed parameter.
The actual command string you send to the meter should not include
any of the conventions indicated above.

First-time SCPI users, see page 183.

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Chapter 4 Remote Interface Reference
Command Summary

Voltage Measurement Configuration Commands
MEASure
[:VOLTage][:DC]?
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}][,(@)]1
[:VOLTage][:DC]:RATio?
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]
[:VOLTage][:DC]:DIFFerence?
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]
CONFigure
[:VOLTage][:DC]
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}][,(@)]1
[:VOLTage][:DC]:RATio [{ | AUTO | MIN | MAX | DEF}] [,{ | MIN | MAX | DEF}]
[:VOLTage][:DC]:DIFFerence[{ | AUTO | MIN | MAX | DEF}] [,{ | MIN | MAX | DEF}]
[SENSe:] | SENSe1: | SENSe2:
FUNCtion "VOLTage[:DC]"
FUNCtion "VOLTage[:DC]:RATio"
FUNCtion "VOLTage[:DC]:DIFFerence"
FUNCtion?
[SENSe:] SENSe1: | SENSe2:
VOLTage[:DC]:RANGe { | MIN | MAX}
VOLTage[:DC]:RANGe? [MIN | MAX]
VOLTage[:DC]:RANGe:AUTO {OFF | ON}
VOLTage[:DC]:RANGe:AUTO?
[SENSe:] | SENSe1: | SENSe2:
VOLTage[:DC]:RESolution { | MIN | MAX}
VOLTage[:DC]:RESolution? [MIN | MAX]
[SENSe:] | SENSe1: | SENSe2:
VOLTage[:DC]:NPLCycles {0.02 | 0.2 | 1 | 2 | 10 | 20 | 100 | 200 | MIN | MAX}
VOLTage[:DC]:NPLCycles? [MIN | MAX]
[SENSe:] | SENSe1: | SENSe2:
VOLTage[:DC]:NULL[:STATe] {OFF | ON}
VOLTage[:DC]:NULL[:STATe]?
VOLTage[:DC]:NULL:VALue { | MIN | MAX}
VOLTage[:DC]:NULL:VALue?
ROUTe
:TERMinals {FRONt | FRONt1 | FRONt2}
:TERMinals?
1

118

is one of: {FRONt | FRONt1 | FRONt2 | 1 | 2}

Chapter 4 Remote Interface Reference
Command Summary

Resistance Measurement Configuration Commands
MEASure
:FRESistance? [{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]
:RESistance? [{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]
CONFigure
:FRESistance | :RESistance
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]
[SENSe:]
FUNCtion "RESistance"
FUNCtion "FRESistance"
FUNCtion?

(2-wire ohms)
(4-wire ohms)

[SENSe:]
FRESistance | RESistance
:RANGe { | MIN | MAX}
:RANGe? [MIN | MAX]
:RANGe:AUTO {OFF | ON}
:RANGe:AUTO?

[SENSe:]
FRESistance | RESistance
:RESolution { | MIN | MAX}
:RESolution? [MIN | MAX]
[SENSe:]
FRESistance | RESistance
:NPLCycles {0.02 | 0.2 | 1 | 2 | 10 | 20 | 100 | 200 | MIN | MAX}
:NPLCycles? [MIN | MAX]
[SENSe:]
FRESistance | RESistance
:NULL[:STATe] {OFF | ON}
:NULL[:STATe]?
:NULL:VALue { | MIN | MAX}
:NULL:VALue?
[SENSe:]
FRESistance | RESistance
:OCOMpensated {OFF | ON}
:OCOMpensated?
[SENSe:]
FRESistance
:POWer:LIMit[:STATe] {OFF | ON}
:POWer:LIMit?
:VOLTage:LIMit[:STATe] {OFF | ON}
:VOLTage:LIMit?
:VOLTage:LIMit:VALue { | MIN | MAX}
:VOLTage:LIMit:VALue? [MIN | MAX]

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Chapter 4 Remote Interface Reference
Command Summary

Temperature Measurement Configuration Commands
MEASure
:TEMPerature? [{TC | THER | FRTD | DEF}][,{ | DEF}][, 1, { | MAX | MIN | DEF}]
CONFigure
:TEMPerature [{TC | THER | FRTD | DEF}][,{ | DEF}][, 1, { | MAX | MIN | DEF}]
[SENSe:]
FUNCtion "TEMPerature"
FUNCtion?
[SENSe:]
TEMPerature:TRANsducer:TYPE {TCouple | THERmistor | FRTD}
TEMPerature:TRANsducer:TYPE?
[SENSe:]
TEMPerature:TRANsducer:TCouple:TYPE {B | E | J | K | N | R | S | T}
TEMPerature:TRANsducer:TCouple:TYPE?
TEMPerature:TRANsducer:TCouple:RJUNction { | MIN | MAX}
TEMPerature:TRANsducer:TCouple:RJUNction? [{MIN | MAX}]
TEMPerature:TRANsducer:TCouple:RJUNction:TYPE {FIX | INT | THER}
TEMPerature:TRANsducer:TCouple:RJUNction:TYPE?
[SENSe:]
TEMPerature:TRANsducer:FRTD:TYPE {85 | 91}
TEMPerature:TRANsducer:FRTD:TYPE?
TEMPerature:TRANsducer:FRTD:RESistance[:REFerence]
TEMPerature:TRANsducer:FRTD:RESistance[:REFerence]?
[SENSe:]
TEMPerature:NULL[:STATe] {OFF | ON}
TEMPerature:NULL[:STATe]?
TEMPerature:NULL:VALue { | MIN | MAX}
TEMPerature:NULL:VALue?
[SENSe:]
TEMPerature:NPLCycles {0.02 | 0.2 | 1 | 2 | 10 | 20 | 100 | 200 | MIN | MAX}
TEMPerature:NPLCycles? {MIN | MAX}
UNIT
:TEMPerature {C | CEL | F | FAR | K}
:TEMPerature?

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Chapter 4 Remote Interface Reference
Command Summary

General Measurement Configuration Commands
CONFigure?
[SENSe:]NULL [{OFF | ON | ONCE}]
INPut:FILTer
:STATe {OFF | ON}
:STATe?
:TYPE {ANALog | DIGital | BOTH}
:TYPE?
:DIGital:RESPonse {SLOW | MEDium | FAST}
:DIGital:RESPonse?
:DIGital:PRECharge:AUTO {ON | OFF}
:DIGItal:PRECharge:AUTO?
ROUTe:TERMinals {FRONt | FRONt1 | FRONt2}
ROUTe:TERMinals?

Math Operation Commands

CALCulate
:FUNCtion {AVERage | SCALe}
:FUNCtion?
[:STATe] {OFF | ON}
[:STATe]?
CALCulate
:AVERage:MINimum?
:AVERage:MAXimum?
:AVERage:AVERage?
:AVERage:COUNt?
:AVERage:PTPeak?
:AVERage:SDEViation?
CALCulate
:SCALe:GAIN {}
:SCALe:GAIN?
:SCALe:OFFSet {}
:SCALe:OFFSet?
DATA
:FEED RDG_STORE,[{"CALC" | ""}]
:FEED? RDG_STORE
:POINts?

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Chapter 4 Remote Interface Reference
Command Summary

Triggering Commands
INITiate
READ?
TRIGger
:SOURce {BUS | IMMediate | EXTernal}
:SOURce?
TRIGger
:DELay { | MIN | MAX}
:DELay? [MIN | MAX]
:DELay:AUTO {OFF | ON}
:DELay:AUTO?
TRIGger
:COUNt { | MIN | MAX | INFinity}
:COUNt? [MIN | MAX]
SAMPle
:COUNt { | MIN | MAX}
:COUNt? [MIN | MAX]

Chart Output Commands
OUTPut
[:STATe] {OFF | ON}
[:STATe]?
:REFerence:OFFSet { | MIN | MAX}
:REFerence:OFFSet? [{MIN | MAX}]
:REFerence:OFFSet:NULL
:REFerence:SPAN [{ | MIN | MAX}]
:REFerence:SPAN? [{MIN | MAX}]
:REFerence:GAIN?
:REFerence:VALue { | MIN | MAX}

System-Related Commands
FETCh?
READ?
DATA
:FEED RDG_STORE,[{"CALC" | ""}]
:FEED? RDG_STORE
:POINts?

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Chapter 4 Remote Interface Reference
Command Summary

System-Related Commands (continued)
DISPlay[:STATe] {OFF | ON}
DISPlay?
DISPlay
:TEXT
:TEXT?
:TEXT:CLEar
SYSTem:ERRor?
SYSTem:PRESet
SYSTem:VERSion?
*RST
*TST?
*IDN?

Status Reporting Commands

4
SYSTem:ERRor?
STATus
:OPERation:CONDition?
:OPERation:ENABle
:OPERation:ENABle?
:OPERation[:EVENt]?
:QUEStionable:CONDition?
:QUEStionable:ENABle
:QUEStionable:ENABle?
:QUEStionable[:EVENt]?
STATus:PRESet
*CLS

*STB?

*ESE
*ESE?

*PSC {0 | 1}
*PSC?

*ESR?

*SRE
*SRE?

*OPC
*OPC?

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Chapter 4 Remote Interface Reference
Command Summary

Calibration Commands
CALibration?
CALibration:COUNt?
CALibration
:ICURrent?
CALibration
:OUTPut {ZERO | GAIN}
:OUTPut?
CALibration
:SECure:CODE
:SECure:STATe {OFF | ON} [,]
:SECure:STATe?
CALibration
:STRing
:STRing?
CALibration
:VALue
:VALue?

Remote Interface Commands
SYSTem
:INTerface {HPIB | RS232}
:INTerface?
SYSTem
:COMMunicate:SERial:BAUD
:COMMunicate:SERial:BAUD?
:COMMunicate:SERial:PARity {EVEN | ODD | NONE}
:COMMunicate:SERial:PARity?
SYSTem
:LANGuage {SCPI | 181}
:LOCal
:REMote
:RWLock
L1X
L2X

(SCPI language)
(181 language)

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Chapter 4 Remote Interface Reference
Command Summary

IEEE-488.2 Common Commands
*CLS
*ESE
*ESE?
*ESR?
*IDN?
*OPC
*OPC?
*PSC {0 | 1}
*PSC?
*RST
*SRE
*SRE?

*STB?
*TRG
*TST?
*WAI

125

Chapter 4 Remote Interface Reference
Simplified Programming Sequence

Simplified Programming Sequence

➡

You can program the meter to take measurements from the remote
interface using the following seven-step sequence.
Throughout this manual, the following conventions are used for SCPI
command syntax. Square brackets ( [] ) indicate optional keywords or
parameters. Braces ( {} ) enclose a list of parameters separated with a
vertical bar ( | ), use only one of the values . Triangle brackets ( <> )
indicate that you must substitute a value for the enclosed parameter.
1. Place the meter in a known state (often the reset state).
2. Change the meter’s settings to achieve the desired configuration.
3. Set-up the triggering conditions.
4. Initiate or arm the meter for a measurement.
5. Trigger the meter to make a measurement.
6. Retrieve the readings from the output buffer or internal memory.
7. Read the measured data into your bus controller.
The MEASure? and CONFigure commands provide the most straightforward method to program the meter for measurements. You can select
the measurement function, range, and resolution all in one command.
The meter uses defaults for other measurement parameters.
Integration time, range, and resolution are local to the function or
channel used in the MEASure? and CONFigure commands. For example,
if you use the MEASure command to make a resistance measurement,
the range, resolution, and integration time set for voltage measurements
are not affected.
Other measurement parameters affect all measurement functions. When
you use the MEASure? and CONFigure commands the meter uses default
parameters. The default measurement parameters, common to all
functions or channels, used by the meter are shown in the table on the
next page.
Using the digital filter is not recommended from the remote interface,
see page 57.

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Chapter 4 Remote Interface Reference
Simplified Programming Sequence

MEASure? and CONFigure Defaults
Setting

SCPI Command System

Defaults Used

ROUTe:TERMinals

Channel 1

Digital Filter

INPut:FILTer

Off

Digital Filter Precharge

INPut:FILTer

Last value set

Analog Filter

INPut:FILTer

Off

TRIGger:SOURce

Immediate

Trigger Delay

TRIGger:DELay

Auto

Trigger Count

TRIGger:COUNt

N Samples

SAMPle:COUNt

CALCulate

Off

DATA:FEED RDG_STORE

"CALC"

DISPlay

(10 plc)

Autorange

SENSe: :NULL

Off

SOURce:FRESistance:OCOMPensated

Off

SOURce:FRESistance:VOLTage:LIMit

Last value set

Low Power Ω

SOURce:FRESistance:POWer:LIMit

Last value set

Transducer

SENSe:TEMPerature:TRANsducer

Last probe set

Probe Type

SENSe:TEMPerature:TRANsducer

Last type set

RTD type and resistance

SENSe:TEMPerature:TRANsducer

Last type set

Input Channel

Common
to all
Functions

Trigger Source

Math
Readings Store
Display (On or Off)
Specific
To Each
Function

Integration Time
(NPLC)
Range
Null
Offset Compensated Ω

Resistance
Specific

Temperature
Specific

Voltage Limited Ω

The MEASure? and CONFigure commands use default parameters for
volatile memory parameters. Non-volatile memory parameters are not
modified and the MEASure? or CONFigure commands use parameters
in memory. See page 112. For example, the temperature units last set
are stored in non-volatile memory
and are not changed by a MEASure? or CONFigure command.

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Chapter 4 Remote Interface Reference
Simplified Programming Sequence

Using the MEASure? Command
The easiest way to program the meter for measurements is by using the
MEASure? command. However, this command does not offer much
flexibility. When you execute the command, the meter uses defaults for
the requested configuration and immediately performs the measurement.
You cannot change any settings (other than function, range, and
resolution) before the measurement is taken. The results are sent to the
output buffer.
Sending the MEASure? command is functionally the same as sending a
CONFigure command followed immediately by a READ? command.

Using the CONFigure Command
For a little more programming flexibility, use the CONFigure command.
When you execute the command, the meter sets the defaults for the
requested configuration (like the MEASure? command). However, the
measurement is not automatically started and you can change
measurement parameters before making measurements. This allows you
to “incrementally” change the meter’s configuration from the default
conditions. The meter offers a variety of low-level commands in the
INPut, SENSe, CALCulate, and TRIGger subsystems. (You can use the
SENSe:FUNCtion command to change the measurement function
without using MEASure? or CONFigure.)
Use the INITiate or READ? command to initiate the measurement.

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Chapter 4 Remote Interface Reference
Simplified Programming Sequence

Using the range and resolution Parameters
With the MEASure? and CONFigure commands, you can select the
measurement function, range, and resolution all in one command. Use
the range parameter to specify a fixed range larger than the expected
value of the input signal. You can set the range parameter to AUTO to
set autoranging.
Use the resolution parameter to specify the desired resolution for the
measurement. Setting the resolution sets the integration time of the
meter. The resolution parameter can be set to any number but the
resulting integration time (NPLC) is one of the following:

Parameter

Integration Time
(NPLC)

< 0.0001 x Range

0.02

< 0.00001 x Range

< 0.000003 x Range

< 0.0000022 x Range

< 0.000001 x Range

< 0.0000008 x Range

< 0.0000003 x Range

100

< 0.00000022 x Range

200

Specify the resolution in the same units as the measurement function,
not in number of digits. For example, for volts measurements, specify the
resolution in volts. For resistance, specify the resolution in ohms.
You must specify a range to use the resolution parameter.

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Simplified Programming Sequence

Using the READ? Command
The READ? command changes the state of the trigger system from the
“idle” state to the “wait-for-trigger” state. Measurements will begin when
the specified trigger conditions are satisfied following the receipt of the
READ? command. Readings are sent immediately to the output buffer.
You must enter the reading data into your bus controller or the meter
will stop making measurements when the output buffer fills. Readings
are not stored in the meter’s internal memory when using the READ?
command.
Sending the READ? command is like sending the INITiate command
followed immediately by the FETCh? command, except readings are not
buffered internally.

Caution

If you send two query commands without reading the response from the
first, and then attempt to read the second response, you may receive some
data from the first response followed by the complete second response. To
avoid this, do not send a query command without reading the response.
When you cannot avoid this situation, send a device clear before sending
the second query command.

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Simplified Programming Sequence

Using the INITiate and FETCh? Commands
The INITiate and FETCh? commands provide the lowest level of control
(with the most flexibility) of measurement triggering and reading
retrieval. Use the INITiate command after you have configured the meter
for the measurement. This changes the state of the triggering system
from the “idle” state to the “wait-for-trigger” state. Measurements will
begin when the specified trigger conditions are satisfied after the
INITiate command is received. The readings are placed in the meter’s
internal memory (up to 1024 readings can be stored). Readings are stored
in memory until you are able to retrieve them.
Use the FETCh? command to transfer the readings from the meter’s internal
memory to the meter’s output buffer where you can read them into your bus
controller.
Configure the meter using the SENSe commands. For voltage
measurements on two channels, you can configure each channel
independently by specifying either SENSe1 or SENSe2. Once configured,
use the ROUTe:TERM command to switch between the input channels.
The INIT and FETCh? commands use the meter’s memory. You can
defeat the storing of readings, and still obtain the statistics on the
readings using the DATA:FEED command. See page 150.

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Simplified Programming Sequence

MEASure?
Example

The following program segment shows how to use the MEASure?
command to make a measurement. This example configures the meter for
voltage measurements on channel 1 using autoranging on the input
signal, automatically places the meter in the “wait-for-trigger” state,
internally triggers the meter to take one reading, and then sends the
reading to the output buffer.
MEAS:VOLT:DC? AUTO,MIN,(@FRONt1)
bus enter statement

This is the simplest way to take a reading. However, you do not have any
flexibility with MEASure? to set the trigger count, sample count, trigger
delay, etc. All measurement parameters except function, range, and
resolution are preset for you automatically (see the table on page 127).

CONFigure
Example 1

The following program segment shows how to use the READ? command
with CONFigure to make an externally-triggered measurement. The
program configures the meter for dc voltage measurements. CONFigure
does not place the meter in the “wait-for-trigger” state. The READ?
command places the meter in the “wait-for-trigger” state, takes a reading
when the Ext Trig terminal is pulsed, and sends the reading to the
output buffer.
CONF:VOLT:DC 10, MIN, (@FRONt1)
TRIG:SOUR EXT
READ?
bus enter statement

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CONFigure
Example 2

The following program segment is similar to the example above but it
uses INITiate to place the meter in the “wait-for-trigger” state. The
INITiate command places the meter in the “wait-for-trigger” state, takes
a reading when the Ext Trig terminal is pulsed, and sends the reading to
the meter’s internal memory. The FETCh? command transfers the
reading from internal memory to the output buffer.
CONF:VOLT:DC 10, MIN, (@FRONt1)
TRIG:SOUR EXT
INIT
FETC?
bus enter statement
Storing readings in memory using the INITiate command is faster than
sending readings to the output buffer using the READ? command. The
meter can store up to 1024 readings in internal memory. If you configure
the meter to take more than 1024 readings (using the sample count and
trigger count), and then send INITiate, a memory error is generated.
After you execute an INITiate command, no further commands are
accepted until the measurement sequence is completed. However, if you
select TRIGger:SOURce BUS, the meter will accept the *TRG command
(bus trigger) or an IEEE-488 Group Execute Trigger message. You can
stop a measurement started with an INITiate command by sending a
device clear (see page 187)

CONFigure
Example 3

The following program segment sets the state of two input channels and
then uses the ROUTe and READ? commands to take measurements on
each. Channel 1 is set to the 10 Volt range with maximum resolution.
Channel 2 is set to the 1 volt range. Note that resolution is common to
both channels, the NPLC in effect will be the NPLC set by the last
CONFigure command the meter receives.
CONFigure:VOLT:DC 10, MAX, (@FRONt1)
CONFigure:VOLT:DC 1, MAX, (@FRONt2)
ROUTe:TERMinals FRONt1
READ?
bus enter statement
ROUTe:TERMinals FRONt2
READ?
bus enter statement

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The MEASure? and CONFigure Commands

The MEASure? and CONFigure Commands
See also “General Measurement Configuration,” starting on page 55 in
chapter 3. Both the MEASure? and CONFigure commands reset
measurement parameters to defaults. See page 127.
• For the range parameter, MIN selects the lowest range for the selected
function; MAX selects the highest range; AUTO or DEF selects
autoranging.
• For the resolution parameter, specify the resolution in the same units
as the measurement function, not in number of digits. MIN selects the
smallest value accepted, which gives the highest resolution; MAX
selects the largest value accepted, which gives the least resolution;
DEF selects the default resolution which is 0.000001 x range (10 PLC).
See the table on page 129.
• You must specify a range to use the resolution parameter.
• For voltage measurements, you can also specify the input channel.
The parameter channel can be set to FRONt1, FRONt2, 1, or 2. In the
command, the channel must be preceded by the ‘@’ symbol and
enclosed in parenthesis ().
MEASure[:VOLTage][:DC]?
[{ | AUTO | MIN | MAX | DEF}]
[,{ | MIN | MAX | DEF}][,(@)]

This command presets and makes a voltage measurement with the
specified range, resolution, and input channel. The reading is sent to the
output buffer.
MEASure[:VOLTage][:DC]:RATio?
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]

This command presets and makes a voltage ratio measurement with the
specified range and resolution. The reading is sent to the output buffer.
For ratio measurements, the specified range applies to the signal
connected to the Channel 1 terminals. Autoranging is selected for
voltage measurements on the Channel 2 terminals.

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The MEASure? and CONFigure Commands

MEASure[:VOLTage][:DC]:DIFFerence?
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]

This command presets and makes a difference measurement with the
specified range and resolution. The reading is sent to the output buffer.
For difference measurements, the specified range applies to the signal
connected to the Channel 1 terminals. Autoranging is selected for voltage
measurements on the Channel 2 terminals.
MEASure:FRESistance?
MEASure:RESistance?
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]

This command presets and makes a 2-wire or 4-wire ohms measurement
with the specified range and resolution. The reading is sent to the output
buffer.
MEASure:TEMPerature?
{TC | DEF},{B | E | J | K | N | R | S | T | DEF}[,1,{ | MIN | MAX | DEF}]
{THER | DEF},{DEF}[,1,{ | MIN | MAX | DEF}]
{FRTD | DEF},{85 | 91 | DEF}[,1,{ | MIN | MAX | DEF}]

This command presets and configures the meter for temperature
measurements using the specified probe type and resolution. The reading
is sent to the output buffer. DEF defaults to the last probe type set.

CONFigure[:VOLTage][:DC]
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}][,(@)]

This command presets and configures the meter for dc voltage
measurements with the specified range, resolution, and input channel.
This command does not initiate the measurement.
CONFigure[:VOLTage][:DC]:RATio
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]

This command presets and configures the meter for dc:dc ratio
measurements with the specified range and resolution. This command
does not initiate the measurement. For ratio measurements, the specified
range applies to the signal connected to the Channel 1 terminals.
Autoranging is selected for voltage measurements on the Channel 2
terminals.

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The MEASure? and CONFigure Commands

CONFigure[:VOLTage][:DC]:DIFFerence
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]

This command presets and configures the meter for difference
measurements with the specified range and resolution. This command
does not initiate the measurement. For difference measurements, the
specified range applies to the signal connected to the Channel 1
terminals. Autoranging is selected for voltage measurements on the
Channel 2 terminals.
CONFigure:FRESistance
CONFigure:RESistance
[{ | AUTO | MIN | MAX | DEF}][,{ | MIN | MAX | DEF}]

This command presets and configures the meter for 2-wire or 4-wire
ohms measurements with the specified range and resolution. This
command does not initiate the measurement.
CONFigure:TEMPerature
{TC | DEF},{B | E | J | K | N | R | S | T | DEF}[,1,{ | MIN | MAX | DEF}]
{THER | DEF},{DEF}[,1,{ | MIN | MAX | DEF}]
{FRTD | DEF},{85 | 91 | DEF}[,1,{ | MIN | MAX | DEF}]

This command presets and configures the meter for temperature
measurements using the specified probe type and resolution. This
command does not initiate the measurement. DEF defaults to the last
probe type set.
CONFigure?

This command queries the meter’s present configuration and return a
quoted string.

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Setting the Function, Range, and Resolution

Setting the Function, Range, and Resolution
See also “General Measurement Configuration,” starting on page 55 in
chapter 3.
[SENSe:]FUNCtion ""

Select a measurement function. The function must be enclosed in quotes
in the command string (for example, FUNC "VOLT:DC"). Use one of
the following strings to set the function:
VOLTage:DC

RESistance (2-wire ohms)

VOLTage:DC:RATio

FRESistance (4-wire ohms)

VOLTage:DC:DIFFerence

TEMPerature

[SENSe:]FUNCtion?

This command queries the measurement function and return a quoted
string.
[{SENSe1: | SENSe2:}]VOLTage[:DC]:RANGe { | MIN | MAX}
[SENSe:]
FRESistance | RESistance
:RANGe { | MIN | MAX}

This command sets the range for the function specified. MIN selects the
lowest range.
MAX selects the highest range. [volatile memory]
[{SENSe1: | SENSe2:}]VOLTage[:DC]:RANGe? [MIN | MAX]
[SENSe:]
FRESistance | RESistance
:RANGe? {MIN | MAX}

This command queries the function range setting.

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Setting the Function, Range, and Resolution

[{SENSe1: | SENSe2:}]VOLTage[:DC]:RANGe:AUTO {OFF | ON}
[SENSe:]
FRESistance | RESistance
:RANGe:AUTO {OFF | ON}

This command disables or enables autoranging for the function.
Autorange thresholds: Down range at <10% of range; Up range at >120%
of range. [volatile memory]
[{SENSe1: | SENSe2:}]VOLTage[:DC]:RANGe:AUTO?
[SENSe:]
FRESistance | RESistance
:RANGe:AUTO?

This command queries the autorange setting for the specified function.
Returns “0” (OFF) or “1” (ON).
[SENSe1: | SENSe2:]VOLTage:[DC:]RESolution { | MIN | MAX}
[SENSe:]
FRESistance | RESistance
:RESolution { | MIN | MAX}

This command sets the resolution for the specified function. Specify the
resolution in the same units as the measurement function, not in number
of digits. MIN selects the smallest value accepted, which gives the most
resolution. MAX selects the largest value accepted which gives the least
resolution. [volatile memory]
[SENSe1: | SENSe2:]VOLTage:[DC:]RESolution? [{MIN | MAX}]
[SENSe:]
FRESistance | RESistance
:RESolution? [{MIN | MAX}]

This command queries the resolution for the selected function.

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Setting the Function, Range, and Resolution

[SENSe1: | SENSe2:]VOLTage[:DC]:NPLCycles
{0.02 | 0.2 | 1 | 2 | 10 | 20 | 100 | 200 | MIN | MAX}
[SENSe:]
FRESistance | RESistance
:NPLCycles {0.02 | 0.2 | 1 | 2 | 10 | 20 | 100 | 200 | MIN | MAX}
[SENSe:]TEMPerature:NPLCycles {0.02 | 0.2 | 1 | 2 | 10 | 20 | 100 | 200 | MIN | MAX}

This command selects the integration time in number of power line cycles
for the present function (the default is 10 PLC). MIN = 0.02. MAX = 200.
[volatile memory]
[SENSe1: | SENSe2:]VOLTage[:DC]:NPLCycles? {MIN | MAX}
[SENSe:]
FRESistance | RESistance
:NPLCycles? {MIN | MAX}
[SENSe:]TEMPerature:NPLCycles? {MIN | MAX}

This command queries the integration time for the selected function.

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Selecting the Input Channel

Selecting the Input Channel
The correct input channel is automatically selected for resistance and
temperature measurement functions. For voltage measurements, you
must select the input channel.
The easiest, but least flexible, method to specify the input channel is by
using the channel parameter in the MEASure? or CONFigure commands.
For example,
CONFigure:VOLTage:DC MAX, MAX, (@FRONt1)
CONFigure:VOLTage:DC MAX, MAX, (@FRONt2)

Channel 1
Channel 2

In the SENSe subsystem, the keyword is modified to select the input
channel. For example,
SENSe1:VOLTage:RANGe 10
SENSe2:VOLTage:RANGe 10

Channel 1 range setting
Channel 2 range setting

For increased flexibility, and to take advantage of the independant null
and range settings for each input channel, you can set each input channel
as desired and switch between the input channels using the
ROUTe:TERMinals command. For example,
SENSe1:VOLTage:RANGe 10
SENSe2:VOLTage:RANGe .1
ROUTe:TERMinals FRONt1
READ?
ROUTe:TERMinals FRONt2
READ?

Channel 1 range 10 V
Channel 2 range 100 mV
Select channel 1
Channel 1 measurement
Select channel 2
Channel 2 measurement

You can determine which input channel is active with the query:
ROUTe:TERMinals?

The query returns either FRON1 or FRON2.

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Special Resistance Measurement Commands

Special Resistance Measurement Commands
The following commands provide offset compensation and low power or
voltage limited resistance measurement capability.
[SENSe:]
FRESistance | RESistance
:OCOMpensated {OFF | ON}
:OCOMpensated?

This command enables or disables the offset compensated resistance
measurements (see page 69). Once enabled, offset compensation will
apply to both 4-wire and 2-wire resistance measurements.
[SENSe:]
FRESistance
:POWer:LIMit[:STATe] {OFF | ON}
:POWer:LIMit[:STATe]?

This command enables or disable the 4-wire low power resistance mode
(see page 69).
[SENSe:]
FRESistance
:VOLTage:LIMit[:STATe] {OFF | ON}
:VOLTage:LIMit[:STATe]?
:VOLTage:LIMit:VALue { | MIN | MAX}
:VOLTage:LIMit:VALue? {MIN | MAX}

This command enables or disables the 4-wire voltage limited resistance
mode (see page 70). The voltage limit parameter will be rounded
to one of three values:
20 mV,
100 mV, or
500 mV
MIN sets 20 mV and MAX sets 500 mV.

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Chapter 4 Remote Interface Reference
Temperature Measurement Commands

Temperature Measurement Commands
See "Temperature Measurement Configuration" on page 71 in Chapter 3.
• The meter stores the last settings used for temperature measurements
in non-volatile memory and uses these values as the default for future
measurements. You can, therefore, make temperature measurements
without having to set the transducer type or reference each time.
• A range setting is not meaningful for temperature measurements.
The range parameter is included in the commands to allow you to set
the resolution. For temperature measurements, set the range to 1.
Other numbers can be entered and are ignored. The range is reported
as 1 in response to a query.
MEASure:TEMPerature?
{TC | DEF},{B | E | J | K | N | R | S | T | DEF}[, 1, { | MIN | MAX | DEF}]
{THER | DEF},DEF[, 1, { | MIN | MAX | DEF}]
{FRTD | DEF},{85 | 91 | DEF}[, 1, { | MIN | MAX | DEF}]

These commands preset and configure the meter for temperature
measurements using the specified probe type and resolution. The reading
is sent to the output buffer. Set the measurement probe type in the first
parameter, either TC (thermocouple), THER (Thermistor), or FRTD
(four-wire RTD). The DEF (default) option sets the last probe type used.
Set the thermocouple or RTD type in the second parameter. Set to DEF
for thermistors. The optional parameter, 1, is a place holder to allow you
to set the resolution.
CONFigure:TEMPerature
{TC | DEF},{B | E | J | K | N | R | S | T | DEF}[, 1, { | MIN | MAX | DEF}]
{THER | DEF},DEF[, 1, { | MIN | MAX | DEF}]
{FRTD | DEF},{85 | 91 | DEF}[, 1, { | MIN | MAX | DEF}]

These commands preset and configure the meter for temperature
measurements using the specified probe type and resolution. This
command does not initiate the measurement. Set the measurement probe
type in the first parameter, either TC (thermocouple), THER
(Thermistor), or FRTD (four-wire RTD). The DEF (default) option sets
the last probe type used. Set the thermocouple type in the second
parameter. Set to DEF for thermistors. The optional parameter, 1, is a
place holder to allow you to set the resolution.

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Temperature Measurement Commands

[SENSe:]TEMPerature:TRANsducer:TYPE {TC | THER | FRTD | DEF}

This command sets the type of temperature transducer to use for
temperature measurements. Choose TC (thermocouples), THER
(thermistors), or FRTD (four-wire RTD). DEF sets FRTD.
[SENSe:]TEMPerature:TRANsducer:TYPE?

This command queries for the current temperature measurement
transducer type.
[SENSe:]TEMPerature:TRANsducer:TCouple:TYPE {B | E | J | K | R | S | T | DEF}

This command sets the type of thermocouple to use for the temperature
measurement. DEF sets the last thermocouple type used.
[SENSe:]TEMPerature:TRANsducer:TCouple:TYPE?

This command queries for the thermocouple type in use.
[SENSe:]TEMPerature:TRANsducer:TCouple:RJUNction { | MIN | MAX}

This command sets the reference junction temperature for thermocouple
measurements when using a fixed temperature reference.
MIN sets 0° C, MAX sets 55° C.
[SENSe:]TEMPerature:TRANsducer:TCouple:RJUNction? [{MIN | MAX}]

This command queries for the reference junction temperature, if set,
when using a fixed temperature reference.
MIN returns 0° C, MAX returns 55° C.
[SENSe:]TEMPerature:TRANsducer:TCouple:RJUNction:TYPE {FIX | INT | THER}

This command sets the reference junction type for thermocouple
measurements. The type can be se to a fixed value (FIX), can be set to use
the internal thermistor (INT), or can use a thermistor connected to
channel 1 (THER). When type is set to FIX, use
SENSe:TEMPerature:TRANsducer:TCouple:RJUNction
to set the reference temperature.
[SENSe:]TEMPerature:TRANsducer:TCouple:RJUNction:TYPE ?

This command queries for the type of reference junction being used for
thermocouple measurements.

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Temperature Measurement Commands

[SENSe:]TEMPerature:TRANsducer:FRTD:TYPE {85 | 91}

This command sets the four-wire RTD type. The alpha is entered as
either 85 (for α = .000385) or 91 (for α = .000391).
[SENSe:]TEMPerature:TRANsducer:FRTD:TYPE?

This command queries for the type of RTD being used.
Returns either +91 or +85.
[SENSe:]TEMPerature:TRANsducer:FRTD:RESistance[:REFerence]

This command sets the four-wire RTD R0 value. The value is in the range
of 4.9 Ω to 2.1 kΩ.
[SENSe:]TEMPerature:TRANsducer:FRTD:RESistance[:REFerence]?

This command queries for the RTD R0 value being used.
UNIT:TEMPerature {C | CEL | F | FAR | K}

This command sets the measurement and reporting units for
temperature measurements.
UNIT:TEMPerature?

This command queries the temperature measurement reporting units.

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Null (Relative) Commands

Null (Relative) Commands
The meter uses independant null values for channel 1 and channel 2
voltage measurements, resistance measurements, and temperature
measurements. See page 77 in Chapter 3.
[SENSe:] | SENSe1: | SENSe2
VOLTage[:DC]:NULL[:STATe] {OFF | ON}
VOLTage[:DC]:NULL[:STATe]?
VOLTage[:DC]:NULL:VALue { | MIN | MAX}
VOLTage[:DC]:NULL:VALue?

These commands enable or disable the null state for voltage
measurements on the selected input channel. Null must be enabled
before the null value can be set. The null value set must be
within ±132 V on each input channel.
[SENSe:]
FRESistance | RESistance
:NULL[:STATe] {OFF | ON}
:NULL[:STATe]?
:NULL:VALue { | MIN | MAX}
:NULL:VALue?

These commands enable or disable the null state for resistance
measurements. Null must be enabled before the null value can be set. The
null value set must be within ±1.2 MΩ. Null is common to both 2-wire and
4-wire resistance measurements, that is, enabling null on 4-wire ohms
measurements also enables null on 2-wire ohms measurements.
[SENSe:]
TEMPerature
:NULL[:STATe] {OFF | ON}
:NULL[:STATe]?
:NULL:VALue { | MIN | MAX}
:NULL:VALue?

These commands enable or disable the null state for temperature
measurements. Null must be enabled before the null value can be set.
The null value set must be in the range of -300° C to 2000° C. Null is
common to all temperature measurements, that is, enabling null for one
probe type enables null for all probe types.
[SENSe:]NULL {OFF | ON | ONCE}

This command enables or disables null for the active channel or function.
OFF or ON disables or enables null using a value set in the null register.
ONCE enables null and makes the next reading the null value.
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Input Filter Commands

Input Filter Commands
See also page 55 in Chapter 3.
Using the input filters from the remote interface is not recommended. To
use the filters with the remote interface be aware of the following:
• The digital filter is a moving average (boxcar) filter. The filter rate sets
the number of readings that will be averaged. A reading is taken and
included in the average with each trigger. You must, therefore, supply
enough triggers to fill up the average before the filter will settle. If
your measurement requires averaging readings, use the math
operations (Stats) instead of the digital filter (see page 148).
• The digital filter average may reset, based upon the measurement
value (see page 57). You must use the STATus:OPERation:CONDition
register to determine if the filter is settled with each reading taken.
• The analog filter significantly slows the reading rate.
The input filters are disabled following a remote interface reset (*RST) or
preset (SYStem:PREset).

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Input Filter Commands

INPut:FILTer
:STATe {OFF | ON}
:STATe?

These commands enable or disable the filter state and query the filter
state.
INPut:FILTer
:TYPE {ANALog | DIGital | BOTH}
:TYPE?

These commands set the filter type and query the filter type.
BOTH enables the digital and analog filters.
INPut:FILTer
:DIGital:RESPonse {SLOW | MEDium | FAST}
:DIGital:RESPonse?

These commands set the averaging for the digital filter and query the
digital filter setting. SLOW sets a 100 reading average, MEDium sets a
50 reading average, and FAST sets a 10 reading average.

INPut:FILTer
:DIGital:PRECharge {OFF | ON}
:DIGital:PRECharge?

These commands enable or disable the digital filter precharge and query
the digital filter precharge setting. Disabling the digital filter precharge
prevents the filter from resetting based upon the measured value (see
page 57 in chapter 3).

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Chapter 4 Remote Interface Reference
Math Operation Commands

Math Operation Commands
See also “Math Operations,” starting on page 74 in chapter 3.
There are two main math operations available; stats and scale, only one
of which can be enabled at a time. Stats performs mathematical
operations on a series of readings. Scale performs a mathematical
operation on each reading.
The selected math operation remains in effect until you disable it, change
functions, turn off the power, or perform a remote interface reset.
CALCulate:FUNCtion {AVERage | SCALe}

This command selects the main math function. Only one function can be
enabled at a time. [volatile memory]
CALCulate:FUNCtion?

This command queries the present math function. Returns SCAL or AVER.
CALCulate[:STATe] {OFF | ON}

This command disables or enables the selected math function.
[volatile memory]
CALCulate[:STATe]?

This command queries the state of the math function.
Returns “0” (OFF) or “1” (ON).

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Math Operation Commands

Statistics operation commands (AVERage)
• You must have set CALC:FUNC AVER and CALC ON to use these
commands.
CALCulate:AVERage:MINimum?

This command returns the minimum value found during a math average
operation. The meter clears the value when math is turned on, when
power has been off, or after a remote interface reset. [volatile memory]
CALCulate:AVERage:MAXimum?

This command returns the maximum value found during a math average
operation. The meter clears the value when math is turned on, when
power has been off, or after a remote interface reset. [volatile memory]
CALCulate:AVERage:AVERage?

This command returns the average of all readings taken since math
average was enabled. The meter clears the value when math is turned
on, when power has been off, or after a remote interface reset.
[volatile memory]
CALCulate:AVERage:COUNt?

This command returns the number of readings taken since math average
was enabled. The meter clears the value when math is turned on, when
power has been off, or after a remote interface reset. [volatile memory]
CALCulate:AVERage:PTPeak?

This command returns the peak-to-peak value of all readings taken since
math was enabled. The meter clears the value when math is turned on,
when power has been off, or after a remote interface reset.
[volatile memory]
CALulate:AVERage:SDEViation

This command returns the standard deviation of all readings taken since
math was enabled. The meter clears the value when math is turned on,
when power has been off, or after a remote interface reset.
[volatile memory]

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Math Operation Commands

DATA:FEED RDG_STORE, {"CALCulate" | " "}

This command selects whether readings taken using the INITiate
command are stored in the meter’s internal memory (default) or not
stored at all.
In the default state (DATA:FEED RDG_STORE, "CALC"), up to 1024
readings are stored in memory when INITiate is executed. The
MEASure? and CONFigure commands automatically select "CALC".
With memory disabled (DATA:FEED RDG_STORE, " "), readings taken
using INITiate are not stored. You can use this method to gather
statistics on any number of readings (no 1024 reading limit). An error
will be generated if you attempt to transfer readings to the output buffer
using the FETCh? command.
DATA:FEED?

This command queries the reading memory state. Returns "CALC" or " ".
DATA:POINts?

This comand queries the number of readings in memory.

Scale operation commands
You must have set CALC:FUNC SCAL and CALC ON to use these
commands.
CALCulate:SCALe:GAIN

This comand sets the slope of the readings scale according to y = mx + b.
The gain is the m value.
CALCulate:SCALe:GAIN?

This command queries the current gain.
CALCulate:SCALe:OFFSet

This command sets the offset of the readings scale according to
y = mx + b. The offset is the b value.
CALCulate:SCALe:OFFSet?

This command queries the current offset.

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Triggering

Triggering
See also “Triggering,” starting on page 80 in chapter 3.

First time SCPI users,
see page 183

The meter’s triggering system allows you to generate triggers either
manually or automatically, take multiple readings per trigger, and insert
a delay before each reading. Normally, the meter will take one reading
each time it receives a trigger, but you can specify multiple readings (up
to 50,000) per trigger. You can also set an infinite trigger.
Triggering the meter from the remote interface is a multi-step process
that offers triggering flexibility.
• First, you must configure the meter for the measurement by
selecting the function, range, resolution, etc.
• Then, you must specify the source from which the meter will accept
the trigger. The meter will accept a software (bus) trigger from the
remote interface, a hardware trigger from the rear-panel Ext Trig
(external trigger) terminal, or an immediate internal trigger.
• Then, you must make sure that the meter is ready to accept a trigger
from the specified trigger source (this is called the wait-for-trigger
state).
The diagram on the next page shows the meter’s triggering system.

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Triggering

Initiate Triggering
MEASure?
READ?
INITiate

Trigger Source
TRIGger:SOURce IMMediate
TRIGger:SOURce EXTernal
TRIGger:SOURce BUS
front-panel "Single" key

Idle
State

Wait-forTrigger
State

Trigger Delay
TRIGger:DELay
Delay

Sample (*)
Annunciator

Measurement
Sample

Yes

Sample
Count >1

Triggering the meter is a multi-step process.

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Count >1
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Triggering

The Wait-for-Trigger State
After you have configured the meter and selected a trigger source, you
must place the meter in the wait-for-trigger state. A trigger will not be
accepted until the meter is in this state. If a trigger signal is present, and
if the meter is in the “wait-for-trigger” state, the measurement sequence
begins and readings are taken.
The “wait-for-trigger” state is a term used primarily for remote
interface operation. From the front panel, the meter is always in the
“wait-for-trigger” state and will accept triggers at any time, unless a
measurement is already in progress.
You can place the meter in the “wait-for-trigger” state by executing any of
the following commands from the remote interface.
MEASure?
READ?
INITiate
The meter requires approximately 20 ms of set-up time after you send a
command to change to the "wait-for-trigger" state. Any external triggers
that occur during this set-up time are ignored.

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Triggering Commands
See also “Triggering,” starting on page 80 in chapter 3.
INITiate

This command changes the state of the triggering system from the “idle”
state to the “wait-for-trigger” state. Measurements will begin when the
specified trigger conditions are satisfied after the INITiate command is
received. The readings are placed in the meter’s internal memory (up to
1024 readings can be stored). Readings are stored in memory until you
are able to retrieve them. Use the FETCh? command to retrieve reading
results.
READ?

This command changes the state of the trigger system from the “idle”
state to the “wait-for-trigger” state. Measurements will begin when the
specified trigger conditions are satisfied following the receipt of the
READ? command. Readings are sent immediately to the output buffer.
TRIGger:SOURce {BUS | IMMediate | EXTernal}

This command selects the source from which the meter will accept a
trigger. The meter will accept a software (bus) trigger, an immediate
internal trigger (this is the default source), or a hardware trigger from
the rear-panel Ext Trig (external trigger) terminal. After you set the
trigger source, you still need to send an INITiate command to move the
meter to the wait-for-trigger state. [volatile memory]
TRIGger:SOURce?

This command queries the present trigger source.
Returns “BUS”, “IMM”, or “EXT”.

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TRIGger:DELay { | MIN | MAX}

This command inserts a trigger delay between the trigger signal and each
sample that follows. If you do not specify a trigger delay, the meter
automatically selects a delay for you (see page 89). Select from 0 to 3600
seconds. MIN = 0 seconds. MAX = 3600 seconds. [volatile memory]
TRIGger:DELay? [{MIN | MAX}]

This command queries the trigger delay.
TRIGger:DELay:AUTO {OFF | ON}

This command enables or disables an automatic trigger delay. The delay
is determined by function, range, integration time, and ac filter setting.
Selecting a specific trigger delay value automatically turns off automatic
trigger delay. [volatile memory]
TRIGger:DELay:AUTO?

This command queries the automatic trigger delay setting.
Returns “0” (OFF) or “1” (ON).

SAMPle:COUNt { | MIN | MAX}

This command sets the number of readings (samples) the meter takes per
trigger. Select from 1 to 50,000 readings per trigger.
MIN = 1 and MAX = 50,000. [volatile memory]
SAMPle:COUNt? [{MIN | MAX}]

This command queries the sample count.
TRIGger:COUNt { | MIN | MAX | INFinity}

This command sets the number of triggers the meter will accept before
returning to the “idle” state. Select from 1 to 50,000 triggers. The
INFinity parameter instructs the meter to continuously accept triggers
(you must send a device clear to return to the “idle” state). Trigger count
is ignored while in local operation. MIN = 1 and MAX = 50,000. [volatile
memory]
TRIGger:COUNt? [{MIN | MAX}]

This command queries the trigger count. If you specify an infinity trigger
count, the query command returns “9.90000000E+37”.

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Chart Output (Analog Out) Commands

Chart Output (Analog Out) Commands
See also "Chart Output", starting on page 98 in chapter 3.
OUTPut
[:STATe] {OFF | ON}
[:STATe]?

These commands enable or disable the chart output (analog output) and
query the output state. When disabled, the output is held at 0 V.
OUTPut
:REFerence:OFFset { | MIN | MAX}
:REFerence:OFFset?
:REFerence:NULL

These commands set or query the offset value. The offset can be set in the
range of -1.0E9 to 1.0E9. MIN sets –1.0E9 V and MAX sets 1.0E9 V.
The :NULL form of this command makes the next measurement value the
null value.
OUTPut
:REFerence:SPAN [{ | MIN | MAX}]
:REFerence:SPAN? [{MIN | MAX}]
:REFerence:GAIN?

These commands set or query the span value. The span can be set in the
range of 5E-9 to 1.0E9. MIN sets 5E-9 and MAX sets 1.0E9. The :GAIN?
query returns the reciprocal of the span value.
OUTPut
:REFerence:VALue { | MIN | MAX}]

This command allows you to set a fixed value output. The value can be
set in the range of ±3.00 V. MIN sets -3.00 V and MAX sets +3.00 V.

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System-Related Commands

System-Related Commands
See also “System-Related Operations,” starting on page 90 in chapter 3.
FETCh?

This command transfers readings stored in the meter’s internal memory
by the INITiate command to the meter’s output buffer where you can
read them into your bus controller.
READ?

This command turns the front-panel display off or on. [volatile memory]
DISPlay?

This command queries the front-panel display setting.
Returns “0” (OFF) or “1” (ON).
DISPlay:TEXT

This command displays a message on the front panel. The meter will
display up to 11 characters in a message; any additional characters are
truncated. [volatile memory]
DISPlay:TEXT?

This command queries the message sent to the front panel and returns a
quoted string.
DISPlay:TEXT:CLEar

This command clears the message in the display.

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SYSTem:ERRor?

This command queries the meter’s error queue. Up to 20 errors can be
stored in the queue. Errors are retrieved in first-in-first out (FIFO) order.
Each error string may contain up to 80 characters.
SYSTem:VERSion?

This command queries the meter to determine the present SCPI version.
Returns "1994.0"
*RST

This command resets the meter to its power-on configuration.
*TST?

This command performs a complete self-test of the meter. Returns “0” if
the self-test is successful, or “1” if the test fails.
*IDN?

This command reads the meter’s identification string (be sure to
dimension a string variable with at least 40 characters).

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The SCPI Status Model

The SCPI Status Model
All SCPI instruments implement status registers in the same way. The
status system records various instrument conditions in four register
groups: the Status Byte register, the Standard Event register, The
Operational Status register, and the Questionable Data register. The
status byte register records high-level summary information reported in
the other register groups. The diagram on the next page illustrates the
SCPI status system used by the meter.
Chapter 6, “Application Programs,” contains example programs showing
the use of the status registers. You may find it useful to refer to the
programs after reading the following section in this chapter.

What is an Event Register?
The standard event and questionable data registers have event registers.
An event register is a read-only register that reports defined conditions
within the meter. Bits in the event registers are latched. Once an event
bit is set, subsequent state changes are ignored. Bits in an event register
are automatically cleared by a query of that register (such as *ESR? or
STAT:QUES:EVEN?) or by sending the *CLS (clear status) command. A
reset (*RST) or device clear will not clear bits in event registers. Querying
an event register returns a decimal value which corresponds to the
binary-weighted sum of all bits set in the register.

What is an Enable Register?
An enable register defines which bits in the corresponding event register
are logically ORed together to form a single summary bit. Enable
registers are both readable and writable. Querying an enable register
will not clear it. The *CLS (clear status) command does not clear enable
registers but it does clear the bits in the event registers. The
STATus:PRESet command will clear the questionable data enable
register. To enable bits in an enable register, you must write a decimal
value which corresponds to the binary-weighted sum of the bits you wish
to enable in the register.

What is a Condition Register?
A condition register actively indicates the current state of the instrument.
Bits in the condition register are not latched, and change as the
conditions within the instrument change. The event register latches the
changes in the condition register bits.

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The SCPI Status Model

SCPI Status System

+ See page 169 for information on the use of this bit.

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The SCPI Status Model

The Status Byte
The status byte summary register reports conditions from other status
registers. Query data that is waiting in the meter’s output buffer is
immediately reported through the “message available” bit (bit 4). Bits in
the summary registers are not latched. Clearing an event register will
clear the corresponding bits in the status byte summary register. Reading
all messages in the output buffer, including any pending queries, will
clear the message available bit.
Bit Definitions — Status Byte Register

Bit

Decimal
Value

Definition

Not Used

Always set to 0

Not Used

Always set to 0

Not Used

Always set to 0

Questionable Data

One or more bits are set in the Questionable
Data register (bits must be "enabled" in the
enable register).

Message Available

Data is available in the meter output buffer

Standard Event

One or more bits are set in the Standard
Event register (bits must be "enabled" in the
enable register).

Request Service

The meter is requesting service (serial poll).

Operational Status

128

One or more bits are set in the Operational
Event register (bits must be "enabled" in the
enable register)

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The status byte summary register is cleared when:
• You execute a *CLS (clear status) command.
• Querying the standard event and questionable data registers will clear
only the respective bits in the summary register.
The status byte enable register (request service) is cleared when:
• You turn on the power and you have previously configured the meter
using the *PSC 1 command.
• You execute a *SRE 0 command.
The status byte enable register will not be cleared at power-on if you
have previously configured the meter using *PSC 0.

Using Service Request (SRQ) and Serial POLL
You must configure your bus controller to respond to the IEEE-488 service
request (SRQ) interrupt to use this capability. Use the status byte enable
register (SRE) to select which summary bits will set the low-level
IEEE-488 SRQ signal. When the status byte “request service” bit (bit 6) is
set, an IEEE-488 SRQ interrupt message is automatically sent to the bus
controller. The bus controller may then poll the instruments on the bus to
identify which one requested service (the one with bit 6 set in its status
byte). The request service bit is only cleared by reading the status byte
using an IEEE-488 serial poll or by reading the event register whose
summary bit is causing the service request.
To read the status byte summary register, send the IEEE-488 serial poll
message. Querying the summary register will return a decimal value
which corresponds to the binary-weighted sum of the bits set in the
register. Serial poll will automatically clear the “request service” bit in
the status byte summary register. No other bits are affected. Performing
a serial poll will not affect instrument throughput.

Caution

The IEEE-488.2 standard does not ensure synchronization between your
bus controller program and the instrument. Use the *OPC? command to
guarantee that commands previously sent to the instrument have
completed. Executing a serial poll before a *RST, *CLS, or other
commands have completed can cause previous conditions to be reported.

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Using *STB? to Read the Status Byte
The *STB? (status byte query) command is similar to a serial poll except
it is processed like any other instrument command. The *STB? command
returns the same result as an IEEE-488 serial poll except that the
“request service” bit (bit 6) is not cleared if a serial poll has occurred.
The *STB? command is not handled automatically by the IEEE-488 bus
interface hardware and the command will be executed only after previous
commands have completed. Polling is not possible using the *STB?
command. Using the *STB? command does not clear the status byte
summary register.

To Interrupt Your Bus Controller Using SRQ
• Send a bus device clear message.
• Clear the event registers with the *CLS (clear status) command.
• Set the *ESE (standard event register) and *SRE (status byte register)
enable masks.
• Send the *OPC? (operation complete query) command and enter the
result to assure synchronization.
• Enable your bus controller’s IEEE-488 SRQ interrupt.

To Determine When a Command Sequence is Completed
Either:
• Send the *OPC? (operation complete query) command and enter the
result to assure synchronization.
Or, to prevent holding the interface bus for commands that take longer
to execute (such as CALibrate commands), :
• Send a device clear message to clear the meter’s output buffer.
• Clear the event registers with the *CLS (clear status) command.
• Enable “operation complete” using the *ESE 1 command (standard
event register).
• Send your programming command string, and place the *OPC
(operation complete) command as the last command.
• Use a serial poll to check to see when bit 5 (standard event) is set in the
status byte summary register. You could also configure the meter for an
SRQ interrupt by sending *SRE 32 (status byte enable register, bit 5).
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How to Use the Message Available Bit (MAV)
You can use the status byte “message available” bit (bit 4) to determine
when data becomes available to read into your bus controller. The meter
sets bit 4 when the first reading trigger occurs (which can be
TRIGger:SOURce:IMMediate). The meter subsequently clears bit 4
only after all messages have been read from the output buffer.
The message available (MAV) bit can only indicate when the first reading
is available following a READ? command. This can be helpful if you do not
know when a trigger event such as BUS or EXTernal will occur.
The MAV bit is set only after all specified measurements have completed
when using the INITiate command followed by FETCh?. Readings are
placed in the meter’s internal memory when using INITiate. Sending
the FETCh? command transfers readings (stored in internal memory
by the INITiate command) to the meter’s output buffer. Therefore, the
MAV bit can only be set after all measurements have been completed.

Using *OPC to Signal When Data is in the Output Buffer
Generally, it is best to use the “operation complete” bit (bit 0) in the
standard event register to signal when a command sequence is
completed. This bit is set in the register after an *OPC command has been
executed. If you send *OPC after a command which loads a message in
the meter’s output buffer (either reading data or query data), you can use
the operation complete bit to determine when the message is available.
However, if too many messages are generated before the *OPC command
executes (sequentially), the output buffer will fill and the meter will stop
taking readings.

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The Standard Event Register
The standard event register reports the following types of instrument events:
power-on detected, command syntax errors, command execution errors, self-test
or calibration errors, query errors, or when an *OPC command is executed. Any
or all of these conditions can be reported in the standard event summary bit
through the enable register. You must write a decimal value using the *ESE
(event status enable) command to set the enable register mask.
An error condition (standard event register bits 2, 3, 4, or 5) will always
record one or more errors in the meter’s error queue, with the following
exception:
A reading overload condition is always reported in both the standard
event register (bit 3) and the questionable data event register (bits 0 or
9). However, no error message is recorded in the meter’s error queue.
Read the error queue using SYSTem:ERRor?.

Bit Definitions — Standard Event Register
Bit

Decimal Value

Definition

Operation
Complete

All commands prior to and including an *OPC
command have been executed.

Not Used

Always set to 0.

Query Error

The meter tried to read the output buffer but it
was empty. Or, a new command line was
received before a previous query had been
read. Or, both the input and output buffers
are full.

Device Error

A self-test, calibration, or reading overload
error occurred.

Execution
Error

An execution error occurred (see error
numbers -211 through -230 in Chapter 5).

Command
Error

A command syntax error occurred (see error
numbers -101 through -158 in Chapter 5).

Not Used

Always set to 0.

Power On

128

Power has been turned off and on since the
last time the event register was read or
cleared.

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The standard event register is cleared when:
• You send a *CLS (clear status) command.
• You query the event register using the *ESR? (event status register)
command.
The standard event enable register is cleared when:
• You turn on the power and you have previously configured the meter
using the *PSC 1 command.
• You execute a *ESE 0 command.
The standard event enable register will not be cleared at power-on if you
have previously configured the meter using *PSC 0.

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The Questionable Data Register
The questionable data register provides information about the quality of the
meter’s measurement results. Overload conditions can be reported in the
questionable data summary bit through the enable register. You must write a
decimal value using the STATus:QUEStionable:ENABle command to set
the enable register mask.
Note: A reading overload condition is always reported in both the
standard event register (bit 3) and the questionable data event register
(bits 0, 1, or 9). However, no error message is recorded in the meter’s error
queue.
Bit Definitions — Questionable Data Register
Bit

Decimal
Value

Definition

Voltage Overload

Range overload on dc volts

Not Used

Always set to 0.

Not Used

Always set to 0.

Not Used

Always set to 0.

Temperature Overload

Range overload on temperature
measurements.

Not Used

Always set to 0.

Not Used

Always set to 0.

Not Used

128

Always set to 0.

Not Used

256

Always set to 0.

Ohms Overload

512

Range overload on 2-wire or 4-wire
Ohms

Not Used

1024

Always set to 0.

Not Used

2048

Always set to 0.

Not Used

4096

Always set to 0.

Not Used

8192

Always set to 0.

Not Used

16384

Always set to 0.

Not Used

32768

Always set to 0.

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The questionable data event register is cleared when:
• You execute a *CLS (clear status) command.
• You query the event register using STATus:QUEStionable:EVENt?.
The questionable data enable register is cleared when:
• You turn on the power (*PSC does not apply).
• You execute the STATus:PRESet command.
• You execute the STATus:QUEStionable:ENABle 0 command.

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The Operational Status and Condition Registers
The operation status register provides information about the operation of
the meter. Bits in the operational status event register are latched from
changes in the bits in the operational status condition register.
The meter only uses a single bit (bit 8) in these registers. This bit
indicates the settling state of the digital filter. If the digital filter is
enabled, bit 8 is set to 1 to indicate that the filter has settled. See page 57
for information about the operation of the digital filter.
You can read the operational status condition register to determine the
digital filter state on a per measurement basis. You can read the
operational status event register to determined if the digital filter ever
settled. The digital filter count can be reset based upon input signal
levels. See page 57.
If you need to know the digital filter state for a given measurement, use
the condition register (STATus:OPERation:CONDition?). This bit
changes with each measurement. Changes to this bit are latched in the
operational status event register and so the event register bit only
indicates if the filter ever settled.

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Bit Definitions — Operational Status Register
Bit
0
1
↓
7
8
9
↓
15

Decimal Value

Not Used
↓

Filter Settled
Not Used
↓

Definition
Always set to 0
↓

256

Digital filter is settled.
Always set to 0.
↓

The operational status event register is cleared when:
• You execute a *CLS (clear status) command.
• You query the event register using STATus:OPERation:EVENt?.
The operational status enable register is cleared when:
• You turn on the power (*PSC does not apply).
• You execute the STATus:PRESet command.
• You execute the STATus:OPERation:ENABle 0 command.

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Status Reporting Commands

Status Reporting Commands
SYSTem:ERRor?

This command queries the questionable status condition register. The
meter returns a decimal value which corresponds to the binary-weighted
sum of all bits set in the register.
STATus:QUEStionable:ENABle

This command enables bits in the Questionable Data enable register. The
selected bits are then reported to the Status Byte.
STATus:QUEStionable:ENABle?

This command queries the Questionable Data enable register. The meter
returns a binary-weighted decimal representing the bits set in the enable
register.
STATus:QUEStionable:EVENt?

This command queries the Questionable Data event register. The meter
returns a decimal value which corresponds to the binary-weighted sum of
all bits set in the register.
STATus:OPERation:CONDition?

This command queries the operational status condition register. The
meter returns a decimal value which corresponds to the binary-weighted
sum of all bits set in the register. Only bit 8 (decimal 256) is used
(indicates the digital filter has settled).
STATus:OPERation:ENABle

This command enables bits in the Questionable Data enable register. The
selected bits are then reported to the Status Byte.
STATus:OPERation:ENABle?

This command queries the Questionable Data enable register. The meter
returns a binary-weighted decimal representing the bits set in the enable
register.

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STATus:OPERation:EVENt?

This command queries the Questionable Data event register. The meter
returns a decimal value which corresponds to the binary-weighted sum of
all bits set in the register. Only bit 8 (decimal 256) is used and latches
the digital filter settled state of the condition register.
STATus:PRESet

This command clears all bits in the Questionable Data enable and
Operational Status enable registers.
*CLS

This command clears the Status Byte summary register and all event
registers.
*ESE

This command enables bits in the Standard Event enable register. The
selected bits are then reported to the Status Byte.
*ESE?

This command queries the Standard Event enable register. The meter
returns a decimal value which corresponds to the binary-weighted sum of
all bits set in the register.
*ESR?

This command queries the Standard event register. The meter returns a
decimal value which corresponds to the binary-weighted sum of all bits
set in the register.
*OPC

This command sets the “operation complete” bit (bit 0) in the Standard
Event register after the command is executed.
*OPC?

This command returns “1” to the output buffer after the command is
executed.

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*PSC {0 | 1}

(Power-on status clear.) This command clears the Status Byte and
Standard Event register enable masks when power is turned on (*PSC
1). When *PSC 0 is in effect, the Status Byte and Standard Event
register enable masks are not cleared when power is turned on.
[non-volatile memory]
*PSC?

This command queries the power-on status clear setting.
Returns “0” (*PSC 0) or “1” (*PSC 1).
*SRE

This command enables bits in the Status Byte enable register.
*SRE?

This command queries the Status Byte enable register. The meter
returns a decimal value which corresponds to the binary-weighted sum of
all bits set in the register.

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Calibration Commands

Calibration Commands
See the Service Guide for a more detailed description of the meter’s
calibration procedures.
CALibration?

This command performs a calibration using the specified calibration
value (CALibration:VALue command).
CALibration:COUNt?

This command queries the meter to determine the number of times it has
been calibrated. Since the value increments by one for each calibration
point, a complete calibration increases the value by several counts.
[non-volatile memory]
CALibration:ICURrent?

This command begins an injected current calibration. The query returns
+0 if the calibration was successful and a +1 if the calibration failed.
CALibration:OUTPut {ZERO | GAIN}

This command sets the Chart Output (Analog Output) to either 0V or 1V
output for calibration purposes. Use the CALibration:VALue and
CALibration? commands to set the values and perform the calibration.
CALibration:OUTPut?

This command query returns "ZERO" or "GAIN" .
CALibration:SECure:CODE

This command enters a new security code. To change the security code,
first unsecure the meter using the old security code. Then, enter the new
code. The calibration code may contain up to 11 characters.
[non-volatile memory]
CALibration:SECure:STATe {OFF | ON},

This command unsecures or secures the meter for calibration. The
calibration code may contain up to 11 characters. [non-volatile memory]
CALibration:SECure:STATe?

This command queries the secured state of the meter.
Returns “0” (OFF) or “1” (ON).

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CALibration:STRing

This command records calibration information about your meter. For
example, you can store such information as the last calibration date or
the next calibration due date. The calibration message may contain up to
40 characters. [non-volatile memory]
CALibration:STRing?

This command queries the calibration message and return a quoted
string.
CALibration:VALue

This command specifies the value of the known calibration signal used by
the calibration procedure.
CALibration:VALue?

This command queries the present calibration value.

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RS-232 Interface Configuration

RS-232 Interface Configuration
See also “Remote Interface Configuration,” on page 101 in chapter 3.
You connect the meter to the RS-232 interface using the 9-pin (DB-9)
serial connector on the rear panel. The meter is configured as a DTE
(Data Terminal Equipment) device. For all communications over the
RS-232 interface, the meter uses two handshake lines: DTR (Data
Terminal Ready) on pin 4 and DSR (Data Set Ready) on pin 6.
The following sections contain information to help you use the meter over
the RS-232 interface. The programming commands for RS-232 are listed
beginning on page 182.

RS-232 Configuration Overview
Configure the RS-232 interface using the parameters shown below. Use
the front-panel I/O MENU to select the baud rate, parity, and number of
data bits (see page 101 for more information).
• Baud Rate:

300, 600, 1200, 2400, 4800, or 9600 baud (factory setting)

• Parity and Data Bits: None / 8 data bits (factory setting)
Even / 7 data bits, or
Odd / 7 data bits
• Number of Start Bits 1 bit (fixed)
• Number of Stop Bits

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RS-232 Interface Configuration

RS-232 Data Frame Format
A character frame consists of all the transmitted bits that make up a
single character. The frame is defined as the characters from the start bit
to the last stop bit, inclusively. Within the frame, you can select the baud
rate, number of data bits, and parity type. The meter uses the following
frame formats for seven and eight data bits.

Connection to a Computer or Terminal
To connect the meter to a computer or terminal, you must have the
proper interface cable. Most computers and terminal are DTE (Data
Terminal Equipment) devices. Since the meter is also a DTE device, you
must use a DTE-to-DTE interface cable. These cables are also called
null-modem, modem-eliminator, or crossover cables.
The interface cable must also have the proper connector on each end and the
internal wiring must be correct. Connectors typically have 9 pins (DB-9
connector) or 25 pins (DB-25 connector) with a "male" or "female" pin
configuration. A male connector has pins inside the connector shell and a
female connector has holes inside the connector shell.
If you cannot find the correct cable for your configuration, you may have to
use a wiring adapter. If you are using a DTE-to-DTE cable, make sure the
adapter is a "straight-through" type. Typical adapters include gender
changers, null-modem adapters, and DB-9 to DB-25 adapters.

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RS-232 Interface Configuration

Refer to the cable and adapter diagrams below to connect the meter to most
computers or terminals. If you configuration is different than those described,
order the 34399A Adapter Kit. This kit contains adapters for connection
to other computers, terminals, and modems. Instructions and pin diagrams
are included with the adapter kit.
DB-9 Serial Connection If your computer or terminal has a 9-pin serial
port with a male connector, use the null-modem cable included with the
34398A Cable Kit. This cable has a 9-pin female connector on each end.
The cable pin diagram is shownbelow.

DB-25 Serial Connection If your computer or terminal has a 25-pin serial
port with a male connector, use the null-modem cable and 25-pin adapter
included with the 34398A Cable Kit. The cable pin diagram is shown below.

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RS-232 Interface Configuration

Connection to a Printer
To connect to a printer you must use a DTE to DCE (Data Communications
Equipment) cable.

GPIB address to 31
Set the meter to the TALK ONLY mode by setting the HP-IB
from the front panel. Then set the RS-232 interface as the active interface.
See pages 187 and 189.

DTR / DSR Handshake Protocol
The meter is configured as a DTE (Data Terminal Equipment) device and
uses the DTR (Data Terminal Ready) and DSR (Data Set Ready) lines of
the RS-232 interface to handshake. The meter uses the DTR line to send
a hold-off signal. The DTR line must be TRUE before the meter will
accept data from the interface. When the meter sets the DTR line
FALSE, the data must cease within 10 characters.
To disable the DTR/DSR handshake, do not connect the DTR line and tie
the DSR line to logic TRUE. If you disable the DTR/DSR handshake, also
select a slower baud rate (300, 600, or 1200 baud) to ensure that the data
is transmitted correctly.

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RS-232 Interface Configuration

The meter sets the DTR line FALSE in the following cases:
1

When the meter’s input buffer is full (when approximately 100 characters
have been received), it sets the DTR line FALSE (pin 4 on the RS-232
connector). When enough characters have been removed to make space in
the input buffer, the meter sets the DTR line TRUE, unless the second
case (see below) prevents this.

When the meter wants to "talk" over the interface (which means that it
has processed a query) and has received a message
terminator, it will set the DTR line FALSE. This implies that once a
query has been sent to the meter, the controller should read the response
before attempting to send more data. It also means that a
must terminate the command string. After the response has been output,
the meter sets the DTR line TRUE again, unless the first case (see above)
prevents this.
The meter monitors the DSR line to determine when the controller is
ready to accept data over the interface. The meter monitors the DSR line
(pin 6 on the RS-232 connector) before each character is sent. The output
is suspended if the DSR line is FALSE. When the DSR line goes TRUE,
transmission will resume.
The meter holds the DTR line FALSE while output is suspended. A form
of interface deadlock exists until the controller asserts the DSR line
TRUE to allow the meter to complete the transmission. You break the
interface deadlock by sending the character, which clears the
operation in progress and discards pending output (this is equivalent the
the IEEE-488 device clear action).

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RS-232 Interface Configuration

RS-232 Troubleshooting
Here are a few things to check if you are having problems using the
RS-232 interface. If you need additional help, refer to the documentation
that came with your computer.
• Verify that the meter and your computer are configured for the same
baud rate, parity, and number of data bits. Make sure that your
computer is set up for 1 start bit and 2 stop bits (these values are fixed
on the meter).
• Make sure to execute the SYSTEM:REMOTE command to place the
meter in the REMOTE mode.
• Verify that you have connected the correct interface cable and
adapters. Even if the cable has the proper connectors for your system,
the internal wiring may not be correct. The 34398A Cable Kit can
be used to connect the meter to most computers or terminals.
• Verify that you have connected the interface cable to the correct serial
port on your computer (COM1, COM2, etc).

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RS-232 Interface Commands

RS-232 Interface Commands
SYSTem:LOCal

This command places the meter in the local mode during RS-232
operation. All keys on the front panel are fully functional.
SYSTem:REMote

This command places the meter in the remote mode during RS-232
operation. All keys on the front panel except the LOCAL key are
disabled. You MUST send this command before any other RS-232
command can be received.
SYSTem:RWLock

This command places the meter in the remote mode during RS-232
operation. All keys on the front panel are disabled, including the LOCAL
key.

Caution

Sending or receiving data over the RS-232 interface when not configured
for REMOTE operation can cause unpredictable results. Always make
sure the meter is configured for remote operation when using the RS-232
interface.

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An Introduction to the SCPI Language

An Introduction to the SCPI Language
Standard Commands for Programmable Instruments (SCPI) defines how
you communicate with an instrument from a bus controller. The SCPI
language uses a hierarchical structure similar to the file systems used by
many bus controllers. The command “tree” is organized with root-level
commands (also called “subsystems”) positioned at the top, with multiple
levels below each root-level command. You must specify the complete
path to execute the individual lower-level commands.
Using a Colon (:) When a colon is the first character of a command
keyword, it indicates that the next command mnemonic is a root-level
command. When a colon is inserted between two command mnemonics,
the colon moves the path down one level in the present path (for the
specified root-level command) of the command tree. You must separate
command mnemonics from each other using a colon. You can omit the
leading colon if the command is the first of a new program line.
Using a Semicolon (;) Use a semicolon to separate two commands
within the same command string. The semicolon does not change the
present path specified. For example, the following two statements are
equivalent.

:TRIG:DELAY 1;:TRIG:COUNT 10
:TRIG:DELAY 1;COUNT 10
Using a Comma (,) If a command requires more than one parameter,
you must separate adjacent parameters using a comma.
Using Whitespace You must use whitespace characters, [tab], or
[space] to separate a parameter from a command keyword. Whitespace
characters are generally ignored only in parameter lists.

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An Introduction to the SCPI Language

Using “ ? ” Commands The bus controller may send commands at any
time, but a SCPI instrument may only send responses when specifically
instructed to do so. Only query commands (commands that end with
a “?”) will instruct the instrument to send a response message. Queries
return either measured values or internal instrument settings.

Caution

Using “ * ” Commands Commands starting with a “ * ” are called
common commands. They are required to perform the identical function
for all instruments that are compliant with the IEEE-488.2 interface
standard. The “ * ” commands are used to control reset, self-test, and
status operations in the meter.

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An Introduction to the SCPI Language

SCPI Data Types
The SCPI language defines different data formats for use in program
messages and response messages. Instruments are flexible listeners and
can accept commands and parameters in various formats. However, SCPI
instruments are precise talkers. This means that SCPI instruments will
always respond to a particular query in a predefined, rigid format.
Numeric Parameters Commands that require numeric parameters will
accept all commonly used decimal representations of numbers including
optional signs, decimal points, and scientific notation. Special values for
numeric parameters like MAXimum, MINimum, and DEFault are also
accepted. You can also send engineering unit suffixes (M, k, or u) with
numeric parameters. If only specific numeric values are accepted, the
meter will automatically round the input numeric parameters.
Discrete Parameters Discrete parameters are used to program settings
that have a limited number of values (like BUS, IMMediate, EXTernal).
They have a short form and a long form just like command keywords. You
can mix upper-case and lower-case letters. Query responses will always
return the short form in upper-case letters.
Boolean Parameters Boolean parameters represent a single binary
condition that is either true or false. For a false condition, the meter will
accept “OFF” or “0”. For a true condition, the meter will accept “ON” or
“1”. When you query a boolean setting, the instrument will always return
“0” or “1”.
String Parameters String parameters can contain virtually any set of
ASCII characters. A string must begin and end with matching quotes;
either with a single quote or with a double quote. You can include the
quote delimiter as part of the string by typing it twice without any
characters in between.

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Input Message Terminators

Input Message Terminators
Program messages sent to a SCPI instrument must terminate with a
character. The IEEE-488 EOI (end or identify) signal is
interpreted as a character and may also be used to terminate
a message in place of the character. A
followed by a is also accepted. Many programming languages
allow you to specify a message terminator character or EOI state to be
automatically sent with each bus transaction. Message termination will
always set the current path back to the root-level.

Output Data Formats
Output data will be in one of formats shown in the table below.

Type of Output Data

Output Data Format

Non-reading queries

<80 ASCII character string

Single reading (IEEE-488)

SD.DDDDDDDDESDD

Multiple readings (IEEE-488)

SD.DDDDDDDDESDD,...,...

Single reading (RS-232)

SD.DDDDDDDDESDD

Multiple readings (RS-232)

SD.DDDDDDDDESDD,...,...
S Negative sign or positive sign
D Numeric digits
E Exponent
newline character
carriage return character

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Using Device Clear to Halt Measurements

Using Device Clear to Halt Measurements
Device clear is an IEEE-488 low-level bus message which can be used to
halt measurements in progress. Different programming languages and
IEEE-488 interface cards provide access to this capability through their
own unique commands. The status registers, the error queue, and all
configuration states are left unchanged when a device clear message is
received. Device clear performs the following actions.
• All measurements in progress are aborted.
• The meter returns to the trigger “idle state”.
• The meter’s input and output buffers are cleared.
• The meter is prepared to accept a new command string.
• For RS-232 operation, sending the control-C character will perform
the equivalent operations of the IEEE-488 device clear message.
The meter’s DTR (data terminal ready) handshake line will be true
following a device clear message. See “DTR / DSR Handshake
Protocol,” on page 179 for further details.

TALK ONLY for Printers
GPIB address to “31” which is the talk only mode.
You can set the meter’s HP-IB
In this mode, the meter can output readings directly to a printer without
being addressed by a bus controller. Address 31 is not a valid address if
HP-IB interface with a bus
you are operating the meter from the GPIB
controller.

GPIB address to the
If you select the RS-232 interface and then set the HP-IB
talk only address (31), the meter will send readings over the RS-232
interface when in the local mode.

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To Set the GPIB Address

To Set the GPIB
HP-IB Address
Each device on the GPIB
HP-IB (IEEE-488) interface must have a unique
address. You can set the meter’s address to any value between 0 and 31.
The address is set to “22” when the meter is shipped from the factory.
The address is displayed on the front panel when you turn on the meter.
On/Off
Shift

Turn on the front-panel menu.
A: MEAS MENU

Move across to the I/O MENU choice on this level.
F: I/O MENU

∨

Move down a level to the HP-IB ADDR command.
1: HP-IB ADDR

∨

Move down to the “parameter” level to set the address.
Use the left/right and down/up arrow keys to change the address.
∧22

Auto/Man

ENTER

ADDR

Save the change and turn off the menu.
The address is stored in non-volatile memory, and does not change when
power has been off or after a remote interface reset.

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To Select the Remote Interface

To Select the Remote Interface
GPIB (IEEE-488) interface and an
The meter is shipped with both a HP-IB
RS-232 interface. Only one interface can be enabled at a time. The GPIB
HP-IB
interface is selected when the meter is shipped from the factory. See also
“Remote Interface Selection,” on page 101.
On/Off
Shift

Turn on the front-panel menu.
A: MEAS MENU

Move across to the I/O MENU choice on this level.
F: I/O MENU

4
v

Move down a level and then across to the INTERFACE command.
2: INTERFACE

∨

Move down to the “parameter” level to select the interface.
Use the left/right arrow keys to see the interface choices. Choose from the
following: HP-IB / 488 or RS-232.
HP-IB / 488

Auto/Man

ENTER

Save the change and turn off the menu.
The interface selection is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset.
Remote Interface: you can set or query the interface using the following
commands:
SYStem
:INTerface {HPIB | RS232}
:INTerface?

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To Set the Baud Rate

To Set the Baud Rate
You can select one of six baud rates for RS-232 operation. The rate is set
to 9600 baud when the meter is shipped from the factory. See also “Baud
Rate Selection,” on page 103.
On/Off
Shift

Turn on the front-panel menu.
A: MEAS MENU

Move across to the I/O MENU choice on this level.
F: I/O MENU

∨

Move down a level and then across to the BAUD RATE command.
3: BAUD RATE

∨

Move down to the “parameter” level to select the baud rate.
Use the left/right arrow keys to see the baud rate choices. Choose from
one of the following: 300, 600, 1200, 2400, 4800, or 9600 baud.
9600

Auto/Man

ENTER

BAUD

Save the change and exit the menu.
The baud rate selection is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset.
Remote Interface: you can set or query the baud rate using the
following commands:
SYStem:COMMunicate:SERial
:BAUD
:BAUD?

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To Set the Parity

To Set the Parity
You can select the parity for RS-232 operation. The meter is configured for
even parity with 7 data bits when shipped from the factory. See also
“Parity Selection,” on page 104.
On/Off
Shift

Turn on the front-panel menu.
A: MEAS MENU

Move across to the I/O MENU choice on this level.
F: I/O MENU

∨

Move down a level and then across to the PARITY command.
4: PARITY

∨

Move down to the “parameter” level to select the parity.
Use the left/right arrow keys to see the parity choices. Choose from one of
the following: None (8 data bits), Even (7 data bits), or Odd (7 data bits).
When you set parity, you are indirectly setting the number of data bits.
EVEN:

Auto/Man

ENTER

7 BITS

Save the change and turn off the menu.
The parity selection is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset.
Remote Interface: you can set or query the parity using the following
commands:
SYStem:COMMunicate:SERial
:PARity {EVEN | ODD | NONE}
:PARity?

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To Select the Programming Language

To Select the Programming Language
You can select one of three language to program the meter from the
selected remote interface. The language is SCPI when the meter is
shipped from the factory. The languge setting is stored in non-volatile
memory and does not change with power off or reset. See also
“Programming Language Selection,” on page 105.
On/Off
Shift

Turn on the front-panel menu.
A: MEAS MENU

Move across to the I/O MENU choice on this level.
F: I/O MENU

∨

Move down a level and then across to the LANGUAGE command.
5: LANGUAGE

∨

Move down to the “parameter” level to select the language.
Choose from one of the following: SCPI or KEITHLEY:181
SCPI

Auto/Man

ENTER

Save the change and turn off the menu.
The language selection is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset.
Remote Interface: you can set the programming language using the
following commands:
SYStem:LANGuage {SCPI | 181}
L1X
(SCPI)
L2X
(Keithley 181)

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Alternate Programming Language Compatibility

Alternate Programming Language Compatibility
You can configure the 34420A to accept and execute the commands
of the the Keithley 181 meter. Remote operation will only allow you to
access the functionality of the meter language selected. You can take
advantage of the full functionality of the 34420A only through the
SCPI programming language. For more information on selecting the
alternate languages from the front panel menu, see “To Select the
Programming Language,” on the previous page.
All of the commands available for the Keithley 181 are implemented in
the 34420A, with the exception of the self-test and calibration
commands. You must always calibrate the 34420A using the SCPI
language setting.
You can use L2X to switch to the Keithley 181 language. L1X switches
back to the SCPI language. Note that once the Keithley 181 language has
been selected you must append the Keithley "end of message" terminator
(X) to any commands.
Be aware that measurement timing may be different in the alternate
language compatibility modes.

Specific Issues
You should be aware of the following differences when using the
Keithley 181 language:
• Unlike the Keithley 181, the status byte is not cleared when read
unless the SRQ bit was set.
• A significant software delay exists between the time a syntax error is
generated and the error is reported in the status byte.
• The meter will always use the next highest range than the one
requested in a Keithley command. For example, if you specify the
Keithley 2 mV range, the meter will use the 10 mV range.
• The digital filter, set to SLOW or MEDium, is used to emulate the
Keithley input filter.
• The meter is always set to 2 NPLC.
• The 34420A has a maximum input range of 100 V. Be sure the test
setup does not require a 1000 V range.
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SCPI Compliance Information

SCPI Compliance Information
The following commands are device-specific to the 34420A. They are
not included in the 1994.0 version of the SCPI standard. However, these
commands are designed with the SCPI format in mind and they follow all
of the syntax rules of the standard.
Many of the required SCPI commands are accepted by the meter but are
not described in this manual for simplicity or clarity. Most of these
non-documented commands duplicate the functionality of a command
already described in this chapter.

CALibration
:COUNt?
:OUTPut
{ ZERO | GAIN }
:OUTPut?
:SECure:CODE
:SECure:STATe
{ OFF | ON | 0 | 1 } [,]
:SECure:STATe?
returns 0 or 1
:STRing

:STRing?
CALCulate
:FUNCtion
{ SCALe | AVERage }
:FUNCtion?
:AVERage:MINimum?
:AVERage:MAXimum?
:AVERage:AVERage?
:AVERage:SDEViation?
:AVERage:PTPeak?
:AVERage:COUNt?
:SCALe:GAIN
:SCALe:GAIN?
:SCALe:OFFSet
:SCALe:OFFSet?

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INPut
:FILTer[:LPASS]:DIGital:PREcharge {ON | OFF}
:FILTer[:LPASS]:DIGital:PREcharge?
:FILTer[:LPASs]:DIGital:RESPonse { SLOW | MEDium | FAST }
:FILTer[:LPASs]:DIGital:RESPonse?
:FILTer[:LPASs]:TYPE
{ ANAlog | DIGital | BOTH }
:FILTer[:LPASs]:TYPE?
OUTPut
:REFerence:OFFSet
{ | MINimum | MAXimum }
:REFerence:OFFSet? [ MINimum | MAXimum ]
:REFerence:OFFSet:NULL [ONCE]
:REFerence:SPAN
{ | MINimum | MAXimum }
:REFerence:SPAN?
[ MINimum | MAXimum ]
:REFerence:GAIN?
:REFerence:VALue

SAMPle
:COUNt
:COUNt?

{ | MINimum | MAXimum }
[ MINimum | MAXimum ]

[SENSe:]
CURRent:BIAS:ZERO[:IMMediate]
NULL [ONCE]
NULL[:STATe]
{ OFF | ON | 0 | 1 }
NULL[:STATe]?
NULL:VALue
{ | MINimum | MAXimum }
NULL:VALue?
[SENSe:]
FRESistance | RESistance
:NULL[:STATe]
{ OFF | ON | 0 | 1 }
:NULL[:STATe]?
:NULL:VALue
{ | MINimum | MAXimum }
:NULL:VALue?
:VOLTage:LIMit[:STATe] { OFF | ON | 0 | 1 }
:VOLTage:LIMit[:STATe]?
:POWer:LIMit[:STATe]
{ OFF | ON | 0 | 1 }
:POWer:LIMit[:STATe]?
:VOLTage:LIMit:VALue { | MIN | MAX }
:VOLTage:LIMit:VALue? [ MINimum | MAXimum ]

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[SENSe:]
TEMPerature
:NULL[:STATe]
{ OFF | ON | 0 | 1 }
:NULL[:STATe]?
:NULL:VALue
{ | MINimum | MAXimum }
:NULL:VALue?
:NPLCycles
{ | MINimum | MAXimum }
:NPLCycles? [ MINimum | MAXimum ]
:TRANsducer:TYPE { DEFault | TCouple | THERmistor | FRTD}
:TRANsducer:TYPE?
:TRANsducer:TCouple:TYPE { DEFault | B|E|J|K|N|R|S|T }
:TRANsducer:TCouple:TYPE?
:TRANsducer:TCouple:RJUNction[:VALue] {|MIN| MAX}
:TRANsducer:TCouple:RJUNction[:VALue]? [MINimum | MAXimum]
:TRANsducer:TCouple:RJUNction:TYPE {FIXed, INTernal, THERmistor }
:TRANsducer:TCouple:RJUNction:TYPE?
:TRANsducer:FRTD:TYPE

:TRANsducer:FRTD:TYPE?
[SENSe:]
VOLTage[:DC]
:NULL[:STATe]
{ OFF | ON | 0 | 1 }
:NULL[:STATe]?
:NULL:VALue
{ | MINimum | MAXimum }
:NULL:VALue?
SYSTem
:INTerface[:TYPE]
:INTerface[:TYPE]?
:REMote
:RWLock
:LOCal

L1X
L2X

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Chapter 4 Remote Interface Reference
IEEE-488 Compliance Information

IEEE-488 Compliance Information
Dedicated Hardware Lines

Addressed Commands

ATN

Attention

DCL

Device Clear

IFC

Interface Clear

EOI

End or Identify

REN

Remote Enable

GET

Group Execute Trigger

SRQ

Service Request Interrupt

GTL

Go to Local

LLO

Local Lock Out

SDC

Selected Device Clear

SPD

Derial Poll disable

SPE

Serial Poll Enable

IEEE-488.2 Common Commands

*CLS
*ESE
*ESE?
*ESR?
*IDN?
*OPC
*OPC?
*PSC {0 | 1}
*PSC?

*RST
*SRE
*SRE?
*STB?
*TRG
*TST?
*WAI

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Error
Messages

Error Messages
When the front-panel ERROR annunciator turns on, one or more
command syntax or hardware errors have been detected. A record of up
to 20 errors is stored in the meter’s error queue. Errors are retrieved in
first-in- first-out (FIFO) order. See also “Error Conditions,” on page 92.
Front-Panel operation: Use the SYStem menu command:
3: ERROR

If the ERROR annunciator is on, press Shift > (Menu Recall) to read the
errors stored in the queue. The errors are listed horizontally on the
“parameter” level. The error queue is cleared when power has been off or
after a *CLS (clear status) command has been executed.
• To read the error queue from the remote interface:
SYSTem:ERRor?
Errors have the following format (the error string may contain up to
80 characters):
-113, "Undefined header"

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Chapter 5 Error Messages
Execution Errors

Execution Errors
-101

Invalid character
An invalid character was found in the command string. You may have
inserted a character such as #, $, or % in the command header or within
a parameter. Example: CONF:VOLT#DC

-102

Syntax error
Invalid syntax was found in the command string. You may have inserted
a blank space before or after a colon in the command header, or before a
comma. Example: SAMP:COUN
,1

-103

Invalid separator
An invalid separator was found in the command string. You may have
used a comma instead of a colon, semicolon, or blank space – or you may
have used a blank space instead of a comma. Example: TRIG:COUN,1
or CONF:TEMP 1000 0.1

-104

Data type error
The wrong parameter type was found in the command string. You may
have specified a number where a string was expected, or vice versa.
Example: DISP:TEXT 5.0

-105

GET not allowed
A Group Execute Trigger (GET) is not allowed within a command string.

-108

Parameter not allowed
More parameters were received than expected for the command. You may
have entered an extra parameter, or you added a parameter to a
command that does not accept a parameter. Example: READ? 10

-109

Missing parameter
Fewer parameters were received than expected for the command. You
omitted one or more parameters that are required for this command.
Example: SAMP:COUN

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Chapter 5 Error Messages
Execution Errors

-112

Program mnemonic too long
A command header was received which contained more than the
maximum 11 characters allowed. Example: CONFIGURATION:VOLT:DC

-113

Undefined header
A command was received that is not valid for this meter. You may have
misspelled the command or it may not be a valid command. If you are
using the short form of the command, remember that it may contain up
to four letters. Example: TRIGG:COUN 3

-121

Invalid character in number
An invalid character was found in the number specified for a parameter
value. Example: STAT:QUES:ENAB #B01010102

-123

Numeric overflow
A numeric parameter was found whose exponent was larger than 32,000.
Example: TRIG:COUN 1E34000

-124

Too many digits
A numeric parameter was found whose mantissa contained more than
255 digits, excluding leading zeros.

-128

Numeric data not allowed
A numeric parameter was found when a string or discrete parameter was
expected.

-131

Invalid suffix
A suffix was incorrectly specified for a numeric parameter. You may have
misspelled the suffix. Example: TRIG:DEL 0.5 SECS

-134

Suffix too long
A suffix for a numeric parameter contained too many characters.

-138

Suffix not allowed
A suffix was received following a numeric parameter which does not
accept a suffix. Example: SAMP:COUN 1 SEC (SEC is not a valid suffix).

202

Chapter 5 Error Messages
Execution Errors

-141

Invalid character data

-144

Character data too long

-148

Character data not allowed
A discrete parameter was received but a character string or a numeric
parameter was expected. Check the list of parameters to verify that you
have used a valid parameter type. Example: DISP:TEXT ON

-151

Invalid string data
An invalid character string was received. Check to see if you have
enclosed the character string in single or double quotes. Example:
DISP:TEXT ’ON
(the ending quote is missing).

-158

String data not allowed
A character string was received but is not allowed for the command.
Check the list of parameters to verify that you have used a valid
parameter type. Example: CALC:STAT ’ON’

-160 to -168

Block data errors
The meter does not accept block data.

-170 to -178

Expression errors
An incorrect expression for the channel specifier was received. The meter
does not accept mathematical expressions.

-211

Trigger ignored
A Group Execute Trigger (GET) or *TRG was received but the trigger was
ignored. Make sure the meter is in the “wait-for-trigger” state before
issuing a trigger, and make sure the correct trigger source is selected.

-213

Init ignored
An INITiate command was received but could not be executed because a
measurement was already in progress. Send a device clear to halt a
measurement in progress and place the meter in the “idle” state.

-214

Trigger deadlock
A trigger deadlock occurs when the trigger source is BUS and a READ?
command is received.

203

Chapter 5 Error Messages
Execution Errors

-221

Settings conflict
This error can be generated in one of the following situations:
You sent a CONFigure or MEASure command with autorange enabled
and with a fixed resolution. Example: CONF:VOLT:DC DEF,0.1
You turned math on (CALC:STAT ON) and then changed to a math
operation that was not valid with the present measurement function.

-222

Data out of range
A numeric parameter value is outside the valid range for the command.
Example: TRIG:COUN -3

-223

Too much data
A character string was received but could not be executed because the
string length was more than 11 characters. This error can be generated
by the CALibration:STRing and DISPlay:TEXT commands.

-224

Illegal parameter value
A discrete parameter was received which was not a valid choice for the
command. You may have used an invalid parameter choice. Example:
CALC:FUNC SCALE (SCALE is not a valid choice).

-230

Data corrupt or stale
A FETCh? command was received but internal reading memory was
empty. The reading retrieved may be invalid.

-330

Self-test failed
The meter’s complete self-test failed from the remote interface (*TST?
command). In addition to this error, more specific self-test errors are also
reported. See also “Self-Test Errors,” starting on page 208.

204

Chapter 5 Error Messages
Execution Errors

-350

Queue overflow
The error queue is full because more than 20 errors have occurred.
No additional errors are stored until you remove errors from the queue.
The error queue is cleared when power has been off, or after a *CLS
(clear status) command has been executed.

-410

Query INTERRUPTED
A command was received which sends data to the output buffer, but the
output buffer contained data from a previous command (the previous
data is not overwritten). The output buffer is cleared when power has
been off, or after a *RST (reset) command has been executed.

-420

Query UNTERMINATED
The meter was addressed to talk (i.e., to send data over the interface) but
a command has not been received which sends data to the output buffer.
For example, you may have executed a CONFigure command (which does
not generate data) and then attempted an ENTER statement to read data
from the remote interface.

-430

Query DEADLOCKED
A command was received which generates too much data to fit in the
output buffer and the input buffer is also full. Command execution
continues but all data is lost.

-440

Query UNTERMINATED after indefinite response
The *IDN? command must be the last query command within a command
string. Example: *IDN?;:SYST:VERS?

501

Isolator UART framing error

502

Isolator UART overrun error

205

Chapter 5 Error Messages
Execution Errors

511

RS-232 framing error

512

RS-232 overrun error

513

RS-232 parity error

514

Command allowed only with RS-232
There are three commands which are only allowed with the RS-232
interface: SYSTem:LOCal, SYSTem:REMote, and SYSTem:RWLock.

521

Input buffer overflow

522

Output buffer overflow

531

Insufficient memory
There is not enough memory to store the requested number of readings in
internal memory using the INITiate command. The product of the
sample count (SAMPle:COUNt) and the trigger count (TRIGger:COUNt)
must not exceed 1024 readings.

532

Cannot achieve requested resolution
The meter cannot achieve the requested measurement resolution. You
may have specified an invalid resolution in the CONFigure or MEASure
command.

540

Cannot use overload as math reference
The meter cannot store an overload reading (9.90000000E+37) as the
math reference for null measurements. The math state is turned off as a
result of this condition.

550

Command not allowed in local
The meter received a READ? command while in the local mode for RS-232
operation. You should always execute the SYSTem:REMote command
before sending other commands over the interface.

552

Command not allowed in current function

206

Chapter 5 Error Messages
Execution Errors

750

Invalid channel name
The meter received a MEAS or CONF command with an invalid channel
specifier.

810

Invalid or unsupported transducer type
An invalid transducer type was detected as a parameter.

820

Temperature out of range for specified transducer

1000

Settings conflict; voltage limit mode has been disabled
After being set to the voltage limited resistance mode, the meter received
a command that changed the settings to an mode or range not allowed.

1001

Settings conflict; power limit mode has been disabled
After being set to the low power resistance mode, the meter received a
command that changed the settings to an mode or range not allowed. For
example, after the low power mode has been enabled, a MEAS:RES
(2-wire Ohms) command is received.

207

Chapter 5 Error Messages
Self-Test Errors

Self-Test Errors
The following errors indicate failures that may occur during a self-test.
Refer to the Service Guide for more information.
601

Front panel does not respond

602

RAM read/write failed

603

A/D sync stuck

604

A/D slope convergence failed

605

Cannot calibrate rundown gain

606

Rundown gain out of range

607

Rundown too noisy

608

Serial configuration readback failed

609

DC gain x1 failed

610

DC gain x10 failed

611

DC gain x100 failed

208

Chapter 5 Error Messages
Self-Test Errors

613

Ohms 5 uA source failed

614

Ohms 10 uA source failed

615

Ohms 100 uA source failed

616

Ohms 1 mA source failed

617

Ohms 10 mA source failed

618

Ohms 20 mV voltage clamp failed

619

Ohms 100 mV voltage clamp failed

620

Ohms 500 mV voltage clamp failed

621

Low Impedance DC gain X100 failed

622

High Impedance DC gain X100 failed

623

Cannot calibrate precharge

624

Unable to sense line frequency

625

I/O processor does not respond

626

I/O processor failed self-test

627

Hardware overload comparator failed

630

Bias current DAC test failed

209

Chapter 5 Error Messages
Calibration Errors

Calibration Errors
The following errors indicate failures that may occur during a calibration.
Refer to the Service Guide for more information.
701

Cal security disabled by jumper
The calibration security feature has been disabled with a jumper inside
the meter. When applicable, this error will occur at power-on to warn you
that the meter is unsecured.

702

Cal secured
The meter is secured against calibration.

703

Invalid secure code
An invalid calibration security code was received when attempting to
unsecure or secure the meter. You must use the same security code to
unsecure the meter as was used to secure it, and vice versa. The security
code may contain up to 11 alphanumeric characters. The first character
must be a letter.

704

Secure code too long
A security code was received which contained more than 11 characters.

705

Cal aborted
A calibration in progress is aborted when you press any front-panel key,
send a device clear, or change the local/remote state of the meter.

706

Cal value out of range
The specified calibration value (CAL:VALue) is invalid for the present
function and range.

707

Cal signal measurement out of range
The specified calibration value (CAL:VALue) does not match the signal
applied to the meter.

709

No cal for this function or range
Attempt to calibrate gain on 1 mV range.

710

Full scale correction out of range

210

Chapter 5 Error Messages
Calibration Errors

720

Cal DCV offset out of range

722

Cal RES offset out of range

723

Cal FRES offset out of range

730

Precharge DAC convergence failed

731

A/D turnover correction out of range

737

Bias current selfcal failed

738

Charge compensation selfcal failed

739

Injected current selfcal failed

740

Cal checksum failed, secure state

741

Cal checksum failed, string data

742

Cal checksum failed, DCV corrections

743

Cal checksum failed, Low Power FRES corrections

744

Cal checksum failed, RES corrections

745

Cal checksum failed, FRES corrections

746

Cal checksum failed, Low Voltage FRES corrections

747

Cal checksum failed, HP-IB address

748

Cal checksum failed, internal data

211

Application
Programs

Application Programs
This chapter contains several remote interface application programs to
help you develop programs for your measurement application. Chapter 4,
"Remote Interface Reference", starting on page 115, lists the syntax for
the SCPI (Standard Commands for Programmable Instruments)
commands available to program the the meter.
This chapter is divided into the following sections:
•
•
•
•
•

HP BASIC Language Programs, page 215
RS-232 Operations with QuickBASIC, page 222
Microsoft® Visual Basic Programs, page 223
C Language Programs, page 230
Microsoft® Excel Macro Example, page 242

214

Chapter 6 Application Programs
HP BASIC Language Programs

HP BASIC Language Programs
All of the HP BASIC examples in this chapter were developed and tested
on an HP 9000 Series 300 controller. Each device on the GPIB
HP-IB
(IEEE-488) interface must have a unique address. You can set the
meter’s address to any value between 0 and 30. The current address is
momentarily displayed on the front panel when you turn on the meter.
The GPIB
HP-IB (IEEE-488) address is set to "22" when the meter is shipped
GPIB address
from the factory. The examples in this chapter assume a HP-IB
of 22. When sending a remote interface command, you append this
address to the GPIB
HP-IB interface’s select code (normally 7). Therefore, with
an address of 22 and a select code of 7, the combination is "722".

GPIB Program Example 1
HP BASIC / HP-IB
This example demonstrates the general sequence of programming and
the use of the MEASure? command to set and obtain a 4-wire Ohms
measurement.
10

! This program configures the meter for a 4-wire ohms measurement on

! Channel 1 using the MEAS command.

REAL Value,Rdg

! Dimension real variables

CLEAR 7

! Clear interface - send "device clear"

ASSIGN @Meter TO 722

! Assign I/O path to address 722

OUTPUT @Meter;"*RST"

! Reset the meter

100

OUTPUT @Meter;"*OPC?"

! Send "1" to output buffer when reset complete

110

ENTER @Meter;Value

! Enter value

120 !
130 ! Select 4-wire ohms on the 10 ohm range with the least resolution;
140 !
150

OUTPUT @Meter;"MEAS:FRES? 10,MAX"

160

ENTER @Meter;Rdg

! Enter reading

170

PRINT Rdg

! Print reading

180

END

215

Chapter 6 Application Programs
HP BASIC Language Programs

HP BASIC / GPIB
HP-IB Program Example 2
This program example demonstrates how two input channels can be
independently configured and used.

! This program configures the meter for voltage measurements on two

! input channels. The channels are set to different ranges and

! resolutions to show the independence of the settings for each channel.

REAL Rdg_ch1,Rdg_ch2,Null_ch1,Null_ch2

! Dimension variables

CLEAR 7

! Clear interface - send "device clear"

ASSIGN @Meter TO 722

! Assign I/O path to address 722

OUTPUT @Meter;"*RST"

! Reset the meter

100

OUTPUT @Meter;"*OPC?"

! Send "1" to output buffer when complete

110

ENTER @Meter;Value

! Enter value

120 !
130 ! Configure channel 1 for dc volts, 1 volt range with 10 mV resolution
140 ! Configure channel 2 for dc volts, 1 mV range with least resolution
150

OUTPUT @Meter;"CONF:VOLT:DC 1,0.01,(@FRON1);:CONF:VOLT:DC 0.001,MAX,(@FRON2)"

160 !
170

OUTPUT @Meter;"ROUT:TERM FRON1"

! Select channel 1

180

OUTPUT @Meter;"READ?"

! Take reading; send to output buffer

190

ENTER @Meter;Rdg_ch1

! Enter reading

200

210

OUTPUT @Meter;"SENS1:VOLT:DC:NULL ON"

! Enable null on channel 1

220

OUTPUT @Meter;"SENS1:VOLT:DC:NULL:VAL ";Rdg_ch1

! Store value in register

230 !
240

OUTPUT @Meter;"READ?"

! Take nulled reading; send to output buffer

250

ENTER @Meter;Null_ch1

! Enter nulled reading

216

Chapter 6 Application Programs
HP BASIC Language Programs

... continued

260
270

PRINT ;Null_ch1

! Print nulled reading

280

OUTPUT @Meter;"ROUT:TERM FRON2"

! Select channel 2

290

OUTPUT @Meter;"READ?"

! Take reading; send to output buffer

300

ENTER @Meter;Rdg_ch2

! Enter reading

310 !
320

OUTPUT @Meter;"SENS2:VOLT:DC:NULL ON"

! Enable null on channel 2

330

OUTPUT @Meter;"SENS2:VOLT:DC:NULL:VAL ";Rdg_ch2 ! Store value in register

340 !
350

OUTPUT @Meter;"READ?"

! Take nulled reading; send to output buffer

360

ENTER @Meter;Null_ch2

! Enter nulled reading

370

PRINT Null_ch2

! Print nulled reading

380 !
390

END

217

Chapter 6 Application Programs
HP BASIC Language Programs

GPIB Program Example 3
HP BASIC / HP-IB
This program example demonstrates the use of an SRQ to indicate when
measurements are complete. The meter is set to use external triggering.
Math scaling is also demonstrated.

! This program configures the meter to make multiple dc voltage measurements

! using an external trigger. The "Operation Complete" bit in the Standard

! Event Register is used to determine when the trigger is received and

! generates an SRQ. This program also shows the use of math scaling.

INTEGER Value,Task

! Dimension variables

CLEAR 7

! Clear interface - send "device clear"

ASSIGN @Meter TO 722

! Assign I/O path to address 722

100

COM @Meter

! Use same address in subprogram

110

OUTPUT @Meter;"*RST"

! Reset the meter

120

OUTPUT @Meter;"*CLS"

! Clear status registers

130

OUTPUT @Meter;"*OPC?"

! Send "1" to output buffer when reset complete

140

ENTER @Meter;Value

! Enter value

150 !
160 ! Configure the Status Register system to generate an SRQ when the
170 ! "Operation Complete" bit is set in the Standard Event Register
180 !
190

OUTPUT @Meter;"*SRE 32"

200
210

! Enable "Standard Event" bit in Status Byte
! to pull the IEEE-488 SRQ line

OUTPUT @Meter;"*ESE 1"

220

! Enable "Operation Complete" to set
! "Standard Event" bit in Status Byte

218

Chapter 6 Application Programs
HP BASIC Language Programs

... continued

230 !
240 ! Configure the GPIB interrupt system to generate an SRQ
250 !
260

Hpib=7

! HP-IB select code is "7"

270

ON INTR Hpib CALL Read_data

! Call subprogram when operation complete

280

Mask=2

! Bit 1 is SRQ

290

ENABLE INTR Hpib;Mask

! Enable SRQ to interrupt program

310

OUTPUT @Meter;"SENS:FUNC ’VOLT:DC’"

! Select dc volts on channel 1 (default)

320

OUTPUT @Meter;"SENS:VOLT:DC:RANG 10" ! Select 10 volt range

330

OUTPUT @Meter;"SENS:VOLT:DC:NPLC 10" ! Select 10 power line cycles

340

OUTPUT @Meter;"CALC:FUNC SCAL"

! Select math scaling function

350

OUTPUT @Meter;"CALC:STAT ON"

! Turn math scaling on

360

OUTPUT @Meter;"CALC:SCAL:GAIN 0.001" ! Set the gain value (1 mV)

370

OUTPUT @Meter;"CALC:SCAL:OFFS 0.5"

! Set the offset value (50 mV)

390

OUTPUT @Meter;"SAMP:COUN 5"

! Take 5 reading per trigger

400

OUTPUT @Meter;"TRIG:SOUR EXT"

! Select external trigger source

410

OUTPUT @Meter;"INIT"

! Initiate measurement, wait for trigger,

300 !

380 !

420
430
440

! and send readings to internal memory
OUTPUT @Meter;"*OPC"

! Set "Operation Complete" bit in

! Standard Event Register when complete

219

Chapter 6 Application Programs
HP BASIC Language Programs

... continued

450 !
460 ! Wait for "Operation Complete"
470 !
480

Task=1

490

WHILE Task=1

500

DISP "Reading..."

510

WAIT .5

520

DISP " "

530

WAIT .5

540

END WHILE

550 !
560

OFF INTR Hpib

570

END

! Disable interrupts

580 !
590 ! After SRQ is generated, transfer the readings to the output buffer and print
600 !
610

SUB Read_data

! Subprogram is called after INIT complete and trigger is received

620

DIM Rdgs(1:5)

! Dimension array for readings

630

COM @Meter

! Use same address as in main program

640

OUTPUT @Meter;"FETC?"

! Transfer readings to output buffer

650

ENTER @Meter;Rdgs(*)

! Enter readings

660

PRINT Rdgs(*)

! Print readings

670

STOP

680

SUBEND

220

Chapter 6 Application Programs
HP BASIC Language Programs

HP BASIC / GPIB
HP-IB Program Example 4
This program example demonstrates how data can be formatted and put
in a file. The program also shows how to use math operations (stats) to
average data.
10

! RE-SAVE "EXAMP"

CONFIGURE SAVE ASCII OFF

! This program will generate a DOS file, in the file will be three columns each

! separated by the Separator$ specified below, The columns are:

! Reading Number,Time,DMM Reading

! This file may be imported into a spreadsheet for analysis

Separator$=","

!What separates the columns

Num_points=25

!How many measurements (rows in file)

100

Address=722

!34420A HPIB address

110

Range=1.E-3

!34420A Range

120

Nplc=1

!34420A Integration time

130

Num_samples=20

!How many samples per measurement

140

ALLOCATE Results$(1:Num_points)[80],Filename$[80]

150

Filename$="B:/EXAMP_DAT"

160

Setup_meter(Address,Range,Nplc,Num_samples)

170

FOR I=1 TO Num_points

180

DISP "Getting "&VAL$(I)&" of "&VAL$(Num_points)&" measurements"

190
OUTPUT Results$(I) USING "4D,A,8A,A,SD.12D";I,Separator$,TIME$(TIMEDATE),Separator$,
FNGetdata(Address)
200

NEXT I

210

ON ERROR GOTO Save_file

220

CREATE Filename$,1

230 Save_file: ASSIGN @File TO Filename$
240

OUTPUT @File;Results$(*)

250

ASSIGN @File TO *

260

DISP "Done"

270

END

221

Chapter 6 Application Programs
HP BASIC Language Programs

... continued
280

!************************************************************************

290 Getdata: DEF FNGetdata(Address)
300

REPEAT

310

UNTIL BIT(SPOLL(Address),5)

!Bit 5 is Standard Event Reg

320

OUTPUT Address;"*CLS"

!Clear status

330

OUTPUT Address;"CALC:AVER:AVER?"

!Get average

340

ENTER Address;Result

350

OUTPUT Address;"CALC:FUNC AVER"

360

OUTPUT Address;"*OPC"

370

OUTPUT Address;"INIT"

380

RETURN Result

!Resets average to 0

!Start taking next readings

390

FNEND

400

!************************************************************************

410 Setup_meter: SUB Setup_meter(Address,Range,Nplc,Num_samples)
420

OUTPUT Address;"*CLS"

!Clear Status

430

OUTPUT Address;"SENSE:VOLTAGE:RANGE "&VAL$(Range) !

440

OUTPUT Address;"INPUT:FILTER:STATE OFF"

450

OUTPUT Address;"SENSE:VOLTAGE:DC:NPLC "&VAL$(Nplc) !

460

OUTPUT Address;"CALC:FUNC AVER"

!Take average of

470

OUTPUT Address;"CALC:STATE ON"

!Num_samples

480

OUTPUT Address;"SAMPLE:COUNT "&VAL$(Num_samples)

490

OUTPUT Address;"TRIGGER:SOURCE IMM"

500

OUTPUT Address;"*ESE 1"

!Enable register mask

510

OUTPUT Address;"*OPC"

!for *OPC

520

OUTPUT Address;"INIT"

530

SUBEND

540

!************************************************************************

222

Chapter 6 Application Programs
RS-232 Operations with QuickBASIC

RS-232 Operations with QuickBASIC
This program example uses QuickBASIC and the 82335B
GPIB Interface Card and command library for IBM® PC compatibles.
HP-IB
CLS
LOCATE 1, 1
DIM cmd$(100), resp$(1000)
’ Set up serial port for 9600 baud, even parity, 7 bits;
’ Ignore Request to Send Carrier Detect; Send line feed;
’ enable parity check, reserve 1000 bytes for input buffer
’
OPEN "com1:9600,e,7,2,rs,cd,lf,pe" FOR RANDOM AS #1 LEN = 1000
’
’ Put the meter into remote operation mode
PRINT #1, "SYST:REM"
’
’ Query the meter’s id string
’ PRINT #1, "*IDN?"
LINE INPUT #1, resp$
PRINT "*IDN? returned: ", resp$
’
’ Get the SCPI revision number
PRINT #1, "SYST:VERS?"
LINE INPUT #1, resp$
PRINT "SYST:VERS returned: ", resp$
’
’ Send a message to the meter’s display

PRINT #1, "DISP:TEXT ’HP 34420A’ "
’
’ Configure the meter for dc voltage measurements, 10 V range,
’ 0.1 V resolution, take 4 readings
PRINT #1, "CONF:VOLT:DC 10, 0.1, ;:SAMP:COUN 4"
’ Trigger the readings and get the results
PRINT #1, "READ?"
LINE INPUT #1, resp$
PRINT "READ? returned: ", resp$
END

223

Chapter 6 Application Programs
Microsoft Visual Basic Language Program

Microsoft Visual Basic Language Program
This example was created in Microsoft® Visual Basic for Windows. The
GPIB control library. You must set up
example uses the 82335B and HP-IB
the GLOBAL.BAS to provide access to the HP-IB.DLL. The
Control Libraries.
GLOBAL.BAS file is included with the Agilent
Hewlett-Packard
control libraries.
In addition to the global declarations, the subroutine check_srq is also
included in the GLOBAL.BAS file.

GPIB (IEEE-488) address is set to "22" when the meter is shipped
The HP-IB
GPIB address
from the factory. The examples in this chapter assume a HP-IB
of 22. When sending a remote interface command, you append this
GPIB interface’s select code (normally 7). Therefore, with
address to the HP-IB
an address of 22 and a select code of 7, the combination is "722".

Sub Command1_Click ()
Rem Set up interface variables
isc& = 7
device& = isc& * 100 + 22
swap% = 2
max% = 4000 * swap%
act% = 0
max1% = 50
TimeVal# = 10#
Rem Clear out text boxes
Text1.Text
Text2.Text
Text3.Text
Text4.Text

=
=
=
=

""
""
""
""

Rem Set up the meter
errnum% = HpibOpen(isc&, hHpib%)
Call check_srq
errnum% = HpibReset(hHpib%, isc&)
Call check_srq
errnum% = HpibTimeout(hHpib%, isc&, TimeVal#)
Call check_srq
rst$ = "*RST; *CLS; *SRE 32; *ESE 60"
errnum% = HpibOutputS(hHpib%, device&, rst$, Len(rst$))
Call check_srq

224

Chapter 6 Application Programs
Microsoft Visual Basic Language Program

... continued
Rem Channel 1 measurement
conf1$ = "CONF:VOLT:DC 1,0.01,(@FRON1)"
errnum% = HpibOutputS(hHpib%, device&, conf1$, Len(conf1$))
Call check_srq
conf2$ = "CONF:VOLT:DC 0.001,MAX,(@FRON2); "
errnum% = HpibOutputS(hHpib%, device&, conf2$, Len(conf2$))
Call check_srq
route$ = "ROUT:TERM FRONT1"
errnum% = HpibOutputS(hHpib%, device&, route$, Len(route$))
’ Take the reading and check for errors.
reed$ = "READ?"
errnum% = HpibOutputS(hHpib%, device&, reed$, Len(reed$))
errnum% = HpibEnter(hHpib%, device&, reading1!)
Text1.Text = Str$(reading1!)
Call check_srq
Rem Channel 2 measurement
route$ = "ROUT:TERM FRONT2"
errnum% = HpibOutputS(hHpib%, device&, route$, Len(route$))
Call check_srq
’ Take the reading and check for errors.
errnum% = HpibOutputS(hHpib%, device&, reed$, Len(reed$))
errnum% = HpibEnter(hHpib%, device&, reading2!)
Text2.Text = Str$(reading2!)
Call check_srq
Rem Nulled Channel 1 Measurement
null_stmt$ = "SENS1:VOLT:DC:NULL ON"
errnum% = HpibOutputS(hHpib%, device&, null_stmt$, Len(null_stmt$))
Call check_srq

null_stmt$ = "SENS1:VOLT:DC:NULL " + Str$(reading1!)
errnum% = HpibOutputS(hHpib%, device&, null_stmt$, Len(null_stmt$))
Call check_srq
errnum% = HpibOutputS(hHpib%, device&, reed$, Len(reed$))
errnum% = HpibEnter(hHpib%, device&, reading!)
Text3.Text = Str$(reading!)
Call check_srq

225

Chapter 6 Application Programs
Microsoft Visual Basic Language Program

... continued
Rem Nulled Channel 2 Measurement
null_stmt$ = "SENS2:VOLT:DC:NULL ON"
errnum% = HpibOutputS(hHpib%, device&, null_stmt$, Len(null_stmt$))
Call check_srq
null_stmt$ = "SENS2:VOLT:DC:NULL " + Str$(reading2!)
errnum% = HpibOutputS(hHpib%, device&, null_stmt$, Len(null_stmt$))
Call check_srq
errnum% = HpibOutputS(hHpib%, device&, reed$, Len(reed$))
errnum% = HpibEnter(hHpib%, device&, reading!)
Text4.Text = Str$(reading!)
Call check_srq
Rem Close the instrument
errnum% = HpibClose(hHpib%)
End Sub
Sub Command2_Click ()
End
End Sub
Sub Command3_Click ()
Rem Set up interface variables
isc& = 7
device& = isc& * 100 + 22
swap% = 2
max% = 4000 * swap%
act% = 0
max1% = 50
TimeVal# = 10#
Rem Set up Measurement variables
Funct$ = "SCAL"
Trig_src$ = "EXT"
range% = 10
nplc% = 100
Gain% = .001
Offset% = .5
samp_count% = 100
ReDim Readings!(samp_count%)
Rem Clear out text boxes
Text1.Text
Text2.Text
Text3.Text
Text4.Text

226

=
=
=
=

""
""
""
""

Chapter 6 Application Programs
Microsoft Visual Basic Language Program

... continued
Rem Set up the meter
errnum% = HpibOpen(isc&, hHpib%)
Call check_srq
errnum% = HpibReset(hHpib%, isc&)
Call check_srq
errnum% = HpibTimeout(hHpib%, isc&, TimeVal#)
Call check_srq
rst$ = "*RST; *CLS; *SRE 32; *ESE 61"
errnum% = HpibOutputS(hHpib%, device&, rst$, Len(rst$))
Call check_srq
Rem Measurement Setup
quote$ = Chr$(34)
cmd$ = "SENS:FUNC " + quote$ + "VOLT:DC" + quote$
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq
cmd$ = "SENS:VOLT:DC:RANG " + Str$(range%)
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq
cmd$ = "SENS:VOLT:DC:NPLC " + Str$(nplc%)
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq
cmd$ = "CALC:FUNC " + Funct$
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq
cmd$ = "CALC:STAT ON"
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq
cmd$ = "CALC:SCAL:GAIN " + Str$(Gain%)
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq

cmd$ = "CALC:SCAL:OFFS " + Str$(Offset%)
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq
cmd$ = "SAMP:COUN " + Str$(samp_count%)
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq
cmd$ = "TRIG:SOUR " + Trig_src$
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq

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Chapter 6 Application Programs
Microsoft Visual Basic Language Program

... continued
Rem Need to set timeout so that sampling and averaging can complete.
Rem This assumes triggers occur at a rate high enough to be a
Rem negligible factor.
errnum% = HpibTimeout(hHpib%, isc&, samp_count% * nplc% / 20)
Call check_srq
Rem Use "INIT" and "FETCH" to initiate measurement and read back
Rem results into an array.
cmd$ = "INIT"
errnum% = HpibOutputS(hHpib%, device&, cmd$, Len(cmd$))
Call check_srq
reed$ = "FETC?"
errnum% = HpibOutputS(hHpib%, device&, reed$, Len(reed$))
errnum% = HpibEnterA(hHpib%, device&, Readings!(0), samp_count%)
Text1.Text = Str$(Readings!(0))
Call check_srq
Rem Close the instrument
errnum% = HpibClose(hHpib%)
End Sub
Sub Command5_Click ()
form1.PrintForm
End Sub

228

Chapter 6 Application Programs
Microsoft Visual Basic Language Program

... continued

The following subroutine may be included in the GLOBAL.BAS file.

’ HPIB.DLL Access
’ Put into your GLOBAL.BAS file
•
•
•
Global isc As Long
Global device As Long
Global hHpib As Integer
Global errnum As Integer
Sub check_srq ()
condition = 1
’ Display any errors caused by the return of an HPIB command.
If errnum% <> NOERROR Then
MsgBox ("Error = " + HpibErrStr$(errnum%))
End If
’ Wait for the completion of the current command.
errnum% = HpibOutPutS(hHpib%, device&, "*OPC?", 5)
errnum% = HpibEnter(hHpib%, device&, done!)
’ If there is an error bit set, obtain the error.
errnum% = HpibSpoll(hHpib%, device&, response%)
If response% And 32 Then
syst_err$ = "SYST:ERR?"
errnum% = HpibOutPutS(hHpib%, device&, syst_err$, Len(syst_err$))
errnum% = HpibEnter(hHpib%, device&, errx!)
actual% = 80
MsgBox ("Error=" + Str$(errx!))
errnum% = HpibOutPutS(hHpib%, device&, "*CLS", 4)
End If

’ Obtain other HPIB errors.
errnum% = HpibStatus(hHpib%, isc&, condition, Status%)
If errnum% <> NOERROR Then
MsgBox ("Error = " + HpibErrStr$(errnum%))
End If
If Status% = 1 Then
errnum% = HpibSpoll(hHpib%, device&, Status%)
If errnum% <> NOERROR Then
MsgBox ("Error = " + HpibErrStr$(errnum%))
End If
End If
End Sub

229

Chapter 6 Application Programs
Microsoft Visual Basic Language Program

... continued

The following function is used by the check_srq subroutine.

Function HpibErrStr$ (errorcode As Integer)
Select Case errorcode
Case NOERR
Msg$ = " No error "
Case EUNKNOWN
Msg$ = " Unknown error "
Case ESEL
Msg$ = " Invalid select code or device address "
Case ERANGE
Msg$ = " Value out of range "
Case ETIME
Msg$ = " Timeout "
Case ECTRL
Msg$ = " HP-IB must be controller "
Case EPASS
Msg$ = " Pass control not permitted "
Case EFILE
Msg$ = " File I/O Error "
Case ENUMB
Msg$ = " Invalid Number "
Case EADDR
Msg$ = " Improper addressing "
Case EOPEN
Msg$ = " Cannot Open This Card "
Case ENOOPEN
Msg$ = " Card is not open "
Case ECLOSE
Msg$ = " Cannot close card "
Case EHANDLE
Msg$ = " Invalid handle for this ISC "
Case Else
Msg$ = " What? "
End Select
HpibErrStr$ = Msg$
End Function

230

Chapter 6 Application Programs
C Language Programs

C Language Programs
All of the C language example programs in this chapter are written for
GPIB Interface Card using the GPIB
the 82335 HP-IB
HP-IB Command Library
for C. Unless otherwise noted, the library functions used in the example
programs are compatible with the ANSI C standard.
All of the C programs were compiled and tested used the following
compilers:
• Microsoft® QuickC® Version 2.0
• Borland® Turbo C®++ Version 1.0

Compiling and Linking a C Program
To run a program, first compile and link the program to make an
executable file. To compile and link a program:
• Make sure the necessary PATH statements have been added to your
AUTOEXEC.BAT file to enable the compiler to find the library and
header files (see your C language manual to specify the proper paths).

GPIB C library file for your compiler (the file is
• Link the appropriate HP-IB
GPIB Command Library disk that came with the
located on the HP-IB
HP-IB
GPIB Interface Card). Use the appropriate library file:
clhpib.lib

for Microsoft® QuickC®

tchhpib.lib

for Borland® Turbo C®++

• If you are not compiling in the "large" or "huge" memory model,
include the "CFUNC.H" header file in your program (the file is located
GPIB Command Library disk that came with your HP-IB
on the HP-IB
Interface Card).

231

Chapter 6 Application Programs
C Language Programs

• To compile Microsoft® QuickC® programs from the DOS command
line (using the "large" memory model), execute the following:
qcl /AL
For example,
qcl /AL b:\meter.c

c:\qc2\lib\clhpib.lib

Change the "/AL" parameter to the appropriate setting when compiling
in the smaller memory models (see your C Language manual for more
information). For some programs, you may also have to change the
stack size using the "/F" parameter.
• To compile Borland® Turbo C®++ programs from the DOS command
line (using the "large" memory model), execute the following:
tcc -ml
For example
tcc -ml b:\meter.c

c:\tc\lib\tchhpib.lib

Change the "-ml" parameter to the appropriate setting when compiling
in smaller memory models (see you C Language manual for more
information).
• Once compiled and linked, and executable file (.EXE) and object file
(.OBJ) are created in the current directory. run the program by typing
the file name with the .EXE extension.

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Chapter 6 Application Programs
C Language Programs

GPIB Example 1
C / HP-IB
This example demonstrates the general sequence of programming and
the use of the MEASure? command to set and obtain a 4-wire Ohms
measurement.
/***************************************************************************
This program configures the meter for a 4-wire ohms measurement on
Channel 1 using the MEAS command.
***************************************************************************/
#include
#include
#include
#include

#define ADDR 722L

/*
/*
/*
/*

Used for printf() */
Used for atoi() */
Used for strlen() */
Header file from GPIB Command Library */

/* Set GPIB address for meter */

/* Function Prototypes */
void rst_clear(void);
void meter_meas(void);
void check_error(char *func_name);
/**************************************************************************/
void main(void)
{
rst_clear();
meter_meas();
}

/* Start of main() */
/* Reset the instrument and clear error queue */
/* Set up meter for measurement */

/**************************************************************************/
void rst_clear(void)
{
/* Reset the meter, clear the error queue, and wait for commands to
complete. A "1" is sent to the output buffer from the *OPC? command
when *RST and *CLS are completed. */

float value;
IOOUTPUTS(ADDR, "*RST;*CLS;*OPC?", 15);
IOENTER(ADDR, &value);
}

233

Chapter 6 Application Programs
C Language Programs

... continued
/**************************************************************************/
void meter_meas(void)
{
/* Configure the meter for 4-wire ohms measurements on channel 1
(default channel). The measurement is made on the 10 ohm range with
the least resolution. */
float ohm_rdg;
IOOUTPUTS(ADDR, "MEAS:FRES? 10, MAX", 18);
IOENTER(ADDR, &ohm_rdg);

/* Configure channel 1 */
/* Enter reading */

printf("Reading: %f\n\n", ohm_rdg);

/* Display reading */

/* Call the function to check for errors */
check_error("meter_meas");
}
/**************************************************************************/
void check_error(char *func_name)
{
/* Read error queue to determine if errors have occurred */
char message[80];
int length = 80;
IOOUTPUTS(ADDR, "SYST:ERR?", 9);
IOENTERS(ADDR, message, &length);

/* Read the error queue */
/* Enter error string */

while (atoi(message) != 0)
/* Loop until all errors are read */
{
printf("Error %s in function %s\n\n", message, func_name);
IOOUTPUTS(ADDR, "SYST:ERR?", 9);
IOENTERS(ADDR, message, &length);
}
}

234

Chapter 6 Application Programs
C Language Programs

C / HP-IB
GPIB Example 2
This program example demonstrates two input channels can be
independently configured and used.
/***************************************************************************
This program configures the meter for voltage measurements on two
input channels. The channels are set to different ranges and resolutions
to show the independence of the settings for each channel.
***************************************************************************/
#include
#include
#include
#include

#define ISC 7L
#define ADDR 722L

/*
/*
/*
/*

Used for printf() */
Used for atoi() */
Used for strlen() */
Header file from GPIB Command Library */

/* Assign GPIB select code */
/* Set GPIB address for meter */

/* Function Prototypes */
void
void
void
void

rst_clear(void);
meter_meas(void);
command_exe(char *commands[], int length);
check_error(char *func_name);

/**************************************************************************/
void main(void)
{
rst_clear();
meter_meas();

/* Start of main() */
/* Reset the instrument and clear error queue */
/* Set up meter for measurement */

}
/**************************************************************************/
void rst_clear(void)
{

/* Reset the meter, clear the error queue, and wait for commands to
complete. A "1" is sent to the output buffer from the *OPC? command
when *RST and *CLS are completed. */
float value;
IOOUTPUTS(ADDR, "*RST;*CLS;*OPC?", 15);
IOENTER(ADDR, &value);
}

235

Chapter 6 Application Programs
C Language Programs

... continued

/**************************************************************************/
void meter_meas(void)
{
/* Configure channel 1 for dc voltage measurements on the 1 volt range
with 10 mV resolution. Configure channel 2 for dc voltage
measurements on the 1 mV range with the least resolution. */
float rdg_ch1, rdg_ch2, null_ch1, null_ch2;
static char state[2] = {13,10};

/* ASCII 13 = carriage return,
ASCII 10 = line feed */

/* Configure measurements on both channels */
IOOUTPUTS(ADDR, "CONF:VOLT:DC 1,0.01,(@FRON1);:CONFVOLT:DC 0.001,MAX,(@FRON2)", 61);
/* Channel 1: initiate measurement, transfer reading to the output buffer */
IOOUTPUTS(ADDR, "ROUT:TERM FRON1", 15);
IOOUTPUTS(ADDR, "READ?", 5);
IOENTER(ADDR, &rdg_ch1);
/* Channel 1: Turn null on */
IOOUTPUTS(ADDR, "SENS1:VOLT:DC:NULL ON", 21);
/* Place the null reading into the Null Register. To do this,
suppress the carriage return (CR) and line feed (LF) before
sending the null reading. */
/* First, disable EOI (End-or-Identify) and EOL (End-of-Line) */
IOEOI(ISC, 0);IOEOL(ISC, " ", 0);
/* Send "SENS" header and suppress CR/LF */
IOOUTPUTS(ADDR, "SENS1:VOLT:DC:NULL:VAL ", 23);
/* Re-enable EOI and EOL for normal GPIB operation and send data */
IOEOI(ISC, 1);IOEOL(ISC, state, 2);
IOOUTPUT(ADDR, rdg_ch1);
/* Channel 2: Initiate measurement, transfer reading to output buffer,
and store reading in variable */
IOOUTPUTS(ADDR, "ROUT:TERM FRON2", 15);
IOOUTPUTS(ADDR, "READ?", 5);
IOENTER(ADDR, &rdg_ch2);

236

Chapter 6 Application Programs
C Language Programs

... continued
/* Channel 2: Turn null on */
IOOUTPUTS(ADDR, "SENS2:VOLT:DC:NULL ON", 21);
/* Place the null reading into the Null Register. To do this,
suppress the carriage return (CR) and line feed (LF) before
sending the null reading. */
/* First, disable EOI (End-or-Identify) and EOL (End-of-Line) */
IOEOI(ISC, 0);IOEOL(ISC, " ", 0);
/* Send "SENS" header and suppress CR/LF */
IOOUTPUTS(ADDR, "SENS2:VOLT:DC:NULL:VAL ", 23);
/* Re-enable EOI and EOL for normal GPIB operation and send data */
IOEOI(ISC,1);IOEOL(ISC, state, 2);
IOOUTPUT(ADDR, rdg_ch2);
/* Channel 1: Take nulled reading, transfer reading to output buffer,
and print nulled reading */
IOOUTPUTS(ADDR, "ROUT:TERM FRON1", 15);
IOOUTPUTS(ADDR, "READ?", 5);
IOENTER(ADDR, &null_ch1);
printf("Nulled Reading (Chan 1): %f\n", null_ch1);
/* Channel 2: Take nulled reading, transfer reading to output buffer,
and print nulled reading */
IOOUTPUTS(ADDR, "ROUT:TERM FRON2", 15);
IOOUTPUTS(ADDR, "READ?", 5);
IOENTER(ADDR, &null_ch2);
printf("Nulled Reading (Chan 2): %f\n", null_ch2);
/* Call the function to check for errors */
check_error("meter_meas");

}

237

Chapter 6 Application Programs
C Language Programs

... continued
/**************************************************************************/
void command_exe(char *commands[], int length)
{
/* Execute one command string at a time using a loop */
int loop;
for (loop = 0; loop length; loop++)
{
IOOUTPUTS(ADDR, commands[loop], strlen(commands[loop]));
}
}
/**************************************************************************/
void check_error(char *func_name)
{
/* Read error queue to determine if errors have occurred */
char message[80];
int length = 80;
IOOUTPUTS(ADDR, "SYST:ERR?", 9);
IOENTERS(ADDR, message, &length);

/* Read the error queue */
/* Enter error string */

while (atoi(message) != 0)
/* Loop until all errors are read */
{
printf("Error %s in function %s\n\n", message, func_name);
IOOUTPUTS(ADDR, "SYST:ERR?", 9);
IOENTERS(ADDR, message, &length);
}
}
/**************************************************************************/

238

Chapter 6 Application Programs
C Language Programs

GPIB Program Example 3
C / HP-IB
This program example demonstrates the use of an SRQ to indicate when
measurements are complete. The meter is set to use external triggering.
Math scaling is also demonstrated.
/***************************************************************************
This program configures the meter to make multiple dc voltage
measurements using an external trigger. The "Operation Complete" bit
in the Standard Event Register is used to determine when the trigger
is received and generates an SRQ. This program also shows the use of
math scaling.
***************************************************************************/
#include
#include
#include
#include

#define ISC 7L
#define ADDR 722L

/*
/*
/*
/*

Used for printf() */
Used for atoi() */
Used for strlen() */
Header file from GPIB Command Library */

/* Assign GPIB select code */
/* Set GPIB address for meter */

/* Function Prototypes */
void
void
void
void
void

rst_clear(void);
setup_status(void);
meter_meas(void);
command_exe(char *commands[], int length);
check_error(char *func_name);

/**************************************************************************/
void main(void)
{
rst_clear();
setup_status();
meter_meas();
}

/* Start of main() */
/* Reset the instrument and clear error queue */
/* Set up 34420A status registers */
/* Set up meter for measurement */

239

Chapter 6 Application Programs
C Language Programs

... continued
/**************************************************************************/
void rst_clear(void)
{
/* Reset the meter, clear the error queue, and wait for commands to
complete. A "1" is sent to the output buffer from the *OPC? command
when *RST and *CLS are completed. */
float value;
IOOUTPUTS(ADDR, "*RST;*CLS;*OPC?", 15);
IOENTER(ADDR, &value);
}
/**************************************************************************/
void setup_status(void)
{
/* An interrupt is to be generated when the external trigger is received
and readings are available in internal memory. To enable the status
registers to generate an interrupt, you must enable bits in the
Status Byte and Standard Event Register. */
/* Enable bit 5 "Standard Event" in the Status Byte to recognize
activity from the Standard Event Register (2^5 = 32) */
IOOUTPUTS(ADDR, "*SRE 32", 7);
/* Enable bit 0 in the Standard Event Register to interrupt the
Status Byte (2^0 = 1) */
IOOUTPUTS(ADDR, "*ESE 1", 6);
/* Call the function to check for errors */
check_error("setup_status");
}

240

Chapter 6 Application Programs
C Language Programs

... continued
/**************************************************************************/
void meter_meas(void)
{
/* Configure the meter for dc voltage measurements on channel 1
(default channel). The measurement is set up on the 10 volt range
with an integration time of 10 PLCs. */
float readings[5];
int stat_cond, i, numvalues =
static char *cmd_string[]=
{
"SENS:FUNC ’VOLT:DC’", /*
"SENS:VOLT:DC:RANG 10", /*
"SENS:VOLT:DC:NPLC 10", /*
"CALC:FUNC SCAL",
/*
"CALC:STAT ON",
/*
"CALC:SCAL:GAIN 0.001", /*
"CALC:SCAL:OFFS 0.5",
/*
"SAMP:COUN 5",
/*
"TRIG:SOUR EXT"
/*
};

5;
Select dc volts on channel 1 */
Select 10 volt range */
Select 10 power line cycles */
Select math scaling function */
Turn math scaling on */
Set the gain value (1 mV) */
Set the offset value (50 mV) */
Take 5 readings per trigger */
Select external trigger source */

/* Call the function to execute the command strings shown above */
command_exe(cmd_string, sizeof(cmd_string)/sizeof(char*));
/* Initiate the measurement, wait for the trigger, and then set bit 0
"Operation Complete" in the Standard Event Register when complete. */
IOOUTPUTS(ADDR, "INIT;*OPC", 9);
/* Loop until the SRQ line is asserted when operation complete */
do
IOSTATUS(ISC, 1, &stat_cond);
while (!stat_cond);

/* Transfer readings from internal memory to the output buffer */
IOOUTPUTS(ADDR, "FETC?", 5);
/* Enter readings and print */
IOENTERA(ADDR, readings, &numvalues);
for (i = 0; i numvalues; i++)
printf("%f \n", readings[i]);

241

Chapter 6 Application Programs
C Language Programs

... continued
/* Use Serial Poll to read the Status Byte and clear all bits */
IOSPOLL(ADDR, &stat_cond);
/* Call the function to check for errors */
check_error("meter_meas");
}
/**************************************************************************/
void command_exe(char *commands[], int length)
{
/* Execute one command string at a time using a loop */
int loop;
for (loop = 0; loop length; loop++)
{
IOOUTPUTS(ADDR, commands[loop], strlen(commands[loop]));
}
}
/**************************************************************************/
void check_error(char *func_name)
{
/* Read error queue to determine if errors have occurred */
char message[80];
int length = 80;
IOOUTPUTS(ADDR, "SYST:ERR?", 9);
IOENTERS(ADDR, message, &length);

/* Read the error queue */
/* Enter error string */

242

Chapter 6 Application Programs
Microsoft Excel Macro Example

Microsoft Excel Macro Example
You can use Windows Dynamic Data Exchange (DDE) to send
commands to the meter and return measurement results directly into a
Microsoft® Excel spreadsheet.

"Instrument Tools"Instrument
for Windows"
This example uses the Hewlett-Packard
Tools for Windows"
and the 82335B GPIB
HB-IB Interface. The "Instrument Tools for
GPIB operations, an
Windows" contains two programs to support HP-IB
GPIB program and a HP-IB
GPIB DDE Server.
Interactive HP-IB
To use the "Instrument Tools for Windows" with Microsoft® Excel, follow
this general procedure:
1
2

Install Tools for Windows (if not already installed).

GPIB application and create and save a configuration
Start the Interactive HP-IB
file (.IBC file) that describes the interface with the meter. Be sure EOI is
disabled and EOL is set to include the character. Refer to the
"Instrument Tools for Windows" User’s Manual for procedures and
descriptions of creating a configuration (.IBC) file.
You can test your interface connection in the Interactive GPIB
HP-IB program
by sending an output string of *IDN? and entering the results. A typical
response is shown in the example in cell F4.

GPIB DDE server. This application starts and minimizes to an
Start the HP-IB
icon.

Run the macro shown in the example.
In the macro, the following commands are part of the GPIB
HP-IB DDE
program and are documented in the "Instrument Tools for Windows"
User’s Manual. All other commands are Microsoft® Excel commands and
are documented in the Excel function reference.
•
•
•
•
•

[Abort]
[clear(device)]
EnterS
EOL
OutputS

243

Chapter 6 Application Programs
Microsoft Excel Macro Example

Macro Comments
• For simplicity, this macro is designed to output and enter data directly
onto the macro sheet. You may wish to output and enter data on a
worksheet.
• The macro sheet is divided into the following columns:
A
contains the variable names used in the macro
B
contains the macro commands
C
contains comments about the macro commands
D
place holder
E
contains the SCPI commands to send
F, G, ... contains the returned data
• The macro takes temperature measurements every 15 minutes for a
12 hour duration, and enters the resulting statistics. Individual
temperature readings are not stored.
• This macro uses the DATA:FEED command to overcome the 1024
memory reading maximum.
• The macro uses the CALCulate:STATe OFF and CALCulate:STATE
ON commands to reset the stats for each 15 minute interval. Without
these commands in the while loop, the stats at each interval would be
an accumulation of readings for all measurements.

244

Chapter 6 Application Programs
Microsoft Excel Macro Example

245

Chapter 6 Application Programs
Microsoft Excel Macro Example

246

Measurement Tutorial

Measurement Tutorial
The 34420A is capable of making highly accurate voltage, resistance
or temperature measurements. In order to achieve the greatest accuracy,
you must take the necessary steps to eliminate potential measurement
errors.
This chapter is divided into two sections. The first section discusses the
causes of measurement errors. The second section describes specific ways
to use the meter to minimize measurement errors.
This chapter is divided into the following sections:
• Measurement Techniques and Sources of Error, page 249.
Voltage Measurements, page 249.
Resistance Measurements, page 258.
Temperature Measurements, page263.
• Cleaning Connector Contacts, page 271.
• Input Connector, page 272.
• Obtaining Parts For the Input Connector, page 273.

248

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Measurement Techniques and Sources of Error
Voltage Measurements
The following table shows voltage measurement error sources. Each of these
sources of error is described in more detail in the sections that follow.
Error Source
Radio Frequency
Interference (RFI)

Thermal EMF Errors

Magnetic Loops

Cabling and
connection
related
Power Line Rejection
(NMR)
Ground Loops

Common Mode Rejection
Loading Errors

Meter
related

Input Bias Current
(Leakage Current)

Injected Current

Correction

Page

Special circuits and shields are used to minimize the effects of
RFI in the measurement. Low emission of RFI also allows the
use of the meter with sensitive devices such as Josephson
junctions where high frequency signals may interfere with
proper operation of the device.
The meter has 99% copper terminals with soldered
connections. The test leads are copper wire with crimped
copper terminals. These test connectors and leads are
recommended to help minimize the effects of thermal EMF
errors.
Use twisted-pair connections to the meter to reduce the noise
pickup loop area, or dress the test leads as close together as
possible. Loose or vibrating test leads will also induce error
voltages. Make sure your test leads are tied down securely
when operating near magnetic fields. Whenever possible, use
magnetic shielding materials or physical separation to reduce
problem magnetic field sources. Use NPLC ≥ 1 if the pickup is
power line related.
Set the integration time to 1 or more PLCs.

250

The best way to eliminate ground loops is to maintain the
meter’s isolation from earth; do not connect the input terminals
to ground. If the meter must be earth-referenced, be sure to
connect it, and the device-under-test, to the same common
ground point. This will reduce or eliminate any voltage
difference between the devices. Also make sure the meter and
device-under-test are connected to the same electrical outlet
whenever possible.
Reduce the series resistance or common mode voltage.
The meter’s input resistance is > 10 GΩ for 1 mV to 10 V
ranges,
10 MΩ for 100 volt range.
The meter’s measuring circuitry exhibits approximately 30pA
of input bias current for ambient temperatures from 0°C to
30°C. Bias current will change at temperatures different than
those at which the meter was calibrated.
A circuit may or may not be sensitive to injected current
depending on the topology of circuit being measured by the
voltmeter, the impedance level of the circuit, and the common
mode or normal mode rejection of the meter.

251

252
253

254
255

256

257

249

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Radio Frequency Interference
Most voltage measuring instruments can generate false readings in the
presense of large high frequency fields. Possible sources of such fields
could include radio, television, communication transmitters, and portable
telephones. The high frequency energy can couple into the meter on the
input leads or cables connected to the rear of the instrument. Keeping the
test leads and rear panel cables as far removed as possible from high
frequency sources will minimize the RFI inteference.
RFI emissions from the meter meet international standards. If your
application is extremely sensitive to RFI radiated from the meter, use a
common mode choke in the input cable as shown.
Torroid

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Measurement Techniques and Sources of Error

Thermal EMF Errors
Thermoelectric voltages are the most common source of error in low-level
dc voltage measurements. Thermoelectric voltages are generated when
you make circuit connections using dissimilar metals at different
temperatures. Each metal-to-metal junction forms a thermocouple, which
generates a voltage proportional to the junction temperature. You should
take the necessary precautions to minimize thermocouple voltages and
temperature variations in low-level voltage measurements. The best
connections are formed using copper-to-copper crimped connections. The
table below shows common thermoelectric voltages for connections
between dissimilar metals.

Copper-to-

Approx. µV/° C

Copper

<0.3

Gold

0.5

Silver

0.5

Brass

Beryllium Copper

Aluminum

Kovar or Alloy 42

Silicon

500

Copper-Oxide

1000

Cadmium-Tin Solder
Tin-Lead Solder

0.2
5

Noise Caused by Magnetic Fields
If you are making measurements near magnetic fields, you should take
the necessary precautions to avoid inducing voltages in the measurement
connections. You should be especially careful when working near
conductors carrying large currents.

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Rejecting Power-Line Noise Voltages
A desirable characteristic of integrating analog-to-digital (A/D)
converters is their ability to reject spurious signals. Integrating
techniques reject power-line related noise present with dc signals on the
input. This is called normal mode rejection or NMR. Normal mode noise
rejection is achieved when the meter measures the average of the input
by “integrating” it over a fixed period. If you set the integration time to a
whole number of power line cycles (PLCs) of the spurious input, these
errors (and their harmonics) will average out to approximately zero.
When you apply power to the meter, it measures the power-line
frequency (50 Hz or 60 Hz), and uses this measurement to determine the
integration time. The table below shows the noise rejection achieved with
various configurations. For better resolution and increased noise
rejection, select a longer integration time.

NPLC’s

NMR

334 µs

(400 µs)

none

3 ms

(4 ms)

none

16.7 ms (20 ms)

60 dB

33.4 ms (40 ms)

90 dB

167 ms (200 ms)

95 dB

334 ms (400 ms)

100 dB

100

1.67 s

(2 s)

105 dB

200

3.34 s

(4 s)

110 dB

0.02

252

Integration Time
60 Hz (50 Hz)

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Noise Caused by Ground Loops
When measuring voltages in circuits where the meter and the
device-under-test are both referenced to a common earth ground, a
“ground loop” is formed. As shown below, any voltage difference between
the two ground reference points (Vground) causes a current to flow
through the LO measurement lead. This causes an error voltage, VL,
which is added to the measured voltage.

RL = Lead Resistance
Ri = Multimeter Isolation
Resistance
Ci = Multimeter Isolation
Capacitance

Ideal
Meter

V ground = Ground Noise Voltage
I = Vground caused current flow =
Z =

Ri ∗ ZCi
Ri + ZCi

= I ∗ RL

Vground
RL + Z

To minimize ground loop errors:
• If Vground is a dc voltage, keep RL small compared to Ri.
• If Vground is an ac voltage, keep RL small compared to Z, and set the
meter’s integration time (NPLC) to 1 or greater. See page 58.

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Common Mode Rejection (CMR)
Ideally, a meter is completely isolated from earth-referenced circuits.
However, there is finite resistance and capacitance between the meter’s
input LO terminal and earth ground. If the input terminals are both
driven by an earth referenced signal, Vf, then a current will flow through
RS and create a voltage drop VL as shown below.
Vf = Common Mode Float voltage
RS = LO Lead Resistance
Ri = Meter Isolation Resistance

Ideal
Meter

Ci = Meter Isolation Capacitance
Zi = Parallel Impedance of Ri + Ci

Error (VL) =

Vf x RS
RS + Z

Any resulting voltage, VL, will appear as an input to the meter. As the
value of RS approaches 0, so does the error. Additionally, if V f is at the
power line frequency (50 Hz or 60 Hz), the noise can be greatly reduced
by setting the meter’s integration time (NPLC) to 1 or greater.
See page 252.

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Measurement Techniques and Sources of Error

Loading Errors Due to Input Resistance (dc volts)
Measurement loading errors occur when the resistance of the deviceunder-test (DUT) is an appreciable percentage of the meter’s own input
resistance. The diagram below shows this error source.

Vs = Ideal DUT voltage
RS = DUT source resistance
Ri = Meter input resistance
(10 MΩ or > 10 GΩ )

Error (%) =

Ideal
Meter

100 x RS

RS + Ri

255

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Loading Errors Due to Input Bias Current (Leakage Current)
The semiconductor devices used in the input circuits of the meter have
slight leakage currents, called bias currents. The effect of the input bias
current is an loading error at the meter’s input terminals.

ib = meter bias current
RS = DUT source resistance
Ci = meter input capacitance

Error (v) ≈ ib x RS

The leakage current will approximately double for every 10°C
temperature rise, making the problem much more apparent at higher
temperatures. You can adjust the input bias current to remove these
errors. The bias current is automatically minimized during the zero
calibration procedure (see chapter 4 in the 34420A Service Guide).
You should perform the zero calibration procedure if you are operating
the meter at a temperature more than 5° C from the calibration
temperature.

256

Ideal
Meter

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Noise Caused by Injected Current
Residual capacitances in the power transformer cause small currents to
flow from the LO of the meter to earth ground. The frequency of the
"injected current" is the power line frequency or possibly power line
frequency harmonics. The injected current is dependent upon the power
line configuration and frequency. You will need to recalibrate the injected
current if you operate the meter with a different power line than the
power line used to calibrate the meter. A simplified circuit is shown.

Ideal
Meter

Injected
Current

In the circuit below, with connection A the injected current flows from the
earth connection provided by the circuit, to the LO terminal of the
voltmeter, and no noise is added to the measurement. However with
connection B, the injected current flows through the resistor R adding
noise to the measurement. With connection B, larger values of R will
make the problem worse.

Ideal
Meter

Ideal
Meter
Injected
Current

CONNECTION A

Injected
Current
CONNECTION B

The noise caused by injected current can be significantly reduced by
setting the integration time of the meter (NPLC) to 1 or greater.
See page 252.

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Measurement Techniques and Sources of Error

Resistance Measurements
Specific resistance measurement techniques are discussed in the
following sections. You should also consider the techniques and errors
discussed earlier in this chapter.
The 4-wire ohms method provides the most accurate way to measure
small resistances. Test lead resistances and contact resistances are
automatically reduced using this method. The connections for resistance
measurements are shown below. See also “Resistance Measurement
Configuration” on page 68.

HI-Sense

R =

Vmeter
Itest

Ideal
Meter

LO-Sense

Removing 2-wire Ohm Test Lead Resistance
To eliminate offset errors associated with the test lead resistance in
2-wire ohms measurements, follow the steps below.
1. Short the ends of the test leads together. The meter displays the test
lead resistance.
2. Press Null from the front panel. The meter displays “0” ohms with the
leads shorted together.

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Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Offset Compensation
A resistance measurement involves measuring a voltage (E) induced
across the resistance by a known current source.

Ideal
Meter

Thermal EMF caused by dissimilar metals can create a parasitic voltage
in the measurement circuit (VEMF). (See page 251 for a description of
thermal EMF). The thermal EMF can be caused by the input lead
connections or internally in resistor R. In general, this voltage will not
change with the current applied to the resistor.

Ideal
Meter

E=IR+VEMF

Ideal
Meter

E=(0*R)+VEMF = VEMF

The voltage measured, and so the resistance calculated, is in error by
VEMF. Using offset compensation can reduce the errors caused by VEMF.
To make an offset compensated measurement, the meter makes two
voltage measurements, one with the current source on and one with the
current source off, and subtracts the two measurements. The actual voltage
drop across the resistor, and the calculated resistance are obtained by:
First Reading − Second Reading = ( I ∗ R + VEMF ) − VEMF = I ∗ R

Offset compensation can be used in 2-Wire or 4-Wire ohms measurements.

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Measurement Techniques and Sources of Error

In the power-on state of the meter, offset compensation is enabled. In
some circumstances it may be desirable to turn offset compensation off.
For example if the resistor being measured does not respond quickly to
changes in current, offset compensation will not produce an accurate
measurement. Resistors with very large inductances or resistors with
large values of parallel capacitance would fall into this category. In these
cases the DELAY parameter can be increased to allow more settling time
after the current source is switched on or off, or the offset compensation
function can be turned off.
Power Dissipation Effects
When measuring resistors designed for temperature measurements (or
other resistive devices with large temperature coefficients), be aware that
the meter will dissipate some power in the device-under-test. The effects
of this power dissipation can affect the measurement accuracy.
If power dissipation is a problem, there are two actions you can take: you
can select a higher measurement range to reduce the errors to acceptable
levels or you can set the meter to the low power mode to limit the test
current (see page 69). The following table shows several examples.

Normal

Low Power

Test Current

DUT Power
(at Full Scale)

Test Current

DUT Power
(at Full Scale)

1Ω

10 mA

100 mW

10 mA

100 mW

10 Ω

10 mA

1 mW

10 mA

1 mW

100 Ω

10 mA

10 mW

1 mA

100 mW

1k Ω

1 mA

1 mW

100 mA

10 k Ω

100 mA

100 mW

10 mA

1 mW

100 k Ω

10 mA

5 mA

2.5

1M Ω

5 mA

Range

260

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Output Clamping
(Dry Circuit Testing)
Resistance measurements on certain types of contacts may require a
limitation on the voltage levels used to make the measurement. Both the
open circuit and the measurement voltage should be considered. The
need for voltage limitation arises from the possibility that oxidation on
the contact surfaces may increase the resistance reading. If the voltage is
too high, the oxide layer may be punctured resulting in a lower resistance
reading.
The meter provides a programmable level of open circuit clamping, called
voltage limited measurements (see page 70). This feature is available on
the 10 and 100 ohm ranges. The open circuit voltage can be clamped at
one of three levels, 20 mV, 100 mV, or 500 mV.
The table below shows the current and voltage levels used.

Test Current

Measurement
Voltage
(at Full Scale)

Open Circuit
Voltage (MV)

10 Ω

1 mA

10 mV

20, 100, or 500 mV

100 Ω

0.1 mA

10 mV

20, 100, or 500 mV

Range

261

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Settling Time Effects
The meter has the ability to insert automatic measurement settling
delays. These delays are adequate for resistance measurements with less
than 200 pF of combined cable and device capacitance. This is
particularly important if you are measuring resistances above 100 kΩ.
Settling due to RC time constant effects can be quite long. Some precision
resistors and multi-function calibrators use large parallel capacitors
(1000 pF to 0.1 µF) with high resistor values to filter out noise currents
injected by their internal circuitry. Non-ideal capacitances due to
dielectric absorption (soak) effects in cables and other devices may have
much longer settling times than expected just by RC time constants.
Errors will be measured when settling after the initial connection and
after a range change. You may need to increase the delay time before a
measurement in these situations (see page 87).
Errors in High Resistance Measurements
When you are measuring large resistances, significant errors can occur
due to insulation resistance and surface cleanliness. You should take the
necessary precautions to maintain a “clean” high-resistance system. Test
leads and fixtures are susceptible to leakage due to moisture absorption
in insulating materials and “dirty” surface films. Nylon and PVC are
relatively poor insulators (109 ohms) when compared to PTFE Teflon
insulators (1013W ). Leakage from nylon or PVC insulators can easily
contribute a 0.1% error when measuring a 1 MΩ resistance in humid
conditions.
 Teflon is a registered trademark of E.I. duPont deNemours and Co.

262

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Temperature Measurements
A temperature measurement is either a resistance measurement or a
voltage measurement, converted to a temperature mathematically inside
the meter. The mathematical conversions requires the knowledge of
specific properties of specific transducer types. The conversion routines
used are compatible with ITS-90. The conversion accuracy (not including
the transducer accuracy) for each transducer type is:
RTD
0.05° C
Thermistor
0.1° C
Thermocouple 0.2° C
Errors associated with temperature measurements include all those
listed for dc Voltage and Resistance Measurements. The largest source of
error in temperature measurements is the transducer itself.
Your measurement requirements determine which temperature
transducer type to use. Each transducer type has a particular
temperature range, accuracy, and cost. Each type of transducer is
described in more detail in the following subsections. The table below
summarizes some general specifications for each type of transducer.
Use the table to help select the general type of transducer to use;
transducer manufacturers can provide you with exact specifications
for a particular transducer.

RTD

Thermistor

Thermocouple

Temperature Range

-200 to 850° C

-80 to 150° C

-210 to 1820° C

Measurement Type

4-wire Resistance

2-wire Resistance

Voltage

Transducer
Sensitivity

≈R0 X 0.004 ° C

/ C

W °

6 to 60 µV/° C

0.01 to 0.1° C

0.1 to 1° C

0.5 to 5° C

$20.00 to $100.00 ea*

$10.00 to $100.00 ea*

$1.00/foot*

Fragile

Rugged

Accuracy
Cost (approx)

≈400

Durability
*Estimated cost in U.S. Dollars

263

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

RTDs
An RTD uses a metal (typically platinum) that changes resistance with a
change in temperature. Your meter can measure this resistance and by
knowing the characteristics of the RTD, calculate the temperature.
RTDs have the highest stability of the temperature transducers. Their
output is also very linear. This makes the RTD the transducer of choice
for high accuracy, long-term measurements. RTDs come in two main
types: a = 0.00385 (DIN/IEC 751) and a = 0.00391.
The RTD resistance at 0° C is referred to as nominal or R0. The meter
can use RTD’s with R0 values from 4.9 Ω to 2.1 kΩ.
The meter always makes a 4-wire measurement of RTDs to preserve
their accuracy.
Thermistors
Thermistors use materials that change resistance with changes in
temperature. Your meter can measure this resistance and by knowing
the characteristics of the thermistor, calculates the temperature.
Thermistors have a higher sensitivity than thermocouples or RTDs. This
makes thermistors the transducer to use when measuring very small
changes in temperature. Thermistors are, however, very non-linear,
especially at high temperatures and function best below 100° C.
Because of their high resistance, thermistors can be measured using two
wire measurement techniques. The meter supports 5000 Ω thermistors.

264

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Thermocouples
A thermocouple converts temperature to voltage. When two wires,
composed of dissimilar metals, are joined, an open circuit voltage is
generated. The voltage is a function of the the junction temperature and
the types of metals in the wire. Since the temperature characteristics of
special dissimilar metals is well known, a conversion from the voltage
generated to the temperature of the junction can be made. For example,
a voltage measurement of a type T thermocouple (made up of copper and
constantan wire) might look like this:

Meter

Notice, however, that the connections made between the thermocouple
wire and the meter make another thermocouple where the thermocouple’s
constantan (C) lead connects to the meter’s copper (Cu) input terminal.
The voltage generated by this second thermocouple affects the voltage
measurement of the type T thermocouple.
If the temperature of the thermocouple created at J2 (the LO input
terminal) is known, the temperature of the type T thermocouple can be
calculated. One way to do this is to connect two type T thermocouples
together to create only copper to copper connections at the meter’s input
terminals, and to hold the second thermocouple at a known temperature.

265

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

An ice bath is used to create a known reference temperature (0° C).
Once the reference temperature and thermocouple type are known, the
temperature of the measurement thermocouple can be calculated.
Meter

Ice Bath

The type T thermocouple is a unique case since one of the conductors (copper)
is the same metal as the meter’s input terminal. If another type of
thermocouple is used, two additional thermocouples are created. For
example, the connections with a type J thermocouple (iron and constantan):
Meter

Ice Bath

Two additional thermocouples have been created where the iron lead
connects to the meter’s copper input terminals. Since these two junctions
will generate opposing voltages, their effect will be to cancel each other.
However, if the input terminals are not at the same temperature, then an
error will be created in the measurement.

266

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

To make a more accurate measurement, the copper test leads of the
meter should be extended closer to the measurement and the connections
to the thermocouple be held at the same temperature.
Meter

Ice Bath

REFERENCE THERMOCOUPLE

This circuit will give accurate temperature measurements. However, it is
not very convenient to make two thermocouple connections and keep all
connections at a known temperature. The "Law of Intermediate Metals"
eliminates the need for the extra connection. This empirical law states
that a third metal (iron (Fe) in the example) inserted between two
dissimilar metals will have no effect upon the output voltage provided the
junctions formed are at the same temperature. Removing the reference
thermocouple makes the connections much easier.

Meter

MEASUREMENT
THERMOCOUPLE

Ice Bath

This circuit is the best solution for accurate thermocouple connections.

267

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

In some measurement situations, however, it would be nice to remove the
need for an ice bath (or other fixed external reference). To do this, an
isothermal block is used to make the connections. An isothermal block is
an electrical insulator, but a good heat conductor. The additional
thermocouples created at J1 and J2 now held at the same temperature by
the isothermal block.
Once the temperature of the isothermal block is known, accurate
temperature measurements can be made. Typically, a thermistor is
mounted to the isothermal block and used to measure the temperature.

METER

REFERENCE
TEMPERATURE

REFERENCE
THERMISTOR

MEASUREMENT
THERMOCOUPLE

ISOTHERMAL BLOCK

Thermocouples come in a variety of types. The type is specified by a
single letter. The following table shows the most commonly used
thermocouple types and some key characteristics of each

268

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Type
B

U.S.
British
DIN
Japanese
French

+ lead

- lead

Platinum – 30%
Rhodium
Gray
N/A
Red
Red
N/A
Iron
White
Yellow
Red
Red
Yellow

Platinum– 60%
Rhodium
Red
N/A
Gray
Gray
N/A
Constantan
Red
Blue
Blue
White
Black

Nickel – Chromium
Yellow
Brown
Red
Red
Yellow

Temperature
Range

Probe
Accuracy

250 to 1820° C

0.5° C

Comments
High Temperature. Beware
of contamination. Do not
insert in metal tubes.

-210 to 1200°
C

1.1 to 2.2° For vacuum, inert
environments.
C
Least expensive.
Not recommended for low
temperature.

Nickel – Aluminum
Red
Blue
Green
White
Purple

-200 to 1370°
C

1.1 to 2.2° For oxidizing environments.
Good linearity above 8° C.
C

Copper
Blue
White
Red
Red
Yellow

Constantan
Red
Blue
Brown
White
Blue

-200 to 400° C

0.5 to 1° C Withstands moisture.
Has a copper lead.
Low temperature
applications.

Nickel – Chromium
Purple
Brown
Red
Red
Yellow

Constantan
Red
Blue
Black
White
Blue

-200 to 1000°
C

1 to 1.7° C Highest output voltage.
Highest resolution.

Nicrosil
Orange
N/A
N/A
N/A
N/A

Nisil
Red
N/A
N/A
N/A
N/A

-200 to 1300°
C

1.1 to 2.2° Superior stability to type K
at high temperatures.
C

Platinum – 13%
Rhodium
Black
White
Red
Red
Yellow
Platinum – 10%
Rhodium
Black
White
Red
Red
Yellow

Rhodium
Red
Blue
White
White
Green

-50 to 1760° C

0.6 to 1.5° High Temperature. Beware
of contamination. Do not
C
insert in metal tubes.

Platinum
Red
Blue
White
White
Green

-50 to 1760° C

0.6 to 1.5° Low error, good stability.
High Temperature. Beware
C
of contamination. Do not
insert in metal tubes.

Constantan = Copper–Nickel, Nicrosil = Nickel–Chromium–Silicon, Nisil = Nickel–Silicone–Magnesium.
N/A = Not Available

269

Chapter 7 Measurement Tutorial
Measurement Techniques and Sources of Error

Thermocouple Measurement Errors
The meter allows you to use one of three types of temperature reference
for thermocouple measurements:
• Fixed Reference value (entered). The fixed reference is the most
accurate, and is the type of thermocouple measurement described
earlier using isothermal blocks and an external known reference
temperature.
• Measured Reference value (external thermistor). A thermistor
is connected to channel 1 input of the meter. The thermistor is then
mounted to the isothermal block. The meter measures the
temperature of the isothermal block and uses the measurement in the
temperature calculation.
• Internal Reference value (internal thermistor). The meter
contains an internal thermistor, mounted just behind the input
connector. The internal thermistor is the least accurate way to
measure temperature. If you use the internal thermistor, you should
connect the thermocouple wire directly to the input connector (do not
use the copper test leads or an isothermal block). See page 272.

270

Chapter 7 Measurement Tutorial
Cleaning the Connector Contacts

Cleaning the Connector Contacts
Because the meter uses connector contacts that are almost pure copper,
they are subject to oxidation. Oxidation can cause measurement errors.
See page 251.
To help prevent the formation of oxides on the connector contacts, keep
the connector engaged whenever possible. After extended periods of time,
it may be necessary to treat the connector contacts. The recommended
treatment uses DeoxITÔ and a small bottle of DeoxIT was included with
the 34420A. Use the following procedure to apply DeoxIT to the
connector terminals.
1

Remove the power cord from the meter.

Remove the input connector.

Stand the meter on a smooth level surface so that the front panel is up.

Apply one drop of DeoxIT to each connector pin in the input connector. A
convenient method to apply a single drop is to use a clean piece of wire to
transfer the liquid from the container provided to the connector.

Remove any excess DeoxIT from the connector by wiping with a clean soft cloth.

Engage and disengage the input cable several times to distribute the
DeoxIT evenly over both halves of the connector.
The input connector may cause measurement problems if the coupling
nut is not tightened properly, the connector keys are not aligned properly,
or the clamping nut is not tightened properly. See the next page.
DeoxIT

Ô is a trademark of CAIG Laboratories, Inc., San Diego, California.
271

Chapter 7 Measurement Tutorial
Input Connector

Input Connector

WIRE: 22 - 28 guage copper
Torque 5 to 7 in-lb

Align keys
Wrap cable shield
(makes earth ground)

Rubber Grommet

Channel 1

DCV
4-WireΩ
2-WireΩ
Thermistor

+
Source +
Source and Sense +
Source and Sense +

–
Source –
Source and Sense –
Source and Sense –

NOTE: key

Channel 2

DCV
4-WireΩ
Thermocouple

272

+
Sense +
+

–
Sense –
–

Chapter 7 Measurement Tutorial
Obtaining Parts For the Input Connector

Obtaining Parts For the Input Connector
Use the following Agilent Technologies part numbers to obtain
replacement input connectors and cables. Contact your nearest Agilent
Technologies Sales Office for replacement.
Part Number

Description

34104A

Low thermal input connector (blank)

34103A

Low thermal 4-wire shorting plug

34102A

Low thermal input connector and 4 foot cable with spade lugs.

You can obtain additional DeoxITÔ, part number D100L2, from:
CAIG Laboratories, Inc.
16744 West Bernardo Drive
San Diego, CA 92172-1904

273

Specifications

Chapter 8 Specifications
34420A Nano Volt/Micro Ohm Meter

ACCURACY SPECIFICATIONS ± (% of reading + % of range) [1]
Function

DC Voltage

Range

[2]

Test
Current

1.0000000 mV

[3]

10.000000 mV
[3]

100.00000 mV
1.0000000 V
10.000000 V
100.00000 V [4]

Temperature Maximum
Coefficient
Per Lead
0°C - 18°C Resistance
28°C - 55°C

24 Hour
23°C ± 1°C

90 Day
23°C ± 5°C

1 Year
23°C ± 5°C

0.0025 + .0020
0.0025 + .0002
0.0015 + .0003
0.0010 + .0003
0.0002 + .0001
0.0010 + .0004

0.0040 + .0020
0.0040 + .0002
0.0030 + .0004
0.0025 + .0004
0.0020 + .0004
0.0025 + .0005

0.0050 + .0020
0.0050 + .0003
0.0040 + .0004
0.0035 + .0004
0.0030 + .0004
0.0035 + .0005

0.0004 + .0001
0.0004 + .00002
0.0004 + .00006
0.0004 + .00004
0.0001 + .00002
0.0004 + .00005

Resistance [5]

1.0000000 Ω
10.000000 Ω
100.00000 Ω
1.0000000 KΩ
10.000000 KΩ
100.00000 KΩ
1.0000000 MΩ

10 mA
10 mA
10 mA
1 mA
100 µA
10 µA
5 µA

0.0015 + .0002
0.0015 + .0002
0.0015 + .0002
0.0015 + .0002
0.0015 + .0002
0.0015 + .0003
0.0020 + .0003

0.0050 + .0002
0.0040 + .0002
0.0040 + .0002
0.0040 + .0002
0.0040 + .0002
0.0040 + .0004
0.0050 + .0004

0.0070 + .0002
0.0060 + .0002
0.0060 + .0002
0.0060 + .0002
0.0060 + .0002
0.0060 + .0004
0.0070 + .0004

0.0005 + .00002
0.0005 + .00001
0.0005 + .00001
0.0005 + .00001
0.0005 + .00001
0.0005 + .00002
0.0006 + .00003

1Ω
1Ω
10 Ω
100 Ω
1 KΩ
1 KΩ
1 KΩ

Low Power
Resistance [5]

1.0000000 Ω
10.000000 Ω
100.00000 Ω
1.0000000 KΩ
10.000000 KΩ
100.00000 KΩ
1.0000000 MΩ

10 mA
10 mA
1 mA
100 µA
10 µA
5 µA
5 µA

0.0015 + .0002
0.0015 + .0002
0.0015 + .0002
0.0015 + .0002
0.0015 + .0004
0.0015 + .0012
0.0020 + .0003

0.0050 + .0002
0.0040 + .0002
0.0040 + .0002
0.0040 + .0002
0.0040 + .0004
0.0040 + .0015
0.0050 + .0004

0.0070 + .0002
0.0060 + .0002
0.0060 + .0002
0.0060 + .0002
0.0060 + .0004
0.0060 + .0015
0.0070 + .0004

0.0005 + .00002
0.0005 + .00001
0.0005 + .00001
0.0005 + .00001
0.0005 + .00003
0.0005 + .00003
0.0006 + .00003

1Ω
1Ω
10 Ω
100 Ω
1 KΩ
1 KΩ
1 KΩ

1 mA
100 µA

0.0020 + .0002
0.0025 + .0002

0.0050 + .0002
0.0050 + .0002

0.0070 + .0002
0.0070 + .0002

0.0005 + .00002
0.0005 + .00002

1Ω
5Ω

Voltage
10.000000 Ω
100.00000 Ω
Limited
[5][6]
Resistance

Channel 1 / Channel 2 (DCV Ratio)
Channel 1 - Channel 2 (DCV Difference)

Ratio Error % = Channel 1 accuracy in % + Channel 2 accuracy in %
Difference Error = Channel 1 (% of reading + % of range) + Channel 2 (% of reading + %
of range)

Temperature
(resolution = 0.001° C)
Thermocouple probe accuracy + 0.2° C
Thermocouple [7]
Thermistor
Thermistor probe accuracy + 0.1° C
RTD
RTD probe accuracy + 0.05° C
[1] Specifications are for Channel 1 or Channel 2, after 2-hour warm-up, resolution at 7.5 digits (100 NPLC), with FILTERS off.
RESISTANCE specifications are for 4-wire ohms or 2-wire ohms using Null. Without Null, add 0.2 Ω additional error in 2-wire ohms
function. With Analog Filter ON, add 0.002% of reading to listed specifications.
[2] 20% overrange on all ranges except 5% on Voltage Limited Resistance.
[3] After using Null. If Null is not used add 100 nanovolts.
[4] Channel 1 only.
[5] Channel 1 only. Resistance measurements, for NPLC <1, add 160 µΩ RMS noise.
[6] Voltage limit can be set to 20 mV (default), 100 mV, or 500 mV. Measured resistance plus Channel 1 HI and LO lead resistance is
limited to 10.5 Ω on the 10 Ω range and 105 Ω on the 100 Ω range.
[7] For fixed reference junction. Add 0.3° C for external reference junction, add 2° C for internal reference junction.

276

Chapter 8 Specifications
34420A Nano Volt/Micro Ohm Meter

DC Voltage Noise Specifications *

MEASUREMENT CHARACTERISTICS
DC Voltage

Observation Period

Measurement Method

Continuously Integrating
Multi-slope III A-D Converter

A-D Linearity

0.00008% of reading + 0.00005% of range

Input Resistance
100V (Ch1 only)
1mV through 10V

10 MΩ ± 1%
>10 GΩ, in parallel with <3.6 nF

14 nVpp

Input Bias Current

<50 pA at 25°C

Injected Current*

<50 nA pp at 50 or 60 Hz

Input Protection

150 V peak any input terminal to
Channel 1 LO, continuous

Channel Isolation

Isolation between input channels
>1010Ω

Earth Isolation

350 V peak any input terminal to
earth. Impedence from any input
terminal to earth is
>10 GΩ and < 400 pF

Maximum Voltage

Channel 1 LO to Channel 2 LO,
150V peak

2-Minute

24-Hour

Range

RMS
Noise

Peak-Peak
Noise

1 mV

1.3 nVRMS

8 nVpp

12 nVpp

10 mV

1.5 nVRMS

10 nVpp

100 mV

10 nVRMS

65 nVpp

80 nVpp

100 nVRMS

650 nVpp

800 nVpp

10 V

450 nVRMS

3 µVpp

3.7 µVpp

100 V

11 µVRMS

75 µVpp

90 µVpp

* After a 2-hour warm-up, ± 1°C, 6.5 digits (10 PLC) with Analog
Filter Off and Digital Filter Medium (50 reading average). 2-Minute
RMS and 24-hour noise typical. For measurements using 0.02 or
0.2 NPLC, add 800 nV RMS noise.

DC Voltage Noise vs Source Resistance *
Source
Resistance

Noise

1.3 nVRMS

Off

Med

100

1.7 nVRMS

Off

Med

4 nVRMS

Off

Med

10k

13 nVRMS

Off

Med

100k

41 nVRMS

Med

90 nVRMS

Slow

Analog Filter Digital Filter

* Typical noise behavior for Ch 1 or Ch 2, after 2 hour warm-up,
6.5 digits (10 PLC), 2 minute observation period on 1 mV range.
For peak-to-peak noise, multiply RMS noise by 6.

Resistance
Measurement Method

Selectable 4-wire or 2-wire ohms.
Current Source referenced to
Channel 1 LO input

Offset Compensation

Used on all ranges except
100 kΩ and 1 MΩ.
Can be turned off if desired

Protection

150V peak

Open Circuit Voltage

For Resistance and Low Power
Resistance <14 V. 20 mV, 100 mV,
500 mV selectable clamp

* Injected current is calibrated at the factory. Different line power
configurations will require recalibration.

8
277

Chapter 8 Specifications
34420A Nano Volt/Micro Ohm Meter

OPERATING CHARACTERISTICS [4]

Temperature
Thermocouple
Thermistor
RTD

Type B, E, J, K, N, R, S, T
Range: -210° C to 1820° C

Integration
Time

Readings/s [5]

71⁄2

200 plc

.15 (.125)

4-wire, 4.9 Ω to 2.1 kΩ
types:
α = .00385 (DIN/IEC 751)
and α = .00391
Range: -200° C to 850° C

Thermocouple 71⁄2

100 plc

.3 (.25)

61⁄2

20 plc

1.5 (1.25)

61⁄2

10 plc

3 (2.5)

51⁄2

1 plc

25 (20.8)

[1]

51⁄2

0.2 plc

100 (100)

41⁄2

0.02 plc

250 (250)

Resistance,

71⁄2

200 plc

.075 (.062)

DCV1/DCV2,

71⁄2

100 plc

.15 (.125)

5 kΩ
Range: -80° C to 150° C

Measurement Noise Rejection 60 (50) Hz
dc CMRR

140 dB

ac CMRR

70 dB

Function
DCV,

Digits

Integration Time

Normal Mode Rejection [2]

DCV 1-2,

61⁄2

20 plc

.75 (.625)

200 plc/3.335 ms (4s)

110 dB [3]

RTD,

61⁄2

10 plc

1.5 (1.25)

100 plc/1.675 ms (2s)

105 dB [3]

Thermistor

51⁄2

1 plc

12.5 (10.4)

20 plc/334 ms (400ms)

100 dB [3]

51⁄2

0.2 plc

50 (50)

10 plc/167ms (200ms)

95 dB [3]

41⁄2

0.02 plc

125 (125)

2 plc/33.3 ms (40 ms)

90 dB [3]

1plc/16.7ms (20ms)

60 dB

<1plc

System Speeds [6]
Configuration Rates

26/s to 50/s

Autorange Rate (DC Volts)

>30/s

ASCII reading to RS-232

55/s

ASCII reading to GPIB

250/s

Max. Internal Trigger Rate

250/s

Max. Ext. Trig. Rate to Memory

250/s

[1] For 1 kΩ unbalanced in LO lead.
[2] For power line frequency ± 0.1%, Filters OFF.
For Digital Filter slow add 20 db, for medium or fast add
10 db for NPLC ≥1.
[3] For power line frequency ± 1%, use 80 db or ± 3% use 60 db.
[4] Speeds are for delay 0, Display OFF, Filters OFF, OCOMP OFF.
[5] Reading speeds for 60 Hz or (50 Hz), 100 mV through 100 V
ranges. 1 mV range 30/s MAX, 10 mV range 170/s MAX,
thermocouple 120/s MAX.
[6] Speeds are for NPLC 0.02, Delay 0, Display OFF, Chart Out
OFF.

278

Chapter 8 Specifications
34420A Nano Volt/Micro Ohm Meter

Triggering and Memory

Standard Programming Languages

Reading HOLD Sensitivity 10%, 1%, 0.1%, or 0.01% of range

SCPI (IEEE 488.2), Keithley 181

Samples/Trigger

1 to 50,000

Accessories Included

Trigger Delay

0 to 3600s; 10µs step size

External Trigger Delay

<1ms

External Trigger Jitter

<500µs

Memory

1024 readings

4 ft low thermal cable with copper spade lugs, 4-wire shorting
plug, user’s manual, service manual, contact cleaner, test
report and power cord

General Specifications
Front Panel Connection shielded, low thermal, 99% copper
contacts

Math Functions
NULL (Channel 1 DCV, Channel 2 DCV, Difference,
MMMNResistance, Temperature)
STATS (Min, Max, Average, Peak-Peak, Standard Deviation,
MMMMIINumber of readings)
SCALE (Allows linear scaling as y=mx+b)
CHART NULL (Establishes zero for rear panel output)

Power Supply

100V/120V/220V(230V)/240V ± 10%

Power Line Frequency

45Hz to 66Hz and 360Hz to 440Hz
Automatically sensed at power-on.

Power Consumption

25VA peak (10W average)

Operating Environment

Full accuracy for 0° C to 55° C
Full accuracy to 80% R.H. up to 40° C

Filter (Analog or Digital or Both)

Storage Environment

-40° C to 75° C

Analog

Low pass 2 pole @ 11Hz, available
for 1, 10, 100mV range

Weight

3 kg (6.5 lbs)

Safety

Digital

Moving average filter, 10 (fast),
50 (medium) or, 100 (slow) reading
averages.

Designed to CSA, UL-1244,
IEC-1010

RFI and ESD

CISPR 11

Chart Out (Analog Out)
Maximum output: ± 3V

Vibration and Shock

MIL-T-28800E, Type III, Class 5

Warranty

3 year

Accuracy: ± 0.1% of output + 1 mV
Output Resistance: 1 kΩ ± 5%
Update rate: once per reading
Span and Offset: Adjustable

8
279

Chapter 8 Specifications
34420A Nano Volt/Micro Ohm Meter

Dimensions

280

Chapter 8
To Calculate Total Measurement Error

To Calculate Total Measurement Error
Each specification includes correction factors which account for errors
present due to operational limitations of the meter. This section explains
these errors and shows how to apply them to your measurements. Refer
to "Interpreting Meter Specifications," starting on page 285, to get a
better understanding of the terminology used and to help you interpret
the meter’s specifications.
The meter’s accuracy specifications are expressed in the form:
(% of reading + % of range)

In addition to the reading error and range conditions, make sure you
apply the conditions as described in the footnotes on the specification
pages.
• If you are operating the meter outside the 23° C ±5° C temperature
range specified, apply an additional temperature coefficient error.
Understanding the " % of reading" Error. The reading error
compensates for inaccuracies that result from the function and range you
select, as well as the input signal level. The reading error varies
according to the input level on the selected range. This error is expressed
in percent of reading. The following table illustrates the reading error
applied to the meter’s 24-hour dc voltage specification.

Range

Input Level

Reading Error
(% of reading)

Reading Error
Voltage

10 V

0.0002

≤ 20 µV

10 V

0.0002

≤ 2 µV

10 V

0.1 V

0.0002

≤ 200 nV

8
281

Chapter 8
To Calculate Total Measurement Error

Understanding the " % of range" Error. The range error compensates
for inaccuracies that result from the function and range you select. The
range error contributes a constant error, expressed as a percent of range,
independent of the input signal level. The following table ilustrates the
range error applied to the meter’s 24-hour dc voltage specification.

Range

Input Level

Range Error
(%of range)

Range Error
Voltage

10 V

0.0001

≤ 10 µV

10 V

0.0001

≤ 10 µV

10 V

0.1 V

0.0001

≤ 10 µV

Total Measurement Error. To compute the total measurement error,
add the reading error and range error. You can then convert the total
measurement error to a "percent of input" error or a
"ppm (part-per-million) of input" error as shown below.
% of input error =

Total Measurement Error
∗ 100
Input Signal Level

ppm of input error =

Total Measurement Error
∗ 1,000,000
Input Signal Level

Total Measurement Assume that a 5 Vdc signal is input to the meter on the 10 Vdc range.
To compute the total measurement error using the 90-day accuracy
Error Example
specifications: ±(0.0020% of reading + 0.0004% of range).
Reading Error = 0.0020% ∗ 5 V = 100 µV
Range Error = 0.0004% ∗ 10 V = 40 µV
Total Error = 100 µV + 40 µV = ±140 µV
% of input error =

± 140 µV
∗ 100 = ± 0.0028% of 5 V
5V

ppm of input error =

282

± 140 µV
5V

∗ 1,000,000 = ± 28 ppm of 5 V

Chapter 8
To Calculate Total Measurement Error

Difference Error
Example

This example demonstrates how to compute the total measurement error
when using the Difference Function. Assume a difference measurement
is made with the following conditions:
• Channel 1, 1 V input on the 1 Volt range
• Channel 2, 1.2 V input on the 10 Volt range
To compute the total measurement error using the 90-day accuracy
specifications for the error:
Channel 1 (% of reading + % of range) + Channel 2 (% of reading + % of range).
Channel 1 Reading Error = 0.0025% ∗ 1 V = 25 µV
Channel 1 Range Error = 0.0004% ∗ 1 V = 4 µV
Channel 2 Reading Error = 0.0020% ∗ 1.2 V = 24 µV
Channel 2 Range Error = 0.0004% ∗ 10 V = 40 µV
Total Error = 25 µV + 4 µV + 24 µV + 40 µV = 93 µV
Difference = 1 V − 1.2 V = − 0.2 V ± 93 µV

For difference measurements, if both channel 1 and channel 2 are using
the same range, the % of reading error can be applied directly to to the
voltage difference. In the example, if both channels are using
the 1 V range, the total reading error can be computed as:
Reading Error = 0.0025% ∗ ( 1.2 V − 1 V ) = 5 µV
Channel 1 RangeError = 0.0004% ∗ 1 V = 4 µV
Channel 2 RangeError = 0.0004% ∗ 1 V = 4 µV
Total Error = 5 µV + 4 µV + 4 µV = 13 µV
Difference = 1 V − 1.2 V = − 0.2 V ± 13 µV

Using NULL on each input channel will reduce the % of range error in
the measurement to the noise level of the meter.

8
283

Chapter 8
To Calculate Total Measurement Error

Ratio Error
Example

This example demonstrates how to compute the total measurement error
when using the Ratio Function. Assume a ratio measurement is made
with the following conditions:
• Channel 1, 5 V input on the 10 Volt range
• Channel 2, 10 mV input on the 10 mV range
To compute the total measurement error using the 90-day accuracy
specifications:
Ratio Error % = Channel 1 accuracy in % + Channel 2 accuracy in %
Channel 1 Reading Error % = 0.0020%
Channel 1 Range Error % = 0.0004% ∗

Range

= .0004% ∗

Reading

10
= .0008%
5

Total Channel 1 Error % = 0.0020% + 0.0008%= .0028%
Channel 2 Reading Error % = 0.0040%
Channel 2 Range Error % = 0.0002% ∗

Range
Reading

= .0002% ∗

10 mV
= .0002%
10 mV

Total Channel 2 Error % = 0.0040% + 0.0002%= .0042%
Ratio Error % = 0.0028% + 0.0042% = .0070%
Ratio =

10 mV

= 500 ± 0.0070% = 500 ± 0.035

For Ratio Measurements, if both input channels use the same range, use
0 for the % of reading error.

284

Chapter 8
Interpreting Meter Specifications

Interpreting Meter Specifications
This section is provided to give you a better understanding of the
terminology used and will help you interpret the meter’s specifications.

Number of Digits and Overrange
The number of digits specification is the most fundamental, and
sometimes, the most confusing characteristic of a meter. The number of
digits is equal to the maximum number of "9’s" the meter can measure or
display. This indicates the number of full digits. Most meters have the
ability to overrange and add a partial or "1/2" digit.
For example, the 34420A can measure 9.999999 Vdc on
the 10 V range. This represents seven full digits of resolution. The
meter can also overrange on the 10 V range and measure up to a
maximum of 12.000000 V. This corresponds to a 7 1/2-digit measurement
with 20% overrange capability.

Sensitivity
Sensitivity is the minimum level that the meter can detect for a given
measurement. Sensitivity defines the ability of the meter to respond to
small changes in the input level. For example, suppose you are
monitoring a 1 mV signal and you want to adjust the level to
within ±1 µV. To be able to respond to an adjustment this small, this
measurement would require a meter with a sensitivity of at least 1 µV.
You could use a 6 1/2-digit meter if it has a 1 Vdc or smaller range. You
could also use a 4 1/2-digit meter with a 10 mV range.

8
285

Chapter 8
Interpreting Meter Specifications

Resolution
Resolution is the numeric ratio of the maximum displayed value divided by
the minimum displayed value on a selected range. Resolution is often
expressed in percent, part-per-million (ppm), counts, or bits. For example,
a 6 1/2-digit meter with 20% overrange capability can display a measurement
with up to 1,200,000 counts of resolution. This corresponds to
about 0.0001% (1 ppm) of full scale, or 21 bits including the sign bit. All four
specifications are equivalent.

Accuracy
Accuracy is a measure of the "exactness" to which the meter’s measurement
uncertainty can be determined relative to the calibration reference used.
Absolute accuracy includes the meter’s relative accuracy specification plus
the known error of the calibration reference relative to national standards
(such as the U.S. National Institute of Standards and Technology). To be
meaningful, the accuracy specifications must be accompanied with the
conditions under which they are valid. These conditions should include
temperature, humidity, and time.
There is no standard convention among meter manufacturers for the
confidence limits at which specifications are set. The table below shows the
probability of non-conformance for each specification with the given
assumptions.

Specification
Criteria

Probability
of Failure

Mean ± 2 sigma

4.5%

Mean ± 3 sigma

0.3%

Mean ± 4 sigma

0.006%

Variations in performance from reading to reading, and instrument to
instrument, decrease for increasing number of sigma for a given specification.
This means that you can achieve greater actual measurement precision for a
specific accuracy specification number. The 34420A is designed and
tested to meet performance better than mean ± 3 sigma of the published
accuracy specifications.

286

Chapter 8
Configuring for Highest Accuracy Measurements

24-Hour Accuracy
The 24-hour accuracy specification indicates the meter’s relative accuracy
over its full measurement range for short time intervals and within a
stable environment. Short-term accuracy is usually specified for a
24-hour period and for a ± 1° C temperature range.

90-Day and 1-Year Accuracy
These long-term accuracy specifications are valid for a 23° C ± 5° C
temperature range. These specifications include the initial calibration
errors plus the meter’s long-term drift errors.

Temperature Coefficients
Accuracy is usually specified for a 23° C ± 5° C temperature range.
This is a common temperature range for many operating environments.
You must add additional temperature coefficient errors to the accuracy
specification if you are operating the meter outside a 23° C ± 5° C
temperature range.

Configuring for Highest Accuracy Measurements
The measurement configurations shown below assume that the meter is
in its power-on or reset state. It is also assumed that manual ranging is
enabled to ensure proper full scale range selection.
• Front Panel: Configure the meter for 10 NPLC and use Digital Filter
type set to MEDIUM (50 readings). Do not use the Analog Filter type.
• Remote Operation: Configure the meter for 200 NPLC and turn the
input filters OFF. Use the statistics functions to reduce noise in the
measurements. (See page 146).
• Use 4-wire Ohms and Offset Compensation for greater resistance
measurement accuracy.
• Use NULL to remove test lead resistance for 2-wire Ω measurements.
• Use NULL to remove to remove interconnection offset voltages for
voltage and temperature measurements.

8
287

Index
If you have questions related to the operation of this meter,
call 1-800-452-4844 in the United States, or contact your nearest
Agilent Technologies Sales Office.

* commands, 184
*STB?, 163
1/2 digit, 24, 43, 62, 285
2-wire ohms, 68, 258
connections, 20
nulling test leads, 258
4-wire ohms, 68, 258
connections, 20
? commands, 184

A
a/d convertor, 58
accessories included, 13
accuracy, 281
configuring for, 287 - 288
accuracy specification, 286
adapter kit, RS-232, 178
address (HPIB), 102, 188
alternate languages, 105, 193
analog filter, 57, 65
analog output
See chart out
analog overload detection, 65
annunciators, 4
auto trigger, 47, 82
autodelay trigger, 89
autorange, 23, 42
threshold values, 23, 42, 64
autoranging, 64
autotrigger, 47

B
BASIC language examples, 215 - 221
baud rate, 176, 190
values, 103
baud rate
setting, 103
BNC connectors, 97
Borland
Turbo C, 230 - 241
bumpers
removing, 27
bus triggering, 84

C (continued)

cable
colors
color code, 17
of input connections, 17
cables
of thermocouple wire, 269
provided, 17
comma separator, 95
RS-232, 106
menu example, 35
calibration, 107
command summary, 117 - 125
commands, 174 - 175
commands
count, 110
*OPC, 164
errors, 210 - 211
*STB?, 163
message, 111
CALCulate, 148 - 150
message string length, 111
CALibration, 174 - 175
security, 107
CONFigure, 126, 134 - 136
calibration security
data formats returned, 186
changing security code, 109
data types used, 185
securing, 109
DATA:FEED, 150
unsecuring, 108
FETch?, 131
carrying handle
INITiate, 131
adjusting, 16
introduction to, 183
removing, 27
math operations, 148 - 150
channel
MEASure?, 126, 134 - 136
input, 41, 66
menu, 33 - 40
scan, 41
READ?, 130
selecting, 41
RS-232 interface, 182
selecting from remote interface, 140
scaling data, 148
channel parameter, 134
SENSe, 137 - 139
chart
statistics, 149
null, 98 - 100
status reporting, 171 - 173
offset, 98 - 100
synchronizing, 163
rollover, 100
syntax described, 183
span, 98 - 100
system, 157 - 158
chart out, 98 - 100
temperature measurement, 142 - 144
commands, 156
terminating, 186
connector, 5, 98 - 100
TRIGger:COUNt INFinity, 85
rollover, 100
triggering, 154 - 155
chassis, 5
when completed, 163
clamping on output, 261
common mode rejection, 254
cleaning contacts, 271
compliance
CLEAR 722, 85
IEEE-488, 197
CMR
SCPI language, 194 - 196
See common mode rejection
condition register, 159, 169
CONFigure command, 128, 134 - 136

289

I
n
d
e
x

Index

C (continued)

D (continued)

E (continued)

conformity, declaration, 295
connections, 17 - 18
2-wire ohms, 20
4-wire ohms, 20
cleaning, 271
computer, 177
dc volts, 19
difference, 49
input, 17 - 18
printer, 106, 179
ratio, 19, 49
resistance, 20
RTD, 21
terminal, 106, 177
thermistor, 21
thermocouple, 22
thermocouple reference, 22
to a terminal or printer, 106
voltage, 19
connector
assembly, 272 - 273
cleaning, 271
DB-25, 178
DB-9, 178
part numbers, 273
connector pinout
input, 18
RS-232, 106
connector pintout
input, 272
connectors
Analog Out, 5, 98 - 100
Chart Out, 5, 98 - 100
Ext Trig, 5, 97
front-panel, 18
HP-IB, 5
input, 272
line power, 5
VM Comp, 5, 97

delay
trigger, 87
delays
settling, 262
DeoxIT cleaner, 271
description, 1
device clear, 85, 187
dielectric absorption, 262
difference
connections, 19, 49
measurements, 49, 67
digital filter, 57, 169
settled, 169
digital overlaod detection, 65
digits
displayed, 24, 62
maximum in display, 58
maximum number displayed, 44
display, 4
annunciators, 4
control, 94
format, 26
displaying a message, 94
dry circuit testing, 261
DTE, 179
DTR, 179
DTR/DSR lines, 179

examples
BASIC programming, 215 - 221
c programming, 230 - 241
chart output rollover, 100
chart output span, 98
comma seperator, 35
CONFigre comand, 133
CONFigure command, 132 - 133
entering a number, 38
Excel, 242 - 246
Excel macro, 242 - 246
FETCh? command, 133
HP-IB address setting, 188
HP-IB DDE, 242 - 246
INItiate command, 133
MEASure? command, 132
menu recall, 37
menu usage, 35
READ? command, 132
reading memory, 50 - 52
ROUTe command, 133
selecting programming language, 192
selecting remote interface, 189
setting baud rate, 190
setting null, 38
setting parity, 191
specification, 282
Visual Basic, 223 - 229
Excel, 242 - 246
Ext Trig terminal, 5, 47, 82 - 83, 97
external temperature reference, 22
external trigger, 97
External Trigger terminal, 47
external triggering, 47, 82 - 83

D
data
output formats, 186
SCPI types of, 185
DB-25 connector, 178
DB-9 connector, 178
dc volts
connections, 19
declaration of conformity, 295
default settings, 112 - 114
CONFigure command, 127
MEASure? command, 127

290

E
earth ground, 18, 253
enable register, 159
EOI, 186
equivalent NPLC, 60
error
% of range, 282
% of reading, 281
calculating, 281 - 284
total measurement, 282
ERROR annunciator, 13
error conditions, 92
error messages, 200
calibration errors, 210 - 211
execution errors, 201 - 207
self-test errors, 208 - 209
error queue, 92
error string length, 92
errors, 92
general measurement, 249 - 270
high resistance measurement, 262
service request generation, 165
test lead resistance, 258
event register, 159

F
factory defaults, 113
features and functions, 54
FETCh? command, 131
filter
analog, 57, 65
count, 57
digital, 57, 169
filter settled
status bit, 169
filters, 55
firmware revision query, 95
fixed range, 64
fixed temperature reference, 22, 270
flowchart
triggering, 80
four-wire ohms, 258

Index

F (continued)

I (continued)

front panel
comma separator, 95
display format, 26
enable/disable, 94
front panel message, 94
front-panel, 2
at a glance, 2
keys , 2
menu, 3
menu tutorial, 33 - 40
front-panel menu
reference, 31 - 32
fuse, 14 - 15

IEEE-488 compliance information, 197
induced voltages, 251
infinity trigger count, 85
INITiate command, 131
injected current noise, 257
input
bias current errors, 256
cable, 273
channels, 66, 140
connections, 17 - 18
connector, 272
overload detection, 65
resistance, 255
input bias current, 249
input channels, 41
input filters, 55
input message terminators, 186
installation, 13
integration time, 25, 44, 58, 60
interface selection, 101, 189
internal memory, 50 - 52, 79
internal reading memory, 93
internal reference thermistor, 22
internal temperature reference, 270
internal triggering, 84
interrupt with SRQ, 163
isothermal block, 22, 268

magnetic loops
noise, 251
manual range, 23, 42, 64
math operations, 74 - 76
scaling, 74
statistics, 75
MAV bit, 164
MEASure command, 134 - 136
MEASure? command, 128
measured temperature reference, 270
measurement connections, 251
measurement tutorial, 248
measurements
halting, 85
highest accuracy, 287 - 288
low power, 260
resistance, 68 - 70, 258
stopping, 187
temperature, 263
temperature RTDs, 72
temperature thermistor, 72
temperature thermocouple, 73
temperature units, 71
units for temperature, 71
voltage, 66 - 67
voltage limited, 261
with null, 45
measuring
resistance, 20
temperature, 21
voltage, 19, 249
memory
defeating max, 150
internal reading, 50 - 52, 90
non-volatile, 112 - 113
readings, 90
volatile, 112
volatile settings, 112
menu
at a glance, 3
recall, 37
reference, 31 - 32
tutorial, 33 - 40
using, 33 - 40
menu messages, 34
message
input terminators, 186
message available bit (MAV), 164
messages displayed
calibration, 111
front-panel menu, 34

G
ground, 5
ground loop noise, 253
Group Execute Trigger (GET), 84

H
half digit, 24, 43
resolution, 62
halting measurements, 85, 187
handle
adjusting, 16
removing, 27
handshake, remote interface, 179
hardware
rack mounting, 27
hardware handshake, 97
high accuracy measurements, 287 - 288
hold
reading, 48, 79
holding readings in the display, 79
HP-IB
address setting, 188
DDE, 242 - 246
HP-IB
connector, 5
HP-IB (IEEE-488) address
factory setting, 102
setting, 102, 188
TALK ONLY mode, 102

I
idle trigger state, 85, 153
IEEE-488 (HP-IB) address
factory setting, 102
setting, 102, 188
TALK ONLY mode, 102

K
Keithley 181
language compatility, 193
keys, 2
number of digits, 24
range, 42

L
language
alternate programming, 193
language restrictions
interface selection, 105
remote interface, 101
lead resistance
nulling, 45, 77
leakage current errors, 256
line frequency, 252
loading errors
input bias current, 256
input resistance, 255
leakage current, 256
low power measurements, 69, 260
commands, 141

291

I
n
d
e
x

Index

M (continued)

Microsoft
Excel, 242 - 246
QuickC, 230 - 241
Visual Basic, 223 - 229
Microsoft Excel, 242 - 246
min-max measurements
front-panel, 46

offset
chart output, 98 - 100
offset compensation, 69, 259
commands, 141
offset voltage, 253
open circuit voltage, 261
operational condition register, 169
operational status register, 169
output buffer, 164
output clamping, 261
output data format, 186
overload, 23, 26, 42, 64
overload detection, 65
overrange, 285
OVLD, 23, 42, 64

rack cabinet, 27
rack mounting, 27 - 28
range
front-panel keys, 23, 42
parameters, 129
selecting, 23, 42
range overload, 23, 26, 42, 64, 167
ranging, 64
ratio
connections, 49
ratio measurements, 67
front-panel, 49
READ? command, 130
reading hold, 48, 79
front-panel, 48
sensitivity band, 48
reading memory, 50 - 52, 79, 90, 93
number of readings stored, 90
reading rate, 60
rear panel, 5
reference to thermocouple, 270
register
condition, 159
enable, 159
operational status, 169
operational status condition, 169
questionable data, 167
standard event, 165
status byte summary, 161
regsister
event, 159
relative
See null
remote interface
language restrictions, 101
selecting HP-IB (IEEE-488), 101
selecting RS-232, 101
selection, 189
setting input channel, 140
triggering, 80
removing
carrying handle, 27
rubber bumper, 27
reset state, 112 - 114
resistance
test current used, 68
test currents used, 260 - 261
resistance measurements, 68 - 70, 258
connections, 20
low power, 69
offset compensated, 69
voltage lmited, 70

N
NMR
See normal mode rejection
noise
ground loop, 253
injected current, 257
magnetic loops, 251
power-line voltage, 252
reducing by averaging, 60
vs NPLC, 60
noise rejection, 24, 43, 58, 252
non-volatile memory, 113
normal mode rejection, 58, 252
NPLC, 25, 44, 58, 60, 129, 252
equivalent, 60
null, 258
2-wire test lead resistance, 258
annunciator operation, 78
chart output, 98 - 100
commands, 145
difference, 49
difference measurement, 67
null measurements, 77
commands, 145
example, 38
front-panel, 45
null test lead resistance, 77
number of digits, 24, 43, 62, 285
number of samples, 86
number of triggers, 86

P
parameters
in commands, 185
menu, 33 - 40
range, 129
resolution, 129
parity, 176, 191
configurations, 104
setting, 104
PLC
See NPLC
power dissipation effects, 260
power line cycles, 58, 252
power-line
fuse holder , 5, 14
voltage setting , 5, 14
power-line frequency, 252
power-on sensing, 252
power-line noise
rejecting, 252
power-on state, 112 - 114
prepare for use, 13
preset, 113
printer connections, 106
printers, 187
programming
sequence simplified, 126 - 133
programming language
compatibility, 193
selection, 105, 192

Q
query commands, 184
questionable data register, 167
QuickC, 230 - 241

292

Index

R (continued)

S (continued)

resolution, 24, 43
1/2 digit, 24, 26, 43
front-panel keys, 24, 43
half digit, 24, 43
parameters, 129
specification described, 286
revision of frimware, 95
RFI, 250
rollover for chart output, 100
RS-232
adapter kit, 178
commands, 182
connector , 5
connector pinout, 106
interface configuration, 176 - 181
talk only, 106
troubleshooting, 181
RS-232 interface
data format, 177
RS-232 interface cables, 106
RTD, 72
connections, 21
described, 264
rubber bumpers
removing, 27

sensitivity band
reading hold, 48, 79
serial poll, 162
service request, 162
setting
alternate languages, 192
baud rate, 103, 190
calibration security code, 107
display off, 94
function on remote interface, 137 - 139
HP-IB address, 188
input channel, 41
integration time, 25, 44
NPLC, 25, 44
null example, 38
number of digits, 24, 43
parity, 104, 191
programming language, 105
range, 23, 42
range on remote interface, 137 - 139
remote interface, 101, 189
resolution on remote interface, 137 - 139
temperature units, 71
settling delays, 262
settling time, 262
shift key, 12
shorting plug, 273
single trigger, 47
single triggering, 82
software (bus) triggering, 84
span
chart, 98 - 100
specifications, 276
interpreting, 285 - 286
temperature coefficients, 287
SRQ, 162 - 163
standard event register, 165
bit definitions, 165
start bit, 177
statistics
See stats
stats, 46, 75, 149
status byte, 161
bit definitions, 161
summary register, 161
using *STB? and, 163

status register
condition, 159, 169
condition register, 159
enable register, 159
event register, 159
operational, 169
status registers, 159
register diagram, 160
status reporting commands, 171 - 173
stop bit, 177
stopping measurements, 85, 187
storing
readings, 50 - 52
stats, 46
supplied items, 13
system commands, 157 - 158

S
sample count, 86
scaling, 74, 150
scan, 19, 41
SCPI
command summary, 117 - 125
compliance information, 194 - 196
data types, 185
language introduction, 183
programming sequence, 126 - 133
status model, 159
version query, 96
security code
changing, 109
rules, 107
self-test, 93
complete, 13, 93
power-on, 93
self-test errors, 208
sensitivity, 285

T
T/C
See thermocouple
talk only, 187
RS-232, 106
TALK ONLY for printers, 187
TALK ONLY mode, 102
temperature
coefficients and accuracy, 287
measurements, 71 - 73, 142 - 144
RTD measurements, 21, 72
thermistor measurements, 21, 72
thermocouple measurements, 22, 73
units, 71
temperature coefficients, 287
terminal connections, 106
test current, 68
test current for resistance
measurements, 68
test currents, 260 - 261
test lead resistance, 258
nulling, 45
thermal EMF errors, 251
thermistor, 72
connections, 21
described, 264
external reference, 270
internal reference, 22, 270

293

I
n
d
e
x

Index

T (continued)

thermocouple, 73
color code, 269
connections, 22
described, 265
errors, 251, 270
external reference, 270
fixed reference, 270
internal reference, 270
types supported, 269
thresholds for autorange, 23
transducer
See thermistor, thermocouple, or RTD
transducer types supported, 263
trigger, 151 - 153
autodelay, 89
commands, 154 - 155
delay, 87
delays, 89
number of, 86
TRIGGER 722, 84
trigger count, 86
trigger delay
automatic, 87
trigger source, 82
triggering, 80 - 89, 151
delay, 87
flowchart, 80
front-panel , 47
idle trigger state, 85
internal, 84
multiple readings, 86
multiple triggers, 86
sources, 82, 151
wait-for-trigger state, 85
triggering
software (bus), 84
troubleshooting, 14 - 15
RS-232, 181
Turbo C, 230 - 241
tutorial
front-panel menu, 33 - 40
twisted-pair connections, 249
two-wire ohms, 258

unsecuring for calibration, 108

294

V
Visual Basic examples, 223 - 229
VM Comp terminal, 97
volatile memory, 112
voltage
connections, 19
difference measurements, 49
loading errors, 255
measurement connections, 19
measurements, 66 - 67
ratio measurements, 49
voltage limited resistance, 70, 261
commands, 141
voltmeter complete, 97
voltmeter complete terminal, 5

W
wait-for-trigger state, 85, 130, 153
Windows, 242 - 246

DECLARATION OF CONFORMITY
According to ISO/IEC Guide 22 and CEN/CENELEC EN 45014

Manufacturer’s Name:
Manufacturer’s Address:

Agilent Technologies, Incorporated
th
815 – 14 St. SW
Loveland, Colorado 80537
USA

Declares, that the product
Product Name:
Model Number:
Product Options:

Nano Volt / Micro Ohm Meter
34420A
This declaration covers all options of the above product(s).

Conforms with the following European Directives:
The product herewith complies with the requirements of the Low Voltage Directive 73/23/EEC and the EMC Directive 89/336/EEC
(including 93/68/EEC) and carries the CE Marking accordingly.

Conforms with the following product standards:
EMC

Standard

Limit

IEC 61326-1:1997+A1:1998 / EN 61326-1:1997+A1:1998
CISPR 11:1990 / EN 55011:1991
IEC 61000-4-2:1995+A1:1998 / EN 61000-4-2:1995
IEC 61000-4-3:1995 / EN 61000-4-3:1995
IEC 61000-4-4:1995 / EN 61000-4-4:1995
IEC 61000-4-5:1995 / EN 61000-4-5:1995
IEC 61000-4-6:1996 / EN 61000-4-6:1996
IEC 61000-4-11:1994 / EN 61000-4-11:1994

Group 1 Class A
4kV CD, 8kV AD
3 V/m, 80-1000 MHz
0.5kV signal lines, 1kV power lines
0.5 kV line-line, 1 kV line-ground
3V, 0.15-80 MHz
Dips: 30% 10ms; 60% 100ms
Interrupt > 95%@5000ms

Canada: ICES-001:1998
Australia/New Zealand: AS/NZS 2064.1
The product was tested in a typical configuration with Agilent Technologies test systems.

Safety

IEC 61010-1:1990+A1:1992+A2:1995 / EN 61010-1:1993+A2:1995
Canada: CSA C22.2 No. 1010.1:1992
UL 3111-1: 1994

18 July 2001
Date

Ray Corson
Product Regulations Program Manager

For further information, please contact your local Agilent Technologies sales office, agent or distributor.
Authorized EU-representative: Agilent Technologies Deutschland GmbH, Herrenberger Straβe 130, D 71034 Böblingen, Germany

Revision: B.01

Issue Date: 18 July 2001

Document 34401A.DOC

Source Exif Data: 
File Type                       : PDF
File Type Extension             : pdf
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Create Date                     : 1998:12:08 10:58:54Z
Creator                         : Windows NT 4.0
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Keywords                        : 34420A, micro ohm meter, nano volt meter, meter, multimeter, manual, user's guide, 34420-90001
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Title                           : HP 34420A User's Guide

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Agilent 34420A User's Guide

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