Agilent 34970A User's Guide Agilent34970A Users

Agilent34970A-UsersGuide

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User’s Guide

Publication Number 34970-90003 (order as 34970-90101 manual set)

Edition 3, March 2003

For Safety information, Warranties, and Regulatory information,

see the pages following the Index.

Agilent 34970A

Data Acquistion / Switch Unit

Cover Page for Web Version ONLY (User’s Guide)

The Agilent Technologies 34970A combines precision measurement

capability with flexible signal connections for your production and

development test systems. Three module slots are built into the rear

of the instrument to accept any combination of data acquisition or

switching modules. The combination of data logging and data

acquisition features makes this instrument a versatile solution for your

testing requirements now and in the future.

Convenient Data Logging Features

•Direct measurement of thermocouples, RTDs, thermistors, dc voltage,

ac voltage, resistance, dc current, ac current, frequency, and period

•Interval scanning with storage of up to 50,000 time-stamped readings

•Independent channel configuration with function, Mx+B scaling,

and alarm limits available on a per-channel basis

•Intuitive user interface with knob for quick channel selection,

menu navigation, and data entry from the front panel

•Portable, ruggedized case with non-skid feet

•BenchLink Data Logger Software for Microsoft ® Windows ® included

Flexible Data Acquisition / Switching Features

•61⁄2-digit multimeter accuracy, stability, and noise rejection

•Up to 60 channels per instrument (120 single-ended channels)

•Reading rates up to 600 readings per second on a single channel and

scan rates up to 250 channels per second

•Choice of multiplexing, matrix, general-purpose Form C switching,

RF switching, digital I/O, totalize, and 16-bit analog output functions

•GPIB (IEEE-488) interface and RS-232 interface are standard

•SCPI (Standard Commands for Programmable Instruments) compatibility

Agilent 34970A

Data Acquisition / Switch Unit

Note: Unless otherwise indicated, this manual applies to all serial numbers.

Page 1 (User’s Guide)

The Front Panel at a Glance

1 State Storage / Remote Interface Menus

2 Scan Start / Stop Key

3 Measurement Configuration Menu

4 Scaling Configuration Menu

5 Alarm / Alarm Output Configuration Menu

6 Scan-to-Scan Interval Menu

7 Scan List Single Step / Read Key

8 Advanced Measurement / Utility Menus

9 Low-Level Module Control Keys

10 Single-Channel Monitor On / Off Key

11 View Scanned Data, Alarms, Errors Menu

12 Shift / Local Key

13 Knob

14 Navigation Arrow Keys

Denotes a menu key. See the next page for details on menu operation.

The Front-Panel Menus at a Glance

Several of the front-panel keys guide you through menus to configure

various parameters of the instrument (see previous page). The following

steps demonstrate the menu structure using the key.

Tip: To review the current configuration of a specific menu, press the menu key several times.

A message NO CHANGES is displayed when you exit the menu.

4 Press the same menu key again to accept the

change and exit the menu. A brief confirmation

message is displayed.

2 Press the same menu key again to move

to the next item of the menu. Typically,

this is where you choose parameter values

for the selected operation.

3 Rotate the knob to view the choices on this

level of the menu. When you reach the end

of the list, rotate the knob in the opposite

direction to view all of the other choices.

The current selection is highlighted for emphasis.

All other choices are dimmed.

1 Press the menu key. You are automatically

guided to the first level of the menu.

Rotate the knob to view the other choices

on the first level of the menu.

The menu will automatically timeout after

about 20 seconds of inactivity. You will be

returned to the operation in progress prior

to entering the menu.

Display Annunciators

To review the display annunciators, hold down the key as you

turn on the instrument.

SCAN

MON

VIEW

CONFIG

ADRS

RMT

ERROR

EXT

ONCE

MEM

LAST

MIN

MAX

SHIFT

Scan is in progress or enabled. Press and hold again to turn off.

Monitor mode is enabled. Press again to turn off.

Scanned readings, alarms, errors, or relay cycles are being viewed.

Channel configuration is in progress on displayed channel.

Measurement is in progress.

Instrument is addressed to listen or talk over the remote interface.

Instrument is in remote mode (remote interface).

Hardware or remote interface errors are detected. Press to read errors.

Instrument is configured for an external scan interval.

Scan Once mode is enabled. Press to initiate and hold key to disable.

Reading memory overflow; new readings will overwrite the oldest readings.

Viewed data is the last reading stored during most recent scan.

Viewed data is the minimum reading stored during most recent scan.

Viewed data is the maximum reading stored during most recent scan.

has been pressed. Press again to turn off.

4-wire function is in use on displayed channel.

Offset compensation is enabled on displayed channel.

Alarms are enabled on displayed channel.

Mx+B scaling is enabled on displayed channel.

HI or LO alarm condition has occurred on indicated alarms.

The Rear Panel at a Glance

WARNING For protection from electrical shock, the power cord ground must not be

defeated. If only a two-contact electrical outlet is available, connect the

instrument’s chassis ground screw (see above) to a good earth ground.

1 Slot Identifier (100, 200, 300)

2 Ext Trig Input / Alarm Outputs / Channel

Advance Input / Channel Closed Output

(for pinouts, see pages 83 and 128)

3 RS-232 Interface Connector

4 Power-Line Fuse-Holder Assembly

5 Power-Line Voltage Setting

6 Chassis Ground Screw

7 GP-IB (IEEE-488) Interface Connector

Use the Menu to:

• Select the GP-IB or RS-232 interface (see chapter 2).

• Set the GP-IB address (see chapter 2).

• Set the RS-232 baud rate, parity, and flow control mode (see chapter 2).

BenchLink Data Logger Software at a Glance

Agilent BenchLink Data Logger is a Windows-based application

designed to make it easy to use the 34970A with your PC for gathering

and analyzing measurements. Use the software to set up your test,

acquire and archive measurement data, and perform real-time display

and analysis of your incoming measurements.

BenchLink Data Logger’s key functions include the following:

•Configure measurements on the spreadsheet-like Scan Setup page.

•Display measurements graphically using the real-time Data Grid,

Strip Chart, Readout, Bar Meter, XY Plot, and Histogram windows.

•Add or configure graphics at any time.

•Use graphical controls to set output voltages, close channels, output

digital values, or view alarms.

•Copy measurement data and graphics to a file or to the Clipboard for

use in other applications.

•Add textual annotation and explanations to measurement results and

test reports.

•Track readings on a single channel through the Monitor toolbar.

•Enter information into the Event Log automatically or manually

while acquiring measurement data or during post-scan analysis.

•Print scan setups, event logs, and graphics.

•Communicate with the instrument using GPIB, RS-232, modem,

or LAN (using a LAN-to-GPIB gateway).

To install the software, refer to “Installing BenchLink Data Logger

Software” on page 18.

To learn more about the software and its capabilities, refer to the

On-Line Help System for BenchLink Data Logger.

The Plug-In Modules at a Glance

For complete specifications on each plug-in module, refer to the module

sections in chapter 9.

34901A 20-Channel Armature Multiplexer

•20 channels of 300 V switching

•Two channels for DC or AC current measurements (100 nA to 1A)

•Built-in thermocouple reference junction

•Switching speed of up to 60 channels per second

•Connects to the internal multimeter

•For detailed information and a module diagram, see page 164.

Each of the 20 channels switches both HI and LO inputs, thus providing

fully isolated inputs to the internal multimeter. The module is divided

into two banks of 10 two-wire channels each. When making four-wire

resistance measurements, channels from Bank A are automatically

paired with channels from Bank B. Two additional fused channels are

included on the module (22 channels total) for making calibrated DC or

AC current measurements with the internal multimeter (external shunt

resistors are not required). You can close multiple channels on this

module only if you have not configured any channels to be part of the

scan list. Otherwise, all channels on the module are break-before-make.

34902A 16-Channel Reed Multiplexer

•16 channels of 300 V switching

•Built-in thermocouple reference junction

•Switching speed of up to 250 channels per second

•Connects to the internal multimeter

•For detailed information and a module diagram, see page 166.

Use this module for high-speed scanning and high-throughput

automated test applications. Each of the 16 channels switches both

HI and LO inputs, thus providing fully isolated inputs to the internal

multimeter. The module is divided into two banks of eight two-wire

channels each. When making four-wire resistance measurements,

channels from Bank A are automatically paired with channels from

Bank B. You can close multiple channels on this module only if you have

not configured any channels to be part of the scan list. Otherwise, all

channels on the module are break-before-make.

34903A 20-Channel Actuator / General-Purpose Switch

•300 V, 1 A actuation and switching

•SPDT (Form C) latching relays

•Breadboard area for custom circuits

•For detailed information and a module diagram, see page 168.

Use this module for those applications that require high-integrity

contacts or quality connections of non-multiplexed signals. This module

can switch 300 V, 1 A (50 W maximum switch power) to your device

under test or to actuate external devices. Screw terminals on the module

provide access to the Normally-Open, Normally-Closed, and Common

contacts for each of the 20 switches. A breadboard area is provided near

the screw terminals to implement custom circuitry, such as simple

filters, snubbers, or voltage dividers.

34904A 4x8 Two-Wire Matrix Switch

•32 two-wire crosspoints

•Any combination of inputs and outputs can be connected at a time

•300 V, 1 A switching

•For detailed information and a module diagram, see page 170.

Use this module to connect multiple instruments to multiple points on

your device under test at the same time. You can connect rows and

columns between multiple modules to build larger matrices such as

8x8 and 4x16, with up to 96 crosspoints in a single mainframe.

34905/6A Dual 4-Channel RF Multiplexers

•34905A (50Ω) / 34906A (75Ω)

•2 GHz bandwidth with on-board SMB connections

•1 GHz bandwidth with SMB-to-BNC adapter cables provided

•For detailed information and a module diagram, see page 172.

These modules offer wideband switching capabilities for high frequency

and pulsed signals. Each module is organized in two independent banks

of 4-to-1 multiplexers. Both modules offer low crosstalk and excellent

insertion loss performance. To create larger RF multiplexers, you can

cascade multiple banks together. Only one channel in each bank may be

closed at a time.

34907A Multifunction Module

•Two 8-bit Digital Input/Output ports, 400 mA sink, 42 V open collector

•100 kHz Totalize input with 1 Vpp sensitivity

•Two ±12 V Calibrated Analog Outputs

•For detailed information and module block diagrams, see page 174.

Use this module to sense status and control external devices such as

solenoids, power relays, and microwave switches. For greater flexibility,

you can read digital inputs and the count on the totalizer during a scan.

34908A 40-Channel Single-Ended Multiplexer

•40 channels of 300 V single-ended (common LO) switching

•Built-in thermocouple reference junction

•Switching speed of up to 60 channels per second

•Connects to the internal multimeter

•For detailed information and a module diagram, see page 176.

Use this module for high-density switching applications which require

single-wire inputs with a common LO. All relays are break-before-make

to ensure that only one relay is connected at any time.

In This Book

Quick Start Chapter 1 helps you get familiar with a few of the

instrument’s front-panel features. This chapter also shows how to

install the BenchLink Data Logger software.

Front-Panel Overview Chapter 2 introduces you to the front-panel

menus and describes some of the instrument’s menu features.

System Overview Chapter 3 gives an overview of a data acquisition

system and describes how parts of a system work together.

Features and Functions Chapter 4 gives a detailed description of the

instrument’s capabilities and operation. You will find this chapter

useful whether you are operating the instrument from the front panel or

over the remote interface.

Remote Interface Reference Chapter 5 contains reference

information to help you program the instrument over the remote

interface using the SCPI language.

Error Messages Chapter 6 lists the error messages that may appear

as you are working with the instrument. Each listing contains enough

information to help you diagnose and solve the problem.

Application Programs Chapter 7 contains several remote interface

program examples to help you develop programs for your application.

Tutorial Chapter 8 discusses measurement considerations and

techniques to help you obtain the best accuracies and reduce sources of

measurement noise.

Specifications Chapter 9 lists the technical specifications for the

mainframe and plug-in modules.

If you have questions relating to the operation of the 34970A,

call 1-800-452-4844 in the United States, or contact your nearest

Agilent Technologies Sales Office.

If your 34970A fails within three years of original purchase, Agilent will

either repair or replace it free of charge. Call 1-877-447-7278 and ask

for “Express Exchange” or contact your local Agilent office.

Contents

Chapter 1 Quick Start

To Prepare the Instrument for Use 17

Installing BenchLink Data Logger Software 18

To Connect Wiring to a Module 20

To Set the Time and Date 22

To Configure a Channel for Scanning 23

To Copy a Channel Configuration 25

To Close a Channel 26

If the Instrument Does Not Turn On 27

To Adjust the Carrying Handle 29

To Rack Mount the Instrument 30

Chapter 2 Front-Panel Overview

Front-Panel Menu Reference 35

To Monitor a Single Channel 37

To Set a Scan Interval 38

To Apply Mx+B Scaling to Measurements 39

To Configure Alarm Limits 40

To Read a Digital Input Port 42

To Write to a Digital Output Port 43

To Read the Totalizer Count 44

To Output a DC Voltage 45

To Configure the Remote Interface 46

To Store the Instrument State 48

Chapter 3 System Overview

Data Acquisition System Overview 50

Signal Routing and Switching 57

Measurement Input 60

Control Output 67

Contents

Chapter 4 Features and Functions

SCPI Language Conventions 73

Scanning 74

Single-Channel Monitoring 93

Scanning With External Instruments 95

General Measurement Configuration 98

Temperature Measurement Configuration 106

Voltage Measurement Configuration 113

Resistance Measurement Configuration 115

Current Measurement Configuration 116

Frequency Measurement Configuration 118

Mx+B Scaling 119

Alarm Limits 122

Digital Input Operations 133

Totalizer Operations 135

Digital Output Operations 138

DAC Output Operations 139

System-Related Operations 140

Remote Interface Configuration 150

Calibration Overview 155

Factory Reset State 160

Instrument Preset State 161

Multiplexer Module Default Settings 162

Module Overview 163

34901A 20-Channel Multiplexer 164

34902A 16-Channel Multiplexer 166

34903A 20-Channel Actuator 168

34904A 4x8 Matrix Switch 170

34905A/6A Dual 4-Channel RF Multiplexers 172

34907A Multifunction Module 174

34908A 40-Channel Single-Ended Multiplexer 176

Contents

Chapter 5 Remote Interface Reference

SCPI Command Summary 181

Simplified Programming Overview 201

The MEASure? and CONFigure Commands 207

Setting the Function, Range, and Resolution 214

Temperature Configuration Commands 219

Voltage Configuration Commands 223

Resistance Configuration Commands 224

Current Configuration Commands 224

Frequency Configuration Commands 225

Scanning Overview 226

Single-Channel Monitoring Overview 237

Scanning With an External Instrument 239

Mx+B Scaling Overview 244

Alarm System Overview 247

Digital Input Commands 255

Totalizer Commands 256

Digital Output Commands 258

DAC Output Commands 258

Switch Control Commands 259

State Storage Commands 261

System-Related Commands 264

Interface Configuration Commands 269

RS-232 Interface Configuration 270

Modem Communications 274

The SCPI Status System 275

Status System Commands 286

Calibration Commands 292

Service-Related Commands 294

An Introduction to the SCPI Language 296

Using Device Clear 302

Chapter 6 Error Messages

Execution Errors 305

Instrument Errors 309

Self-Test Errors 314

Calibration Errors 315

Plug-In Module Errors 317

Contents

Chapter 7 Application Programs

Example Programs for Excel 7.0 321

Example Programs for C and C++ 328

Chapter 8 Tutorial

System Cabling and Connections 335

Measurement Fundamentals 343

Low-Level Signal Multiplexing 378

Actuators and General-Purpose Switching 384

Matrix Switching 388

RF Signal Multiplexing 390

Multifunction Module 392

Relay Life and Preventative Maintenance 399

Chapter 9 Specifications

DC, Resistance, and Temperature Accuracy Specifications 404

DC Measurement and Operating Characteristics 405

AC Accuracy Specifications 406

AC Measurement and Operating Characteristics 407

Measurement Rates and System Characteristics 408

Module Specifications 409

BenchLink Data Logger Software Specifications 412

Product and Module Dimensions 413

To Calculate Total Measurement Error 414

Interpreting Internal DMM Specifications 416

Configuring for Highest Accuracy Measurements 419

Index

Contents

Quick Start

One of the first things you will want to do with your instrument is to

become acquainted with the front panel. We have written the exercises

in this chapter to prepare the instrument for use and help you get

familiar with some of its front-panel operations.

The front panel has several groups of keys to select various functions

and operations. A few keys have a shifted function printed in blue below

the key. To perform a shifted function, press (the SHIFT annunciator

will turn on). Then, press the key that has the desired label below it.

For example, to select the Utility Menu, press .

If you accidentally press , just press it again to turn off the SHIFT

annunciator.

This chapter is divided into the following sections:

•To Prepare the Instrument for Use, on page 17

•Installing BenchLink Data Logger Software, on page 18

•To Connect Wiring to a Module, on page 20

•To Set the Time and Date, on page 22

•To Configure a Channel for Scanning, on page 23

•To Copy a Channel Configuration, on page 25

•To Close a Channel, on page 26

•If the Instrument Does Not Turn On, on page 27

•To Adjust the Carrying Handle, on page 29

•To Rack Mount the Instrument, on page 30

To Prepare the Instrument for Use

1 Check the list of supplied items.

Verify that you have received the following items with your instrument.

If anything is missing, contact your nearest Agilent Technologies Sales Office.

One power cord.

This User’s Guide.

One Service Guide.

One Quick Reference Guide.

Certificate of Calibration (if you ordered the internal DMM).

Quick Start Package (if you ordered the internal DMM):

• One RS-232 cable.

• BenchLink Data Logger Software CD-ROM.

To install the software, see page 18.

• One J-type thermocouple and a flatblade screwdriver.

Any plug-in modules that you ordered are delivered in a separate

shipping container.

2 Connect the power cord and turn on the instrument.

The front-panel display will light up briefly while the instrument

performs its power-on self-test. The GPIB address is also displayed.

The instrument initially powers up with all measurement channels

turned off. To review the power-on display with all annunciators

turned on, hold down as you turn on the instrument. If the

instrument does not turn on properly, see page 27.

3Perform a complete self-test.

The complete self-test performs a more extensive set of tests than those

performed at power-on. Hold down as you turn on the instrument

and hold down the key until you hear a long beep. The self-test will begin

when you release the key following the beep.

If the self-test fails, see the 34970A Service Guide for instructions on

returning the instrument to Agilent for service.

On/Standby

Switch

WARNING

Note that this switch

is Standby only.

To disconnect the

mains from the

instrument, remove

the power cord.

Chapter 1 Quick Start

To Prepare the Instrument for Use

Installing BenchLink Data Logger Software

If you ordered the 34970A with the internal DMM, then the BenchLink

Data Logger software is included. The software is shipped on one

CD-ROM, but includes a utility to build installation floppy disks.

To install the software on your PC, you will need a minimum of 12 MB

of free disk space.

For system requirements and additional details on the features of the

software, refer to the specifications in chapter 9.

Installation Procedure

If you are running Windows 95 or Windows NT 4.0 ®

1. Insert the CD-ROM into your drive.

2. Select Settings | Control Panel from the Start menu. Double-click on

the

Add/Remove Programs icon.

3. Select the Install/Uninstall tab on the Add/Remove Programs property

sheet. Click on Install and follow the on-screen instructions.

If you are running Windows ® 3.1

1. Insert the CD-ROM into your drive.

2. Select File | Run from the Program Manager menu bar.

3. Type <drive>:\setup, where drive is the letter representing your

CD-ROM drive. Click OK to continue and follow the on-screen

instructions.

Chapter 1 Quick Start

Installing BenchLink Data Logger Software

Creating Installation Floppy Disks

You have the option to create an installation on floppy disks from the

CD-ROM installation utility. This utility is provided so that you can

install BenchLink Data Logger on a computer that does not have a

CD-ROM drive.

Note: You will need a total of five (5) formatted floppy disks to create

an installation.

1. Go to a computer that is equipped with a CD-ROM drive.

2. Start the installation procedure as described on the previous page.

3. Select Create disks... on the initial display of the installation

procedures and follow the on-screen instructions.

On-Line Help System

The software is shipped with an extensive on-line Help system to help

you learn the features of the software as well as troubleshoot any

problems that might arise as you are using the software. As you are

installing the software, you will notice that the on-line Help system is

available in several languages.

Chapter 1 Quick Start

Installing BenchLink Data Logger Software

To Connect Wiring to a Module

6 mm

20 AWG Typical

Channel Number:

Slot Channel

5 Install the module into mainframe. Wiring Hints...

• For detailed information on each module,

refer to the section starting on page 163.

• To reduce wear on the internal DMM relays,

wire like functions on adjacent channels.

• For information on grounding and shielding,

see page 335.

• The diagrams on the next page show how to

connect wiring to a multiplexer module for

each measurement function.

1 Remove the module cover. 2 Connect wiring to the screw terminals.

4 Replace the module cover.

Cable Tie Wrap

(optional)

3 Route wiring through strain relief.

Chapter 1 Quick Start

To Connect Wiring to a Module

DC Voltage / AC Voltage / Frequency Thermocouple

Thermocouple Types: B, E, J, K, N, R, S, T

See page 351 for thermocouple color codes. Ranges: 100 mV, 1 V, 10 V, 100 V, 300 V

4-Wire Ohms / RTD 2-Wire Ohms / RTD / Thermistor

Ranges: 100, 1 k, 10 k, 100 k, 1 M, 10 M, 100 MΩ

RTD Types: 0.00385, 0.00391

Thermistor Types: 2.2 k, 5 k, 10 k

Channel n (source) is automatically paired with

Channel n+10 (sense) on the 34901A or

Channel n+8 (sense) on the 34902A.

Ranges: 100, 1 k, 10 k, 100 k, 1 M, 10 M, 100 MΩ

RTD Types: 0.00385, 0.00391

DC Current / AC Current

Valid only on channels 21 and 22 on the 34901A.

Ranges: 10 mA, 100 mA, 1A

Chapter 1 Quick Start

To Connect Wiring to a Module

To Set the Time and Date

All readings during a scan are automatically time stamped and stored

in non-volatile memory. In addition, alarm data is time stamped and

stored in a separate non-volatile memory queue.

1 Set the time of day.

Use and to select the field to modify and turn the knob to change

the value. You can also edit the AM/PM field.

7,0(30

2 Set the date.

Use and to select the field to modify and turn the knob to change

the value.

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Utility

Chapter 1 Quick Start

To Set the Time and Date

To Configure a Channel for Scanning

Any channel that can be “read” by the instrument can also be included

in a scan. This includes readings on multiplexer channels, a read of a

digital port, or a read of the count on a totalizer channel. Automated

scanning is not allowed with the RF multiplexer, matrix, actuator,

digital output, or voltage output (DAC) modules.

1 Select the channel to be added to the scan list.

Turn the knob until the desired channel is shown on the right side of

front-panel display. The channel number is a three-digit number;

the left-most digit represents the slot number (100, 200, or 300) and the

two digits on the right indicate the channel number (102, 110, etc.).

Note: You can use and to skip to the beginning of the previous

or next slot.

For this example, assume that you have the 34901A multiplexer

installed in slot 100 and select channel 103.

2 Select the measurement parameters for the selected channel.

Use the knob to scroll through the measurement choices on each level

of the menu. When you press to make your selection, the menu

automatically guides you through all relevant choices to configure a

measurement on the selected function. When you have finished

configuring the parameters, you are automatically exited from the menu.

The current selection (or default) is displayed in full bright for easy

identification. When you make a different selection, the new choice is

shown in full bright and it becomes the default selection. The order of

the choices always remains the same; however, you always enter the

menu at the current (full bright) setting for each parameter.

Note: The menu will timeout after about 20 seconds of inactivity and

any changes made previously will take effect.

For this example, configure channel 103 to measure a J-type thermocouple

with 0.1 °C of display resolution.

Chapter 1 Quick Start

To Configure a Channel for Scanning

Note: Press to sequentially step through the scan list and take a

measurement on each channel (readings are not stored in memory).

This is an easy way to verify your wiring connections before initiating

the scan.

3 Run the scan and store the readings in non-volatile memory.

The instrument automatically scans the configured channels in

consecutive order from slot 100 through slot 300 (the SCAN annunciator

turns on). Channels that are not configured are skipped during the scan.

In the default configuration, the instrument continuously scans the

configured channels at a 10-second interval.

Press and hold to stop the scan.

4 View the data from the scan.

All readings taken during a scan are automatically time stamped and

stored in non-volatile memory. During the scan, the instrument

calculates and stores the minimum, maximum, and average on all

channels in the scan list. You can read the contents of memory at any

time, even during a scan.

From the front panel, data is available for the last 100 readings on each

channel readings taken during a scan (all of the data is available from

the remote interface). From the View menu, select READINGS and press

again. Then press and to choose the data you want to view

for the selected channel as shown in the table below.

and

Select Channel Last Reading on Channel

Time of Last Reading

Minimum Reading on Channel

Time of Minimum Reading

Maximum Reading on Channel

Time of Maximum Reading

Average of Readings on Channel

Second Most Recent Reading on Channel

Third Most Recent Reading on Channel

99th Most Recent Reading on Channel

Chapter 1 Quick Start

To Configure a Channel for Scanning

To Copy a Channel Configuration

After configuring a channel to be included in the scan list, you can

copy that same configuration to other channels in the instrument

(including digital channels on the multifunction module). This feature

makes it easy to configure several channels for the same measurement.

When you copy the configuration from one channel to another, the

following parameters are automatically copied to the new channel:

•Measurement configuration

•Mx+B scaling configuration

•Alarm configuration

•Advanced measurement configuration

1 Select the channel to copy the configuration from.

Turn the knob until the desired channel is shown on the right side of

front-panel display. For this example, let’s copy the configuration from

channel 103.

2 Select the copy function.

Use the knob to scroll through the measurement choices until you see

COPY CONFIG. When you press to make your selection, the menu

automatically guides you to the next step.

3 Select the channel to copy the configuration to.

Turn the knob until the desired channel is shown on the right side of

front-panel display. For this example, let’s copy the configuration to

channel 105.

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4 Copy the channel configuration to the selected channel.

Note: To copy the same configuration to other channels, repeat this procedure.

Chapter 1 Quick Start

To Copy a Channel Configuration

To Close a Channel

On the multiplexer and switch modules, you can close and open individual

relays on the module. However, note that if you have already configured

any multiplexer channels for scanning, you cannot independently close

and open individual relays on that module.

1 Select the channel.

Turn the knob until the desired channel is shown on the right side of

front-panel display. For this example, select channel 213.

2 Close the selected channel.

3 Open the selected channel.

Note: will sequentially open all channels on the module in the

selected slot.

The table below shows the low-level control operations available for

each of the plug-in modules.

Plug-In Module ,

34901A 20-Channel Mux ••• •

34902A 16-Channel Mux ••• •

34908A 40-Channel Single-Ended Mux [1] ••• •

34903A 20-Channel Actuator ••

34904A 4x8 Matrix ••

34905A Dual 4-Channel RF Mux (50Ω) [2] •

34906A Dual 4-Channel RF Mux (75Ω) [2] •

34907A Multifunction Module (DIO) •• •

34907A Multifunction Module (Totalizer) ••

34907A Multifunction Module (DAC) •

[1] Only one channel can be closed at a time on this module.

[2] Only one channel in each bank can be closed at a time on this module.

Chapter 1 Quick Start

To Close a Channel

If the Instrument Does Not Turn On

Use the following steps to help solve problems you might encounter

when turning on the instrument. If you need more help, refer to the

34970A Service Guide for instructions on returning the instrument to

Agilent for service.

1 Verify that there is ac power to the instrument.

First, verify that the power cord is firmly plugged into the power

receptacle on the rear panel of the instrument. You should also make

sure that the power source you plugged the instrument into is

energized. Then, verify that the instrument is turned on.

The On/Standby switch is located on the lower left side of the front panel.

2 Verify the power-line voltage setting.

The line voltage is set to the proper value for your country when the

instrument is shipped from the factory. Change the voltage setting if

it is not correct. The settings are: 100, 120, 220, or 240 Vac.

Note: For 127 Vac operation, use the 120 Vac setting.

For 230 Vac operation, use the 220 Vac setting.

See the next page if you need to change the line voltage setting.

3 Verify that the power-line fuse is good.

The instrument is shipped from the factory with a 500 mA fuse installed.

This is the correct fuse for all line voltages.

See the next page if you need to replace the power-line fuse.

To replace the 500 mAT, 250 V fuse, order Agilent part number 2110-0458.

Chapter 1 Quick Start

If the Instrument Does Not Turn On

1 Remove the power cord. Remove the

fuse-holder assembly from the rear panel. 2 Remove the line-voltage selector from

the assembly.

3 Rotate the line-voltage selector until the

correct voltage appears in the window. 4 Replace the fuse-holder assembly in

the rear panel.

Verify that the correct line voltage is selected and the power-line fuse is good.

Fuse: 500 mAT (for all line voltages)

Agilent Part Number: 2110-0458

100, 120 (127), 220 (230) or 240 Vac

Chapter 1 Quick Start

If the Instrument Does Not Turn On

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 Adjust the Carrying Handle

To Rack Mount the Instrument

You can mount the instrument 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 Agilent System II

instrument of the same size can be rack-mounted beside the 34970A.

Note: Remove the carrying handle, and the front and rear rubber bumpers,

before rack-mounting the instrument.

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

Front Rear (bottom view)

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

Chapter 1 Quick Start

To Rack Mount the Instrument

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

flange kit 5063-9212. Be sure to use the support rails inside the rack cabinet.

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).

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

Chapter 1 Quick Start

To Rack Mount the Instrument

Front-Panel

Overview

Front-Panel Overview

This chapter introduces you to the front-panel keys and menu operation.

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 many front-panel operations. See chapter 4

“Features and Functions,” starting on page 71, for a complete discussion

of the instrument’s capabilities and operation.

This chapter is divided into the following sections:

•Front-Panel Menu Reference, on page 35

•To Monitor a Single Channel, on page 37

•To Set a Scan Interval, on page 38

•To Apply Mx+B Scaling to Measurements, on page 39

•To Configure Alarm Limits, on page 40

•To Read a Digital Input Port, on page 42

•To Write to a Digital Output Port, on page 43

•To Read the Totalizer Count, on page 44

•To Output a DC Voltage, on page 45

•To Configure the Remote Interface, on page 46

•To Store the Instrument State, on page 48

Front-Panel Menu Reference

This section gives an overview of the front-panel menus. The menus are

designed to automatically guide you through all parameters required to

configure a particular function or operation. The remainder of this

chapter shows examples of using the front-panel menus.

Configure the measurement parameters on the displayed channel.

• Select measurement function (dc volts, ohms, etc.) on the displayed channel.

• Select transducer type for temperature measurements.

• Select units (°C, °F, or K) for temperature measurements.

• Select measurement range or autorange.

• Select measurement resolution.

• Copy and paste measurement configuration to other channels.

Configure the scaling parameters for the displayed channel.

• Set the gain (“M”) and offset (“B”) value for the displayed channel.

• Make a null measurement and store it as the offset value.

• Specify a custom label (RPM, PSI, etc.) for the displayed channel.

Configure alarms on the displayed channel.

• Select one of four alarms to report alarm conditions on the displayed channel.

• Configure a high limit, low limit, or both for the displayed channel.

• Configure a bit pattern which will generate an alarm (digital input only).

Configure the four Alarm Output hardware lines.

• Clear the state of the four alarm output lines.

• Select the “Latch” or “Track” mode for the four alarm output lines.

• Select the slope (rising or falling edge) for the four alarm output lines.

Configure the event or action that controls the scan interval.

• Select the scan interval mode (interval, manual, external, or alarm).

• Select the scan count.

Chapter 2 Front-Panel Overview

Front-Panel Menu Reference

Configure the advanced measurement features on displayed channel.

• Set the integration time for measurements on the displayed channel.

• Set the channel-to-channel delay for scanning.

• Enable/disable the thermocouple check feature (T/C measurements only).

• Select the reference junction source (T/C measurements only).

• Set the low frequency limit (ac measurements only).

• Enable/disable offset compensation (resistance measurements only).

• Select the binary or decimal mode for digital operations (digital input/output only).

• Configure the totalizer reset mode (totalizer only).

• Select which edge is detected (rising or falling) for totalizer operations.

Configure system-related instrument parameters.

• Set the real-time system clock and calendar.

• Query the firmware revisions for the mainframe and installed modules.

• Select the instrument’s power-on configuration (last or factory reset).

• Enable/disable the internal DMM.

• Secure/unsecure the instrument for calibration.

View readings, alarms, and errors.

• View the last 100 scanned readings from memory (last, min, max, and average).

• View the first 20 alarms in the alarm queue (reading and time alarm occurred).

• View up to 10 errors in the error queue.

• Read the number of cycles for the displayed relay (relay maintenance feature).

Store and recall instrument states.

• Store up to five instrument states in non-volatile memory.

• Assign a name to each storage location.

• Recall stored states, power-down state, factory reset state, or preset state.

Configure the remote interface.

• Select the GPIB address.

• Configure the RS-232 interface (baud rate, parity, and flow control).

Chapter 2 Front-Panel Overview

Front-Panel Menu Reference

To Monitor a Single Channel

You can use the Monitor function to continuously take readings on a single

channel, even during a scan. This feature is useful for troubleshooting your

system before a test or for watching an important signal.

1 Select the channel to be monitored.

Only one channel can be monitored at a time but you can change the

channel being monitored at any time by turning the knob.

2 Enable monitoring on the selected channel.

Any channel that can be “read” by the instrument can be monitored

(the MON annunciator turns on). This includes any combination of

temperature, voltage, resistance, current, frequency, or period

measurements on multiplexer channels. You can also monitor a digital

input port or the totalizer count on the multifunction module.

To disable monitoring, press again.

Chapter 2 Front-Panel Overview

To Monitor a Single Channel

To Set a Scan Interval

You can set the instrument’s internal timer to automatically scan at a

specific interval (e.g., start a new scan sweep every 10 seconds) or when

an external TTL trigger pulse is received. You can configure the

instrument to scan continuously or to stop after sweeping through the

scan list a specified number of times.

1 Select the interval scan mode.

For this example, select the Interval Scan mode which allows you to set

the time from the start of one scan sweep to the start of the next scan

sweep. Set the interval to any value between 0 and 99 hours.

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2 Select the scan count.

You can specify the number of times that the instrument will sweep

through the scan list (the default is continuous). When the specified

number of sweeps have occurred, the scan stops. Set the scan count to

any number between 1 and 50,000 scans (or continuous).

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3 Run the scan and store the readings in memory.

Chapter 2 Front-Panel Overview

To Set a Scan Interval

To Apply Mx+B Scaling to Measurements

The scaling function allows you to apply a gain and offset to all readings

on a specified multiplexer channel during a scan. In addition to setting

the gain (“M”) and offset (“B”) values, you can also specify a custom

measurement label for your scaled readings (RPM, PSI, etc.).

1 Configure the channel.

You must configure the channel (function, transducer type, etc.) before

applying any scaling values. If you change the measurement

configuration, scaling is turned off on that channel and the gain and

offset values are reset (M=1 and B=0).

2 Set the gain and offset values.

The scaling values are stored in non-volatile memory for the specified

channels. A Factory Reset turns off scaling and clears the scaling values

on all channels. An Instrument Preset or Card Reset does not clear the

scaling values and does not turn off scaling.

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3 Select the custom label.

You can specify an optional three-character label for your scaled

readings (RPM, PSI, etc.). The default label is the standard engineering

unit for the selected function (VDC, OHM, etc.).

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4 Run the scan and store the scaled readings in memory.

Set Gain

Set Offset

Chapter 2 Front-Panel Overview

To Apply Mx+B Scaling to Measurements

To Configure Alarm Limits

The instrument has four alarms which you can configure to alert you

when a reading exceeds specified limits on a channel during a scan.

You can assign a high limit, a low limit, or both to any configured

channel in the scan list. You can assign multiple channels to any of the

four available alarms (numbered 1 through 4).

1 Configure the channel.

You must configure the channel (function, transducer type, etc.) before

setting any alarm limits. If you change the measurement configuration,

alarms are turned off and the limit values are cleared. If you plan to use

Mx+B scaling on a channel which will also use alarms, be sure to

configure the scaling values first.

2 Select which of the four alarms you want to use.

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3 Select the alarm mode on the selected channel.

You can configure the instrument to generate an alarm when a

measurement exceeds the specified HI or LO limits (or both) on a

measurement channel.

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Chapter 2 Front-Panel Overview

To Configure Alarm Limits

4 Set the limit value.

The alarm limit values are stored in non-volatile memory for the

specified channels. The default values for the high and low limits are “0”.

The low limit must always be less than or equal to the high limit, even if

you are using only one of the limits. A Factory Reset clears all alarm

limits and turns off all alarms. An Instrument Preset or Card Reset does

not clear the alarm limits and does not turn off alarms.

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5 Run the scan and store the readings in memory.

If an alarm occurs on a channel as it is being scanned, then that

channel’s alarm status is stored in reading memory as the readings are

taken. Each time you start a new scan, the instrument clears all

readings (including alarm data) stored in reading memory from the

previous scan. As alarms are generated, they are also logged in an

alarm queue, which is separate from reading memory. Up to 20 alarms

can be logged in the alarm queue. Reading the alarm queue using the

View menu clears the alarms in the queue.

Chapter 2 Front-Panel Overview

To Configure Alarm Limits

To Read a Digital Input Port

The multifunction module (34907A) has two non-isolated 8-bit

input/output ports which you can use for reading digital patterns.

You can read the live status of the bits on the port or you can configure

a scan to include a digital read.

1 Select the Digital Input port.

Select the slot containing the multifunction module and continue

turning the knob until DIN is displayed (channel 01 or 02).

2 Read the specified port.

You can specify whether you want to use binary or decimal format.

Once you have selected the number base, it is used for all input or

output operations on the same port. To change the number base,

press the key and select USE BINARY or USE DECIMAL.

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The bit pattern read from the port will be displayed until you press

another key, turn the knob, or until the display times out.

Note: To add a digital input channel to a scan list, press and select

the DIO READ choice.

Binary Display Shown

Bit 7 Bit 0

Chapter 2 Front-Panel Overview

To Read a Digital Input Port

To Write to a Digital Output Port

The multifunction module (34907A) has two non-isolated 8-bit

input/output ports which you can use for outputting digital patterns.

1 Select the Digital Output port.

Select the slot containing the multifunction module and continue

turning the knob until DIN is displayed (channel 01 or 02).

2 Enter the bit pattern editor.

Notice that the port is now converted to an output port (DOUT).

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3 Edit the bit pattern.

Use the knob and or keys to edit the individual bit values.

You can specify whether you want to use binary or decimal format.

Once you have selected the number base, it is used for all input or

output operations on the same port. To change the number base,

press the key and select USE BINARY or USE DECIMAL.

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4 Output the bit pattern to the specified port.

The specified bit pattern is latched on the specified port. To cancel an

output operation in progress, wait for the display to time out.

Binary Display Shown

Bit 7 Bit 0

Decimal Display Shown

Chapter 2 Front-Panel Overview

To Write to a Digital Output Port

To Read the Totalizer Count

The multifunction module (34907A) has a 26-bit totalizer which can

count pulses at a 100 kHz rate. You can manually read the totalizer

count or you can configure a scan to read the count.

1 Select the totalizer channel.

Select the slot containing the multifunction module and continue

turning the knob until TOTALIZE is displayed (channel 03).

2 Configure the totalize mode.

The internal count starts as soon as you turn on the instrument.

You can configure the totalizer to reset the count to “0” after being read

or it can count continuously and be manually reset.

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3 Read the count.

The count is read once each time you press ; the count does not

update automatically on the display. As configured in this example,

the count is automatically reset to “0” each time you read it.

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The count will be displayed until you press another key, turn the knob,

or until the display times out. To manually reset the totalizer count,

press .

Note: To add a totalizer channel to a scan list, press and select the

TOT READ choice.

Chapter 2 Front-Panel Overview

To Read the Totalizer Count

To Output a DC Voltage

The multifunction module (34907A) has two analog outputs capable of

outputting calibrated voltages between ±12 volts.

1Select a DAC Output channel.

Select the slot containing the multifunction module and continue

turning the knob until DAC is displayed (channel 04 or 05).

2 Enter the output voltage editor.

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3 Set the desired output voltage.

Use the knob and or keys to edit the individual digits.

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4 Output the voltage from the selected DAC.

The output voltage will be displayed until you press another key or turn

the knob. To manually reset the output voltage to 0 volts, press .

Chapter 2 Front-Panel Overview

To Output a DC Voltage

To Configure the Remote Interface

The instrument is shipped with both an GPIB (IEEE-488) interface

and an RS-232 interface. Only one interface can be enabled at a time.

The GPIB interface is selected when the instrument is shipped from

the factory.

GPIB Configuration

1 Select the GPIB (HPIB) interface.

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2 Select the GPIB address.

You can set the instrument’s address to any value between 0 and 30.

The factory setting is address “9”.

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3 Save the change and exit the menu.

Note: Your computer’s GPIB interface card has its own address.

Be sure to avoid using the computer’s address for any instrument on the

interface bus. Agilent’s GPIB interface cards generally use address “21”.

Interface

Chapter 2 Front-Panel Overview

To Configure the Remote Interface

RS-232 Configuration

1 Select the RS-232 interface.

56

2 Select the baud rate.

Select one of the following: 1200, 2400, 4800, 9600, 19200, 38400,

57600 (factory setting), or 115200 baud.

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3 Select the parity and number of data bits.

Select one of the following: None (8 data bits, factory setting),

Even (7 data bits), or Odd (7 data bits). When you set the parity,

you are also indirectly setting the number of data bits.

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4 Select the flow control method.

Select one of the following: None (no flow control), RTS/CTS, DTR/DSR,

XON/XOFF (factory setting), or Modem.

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5 Save the changes and exit the menu.

Interface

Chapter 2 Front-Panel Overview

To Configure the Remote Interface

To Store the Instrument State

You can store the instrument state in one of five non-volatile storage

locations. A sixth storage location automatically holds the power-down

configuration of the instrument. When power is restored, the instrument

can automatically return to its state before power-down (a scan in

progress before power-down will also be resumed).

1 Select the storage location.

From the front panel, you have the ability to assign names (up to 12

characters) to each of the five stored states.

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The storage locations are numbered 1 through 5. The power-down

state is automatically stored and can be recalled from the front panel

(the state is named LAST PWR DOWN).

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67$7(

2 Store the instrument state.

The instrument stores all channel configurations, alarm values, scaling

values, scan interval setups, and advanced measurement configurations.

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Chapter 2 Front-Panel Overview

To Store the Instrument State

System Overview

This chapter provides an overview of a computer-based system and

describes the parts of a data acquisition system. This chapter is divided

into the following sections:

•Data Acquisition System Overview, see below

•Signal Routing and Switching, starting on page 57

•Measurement Input, starting on page 60

•Control Output, starting on page 67

Data Acquisition System Overview

You can use the Agilent 34970A as a stand-alone instrument but there are

many applications where you will want to take advantage of the built-in PC

connectivity features. A typical data acquisition system is shown below.

Computer

and Software Interface Cable 34970A Plug-in

Modules System

Cabling

Transducers,

Sensors,

and Events

The system configuration shown on the previous page offers the

following advantages:

•You can use the 34970A to perform data storage, data reduction,

mathematical calculations, and conversion to engineering units.

You can use the PC to provide easy configuration and data presentation.

•You can remove the analog signals and measurement sensors from

the noisy PC environment and electrically isolate them from both the

PC and earth ground.

•You can use a single PC to monitor multiple instruments and

measurement points while performing other PC-based tasks.

The Computer and Interface Cable

Since computers and operating systems are the subject of many books

and periodicals, they are not discussed in this chapter. In addition to the

computer and operating system, you will need a serial port (RS-232) or

GPIB port (IEEE-488) and an interface cable.

Serial (RS-232) GPIB (IEEE-488)

Advantages Disadvantages Advantages Disadvantages

Often built into the computer;

no additional hardware is

required.

Cable length is limited

to 45 ft (15 m). *Speed; faster data and

command transfers. Cable length is limited

to 60 ft (20 m). *

Drivers usually included in

the operating system. Only one instrument or

device can be connected

per serial port.

Additional system flexibility,

multiple instruments can

be connected to the

same GPIB port.

Requires an expansion

slot plug-in card in PC

and associated drivers.

Cables readily available

and inexpensive.

The 34970A is

shipped with a serial cable

(if internal DMM is ordered).

Cabling is susceptible to

noise, causing slow or

lost communications.

Varying connector pinouts

and styles.

Direct Memory Transfers

are possible. Requires special cable.

Data transfers up to

85,000 characters/sec. Data transfers up to

750,000 characters/sec.

* You can overcome these cable length limitations using special communications hardware.

For example, you can use the Agilent E5810A LAN-to-GPIB Gateway interface or a serial modem.

Chapter 3 System Overview

Data Acquisition System Overview

Measurement Software

A variety of software is available to configure your data acquisition

hardware and manipulate and display your measurement data.

Data Logging and Monitoring

Agilent BenchLink Data Logger is a Windows®-based application

designed to make it easy to use the 34970A with your PC for gathering

and analyzing measurements. The software is included with the 34970A

when you order the internal DMM. Use this software to set up your test,

acquire and archive measurement data, and perform real-time display

and analysis of your incoming measurements.

Automated Testing with Multiple Instruments

•Agilent VEE

•TransEra HTBASIC® for Windows

•National Instruments LabVIEW

•Microsoft® Visual Basic or Visual C++

Agilent BenchLink Data Logger

Chapter 3 System Overview

Data Acquisition System Overview

The 34970A Data Acquisition / Switch Unit

As shown below, the logic circuitry for the 34970A is divided into two

sections: earth-referenced and floating. These two sections are isolated

from each other in order to maintain measurement accuracy and

repeatability (for more information on ground loops, see page 341).

The earth-referenced and floating circuitry communicate with each

other via an optically-isolated data link. The earth-referenced section

communicates with the floating section to provide PC connectivity.

The instrument is shipped with both an GPIB (IEEE-488) interface

and an RS-232 interface. Only one interface can be enabled at a time.

The earth-referenced section also provides four hardware alarm outputs

and external trigger lines. You can use the alarm output lines to trigger

external alarm lights, sirens, or send a TTL pulse to your control system.

The floating section contains the main system processor and controls all

of the basic functionality of the instrument. This is where the instrument

communicates with the plug-in modules, scans the keyboard, controls the

front-panel display, and controls the internal DMM. The floating section

also performs Mx+B scaling, monitors alarm conditions, converts

transducer measurements to engineering units, time stamps scanned

measurements, and stores data in non-volatile memory.

To Computer

AC Power

Alarms

GPIB

RS-232

Earth

Referenced

Logic

Floating

Logic

Internal

DMM

Digital

Bus Analog Bus

Plug-In

Slots

100

200

300

External Trigger

Control

Optional

= Optical Isolators

OUT

IN 3

Chapter 3 System Overview

Data Acquisition System Overview

Plug-In Modules

The 34970A offers a complete selection of plug-in modules to give you

high-quality measurement, switching, and control capabilities.

The plug-in modules communicate with the floating logic via the internal

isolated digital bus. The multiplexer modules also connect to the

internal DMM via the internal analog bus. Each module has its own

microprocessor to offload the mainframe processor and minimize

backplane communications for faster throughput. The table below shows

some common uses for each plug-in module.

For more information on each module, refer to the module sections in

chapter 4, starting on page 163.

Model Number Module Name Common Uses

Measurement Input

34901A 20-Channel Mux with T/C

Compensation Scanning and direct measurement of

temperature, voltage, resistance, frequency,

and current (34901A only) using the

internal DMM.

34902A 16-Channel Reed Mux with T/C

Compensation

34908A 40-Channel Single-Ended Mux

with T/C Compensation Scanning and direct measurement of

temperature, voltage, and resistance using

the internal DMM.

34907A Multifunction Module Digital Input, Event Counting.

Signal Routing

34901A 20-Channel Mux with T/C

Compensation Multiplexing of signals to or from external

instruments.

34902A 16-Channel Reed Mux with T/C

Compensation

34908A 40-Channel Single-Ended Mux

with T/C Compensation

34904A 4x8 Matrix Switch 32 Crosspoint Matrix switching.

34905A Dual 4-Channel RF Mux (50Ω)50Ω high-frequency applications (< 2 GHz).

34906A Dual 4-Channel RF Mux (75Ω)75Ω high-frequency applications (< 2 GHz).

Control Output

34903A 20-Channel Actuator General-purpose switching and control

using Form C (SPDT) switches.

34907A Multifunction Module Digital Output, Voltage (DAC) Outputs.

Chapter 3 System Overview

Data Acquisition System Overview

System Cabling

The plug-in modules have screw-terminal connectors to make it easy to

connect your system cabling. The type of cabling that you use to connect

your signals, transducers, and sensors to the module is critical to

measurement success. Some types of transducers, such as thermocouples,

have very specific requirements for the type of cable that can be used to

make connections. Be sure to consider the usage environment when

choosing wire gauge and insulation qualities. Wire insulation typically

consists of materials such as PVC or Teflon®. The table below lists

several common cable types and describes their typical uses.

Note: Wiring insulation and usage is described in more detail in

“System Cabling and Connections” starting on page 335.

Cable Type Common Uses Comments

Thermocouple

Extension Wire Thermocouple measurements. Available in specific thermocouple types.

Also available in a shielded cable for

added noise immunity.

Twisted Pair,

Shielded Twisted Pair Measurement inputs, voltage

outputs, switching, counting. Most common cable for low-frequency

measurement inputs. Twisted pair

reduces common mode noise.

Shielded-twisted pair provides additional

noise immunity.

Shielded Coaxial,

Double-Shielded

Coaxial

VHF signal switching. Most common cable for high-frequency

signal routing. Available in specific

impedance values (50Ω or 75Ω).

Provides excellent noise immunity.

Double-shielded cable improves

isolation between channels. Requires

special connectors.

Flat Ribbon,

Twisted Pair Ribbon Digital Input/Output Often used with mass termination

connectors. These cables provide little

noise immunity.

Teflon is a registered trademark of E.I. duPont deNemours and Company.

Chapter 3 System Overview

Data Acquisition System Overview

Transducers and Sensors

Transducers and sensors convert a physical quantity into an electrical

quantity. The electrical quantity is measured and the result is then

converted to engineering units. For example, when measuring a

thermocouple, the instrument measures a dc voltage and mathematically

converts it to a corresponding temperature in °C, °F, or K.

Measurement Typical Transducer Types Typical Transducer Output

Temperature Thermocouple 0 mV to 80 mV

RTD 2-wire or 4-wire resistance

from 5Ω to 500Ω

Thermistor 2-wire resistance from

10Ω to 1 MΩ

Pressure Solid State ±10 Vdc

Flow Rotary Type

Thermal Type 4 mA to 20 mA

Strain Resistive Elements 4-wire resistance from

10Ω to 10 kΩ

Events Limit Switches

Optical Counters

Rotary Encoder

0V or 5V Pulse Train

Digital System Status TTL Levels

Alarm Limits

The 34970A has four alarm outputs which you can configure to alert you

when a reading exceeds specified limits on a channel during a scan.

You can assign a high limit, a low limit, or both to any configured

channel in the scan list. You can assign multiple channels to any of the

four available alarms (numbered 1 through 4). For example, you can

configure the instrument to generate an alarm on Alarm 1 when a limit

is exceeded on any of channels 103, 205, or 320.

You can also assign alarms to channels on the multifunction module.

For example, you can generate an alarm when a specific bit pattern or

bit pattern change is detected on a digital input channel or when a specific

count is reached on a totalizer channel. With the multifunction module,

the channels do not have to be part of the scan list to generate an alarm.

Chapter 3 System Overview

Data Acquisition System Overview

Signal Routing and Switching

The switching capabilities of the plug-in modules available with the

34970A provide test system flexibility and expandability. You can use

the switching plug-in modules to route signals to and from your test

system or multiplex signals to the internal DMM or external instruments.

Relays are electromechanical devices which are subject to wear-out

failure modes. The life of a relay, or the number of actual operations

before failure, is dependent upon how it is used – applied load, switching

frequency, and environment. The 34970A Relay Maintenance System

automatically counts the cycles of each relay in the instrument and

stores the total count in non-volatile memory on each switch module.

Use this feature to track relay failures and to predict system maintenance

requirements. For more information on using this feature, refer to

“Relay Cycle Count” on page 147.

Switching Topologies

Several switching plug-in modules are available with different

topologies for various applications. The following switching topologies

are available:

•Multiplexer (34901A, 34902A, 34905A, 34906A, 34908A)

•Matrix (34904A)

•Form C – Single Pole, Double Throw (34903A)

The following sections describe each of these switching topologies.

Chapter 3 System Overview

Signal Routing and Switching

Multiplexer Switching Multiplexers allow you to connect one of

multiple channels to a common channel, one at a time. A simple 4-to-1

multiplexer is shown below. When you combine a multiplexer with a

measurement device, like the internal DMM, you create a scanner.

For more information on scanning, see page 62.

Multiplexers are available in several types:

•One-Wire (Single-Ended) Multiplexers for common LO measurements.

For more information, see page 379.

•Two-Wire Multiplexers for floating measurements. For more

information, see page 379.

•Four-Wire Multiplexers for resistance and RTD measurements.

For more information, see page 380.

•Very High Frequency (VHF) Multiplexers for switching frequencies

up to 2.8 GHz. For more information, see page 390.

Common

Channel 1

Channel 4

Channel 3

Channel 2

Chapter 3 System Overview

Signal Routing and Switching

Matrix Switching A matrix switch connects multiple inputs to

multiple outputs and therefore offers more switching flexibility than a

multiplexer. Use a matrix for switching low-frequency (less than 10 MHz)

signals only. A matrix is arranged in rows and columns. For example,

a simple 3x3 matrix could be used to connect three sources to three test

points as shown below.

Any one of the signal sources can be connected to any one of the test

inputs. Be aware that with a matrix, it is possible to connect more than

one source at the same time. It is important to make sure that dangerous

or unwanted conditions are not created by these connections.

Form C (SPDT) Switching The 34903A Actuator contains 20 Form C

switches (also called single-pole, double-throw). You can use Form C

switches to route signals but they are typically used to control external

devices.

Source 2

Test 1 Test 2 Test 3

Source 3

Source 1

COM

Channel Open

(NC Contact Connected) Channel Closed

(NO Contact Connected)

NO = Normally Open

NC = Normally Closed

Chapter 3 System Overview

Signal Routing and Switching

Measurement Input

The 34970A allows you to combine a DMM (either internal or external)

with multiplexer channels to create a scan. During a scan, the instrument

connects the DMM to the configured multiplexer channels one at a time

and makes a measurement on each channel.

Any channel that can be “read” by the instrument can also be included

in a scan. This includes any combination of temperature, voltage,

resistance, current, frequency, or period measurements on multiplexer

channels. A scan can also include a read of a digital port or a read of the

totalizer count on the multifunction module.

The Internal DMM

A transducer or sensor converts a physical quantity being measured

into an electrical signal which can be measured by the internal DMM.

To make these measurements, the internal DMM incorporates the

following functions:

•Temperature (thermocouple, RTD, and thermistor)

•Voltage (dc and ac up to 300V)

•Resistance (2-wire and 4-wire up to 100 MΩ)

•Current (dc and ac up to 1A)

•Frequency and Period (up to 300 kHz)

The internal DMM provides a universal input front-end for measuring

a variety of transducer types without the need for additional external

signal conditioning. The internal DMM includes signal conditioning,

amplification (or attenuation), and a high resolution (up to 22 bits)

analog-to-digital converter. A simplified diagram of the internal DMM is

shown below.

= Optical Isolators

Analog

Input

Signal

Conditioning Amp Main

Processor

To / From

Earth

Referenced

Section

Analog to

Digital

Converter

Chapter 3 System Overview

Measurement Input

Signal Conditioning, Ranging, and Amplification Analog input

signals are multiplexed into the internal DMM’s signal-conditioning

section – typically comprising switching, ranging, and amplification

circuitry. If the input signal is a dc voltage, the signal conditioner

is composed of an attenuator for the higher input voltages and a

dc amplifier for the lower input voltages. If the input signal is an

ac voltage, a converter is used to convert the ac signal to its equivalent

dc value (true RMS value). Resistance measurements are performed by

supplying a known dc current to an unknown resistance and measuring

the dc voltage drop across the resistor. The input signal switching and

ranging circuitry, together with the amplifier circuitry, convert the

input to a dc voltage which is within the measuring range of the

internal DMM’s analog-to-digital converter (ADC).

You can allow the instrument to automatically select the measurement

range using autoranging or you can select a fixed measurement range

using manual ranging. Autoranging is convenient because the instrument

automatically decides which range to use for each measurement based

on the input signal. For fastest scanning operation, use manual ranging

for each measurement (some additional time is required for autoranging

since the instrument has to make a range selection).

Analog-to-Digital Conversion (ADC) The

ADC takes a prescaled

dc voltage from the signal-conditioning circuitry and converts it to digital

data for output and display on the front panel. The ADC governs some of

the most basic measurement characteristics. These include measurement

resolution, reading speed, and the ability to reject spurious noise. There

are several analog-to-digital conversion techniques but they can be

divided into two types: integrating and non-integrating. The integrating

techniques measure the average input value over a defined time

interval, thus rejecting many noise sources. The non-integrating

techniques sample the instantaneous value of the input, plus noise,

during a very short interval. The internal DMM uses an integrating

ADC technique.

You can select the resolution and reading speed from 6 digits (22 bits) at

3 readings per second to 4 digits (16 bits) at up to 600 readings per second.

The Advanced menu from the 34970A front panel allows you to control

the integration period for precise rejection of noise signals.

Chapter 3 System Overview

Measurement Input

Main Processor The main processor, located in the floating logic

section, controls the input signal conditioning, ranging, and the ADC.

The main processor accepts commands from, and sends measurement

results to, the earth-referenced logic section. The main processor

synchronizes measurements during scanning and control operations.

The main processor uses a multi-tasking operating system to manage

the various system resources and demands.

The main processor also calibrates measurement results, performs

Mx+B scaling, monitors alarm conditions, converts transducer

measurements to engineering units, time stamps scanned measurements,

and stores data in non-volatile memory.

Scanning

The instrument allows you to combine a DMM (either internal or external)

with multiplexer channels to create a scan. During a scan, the instrument

connects the DMM to the configured multiplexer channels one at a time

and makes a measurement on each channel.

Before you can initiate a scan, you must set up a scan list to include all

desired multiplexer or digital channels. Channels which are not in the

scan list are skipped during the scan. The instrument automatically

scans the list of channels in ascending order from slot 100 through

slot 300. Measurements are taken only during a scan and only on those

channels which are included in the scan list.

You can store up to 50,000 readings in non-volatile memory during

a scan. Readings are stored only during a scan and all readings are

automatically time stamped. Each time you start a new scan, the

instrument clears all readings stored in memory from the previous scan.

Therefore, all readings currently stored in memory are from the most

recent scan.

Chapter 3 System Overview

Measurement Input

You can configure the event or action that controls the onset of each

sweep through the scan list (a sweep is one pass through the scan list):

•You can set the instrument’s internal timer to automatically scan at

a specific interval as shown below. You can also program a time delay

between channels in the scan list.

•You can manually control a scan by repeatedly pressing from

the front panel.

•You can start a scan by sending a software command from the

remote interface.

•You can start a scan when an external TTL trigger pulse is received.

•You can start a scan when an alarm condition is logged on the

channel being monitored.

Scan List (1 sweep)

Scan-to-Scan Interval

(0 to 99:59:59 hours)

Scan Count

(1 to 50,000 scans, or continuous) 3

Chapter 3 System Overview

Measurement Input

Scanning With External Instruments

If your application doesn’t require the built-in measurement capabilities

of the 34970A, you can order it without the internal DMM. In this

configuration, you can use the 34970A for signal routing or control

applications. If you install a multiplexer plug-in module, you can use the

34970A for scanning with an external instrument. You can connect an

external instrument (such as a DMM) to the multiplexer COM terminal.

To control scanning with an external instrument, two control lines are

provided. When the 34970A and the external instrument are properly

configured, you can synchronize a scan sequence between the two.

Common Terminals

(COM)

Input

Channels

External DMM

VM Complete OUT Ext Trig IN

GND

Ext Trig IN

Channel Closed OUT

External DMM

34970A

Chapter 3 System Overview

Measurement Input

The Multifunction Module

The multifunction module (34907A) adds two additional measurement

input capabilities to the system: digital input and event totalize.

The multifunction module also contains a dual voltage output (DAC)

which is described in more detail on page 68.

Digital Input The multifunction module has two non-isolated 8-bit

input/output ports which you can use for reading digital patterns.

You can read the live status of the bits on the port or you can configure

a scan to include a digital read. Each port has a separate channel

number on the module and contains 8-bits. You can combine the two

ports to read a 16-bit word.

Bit 0

Digital

Input

Bit 7

Bit 0

Bit 7

Port 1 (LSB)

Channel 01

Port 2 (MSB)

Channel 02

Chapter 3 System Overview

Measurement Input

Totalizer The multifunction module has a 26-bit totalizer which can

count pulses at a 100 kHz rate. You can manually read the totalizer

count or you can configure a scan to read the count.

•You can configure the totalizer to count on the rising edge or falling

edge of the input signal.

•The maximum count is 67,108,863 (226- 1). The count rolls over to “0”

after reaching the maximum allowed value.

•You can configure the totalizer to read without affecting the count or

reset the count to zero without losing any counts.

+IN

Gate

-IN

Gate

Totalize

26 Bits Channel 03

Chapter 3 System Overview

Measurement Input

Control Output

In addition to signal routing and measurement, you can also use the

34970A to provide simple control outputs. For example, you can control

external high-power relays using the actuator module or a digital output

channel.

The Multifunction Module

The multifunction module (34907A) adds two additional control output

capabilities to the system: digital output and voltage (DAC) output.

The multifunction module also contains digital input and event totalizer

capabilities which are described in more detail on pages 65 and 66.

Digital Output The multifunction module has two non-isolated 8-bit

input/output ports which you can use to output digital patterns. Each

port has a separate channel number on the module and contains 8-bits.

You can combine the two ports to output a 16-bit word.

Bit 0

Digital

Output

Bit 7

Bit 0

Bit 7

Port 1 (LSB)

Channel 01

Port 2 (MSB)

Channel 02

Chapter 3 System Overview

Control Output

Voltage (DAC) Output The multifunction module has two analog

outputs capable of outputting calibrated voltages between ±12 volts with

16 bits of resolution. Each DAC (Digital-to-Analog Converter) channel can

be used as a programmable voltage source for analog input control of

other devices. A simplified diagram is shown below.

•You can set the output voltage to any value between +12 Vdc and

-12 Vdc, in 1 mV steps. Each DAC is earth referenced, it cannot float.

•Each DAC channel is capable of supplying 10 mA maximum current.

Note: You must limit the output current to 40 mA total for all three

slots (six DAC channels).

DAC 1

16 Channel 04

16 DAC 2 Channel 05

Chapter 3 System Overview

Control Output

The Actuator / General-Purpose Switch

You can think of the 34903A Actuator as a control output because it is

often used to control external power devices. The actuator provides

20 independent, isolated Form C (SPDT) switches.

Each channel can switch up to 300V dc or ac rms. Each switch can also

switch up to 1 A dc or ac rms up to 50 W maximum. For example, the

maximum current that you can switch at 120 V is 0.45 A as shown below.

For control applications, the actuator has the following advantages:

•Higher voltage and power rating than the digital output channels.

The actuator switches can also be used to control power devices.

•When used with high-power devices, however, it is critical that you

provide protection to the switch from capacitive and inductive loads

to ensure maximum relay life (for more information on attenuators,

see the discussion on page 387).

COM

Channel Open

(NC Contact Connected) Channel Closed

(NO Contact Connected)

NO = Normally Open

NC = Normally Closed

Voltage

Current

Chapter 3 System Overview

Control Output

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 34970A. Whether you are operating

the instrument from the front panel or over the remote interface, this

chapter will be useful. This chapter is divided into the following sections:

•SCPI Language Conventions, on page 73

•Scanning, starting on page 74

•Single-Channel Monitoring, starting on page 93

•Scanning With External Instruments, starting on page 95

•General Measurement Configuration, starting on page 98

•Temperature Measurement Configuration, starting on page 106

•Voltage Measurement Configuration, starting on page 113

•Resistance Measurement Configuration, on page 115

•Current Measurement Configuration, starting on page 116

•Frequency Measurement Configuration, starting on page 118

•Mx+B Scaling, starting on page 119

•Alarm Limits, starting on page 122

•Digital Input Operations, starting on page 133

•Totalizer Operations, starting on page 135

•Digital Output Operations, on page 138

•DAC Output Operations, on page 139

•System-Related Operations, starting on page 140

•Remote Interface Configuration, starting on page 150

•Calibration Overview, starting on page 155

•Factory Reset State, on page 160

•Instrument Preset State, on page 161

•Multiplexer Module Default Settings, on page 162

•Module Overview, on page 163

•34901A 20-Channel Multiplexer, starting on page 164

•34902A 16-Channel Multiplexer, starting on page 166

•34903A 20-Channel Actuator, starting on page 168

•34904A 4x8 Matrix Switch, starting on page 170

•34905A/6A Dual 4-Channel RF Multiplexers, starting on page 172

•34907A Multifunction Module, starting on page 174

•34908A 40-Channel Single-Ended Multiplexer, starting on page 176

SCPI Language Conventions

Throughout this manual, the following conventions are used for

SCPI command syntax for remote interface programming:

•Square brackets ( [ ] ) indicate optional keywords or parameters.

•Braces ( { } ) enclose parameter choices within a command string.

•Triangle brackets ( < > ) enclose parameters for which you must

substitute a value.

•A vertical bar ( | ) separates multiple parameter choices.

Rules for Using a Channel List

Many of the SCPI commands for the 34970A include a scan_list

or ch_list parameter which allow you to specify one or more channels.

The channel number has the form (@scc), where s is the slot number

(100, 200, or 300) and cc is the channel number. You can specify a single

channel, multiple channels, or a range of channels as shown below.

•The following command configures a scan list to include only

channel 10 on the module in slot 300.

ROUT:SCAN (@310)

•The following command configures a scan list to include multiple

channels on the module in slot 200. The scan list now contains only

channels 10, 12, and 15 (the scan list is redefined each time you send

a new ROUTe:SCAN command).

ROUT:SCAN (@210,212,215)

•The following command configures a scan list to include a range of

channels. When you specify a range of channels, the range may

contain invalid channels (they are ignored), but the first and last

channel in the range must be valid. The scan list now contains

channels 5 through 10 (slot 100) and channel 15 (slot 200).

ROUT:SCAN (@105:110,215)

Chapter 4 Features and Functions

SCPI Language Conventions

Scanning

The instrument allows you to combine a DMM (either internal or external)

with multiplexer channels to create a scan. During a scan, the instrument

connects the DMM to the configured multiplexer channels one at a time

and makes a measurement on each channel.

Any channel that can be “read” by the instrument can also be included

in a scan. This includes any combination of temperature, voltage,

resistance, current, frequency, or period measurements on multiplexer

channels. A scan can also include a read of a digital port or a read of the

totalizer count on the multifunction module. Scanning is allowed with

the following modules:

• 34901A 20-Channel Multiplexer

• 34902A 16-Channel Multiplexer

• 34907A Multifunction Module (digital input and totalizer only)

• 34908A 40-Channel Single-Ended Multiplexer

Automated scanning is not allowed with the actuator module, the matrix

module, or the RF multiplexer modules. In addition, a scan cannot

include a write to a digital port or a voltage output from a DAC channel.

However, you can write your own program to manually create a “scan”

to include these operations.

Rules for Scanning

•Before you can initiate a scan, you must set up a scan list to include

all desired multiplexer or digital channels. Channels which are not

in the scan list are skipped during the scan. The instrument

automatically scans the list of channels in ascending order from

slot 100 through slot 300. Measurements are taken only during a

scan and only on those channels which are included in the scan list.

The “ ” (sample) annunciator turns on during each measurement.

•You can store up to 50,000 readings in non-volatile memory during

a scan. Readings are stored only during a scan and all readings are

automatically time stamped. If memory overflows (the MEM annunciator

will turn on), a status register bit is set and new readings will

overwrite the first readings stored (the most recent readings are

always preserved). You can read the contents of memory at any time,

even during a scan. Reading memory is not cleared when you read it.

Chapter 4 Features and Functions

Scanning

•Each time you start a new scan, the instrument clears all readings

(including alarm data) stored in reading memory from the previous

scan. Therefore, the contents of memory are always from the most

recent scan.

•While a scan is running, the instrument automatically stores the

minimum and maximum readings and calculates the average for each

channel. You can read these values at any time, even during a scan.

•Mx+B scaling and alarm limits are applied to measurements during a

scan and all data is stored in non-volatile memory. You can read the

contents of reading memory or the alarm queue at any time, even

during a scan.

•In the Monitor function, the instrument takes readings as often as it

can on a single channel, even during a scan (see “Single-Channel

Monitoring” on page 93). This feature is useful for troubleshooting

your system before a test or for watching an important signal.

•If you abort a scan that is running, the instrument will complete the

one measurement in progress (the entire scan will not be completed)

and the scan will stop. You cannot resume the scan from where it

left off. If you initiate a new scan, all readings are cleared from memory.

•When you add a multiplexer channel to a scan list, that entire module

is dedicated to the scan. The instrument issues a Card Reset to open

all channels on that module. You cannot perform low-level close or

open operations on any channels on that module (even those channels

that are not configured).

•While a scan is running, you can perform some low-level control

operations on modules that do not contain channels in the scan list.

For example, you can open or close channels or issue a Card Reset

on switching modules that do not contain channels in the scan list.

However, you cannot change any parameters that affect the scan

(channel configuration, scan interval, scaling values, alarm limits,

Card Reset, etc.) while a scan is running.

Chapter 4 Features and Functions

Scanning

•When you add a digital read (multifunction module) to a scan list,

that port is dedicated to the scan. The instrument issues a Card

Reset to make that port an input port (the other port is not affected).

•While a scan is running, you can perform low-level control operations

on any channels on the multifunction module that are not in the scan.

For example, you can output a DAC voltage or write to a digital port

(even if the totalizer is part of the scan list). However, you cannot

change any parameters that affect the scan (channel configuration,

scan interval, Card Reset, etc.) while a scan is running.

•If a scan includes a read of the totalizer, multifunction module,

the count is reset each time it is read during the scan only when the

totalizer reset mode is enabled (TOTalize:TYPE RRESet command

or the Advanced menu for the totalizer).

•If you install a module while a scan is running, the instrument will

cycle power and resume scanning. If you remove a module while a

scan is running, the instrument will cycle power and resume

scanning (even if the removed module was part of the scan list).

•You can use either the internal DMM or an external DMM to make

measurements of your configured channels. However, the instrument

allows only one scan list at a time; you cannot scan some channels

using the internal DMM and others using an external DMM.

Readings are stored in 34970A memory only when the internal DMM

is used.

•If the internal DMM is installed and enabled, the instrument will

automatically use it for scanning. For externally-controlled scans,

you must either remove the internal DMM from the 34970A

or disable it (see “Internal DMM Disable” on page 145).

Chapter 4 Features and Functions

Scanning

Power Failure

•When shipped from the factory, the instrument is configured to

automatically recall the power-down state when power is restored.

In this configuration, the instrument will automatically recall the

instrument state at power-down and resume a scan in progress.

If you do not want the power-down state to be recalled when power

is restored, send the MEMory:STATe:RECall:AUTO OFF command

(also see the Utility menu); a Factory Reset (*RST command) is then

issued when power is restored.

•If the instrument is in the middle of a scan sweep when power fails,

all readings from that partially completed sweep will be discarded

(a sweep is one pass through the scan list). For example, assume that

your scan list includes four multiplexer channels and you want to

sweep through the scan list three times (see diagram). A power

failure occurs after the second reading in the third scan sweep.

The instrument will discard the last two of the 10 readings and will

resume scanning at the beginning of the third scan sweep.

•If you remove a module or move a module to a different slot while

power is off, the scan will not resume when power is restored.

No error is generated.

•If you replace a module with a module of the same type while power

is off, the instrument will continue scanning when power is restored.

No error is generated.

Power Fails

Sweep 1:

Sweep 3:

Sweep 2:

Chapter 4 Features and Functions

Scanning

Adding Channels to a Scan List

Before you can initiate a scan, you must configure the channels to be

scanned and set up a scan list (these two operations occur simultaneously

from the front panel). The instrument automatically scans the

configured channels in ascending order from slot 100 through slot 300.

To Build a Scan List From the Front Panel:

To add the active channel to the scan list, press . Select the

function, range, resolution, and other measurement parameters for this

channel. You can also press to sequentially step through the scan

list and take a measurement on each channel (readings are not stored in

memory). This is an easy way to verify your wiring connections and

channel configuration (also valid during a scan).

•When you reconfigure a channel and add it to the scan list, it is

important to note that the previous configuration on that channel

is lost. For example, assume that a channel is configured for

dc voltage measurements. When you reconfigure that channel for

thermocouple measurements, the previous range, resolution, and

channel delay are set to their Factory Reset (*RST command) state.

•To remove the active channel from the scan list, press and select

CHANNEL OFF. If you decide to add that channel back to the scan list

with the same function, the original channel configuration (including

scaling and alarm values) is still present.

•To initiate a scan and store all readings in memory, press

(the SCAN annunciator will turn on). Each time you initiate a

new scan, the instrument clears all previously stored readings.

•To stop a scan, press and hold .

Chapter 4 Features and Functions

Scanning

To Build a Scan List From the Remote Interface:

•The MEASure?, CONFigure, and ROUTe:SCAN commands contain a

scan_list parameter which defines the list of channels in the scan list.

Note that each time you send one of these commands, it redefines the

scan list. To determine which channels are currently in the scan list,

you can send the ROUTe:SCAN? query command.

•To initiate a scan, execute the MEASure?, READ?, or INITiate

command. The MEASure? and READ? commands send readings

directly to the instrument’s output buffer but readings are not stored

in memory. The INITiate command stores readings in memory.

Use the FETCh? command to retrieve stored readings from memory.

See the examples starting on page 201 in chapter 5 for more

information on using these commands.

•When you reconfigure a channel and add it to the scan list using

MEASure? or CONFigure, it is important to note that the previous

configuration on that channel is lost. For example, assume that a

channel is configured for dc voltage measurements. When you

reconfigure that channel for thermocouple measurements,

the previous range, resolution, and channel delay are set to their

Factory Reset (*RST command) state.

•Each time you initiate a new scan, the instrument clears all

previously stored readings.

•To stop a scan, execute the ABORt command.

Chapter 4 Features and Functions

Scanning

Scan Interval

You can configure the event or action that controls the onset of each

sweep through the scan list (a sweep is one pass through the scan list):

•You can set the instrument’s internal timer to automatically scan at a

specific interval. You can also program a time delay between

channels in the scan list.

•You can manually control a scan by repeatedly pressing from

the front panel.

•You can start a scan by sending a software command from the

remote interface (MEASure? or INITiate command).

•You can start a scan when an external TTL trigger pulse is received.

•You can start a scan when an alarm event is logged on the channel

being monitored.

Interval Scanning In this configuration, you control the frequency of

scan sweeps by selecting a wait period from the start of one sweep to the

start of the next sweep (called the scan-to-scan interval). The count-

down time is shown on the front-panel display between one scan sweep

and the start of the next sweep. If the scan interval is less than the time

required to measure all channels in the scan list, the instrument will

scan continuously, as fast as possible (no error is generated).

Scan List (1 sweep)

Scan-to-Scan Interval

(0 to 99:59:59 hours)

Scan Count

(1 to 50,000 scans, or continuous)

Chapter 4 Features and Functions

Scanning

•You can set the scan interval to any value between 0 seconds

and 99:59:59 hours (359,999 seconds), with 1 ms resolution.

•Once you have initiated the scan, the instrument will continue

scanning until you stop it or until the scan count is reached.

See “Scan Count” on page 86 for more information.

•Mx+B scaling and alarm limits are applied to measurements during

a scan and all data is stored in non-volatile memory.

•The MEASure? and CONFigure commands automatically set the

scan interval to immediate (0 seconds) and the scan count to 1 sweep.

•From the front panel, a Factory Reset (Sto/Rcl menu) sets the scan

interval to 10 seconds and the scan count to continuous. From the

remote interface, a Factory Reset (*RST command) sets the

scan interval to immediate (0 seconds) and the scan count to 1 sweep.

•Front-Panel Operation: To select interval scanning and set a scan

interval time (hour:minutes:seconds), choose the following item.

INTERVAL SCAN

To initiate the scan and store all readings in memory, press

(the SCAN annunciator will turn on). Between scan sweeps,

the count-down time is shown on the front-panel (00:04 TO SCAN).

Note: To stop a scan, press and hold .

•Remote Interface Operation: The following program segment

configures the instrument for an interval scan.

TRIG:SOURCE TIMER Select the interval timer configuration

TRIG:TIMER 5 Set the scan interval to 5 seconds

TRIG:COUNT 2 Sweep the scan list 2 times

INIT Initiate the scan

Note: To stop a scan, send the ABORt command.

Chapter 4 Features and Functions

Scanning

Scan Once In this configuration, the instrument waits for either a

front-panel key press or a remote interface command before sweeping

through the scan list.

•All readings from the scan are stored in non-volatile memory.

Readings accumulate in memory until the scan is terminated (until the

scan count is reached or until you abort the scan).

•You can specify a scan count which sets the number of front-panel

key presses or scan trigger commands that will be accepted before

terminating the scan. See “Scan Count” on page 86 for more

information.

•Mx+B scaling and alarm limits are applied to measurements during

a Scan Once operation and all data is stored in non-volatile memory.

•Front-Panel Operation:

MANUAL SCAN

To initiate the scan and store all readings in memory, press .

The ONCE annunciator turns on as a reminder that a Scan Once

operation is in progress.

Note: To stop a scan, press and hold .

•Remote Interface Operation: The following program segment

configures the instrument for a Scan Once operation.

TRIG:SOURCE BUS Select the bus (once) configuration

TRIG:COUNT 2 Sweep the scan list 2 times

INIT Initiate the scan

Then, send the *TRG (trigger) command to begin each scan sweep.

You can also trigger the instrument from the GPIB interface by

sending the IEEE-488 Group Execute Trigger (GET) message.

The following statement shows how to send a GET message.

TRIGGER 709 Group Execute Trigger

Note: To stop a scan, send the ABORt command.

Chapter 4 Features and Functions

Scanning

External Scanning In this configuration, the instrument sweeps

through the scan list once each time a low-going TTL pulse is received

on the rear-panel Ext Trig Input line (pin 6).

•You can specify a scan count which sets the number of external

pulses the instrument will accept before terminating the scan.

See “Scan Count” on page 86 for more information.

•If the instrument receives an external trigger before it is ready to

accept one, it will buffer one trigger before generating an error.

•All readings from the scan are stored in non-volatile memory.

Readings accumulate in memory until the scan is terminated

(until the scan count is reached or until you abort the scan).

•Mx+B scaling and alarm limits are applied to measurements during

the scan and all data is stored in non-volatile memory.

•Front-Panel Operation:

EXTERNAL SCAN

To initiate the scan, press . The EXT annunciator turns on as a

reminder that an External Scan is in progress. When a TTL pulse is

received, the scan starts and readings are stored in memory. To stop

a scan, press and hold .

•Remote Interface Operation: The following program segment

configures the instrument for an External Scan.

TRIG:SOURCE EXT Select the external trigger configuration

TRIG:COUNT 2 Sweep the scan list 2 times

INIT Initiate the scan

Note: To stop a scan, send the ABORt command.

Ext Trig Input

Gnd

Ext Trig Connector

0 V

Input

5 V

> 1 µs

Chapter 4 Features and Functions

Scanning

Scanning on Alarm In this configuration, the instrument sweeps the

scan list once each time a reading crossing an alarm limit on a channel.

You can also assign alarms to channels on the multifunction module.

For example, you can generate an alarm when a specific bit pattern

is detected or when a specific count is reached.

Note: For complete details on configuring and using alarms, refer to

“Alarm Limits” starting on page 122.

•In this scan configuration, you may use the Monitor function to

continuously take readings on a selected channel and wait for an

alarm on that channel. The monitored channel can be part of the scan

list but you can also use a channel on the multifunction module

(which does not have to be part of the scan list and you do not have to

use the Monitor function). For example, you can generate an alarm

on a totalizer channel which will initiate a scan when a specific count

is reached.

•You can specify a scan count which sets the number of alarms that

will be allowed before terminating the scan. See “Scan Count”

on page 86 for more information.

•All readings from the scan are stored in non-volatile memory.

Readings accumulate in memory until the scan is terminated

(until the scan count is reached or until you abort the scan).

•Mx+B scaling and alarm limits are applied to measurements during

the scan and all data is stored in non-volatile memory.

•Front-Panel Operation:

SCAN ON ALARM

To enable the Monitor function select the desired channel and then

press . To initiate the scan, press . When an alarm event

occurs, the scan starts and readings are stored in memory.

Note: To stop a scan, press and hold .

Chapter 4 Features and Functions

Scanning

•Remote Interface Operation: The following program segment configures

the instrument to scan when an alarm occurs.

TRIG:SOURCE ALARM1 Select the alarm configuration

TRIG:COUNT 2 Sweep the scan list 2 times

CALC:LIM:UPPER 5,(@103) Set the upper limit

CALC:LIM:UPPER:STATE ON,(@103) Enable the upper limit

OUTPUT:ALARM1:SOURCE (@103) Report alarms on Alarm 1

ROUT:MON (@103) Select monitor channel

ROUT:MON:STATE ON Enable monitoring

INIT Initiate the scan

Note: To stop a scan, send the ABORt command. 4

Chapter 4 Features and Functions

Scanning

Scan Count

You can specify the number of times the instrument will sweep through

the scan list. When the specified number of sweeps have occurred, the

scan stops.

•Select a scan count between 1 to 50,000 scan sweeps, or continuous.

•During an Interval Scan (see page 80), the scan count sets the number

of times the instrument will sweep through the scan list and therefore

determines the overall duration of the scan.

•During a Scan Once operation (see page 82), the scan count sets the

number of front-panel key presses or scan trigger commands that will

be accepted before terminating the scan.

•During an External Scan (see page 83), the scan count sets the

number of external trigger pulses that will be accepted before

terminating the scan.

•During an Alarm Scan (see page 84), the scan count sets the number

of alarms that will be allowed before terminating the scan.

•You can store up to 50,000 readings in non-volatile memory during

a scan. If you set a continuous scan and memory overflows (the MEM

annunciator will turn on), a status register bit is set and new

readings will overwrite the first readings stored (the most recent

readings are always preserved).

•The MEASure? and CONFigure commands automatically set the

scan count to 1.

•From the front panel, a Factory Reset (Sto/Rcl menu) sets the scan

count to continuous. From the remote interface, a Factory Reset

(*RST command) sets the scan count to 1 sweep.

•Front-Panel Operation:

00020 SCANS

The default is CONTINUOUS. To set the count to a value between

1 and 50,000 scans, turn the knob clockwise and enter a number.

•Remote Interface Operation:

TRIG:COUNT 20

Note: To configure a continuous scan, send TRIG:COUNT INFINITY.

Chapter 4 Features and Functions

Scanning

Reading Format

During a scan, the instrument automatically adds a time stamp to

all readings and stores them in non-volatile memory. Each reading is

stored with measurement units, time stamp, channel number, and

alarm status information. From the remote interface, you can specify

which information you want returned with the readings (from the front

panel, all of the information is available for viewing). The reading

format applies to all readings being removed from the instrument from

a scan; you cannot set the format on a per-channel basis.

•From the remote interface, the time stamp information is returned

either in absolute time (time of day with date) or relative time

(time since start of scan). Use the FORMat:READ:TIME:TYPE

command to select absolute or relative time. From the front panel,

the time stamp is always returned in absolute time.

•The MEASure? and CONFigure commands automatically turn off the

units, time, channel, and alarm information.

•A Factory Reset (*RST command) turns off the units, time, channel,

and alarm information.

•Remote Interface Operation: The following commands select the

format of readings returned from a scan.

FORMat:READing:ALARm ON

FORMat:READing:CHANnel ON

FORMat:READing:TIME ON

FORMat:READing:TIME:TYPE {ABSolute|RELative}

FORMat:READing:UNIT ON

The following is an example of a reading stored in memory with all

fields enabled (relative time is shown).

1 Reading with Units (26.195 °C)

2 Time Since Start of Scan (17 ms) 3 Channel Number

4 Alarm Limit Threshold Crossed

(0 = No Alarm, 1 = LO, 2 = HI)

Chapter 4 Features and Functions

Scanning

Channel Delay

You can control the pace of a scan sweep by inserting a delay between

multiplexer channels in the scan list (useful for high-impedance or

high-capacitance circuits). The delay is inserted between the relay

closure and the actual measurement on the channel. The programmed

channel delay overrides the default channel delay that the instrument

automatically adds to each channel.

•You can set the channel delay to any value between 0 seconds and

60 seconds, with 1 ms resolution. You can select a different delay for

each channel. The default channel delay is automatic; the instrument

determines the delay based on function, range, integration time,

and ac filter setting (see “Automatic Channel Delays” on the next page).

•The MEASure? and CONFigure commands set the channel delay

to automatic. A Factory Reset (*RST command) also sets the channel

delay to automatic.

•Front-Panel Operation:

CH DELAY TIME

•Remote Interface Operation: The following command adds a 2-second

channel delay to channel 101.

ROUT:CHAN:DELAY 2,(@101)

Scan List

Channel Delay

Ch 1 Ch 2 Ch 3 Ch 4 Ch 5 Ch 6

Chapter 4 Features and Functions

Scanning

Automatic Channel Delays

If you do not specify a channel delay, the instrument selects a delay

for you. The delay is determined by function, range, integration time,

and ac filter setting as shown below.

DC Voltage, Thermocouple, DC Current (for all ranges):

Integration Time Channel Delay

PLC > 1

PLC ≤ 1 2.0 ms

1.0 ms

Resistance, RTD, Thermistor (2- and 4-wire):

Range Channel Delay

(For PLC > 1) Range Channel Delay

(For PLC ≤ 1)

100Ω

1 kΩ

10 kΩ

100 kΩ

1 MΩ

10 MΩ

100 MΩ

2.0 ms

25 ms

30 ms

200 ms

100Ω

1 kΩ

10 kΩ

100 kΩ

1 MΩ

10 MΩ

100 MΩ

1.0 ms

20 ms

25 ms

200 ms

AC Voltage, AC Current (for all ranges):

AC Filter Channel Delay

Slow (3 Hz)

Medium (20 Hz)

Fast (200 Hz)

7.0 sec

1.0 sec

120 ms

Frequency, Period:

AC Filter Channel Delay

Slow (3 Hz)

Medium (20 Hz)

Fast (200 Hz)

0.6 sec

0.3 sec

0.1 sec

Digital Input, Totalize:

Channel Delay

0 sec

Chapter 4 Features and Functions

Scanning

•Front-Panel Operation:

CH DELAY AUTO

•Remote Interface Operation: The following command enables an

automatic channel delay on channel 01.

ROUT:CHAN:DELAY:AUTO ON,(@101)

Selecting a specific channel delay using the ROUTe:CHANnel:DELay

command disables the automatic channel delay.

Viewing Readings Stored in Memory

During a scan, the instrument automatically adds a time stamp to

all readings and stores them in non-volatile memory. Readings are

stored only during a scan. You can read the contents of memory at any

time, even during a scan.

•You can store up to 50,000 readings in non-volatile memory during

a scan. From the front panel, you can view the last 100 readings and

all of the readings are available from the remote interface. If memory

overflows (the MEM annunciator will turn on), a status register bit

is set and new readings will overwrite the first readings stored

(the most recent readings are always preserved).

•Each time you start a new scan, the instrument clears all readings

(including alarm data) stored in reading memory from the previous

scan. Therefore, the contents of memory are always from the most

recent scan.

•The instrument clears all readings in memory after a Factory Reset

(*RST command) or Instrument Preset (SYSTem:PRESet command).

Reading memory is not cleared when you read it.

•While a scan is running, the instrument automatically stores the

minimum and maximum readings and calculates the average for each

channel. You can read these values at any time, even during a scan.

•Each reading is stored with measurement units, time stamp, channel

number, and alarm status information. From the remote interface,

you can specify which information you want returned with the

readings (from the front panel, all of the information is available for

viewing). For more information, see “Reading Format” on page 87.

Chapter 4 Features and Functions

Scanning

•Readings acquired during a Monitor are not stored in memory

(however, all readings from a scan in progress at the same time are

stored in memory).

•The MEASure? and READ? commands send readings directly to the

instrument’s output buffer but readings are not stored in memory.

You will not be able to view these readings.

•The INITiate command stores readings in memory. Use the FETCh?

command to retrieve stored readings from memory (the readings

are not erased when you read them).

•Front-Panel Operation: From the front panel, data is available for

the last 100 readings on each channel readings taken during a scan

(all of the data is available from the remote interface). After turning

the knob to the desired channel, press the and keys to choose

the data that you want to view for the selected channel as shown below

(the LAST, MIN, MAX, and AVG annunciators turn on to indicate what

data is currently being viewed). Reading memory is not cleared when

you read it. Note that you can view readings from the front panel

even while the instrument is in remote.

READINGS

and

Select Channel Last Reading on Channel

Time of Last Reading

Minimum Reading on Channel

Time of Minimum Reading

Maximum Reading on Channel

Time of Maximum Reading

Average of Readings on Channel

Second Most Recent Reading on Channel

Third Most Recent Reading on Channel

99th Most Recent Reading on Channel

Chapter 4 Features and Functions

Scanning

•Remote Interface Operation: The following command retrieves stored

readings from memory (the readings are not erased).

FETCH?

Use the following commands to query the statistics on the readings

stored in memory for a specific channel. These commands do not

remove the data from memory.

CALC:AVER:MIN? (@305) Minimum reading on channel

CALC:AVER:MIN:TIME? (@305) Time minimum was logged

CALC:AVER:MAX? (@305) Maximum reading on channel

CALC:AVER:MAX:TIME? (@305) Time maximum was logged

CALC:AVER:AVER? (@305) Average of all readings on channel

CALC:AVER:COUNT? (@305) Number of readings taken on channel

CALC:AVER:PTPEAK? (@305) Peak-to-peak (maximum-minimum)

The following command retrieves the last reading taken on channel

301 during a scan.

DATA:LAST? (@301)

The following command clears the contents of statistics memory for

the selected channel.

CALC:AVER:CLEAR (@305)

Use the following command to determine the total number of

readings stored in memory (all channels) from the most recent scan.

DATA:POINTS?

The following command reads and clears the specified number of

readings from memory. This allows you to continue a scan without

losing data stored in memory (if memory becomes full, new readings

will overwrite the first readings stored). The specified number of

readings are cleared from memory, starting with the oldest reading.

DATA:REMOVE? 12

Chapter 4 Features and Functions

Scanning

Single-Channel Monitoring

In the Monitor function, the instrument takes readings as often as it can

on a single channel, even during a scan. This feature is useful for trouble-

shooting your system before a test or for watching an important signal.

Any channel that can be “read” by the instrument can be monitored.

This includes any combination of temperature, voltage, resistance,

current, frequency, or period measurements on multiplexer channels.

You can also monitor a digital input port or the totalizer count on the

multifunction module. Monitoring is not allowed with the actuator

module, the matrix module, or the RF multiplexer modules.

•The Monitor function is equivalent to making continuous

measurements on a single channel with an infinite scan count.

Only one channel can be monitored at a time but you can change the

channel being monitored at any time.

•Readings acquired during a Monitor are not stored in memory but

they are displayed on the front panel (however, all readings from a

scan in progress at the same time are stored in memory).

•Mx+B scaling and alarm limits are applied to the selected channel

during a Monitor and all alarm data is stored in the alarm queue

(which will be cleared if power fails).

•A scan in progress always has priority over the Monitor function.

The instrument will take at least one monitor reading per scan sweep

and will take more as time permits.

•You can monitor a multiplexer channel only if the internal DMM is

installed and enabled (see “Internal DMM Disable” on page 145).

The channel must also be configured to be part of the scan list.

•You can monitor a digital input channel or totalizer channel even if

the channel is not part of the scan list (the internal DMM is not

required either). The count on a totalizer channel is not reset when it

is being monitored (the Monitor ignores the totalizer reset mode).

Chapter 4 Features and Functions

Single-Channel Monitoring

•In the Alarm Scan configuration (see “Scanning on Alarm” on page 84),

the instrument sweeps the scan list once each time a reading crosses

an alarm limit on a channel. In this configuration, you may use the

Monitor function to continuously take readings on a selected channel

and wait for an alarm on that channel. The monitored channel can be

part of the scan list but you can also use a channel on the multifunction

module (which does not have to be part of the scan list and you do not

have to use the Monitor function).

•Front-Panel Operation: To start a Monitor, press . Turn the

knob to advance to the desired channel. The instrument begins

monitoring after you pause for a few seconds on a configured channel.

To stop a Monitor, press again. Note that while the instrument

in in the remote mode, you can still turn on the Monitor function and

select the desired channel.

•Remote Interface Operation: The following program segment selects

the channel to be monitored (specify only one channel) and enables

the Monitor function.

ROUT:MON (@101)

ROUT:MON:STATE ON

To read the monitor data from the selected channel, send the

following command. This command returns the reading only;

the units, time, channel, and alarm information are not returned

(the FORMat:READing commands do not apply to monitor readings).

ROUT:MON:DATA?

Chapter 4 Features and Functions

Single-Channel Monitoring

Scanning With External Instruments

If your application doesn’t require the built-in measurement capabilities

of the 34970A, you can order it without the internal DMM. In this

configuration, you can use the system for signal routing or control

applications. If you install a multiplexer plug-in module, you can use the

system for scanning with an external instrument. You can connect an

external instrument (such as a DMM) to the multiplexer COM terminal.

To control scanning with an external instrument, two control lines are

provided. When the 34970A and the external instrument are properly

configured, you can synchronize a scan sequence between the two.

Input

Channels

External DMM

L Common Terminals

(COM)

VM Complete OUT Ext Trig IN

GND

Ext Trig IN

Channel Closed OUT

External DMM

34970A

Chapter 4 Features and Functions

Scanning With External Instruments

In this configuration, you must set up a scan list to include all desired

multiplexer or digital channels. Channels which are not in the list are

skipped during the scan. The instrument automatically scans the list of

channels in ascending order from slot 100 through slot 300.

For an externally-controlled scan, you must either remove the internal

DMM from the 34970A or disable it (see “Internal DMM Disable” on

page 145). Since the internal DMM is not used, readings from

multiplexer channels are not stored in internal reading memory.

External connections are required to synchronize the scan sequence

between the 34970A and the external instrument. The 34970A must

notify the external instrument when a relay is closed and settled

(including channel delay). The 34970A outputs a Channel Closed pulse

from pin 5 on the rear-panel connector (see previous page). In response,

the external instrument must notify the 34970A when it has finished its

measurement and is ready to advance to the next channel in the scan list.

The 34970A accepts a Channel Advance signal on the External Trigger

input line (pin 6).

•You can configure the event or action that controls the onset of each

sweep through the scan list (a sweep is one pass through the scan list).

When the internal DMM is removed (or disabled), the default scan

interval source is “timer”. For more information, refer to “Scan Interval”

on page 80.

•You can configure the event or action that notifies the 34970A to

advance to the next channel in the scan list. Note that the Channel

Advance source shares the same sources as the scan interval.

However, an error is generated if you attempt to set the channel

advance source to the same source used for the scan interval.

•You can specify the number of times the instrument will sweep

through the scan list. When the specified number of sweeps have

occurred, the scan stops. For more information, refer to “Scan Count”

on page 86.

Chapter 4 Features and Functions

Scanning With External Instruments

•An externally-controlled scan can also include a read of a digital port

or a read of the totalizer count on the multifunction module. When

the channel advance reaches the first digital channel, the instrument

scans through all of the digital channels in that slot and stores the

readings in reading memory (only one channel advance signal is

required).

•You can configure the list of channels for 4-wire external scanning

without the internal DMM. When enabled, the instrument

automatically pairs channel n with channel n+10 (34901A) or n+8

(34902A) to provide the source and sense connections.

•Front-Panel Operation: To select the channel advance source, choose

from the following items.

AUTO ADVANCE , EXT ADVANCE

To initiate the scan, press (the SCAN annunciator will turn on).

To configure the instrument for 4-wire external scanning, choose the

following item.

4W SCAN

•Remote Interface Operation: The following program segment

configures the instrument for an externally-controlled scan.

TRIG:SOUR TIMER Select the scan interval

ROUT:CHAN:ADV:SOUR EXT Select the channel advance source

TRIG:TIMER 5 Set the scan interval to 5 seconds

TRIG:COUNT 2 Sweep the scan list 2 times

INIT Initiate the scan

To configure the instrument for 4-wire external scanning, send the

following command.

ROUTe:CHANnel:FWIRe {OFF|ON}[,(@<ch_list>)]

Chapter 4 Features and Functions

Scanning With External Instruments

General Measurement Configuration

This section contains general information to help you configure the

instrument for making measurements during a scan. Since these

parameters are used by several measurement functions, the discussion

is combined into one common section. Refer to the later sections in this

chapter for more information on parameters that are specific to a

particular measurement function.

Note: It is important that you select the measurement function before

selecting other parameters on a given channel. When you change the

function on a channel, all other settings (range, resolution, etc.) are reset

to their default values.

Measurement Range

You can allow the instrument to automatically select the measurement

range using autoranging or you can select a fixed range using manual

ranging. Autoranging is convenient because the instrument decides

which range to use for each measurement based on the input signal.

For fastest scanning operation, use manual ranging on each

measurement (some additional time is required for autoranging since

the instrument has to make a range selection).

•Autorange thresholds:

Down range at <10% of range

Up range at >120% of range

•If the input signal is greater than can be measured on the selected

range, the instrument gives an overload indication: “±OVLD” from

the front panel or “±9.90000000E+37” from the remote interface.

•For a complete list of the measurement ranges available for each

function, refer to the instrument specifications in chapter 9.

•For temperature measurements, the instrument internally selects

the range; you cannot select which range is used. For thermocouple

measurements, the instrument internally selects the 100 mV range.

For thermistor and RTD measurements, the instrument autoranges

to the correct range for the transducer resistance measurement.

Chapter 4 Features and Functions

General Measurement Configuration

•For frequency and period measurements, the instrument uses one

“range” for all inputs between 3 Hz and 300 kHz. The range parameter

is required only to specify the resolution. Therefore, it is not

necessary to send a new command for each new frequency to

be measured.

•The MEASure? and CONFigure commands contain an optional range

parameter which allows you to specify the range or autoranging.

•The instrument returns to autoranging when the measurement

function is changed and after a Factory Reset (*RST command).

An Instrument Preset (SYSTem:PRESet command) or Card Reset

(SYSTem:CPON command) does not change the range setting.

•Front-Panel Operation: First, select the measurement function on

the active channel. You are automatically guided to the next level of

the menu where you can select a specific range or autorange.

100 mV RANGE

•Remote Interface Operation: You can select the range using

parameters in the MEASure? and CONFigure commands.

For example, the following statement selects the 10 Vdc range on

channel 301.

CONF:VOLT:DC 10,DEF,(@301)

Chapter 4 Features and Functions

General Measurement Configuration

Measurement Resolution

Resolution is expressed in terms of number of digits the instrument can

measure or display on the front panel. You can set the resolution to

4, 5, or 6 full digits, plus a “1⁄2” digit which can only be a “0” or “1”.

To increase your measurement accuracy and improve noise rejection,

select 61⁄2 digits. To increase your measurement speed, select 41⁄2 digits.

  9'&

This is the 10 Vdc range, 51⁄2 digits are displayed.

 P9'&

This is the 100 mVdc range, 41⁄2 digits are displayed.

,2+0

This is the 100 ohm range, 61⁄2 digits are displayed.

•For temperature measurements taken from the remote interface,

the resolution is fixed at 61⁄2 digits. From the front panel, you can set

the resolution in terms of the number of digits displayed past the

decimal point (Measure menu).

•For ac voltage measurements, the resolution is fixed at 61⁄2 digits.

The only way to control the reading rate for ac measurements is by

changing the channel delay (see page 88) or by setting the ac filter to

the highest frequency limit (see page 114).

5 digits

“1⁄2” digit

Chapter 4 Features and Functions

General Measurement Configuration

100

•The specified resolution is used for all measurements on the selected

channel. If you have applied Mx+B scaling or have assigned alarms to

the selected channel, those measurements are also made using the

specified resolution. Measurements taken during the Monitor

function also use the specified resolution.

•Changing the number of digits does more than just change the

resolution of the instrument. It also changes the integration time,

which is the period the instrument’s analog-to-digital (A/D) converter

samples the input signal for a measurement. See “Custom A/D

Integration Time,” on page 103 for more information.

•The MEASure? and CONFigure commands contain an optional

resolution parameter which allows you to specify the resolution.

•The instrument returns to 51⁄2 digits when the measurement function

is changed and after a Factory Reset (*RST command). An Instrument

Preset (SYSTem:PRESet command) or Card Reset (SYSTem:CPON

command) does not change the resolution setting.

•Front-Panel Operation: First, select the measurement function on

the active channel. You are automatically guided to the next level of

the menu where you can select the number of digits. The default is

51⁄2 digits.

6 1/2 DIGITS

For temperature measurements, go to the menu and select the number

of digits displayed past the decimal point on the selected channel.

DISPLAY 1 °C

Chapter 4 Features and Functions

General Measurement Configuration

101

•Remote Interface Operation: Specify the resolution in the same units

as the measurement function, not in number of digits. For example,

if the function is dc volts, specify the resolution in volts. For frequency,

specify the resolution in hertz.

You can select the resolution using parameters in the MEASure? and

CONFigure commands. For example, the following statement selects

the 10 Vdc range with 41⁄2 digits of resolution on channel 301.

CONF:VOLT:DC 10,0.001,(@301)

The following statement selects the 1 A range with 61⁄2 digits of

resolution on channel 221.

MEAS:CURR:AC? 1,1E-6,(@221)

You can also select the resolution using the SENSe commands.

For example, the following statement specifies a 4-wire ohms

measurement with 100Ω of resolution on channel 103.

SENS:FRES:RES 100,(@103)

Chapter 4 Features and Functions

General Measurement Configuration

102

Custom A/D Integration Time

Integration time is the period of time that the instrument’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 (PLCs).

Select from 0.02, 0.2, 1, 2, 10, 20, 100, or 200 power line cycles.

The default is 1 PLC.

•Only the integral number of power line cycles (1, 2, 10, 20, 100, or

200 PLCs) provide normal mode (line frequency noise) rejection.

•You can also specify integration time directly in seconds (this is

called aperture time). Select a value between 400 µs and 4 seconds,

with 10 µs resolution.

•For temperature measurements, the integration time is fixed at

1 PLC.

•The only way to control the reading rate for ac measurements is by

changing the channel delay (see page 88) or by setting the ac filter

to the highest frequency limit (see page 114).

•The specified integration time is used for all measurements on the

selected channel. If you have applied Mx+B scaling or have assigned

alarms to the selected channel, those measurements are also made

using the specified integration time. Measurements taken during the

Monitor function also use the specified integration time.

•The following table shows the relationship between integration time,

measurement resolution, number of digits, and number of bits.

Integration Time Resolution Digits Bits

0.02 PLC

0.2 PLC

1 PLC

2 PLC

10 PLC

20 PLC

100 PLC

200 PLC

< 0.0001 x Range

< 0.00001 x Range

< 0.000003 x Range

< 0.0000022 x Range

< 0.000001 x Range

< 0.0000008 x Range

< 0.0000003 x Range

< 0.00000022 x Range

41⁄2 Digits

51⁄2 Digits

61⁄2 Digits

Chapter 4 Features and Functions

General Measurement Configuration

103

•The instrument selects 1 PLC when the measurement function is

changed and after a Factory Reset (*RST command). An Instrument

Preset (SYSTem:PRESet command) or Card Reset (SYSTem:CPON

command) does not change the integration time setting.

•Front-Panel Operation: First, select the measurement function on

the active channel. Then, go to the Advanced menu and select one of

the choices in PLCs for the active channel.

INTEG 2 PLC

To select the aperture time, select INTEGRATE T from the Advanced

menu and then specify a value in seconds for the active channel.

INTEGRATE T

•Remote Interface Operation: You can set the integration time using

the SENSe commands. For example, the following statement specifies

an integration time of 10 PLC for dc voltage measurements on

channel 301.

SENS:VOLT:DC:NPLC 10,(@301)

You can also select an aperture time using the SENSe commands.

For example, the following statement specifies an aperture time of

2 ms for resistance measurements on channel 104.

SENS:RES:APER 0.002,(@104)

Chapter 4 Features and Functions

General Measurement Configuration

104

Autozero

When autozero is enabled (default), the instrument internally

disconnects the input signal following each measurement, and takes a

zero reading. It then subtracts the zero reading from the preceding

reading. This prevents offset voltages present on the instrument’s input

circuitry from affecting measurement accuracy.

When autozero is disabled, the instrument takes one zero reading and

subtracts it from all subsequent measurements. It takes a new zero

reading each time you change the function, range, or integration time.

•Applies to temperature, dc voltage, 2-wire ohms, and dc current

measurements only. Autozero is enabled when you select 4-wire ohms

measurements.

•The autozero mode is set indirectly when you set the resolution and

integration time. Autozero is automatically turned off when you

select an integration time less than 1 PLC.

•You can set autozero from the remote interface only; you cannot

directly set autozero from the front panel.

•The autozero setting is stored in non-volatile memory, and does not

change when power has been off, after a Factory Reset (*RST

command), or after an Instrument Preset (SYSTem:PRESet

command).

•Remote Interface Operation: The OFF and ONCE parameters have a

similar effect. Autozero OFF does not issue a new zero measurement.

Autozero ONCE issues an immediate zero measurement.

ZERO:AUTO {OFF|ONCE|ON}[,(@<ch_list>)]

Chapter 4 Features and Functions

General Measurement Configuration

105

Temperature Measurement Configuration

This section contains information to help you configure the instrument

for making temperature measurements. For more information on the

types of temperature transducers, see “Temperature Measurements”

starting on page 345 in chapter 8.

The instrument supports direct measurement of thermocouples, RTDs,

and thermistors. The instrument supports the following specific types

of transducers in each category:

Thermocouples

Supported RTDs

Supported Thermistors

Supported

B, E, J, K, N, R, S, T R0 = 49Ω to 2.1 kΩ

α = 0.00385 (DIN / IEC 751)

α = 0.00391

2.2 kΩ, 5 kΩ, 10 kΩ,

44000 Series

Measurement Units

•The instrument can report temperature measurements in

°C (Celsius), °F (Fahrenheit), or K (Kelvins). You can mix

temperature units on different channels within the instrument

and on the same module.

•The instrument selects Celsius when the probe type is changed and

after a Factory Reset (*RST command). An Instrument Preset

(SYSTem:PRESet command) or Card Reset (SYSTem:CPON command)

does not change the units setting.

•Setting the Mx+B measurement label to °C, °F, or K has no effect on

the temperature measurement units currently selected.

•Front-Panel Operation: First, select the temperature function on the

active channel. Then, select the temperature units.

UNITS °F

•Remote Interface Operation:

UNIT:TEMP F,(@103)

Chapter 4 Features and Functions

Temperature Measurement Configuration

106

Thermocouple Measurements

To connect a thermocouple to the module’s screw terminals, see page 21.

•The instrument supports the following thermocouple types:

B, E, J, K, N, R, S, and T using ITS-90 software conversions.

The default is a J-Type thermocouple.

•Thermocouple measurements require a reference junction temperature.

For the reference junction temperature, you can use an internal

measurement on the module, an external thermistor or RTD

measurement, or a known fixed junction temperature.

•If you select an external reference, the instrument automatically

reserves channel 01 on the multiplexer in the lowest slot as the

reference channel (thermistor or RTD measurement). If you have

more than one multiplexer installed, channel 01 on the module in the

lowest slot is used as the reference for the entire instrument.

•Before configuring a thermocouple channel with an external

reference, you must configure the reference channel (channel 01)

for a thermistor or RTD measurement. An error is generated if you

attempt to select the external reference source before configuring the

reference channel. An error is also generated if you change the

function on the reference channel after selecting the external

reference for a thermocouple channel.

•If you select a fixed reference temperature, specify a value between

-20 °C and +80 °C (always specify the temperature in °C regardless

of the temperature units currently selected).

•The accuracy of the measurement is highly dependent upon the

thermocouple connections and the type of reference junction used.

Use a fixed temperature reference for the highest accuracy

measurements. The internal isothermal block reference provides

the lowest accuracy measurements. For more information on

reference junction temperature measurements and associated errors,

see the sections on pages 345 and 352.

•The thermocouple check feature allows you to verify that your

thermocouples are properly connected to the screw terminals for

measurements. If you enable this feature, the instrument measures

the channel resistance after each thermocouple measurement to

ensure a proper connection. If an open connection is detected (greater

than 5 kΩ on the 10 kΩ range), the instrument reports an overload

condition for that channel (or displays “OPEN T/C” on the front panel).

Chapter 4 Features and Functions

Temperature Measurement Configuration

107

•Front-Panel Operation: To select the thermocouple function on the

active channel, choose the following items.

TEMPERATURE , THERMOCOUPLE

To select the thermocouple type for the active channel, choose the

following item.

J TYPE T/C

To enable the thermocouple check feature on the active channel

(opens are reported as “OPEN T/C”), choose the following item.

T/C CHECK ON

To select the reference junction source for the active channel, choose

one of the following items.

INTERNAL REF , EXTERNAL REF , FIXED REF

Note: Before selecting an external source, be sure to configure

channel 01 in the lowest slot for a thermistor or RTD measurement.

Chapter 4 Features and Functions

Temperature Measurement Configuration

108

•Remote Interface Operation: You can use the MEASure? or

CONFigure command to select the probe type and thermocouple type.

For example, the following statement configures channel 301 for a

J-type thermocouple measurement.

CONF:TEMP TC,J,(@301)

You can also use the SENSe command to select the probe type and

thermocouple type. For example, the following statement configures

channel 203 for a J-type thermocouple measurement.

SENS:TEMP:TRAN:TC:TYPE J,(@203)

The following statements use the SENSe command to set a fixed

reference junction temperature of 40 degrees (always in °C) on

channel 203.

SENS:TEMP:TRAN:TC:RJUN:TYPE FIXED,(@203)

SENS:TEMP:TRAN:TC:RJUN 40,(@203)

The following statement enables the thermocouple check feature on

the specified channels (opens are reported as “+9.90000000E+37”).

SENS:TEMP:TRAN:TC:CHECK ON,(@203,301)

Chapter 4 Features and Functions

Temperature Measurement Configuration

109

RTD Measurements

To connect an RTD to the module’s screw terminals, see page 21.

•The instrument supports RTDs with α = 0.00385 (DIN / IEC 751)

using ITS-90 software conversions or α = 0.00391 using IPTS-68

software conversions. The default is α = 0.00385.

•The resistance of an RTD is nominal at 0 °C and is referred to as R0.

The instrument can measure RTDs with R0 values from 49Ω to 2.1 kΩ.

The default is R0 = 100Ω.

•“PT100” is a special label that is sometimes used to refer to an

RTD with α = 0.00385 and R0 = 100Ω.

•You can measure RTDs using a 2-wire or 4-wire measurement

method. The 4-wire method provides the most accurate way to

measure small resistances. Connection lead resistance is

automatically removed using the 4-wire method.

•For 4-wire RTD measurements, the instrument automatically pairs

channel n with channel n+10 (34901A) or n+8 (34902A) to provide

the source and sense connections. For example, make the source

connections to the HI and LO terminals on channel 2 and the sense

connections to the HI and LO terminals on channel 12.

•Front-Panel Operation: To select the 2-wire or 4-wire RTD function

for the active channel, choose the following items.

TEMPERATURE , RTD , RTD 4W

To select the nominal resistance (R0) for the active channel, choose

the following item.

Ro:100.000,0 OHM

To select the RTD type (α = 0.00385 or 0.00391) for the active

channel, choose the following item.

ALPHA 0.00385

Chapter 4 Features and Functions

Temperature Measurement Configuration

110

•Remote Interface Operation: You can use the MEASure? or

CONFigure command to select the probe type and RTD type.

For example, the following statement configures channel 301 for

2-wire measurements of an RTD with α = 0.00385 (use “85” to specify

α = 0.00385 or “91” to specify α = 0.00391).

CONF:TEMP RTD,85,(@301)

You can also use the SENSe command to select the probe type,

RTD type, and nominal resistance. For example, the following

statement configures channel 103 for 4-wire measurements of an

RTD with α = 0.00391 (channel 103 is automatically paired with

channel 113 for the 4-wire measurement).

SENS:TEMP:TRAN:FRTD:TYPE 91,(@103)

The following statement sets the nominal resistance (R0) to 1000Ω

on channel 103.

SENS:TEMP:TRAN:FRTD:RES 1000,(@103)

Chapter 4 Features and Functions

Temperature Measurement Configuration

111

Thermistor Measurements

To connect a thermistor to the module’s screw terminals, see page 21.

•The instrument supports 2.2 kΩ (44004), 5 kΩ (44007), and 10 kΩ

(44006) thermistors.

•Front-Panel Operation: To select the thermistor function for the

active channel, choose the following items.

TEMPERATURE , THERMISTOR

To select the thermistor type for the active channel, choose from the

following items.

TYPE 2.2 KOHM , TYPE 5 KOHM , TYPE 10 KOHM

•Remote Interface Operation: You can use the MEASure? or

CONFigure command to select the probe type and thermistor type.

For example, the following statement configures channel 301 for

measurements of a 5 kΩ thermistor:

CONF:TEMP THER,5000,(@301)

You can also use the SENSe command to select the probe type and

thermistor type. For example, the following statement configures

channel 103 for measurements of a 10 kΩ thermistor:

SENS:TEMP:TRAN:THERM:TYPE 10000,(@103)

Chapter 4 Features and Functions

Temperature Measurement Configuration

112

Voltage Measurement Configuration

To connect voltage sources to the module’s screw terminals, see page 21.

This section contains information to help you configure the instrument

for making voltage measurements. The instrument can measure dc and

true RMS ac-coupled voltages on the measurement ranges shown below.

100 mV 1 V 10 V 100 V 300 V Autorange

DC Input Resistance

Normally, the instrument’s input resistance is fixed at 10 MΩ for all

dc voltage ranges to minimize noise pickup. To reduce the effects of

measurement loading errors, you can set the input resistance to greater

than 10 GΩ for the 100 mVdc, 1 Vdc, and 10 Vdc ranges.

Applies to dc voltage measurements only.

Input Resistance

Setting Input Resistance

100 mV, 1 V, 10 V ranges Input Resistance

100 V, 300 V ranges

Input R Auto OFF

Input R Auto ON 10 M

Ω

> 10 GΩ 10 MΩ

10 MΩ

•The instrument selects 10 MΩ (fixed input resistance on all

dc voltage ranges) when the measurement function is changed or

after a Factory Reset (*RST command). An Instrument Preset

(SYSTem:PRESet command) or Card Reset (SYSTem:CPON command)

does not change the input resistance setting.

•Front-Panel Operation: First, select the dc voltage function on the

active channel. Then, go to the Advanced menu and select 10 MΩ

(fixed resistance for all dc voltage ranges) or >10 GΩ. The default

is 10 MΩ.

INPUT R >10 G

Chapter 4 Features and Functions

Voltage Measurement Configuration

113

•Remote Interface Operation: You can enable or disable the automatic

input resistance mode on the specified channels. With AUTO OFF

(default), the input resistance is fixed at 10 MΩ for all ranges.

With AUTO ON, the input resistance is set to >10 GΩ for the three

lowest dc voltage ranges. The MEASure? and CONFigure commands

automatically select AUTO OFF.

INPUT:IMPEDANCE:AUTO ON,(@103)

AC Low Frequency Filter

The instrument uses three different ac filters which enable you to either

optimize low frequency accuracy or achieve faster ac settling times.

The instrument selects the slow, medium, or fast filter based on the

input frequency that you specify for the selected channels.

Applies to ac voltage and ac current measurements only.

Input Frequency Default Settling Delay Minimum Settling Delay

3 Hz to 300 kHz (Slow)

20 Hz to 300 kHz (Medium)

200 Hz to 300 kHz (Fast)

7 seconds / reading

1 second / reading

0.12 seconds / reading

1.5 seconds

0.2 seconds

0.02 seconds

•The instrument selects the medium filter (20 Hz) when the function

is changed or after a Factory Reset (*RST command). An Instrument

Preset (SYSTem:PRESet command) or Card Reset (SYSTem:CPON

command) does not change the setting.

•Front-Panel Operation: First, select the ac voltage (or ac current)

function on the active channel. Then, go to the Advanced menu and

select the slow filter (3 Hz), medium filter (20 Hz), or fast filter

(200 Hz) for the active channel. The default is the medium filter.

LF 3 HZ:SLOW

•Remote Interface Operation: Specify the lowest frequency expected in

the input signal on the specified channels. The instrument selects the

appropriate filter based on the frequency you specify (see table above).

The MEASure? and CONFigure commands automatically select the

20 Hz (medium) filter.

SENS:VOLT:AC:BAND 3,(@203) Select the slow filter (3 Hz)

Chapter 4 Features and Functions

Voltage Measurement Configuration

114

Resistance Measurement Configuration

To connect resistances to the module’s screw terminals, see page 21.

This section contains information to help you configure the instrument

for making resistance measurements. Use the 2-wire method for ease of

wiring and higher density or the 4-wire method for improved

measurement accuracy. The measurement ranges are shown below.

100Ω1 kΩ10 kΩ100 kΩ1 MΩ10 MΩ100 MΩAutorange

Offset Compensation

Offset compensation removes the effects of any dc voltages in the circuit

being measured. The technique involves taking the difference between

two resistance measurements on the specified channels, one with the

current source turned on and one with the current source turned off.

Applies only to 2-wire and 4-wire ohms measurements on the 100Ω, 1 kΩ,

and 10 kΩ ranges.

•For detailed information about offset compensation, see page 371.

•The instrument disables offset compensation when the measurement

function is changed or after a Factory Reset (*RST command).

An Instrument Preset (SYSTem:PRESet command) or Card Reset

(SYSTem:CPON command) does not change the setting.

•Front-Panel Operation: First, select the 2-wire or 4-wire ohms

function on the active channel. Then, go to the Advanced menu and

enable or disable offset compensation.

OCOMP ON

•Remote Interface Operation:

RES:OCOM ON,(@203) Enable offset compensation (2-wire)

FRES:OCOM ON,(@208) Enable offset compensation (4-wire)

For 4-wire measurements, specify the paired channel in the lower

bank (source) as the ch_list parameter.

Chapter 4 Features and Functions

Resistance Measurement Configuration

115

Current Measurement Configuration

To connect a current source to the module’s screw terminals, see page 21.

This section contains information to help you configure the instrument

for making current measurements on the 34901A multiplexer module.

This module has two fused channels for direct dc and ac current

measurements on the measurement ranges shown below.

10 mA 100 mA 1 A Autorange

Note: Current measurements are allowed only on channels 21 and 22

on the 34901A module.

AC Low Frequency Filter

The instrument uses three different ac filters which enable you to either

optimize low frequency accuracy or achieve faster ac settling times.

The instrument selects the slow, medium, or fast filter based on the

input frequency that you specify for the selected channels.

Applies to ac current and ac voltage measurements only.

Input Frequency Default Settling Delay Minimum Settling Delay

3 Hz to 300 kHz (Slow)

20 Hz to 300 kHz (Medium)

200 Hz to 300 kHz (Fast)

7 seconds / reading

1 second / reading

0.12 seconds / reading

1.5 seconds

0.2 seconds

0.02 seconds

•The instrument selects the medium filter (20 Hz) when the function is

changed or after a Factory Reset (*RST command). An Instrument

Preset (SYSTem:PRESet command) or Card Reset (SYSTem:CPON

command) does not change the setting.

Chapter 4 Features and Functions

Current Measurement Configuration

116

•Front-Panel Operation: First, select the ac current (or ac voltage)

function on the active channel. Then, go to the Advanced menu and

select the slow filter (3 Hz), medium filter (20 Hz), or fast filter

(200 Hz) for the active channel. The default is the medium filter.

LF 3 HZ:SLOW

•Remote Interface Operation: Specify the lowest frequency expected in

the input signal on the specified channels. The instrument selects the

appropriate filter based on the frequency you specify (see table on

previous page). The MEASure? and CONFigure commands

automatically select the 20 Hz (medium) filter.

SENS:CURR:AC:BAND 3,(@221) Select the slow filter (3 Hz)

Chapter 4 Features and Functions

Current Measurement Configuration

117

Frequency Measurement Configuration

To connect an ac source to the module’s screw terminals, see page 21.

Low Frequency Timeout

The instrument uses three different timeout ranges for frequency

measurements. The instrument selects a slow, medium, or fast timeout

based on the input frequency that you specify for the selected channels.

Input Frequency Timeout

3 Hz to 300 kHz (Slow)

20 Hz to 300 kHz (Medium)

200 Hz to 300 kHz (Fast)

1 s

100 ms

10 ms

•The instrument selects the medium timeout (20 Hz) when the

function is changed or after a Factory Reset (*RST command).

An Instrument Preset (SYSTem:PRESet command) or Card Reset

(SYSTem:CPON command) does not change the setting.

•Front-Panel Operation: First, select the frequency function on the

active channel. Then, go to the Advanced menu and select the slow

timeout (3 Hz), medium timeout (20 Hz), or fast timeout (200 Hz) for

the active channel. The default is the medium timeout value.

LF 3 HZ:SLOW

•Remote Interface Operation: Specify the lowest frequency expected in

the input signal on the specified channels. The instrument selects the

appropriate timeout based on the frequency you specify (see table

above). The MEASure? and CONFigure commands automatically

select the 20 Hz (medium) timeout.

SENS:FREQ:RANG:LOW 3,(@203) Select the slow timeout (3 Hz)

Chapter 4 Features and Functions

Frequency Measurement Configuration

118

Mx+B Scaling

The scaling function allows you to apply a gain and offset to all readings

on a specified multiplexer channel during a scan. In addition to setting

the gain (“M”) and offset (“B”) values, you can also specify a custom

measurement label for your scaled readings (RPM, PSI, etc.). You can

apply scaling to any multiplexer channels and for any measurement

function. Scaling is not allowed with any of the digital channels on the

multifunction module.

•Scaling is applied using the following equation:

Scaled Reading = (Gain x Measurement) - Offset

•You must configure the channel (function, transducer type, etc.)

before applying any scaling values. If you change the measurement

configuration, scaling is turned off on that channel and the gain and

offset values are reset (M=1 and B=0). Scaling is also turned off when

you change the temperature probe type, temperature units, or disable

the internal DMM.

•If you plan to use scaling on a channel which will also use alarms,

be sure to configure the scaling values first. If you attempt to assign

the alarm limits first, the instrument will turn off alarms and clear

the limit values when you enable scaling on that channel. If you

specify a custom measurement label with scaling, it is automatically

used when alarms are logged on that channel.

•If you remove a channel from the scan list (by selecting CHANNEL OFF

from the front panel or by redefining the scan list from the remote

interface), scaling is turned off for that channel but the gain and

offset values are not cleared. If you decide to add that channel back

to the scan list (without changing the function), the original gain and

offset values are restored and scaling is turned back on. This makes it

easy to temporarily remove a channel from the scan list without

entering the scaling values again.

•You can make a null measurement on a channel and store it as the

offset (“B”) for subsequent measurements. This allows you to adjust

for voltage or resistive offsets through your wiring to the point of the

measurement.

Chapter 4 Features and Functions

Mx+B Scaling

119

•During a Monitor operation, the gain and offset values are applied to

all readings on the specified channel.

•You can specify a custom label with up to three characters. You can

use letters (A-Z), numbers (0-9), an underscore ( _ ), or the “#” character

which displays a degree symbol ( ° ) on the front panel (displayed as a

blank space in an output string from the remote interface). The first

character must be a letter or the “#” character (the “#” character is

allowed only as the leftmost character in the label). The remaining

two characters can be letters, numbers, or an underscore.

Note: If you set the measurement label to °C, °F, or K, note that this

has no effect on the temperature units set in the Measure menu.

•Although the instrument does not directly support strain gage

measurements, you can measure a strain gage using a 4-wire

resistance measurement with scaling. For more information, refer to

“Strain Gage Measurements” on page 373.

Note: Agilent BenchLink Data Logger software has built-in

strain gage measurement capability.

Use the following equations to calculate the gain and offset.

M = 1

GF x R0 B = − 1

Where GF is the gage factor and R0 is the unstrained gage resistance.

For example, a 350Ω strain gage with a gage factor of 2 would use the

following gain and offset values: M=0.001428571, B=-0.5 (be sure to

use 61⁄2 digits of resolution for this measurement).

•The maximum gain allowed is ±1E+15 and the maximum offset

allowed is ±1E+15.

•The MEASure? and CONFigure commands automatically set the

gain (“M”) to 1 and offset (“B”) to 0.

•A Factory Reset (*RST command) turns off scaling and clears the

scaling values on all channels. An Instrument Preset (SYSTem:PRESet

command) or Card Reset (SYSTem:CPON command) does not clear the

scaling values and does not turn off scaling.

Chapter 4 Features and Functions

Mx+B Scaling

120

•Front-Panel Operation: The menu automatically guides you through

the gain, offset, and measurement label settings.

SET GAIN , SET OFFSET , SET LABEL

To reset the gain, offset, and measurement label to their defaults,

go to the corresponding level in the menu and turn the knob. To turn

scaling off (without clearing the gain and offset values), go to the first

level in the menu and select SCALING OFF.

SET GAIN TO 1 , SET OFST TO 0 , DEFAULT LABEL

To make a null measurement and store it as the offset, go to

SET OFFSET in the menu and turn the knob.

MEAS OFFSET

•Remote Interface Operation: Use the following commands to set the

gain, offset, and custom measurement label.

CALC:SCALE:GAIN 1.2,(@101)

CALC:SCALE:OFFSET 10,(@101)

CALC:SCALE:UNIT ’PSI’,(@101)

After setting the gain and offset values, send the following command

to enable the scaling function on the specified channel.

CALC:SCALE:STATE ON,(@101)

To make a null measurement and store it as the offset, send the

following command.

CALC:SCALE:OFFSET:NULL (@101)

Chapter 4 Features and Functions

Mx+B Scaling

121

Alarm Limits

The instrument has four alarms which you can configure to alert you

when a reading exceeds specified limits on a channel during a scan.

You can assign a high limit, a low limit, or both to any configured

channel in the scan list. You can assign multiple channels to any of the

four available alarms (numbered 1 through 4). For example, you can

configure the instrument to generate an alarm on the Alarm 1 output

when a limit is exceeded on any of channels 103, 205, or 320.

You can also assign alarms to channels on the multifunction module.

For example, you can generate an alarm when a specific bit pattern or

bit pattern change is detected on a digital input channel or when a

specific count is reached on a totalizer channel. With the multifunction

module, the channels do not have to be part of the scan list to generate

an alarm. For complete details, see “Using Alarms With the Multifunction

Module” on page 130.

Alarm data can be stored in one of two locations depending on whether

a scan is running when the alarm occurs.

1. If an alarm event occurs on a channel as it is being scanned, then

that channel’s alarm status is stored in reading memory as the

readings are taken. Each reading that is outside the specified alarm

limits is logged in memory. You can store up to 50,000 readings in

memory during a scan. You can read the contents of reading memory

at any time, even during a scan. Reading memory is not cleared when

you read it.

2. As alarm events are generated, they are also logged in an alarm queue,

which is separate from reading memory. This is the only place where

non-scanned alarms get logged (alarms during a monitor, alarms

generated by the multifunction module, etc.). Up to 20 alarms can be

logged in the alarm queue. If more than 20 alarm events are generated,

they will be lost (only the first 20 alarms are saved). Even if the

alarm queue is full, the alarm status is still stored in reading memory

during a scan. The alarm queue is cleared by the *CLS (clear status)

command, when power is cycled, and by reading all of the entries.

A Factory Reset (*RST command) does not clear the alarm queue.

Chapter 4 Features and Functions

Alarm Limits

122

•You can assign an alarm to any configured channel and multiple

channels can be assigned to the same alarm number. However,

you cannot assign alarms on a specific channel to more than one

alarm number.

•When an alarm occurs, the instrument stores relevant information

about the alarm in the queue. This includes the reading that caused

the alarm, the time of day and date of the alarm, and the channel

number on which the alarm occurred. The information stored in the

alarm queue is always in absolute time format and is not affected by

the FORMat:READing:TIME:TYPE command setting.

•You must configure the channel (function, transducer type, etc.)

before setting any alarm limits. If you change the measurement

configuration, alarms are turned off and the limit values are cleared.

Alarms are also turned off when you change the temperature probe

type, temperature units, or disable the internal DMM.

•If you plan to use alarms on a channel which will also use scaling,

be sure to configure the scaling values first. If you attempt to assign

the alarm limits first, the instrument will turn off alarms and clear

the limit values when you enable scaling on that channel. If you

specify a custom measurement label with scaling, it is automatically

used when alarms are logged on that channel.

•If you remove a channel from the scan list (by selecting CHANNEL OFF

from the front panel or by redefining the scan list from the remote

interface), alarms are no longer evaluated on that channel (during a

scan) but the limit values are not cleared. If you decide to add that

channel back to the scan list (without changing the function), the

original limit values are restored and alarms are turned back on.

This makes it easy to temporarily remove a channel from the scan list

without entering the alarm values again.

•Each time you start a new scan, the instrument clears all readings

(including alarm data) stored in reading memory from the previous

scan. Therefore, the contents of reading memory are always from the

most recent scan.

Chapter 4 Features and Functions

Alarm Limits

123

•Alarms are logged in the alarm queue only when a reading crosses a

limit, not while it remains outside the limit and not when it returns

to within limits.

•Four TTL alarm outputs are available on the rear-panel Alarms

connector. You can use these hardware outputs to trigger external

alarm lights, sirens, or send a TTL pulse to your control system.

You can also initiate a scan sweep (no external wiring required) when

an alarm event is logged on a channel. For complete details, refer to

“Using the Alarm Output Lines” on page 128.

•The following table shows the different combinations of front-panel

annunciators that may appear while using alarms.

•In addition to being stored in reading memory, alarms are also

recorded in their own SCPI status system. You can configure the

instrument to use the status system to generate a Service Request

(SRQ) when alarms are generated. See “The SCPI Status System,”

starting on page 275 for more information.

•The default values for the upper and lower alarm limits are “0”.

The lower limit must always be less than or equal to the upper limit,

even if you are using only one of the limits.

Upper Limit

Lower Limit

Alarm Event No Alarm

An alarm is enabled on the displayed channel.

The indicated HI or LO limit is being configured on the indicated alarm

(shown while in the Alarm menu).

An alarm has occurred on one or more channels. The behavior of the

alarm output lines tracks the alarm annunciators on the front panel.

The alarm output lines have been cleared but alarms remain in the queue.

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•For details on configuring alarms on the multifunction module,

see “Using Alarms With the Multifunction Module” on page 130.

•A Factory Reset (*RST command) clears all alarm limits and turns off

all alarms. An Instrument Preset (SYSTem:PRESet command) or

Card Reset (SYSTem:CPON command) does not clear the alarm limits

and does not turn off alarms.

•Front-Panel Operation: To select the alarm for use on the active

channel, choose from the following items.

NO ALARM , USE ALARM 1 , ... USE ALARM 4

Then, choose from the following alarm conditions.

HI+LO ALARMS , HI ALARM ONLY , LO ALARM ONLY

Then, set the desired limit values and exit the menu. Note that the

instrument does not start evaluating the alarm conditions until you

exit the Alarm menu.

•Remote Interface Operation: To assign the alarm number to report

any alarm conditions on the specified channels, use the following

command (if not assigned, all alarms on all channels are reported on

Alarm 1 by default).

OUTPUT:ALARM2:SOURCE (@103,212)

To set the upper and lower alarm limits on the specified channels,

use the following commands.

CALC:LIMIT:UPPER 5.25,(@103,212)

CALC:LIMIT:LOWER 0.025,(@103,212)

To enable the upper and lower alarm limits on the specified channels,

use the following commands.

CALC:LIMIT:UPPER:STATE ON,(@103,212)

CALC:LIMIT:LOWER:STATE ON,(@103,212)

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Viewing Stored Alarm Data

If an alarm occurs on a channel as it is being scanned, then that channel’s

alarm status is stored in reading memory as the readings are taken.

As alarm events are generated, they are also logged in an alarm queue,

which is separate from reading memory. This is the only place where

non-scanned alarms get logged (alarms during a monitor, alarms

generated by the multifunction module, etc.).

•You can store up to 50,000 readings in memory during a scan.

You can read the contents of reading memory at any time, even

during a scan. Reading memory is not cleared when you read it.

•Each time you start a new scan, the instrument clears all readings

(including alarm data) stored in reading memory from the previous

scan. Therefore, the contents of memory are always from the most

recent scan.

•Up to 20 alarms can be logged in the alarm queue. If more than

20 alarms are generated, they will be lost (only the first 20 alarms

are saved).

•The alarm queue is cleared by the *CLS (clear status) command,

when power is cycled, and by reading all of the entries. A Factory

Reset (*RST command) or Instrument Preset (SYSTem:PRESet

command) does not clear the alarm queue.

•Front-Panel Operation: From the front panel, you can view the first

20 alarms in the queue. After turning the knob to the desired

channel, press and to view either the alarm reading or the time

that the alarm occurred. Notice that the annunciators indicate which

alarm is being viewed.

ALARMS

Note: The alarm queue is cleared when you read the alarms.

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•Remote Interface Operation: The following command reads data from

the alarm queue (one alarm event is read and cleared each time this

command is executed).

SYSTEM:ALARM?

The following is an example of an alarm stored in the alarm queue

(if no alarm data is in the queue, the command returns “0” for each field).

The following command retrieves scanned readings and alarm data

from reading memory (the readings are not erased).

FETCH?

1 Reading with Units (31.009 °C)

2 Date (May 1, 1997)

3 Time (2:39:40.058 PM)

4 Channel Number

5 Limit Threshold Crossed (0 = No Alarm,

1 = LO, 2 = HI)

6 Alarm Number Reported (1, 2, 3, or 4)

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Using the Alarm Output Lines

Four TTL alarm outputs are available on the rear-panel Alarms

connector. You can use these hardware outputs to trigger external

alarm lights, sirens, or send a TTL pulse to your control system. You can

assign an alarm to any configured channel and multiple channels can be

assigned to the same alarm number. Each alarm output line represents

the logical “OR” of all channels assigned to that alarm number (an alarm

on any of the associated channels will pulse the line).

You can configure the behavior of the alarm output lines as described

below. The behavior of the alarm annunciators on the front panel also

tracks the alarm output configuration. The configuration that you select

is used for all four alarm output lines. A Factory Reset (*RST command)

clears all four alarm outputs but does not clear the alarm queue in

either configuration.

•Latch Mode: In this mode, the corresponding output line is latched

true when the first alarm occurs and remains asserted until you clear

it by initiating a new scan or cycling power. You can manually clear the

output lines at any time (even during a scan) and the alarm data in

memory is not cleared (however, data is cleared when you initiate

a new scan).

•Track Mode: In this mode, the corresponding output line is asserted

only when a reading crosses a limit and remains outside the limit.

When a reading returns to within limits, the output line is automatically

cleared. You can manually clear the output lines at any time (even

during a scan) and the alarm data in memory is not cleared (however,

data is cleared when you initiate a new scan). The alarm outputs are

also cleared when you initiate a new scan.

Gnd

Alarm 4 Output

Alarm 3 Output

Alarm 2 Output

Alarm 1 Output

Alarms Connector

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•You can control the slope of the pulse from the alarm outputs

(the selected configuration is used for all four outputs). In the

falling edge mode, 0V (TTL low) indicates an alarm. In the rising edge

mode, +5V (TTL high) indicates an alarm. A Factory Reset (*RST

command) will reset the slope to falling edge.

Note: Changing the slope of the output lines may cause the lines

to change state.

•Front-Panel Operation: To specify if you want to manually clear

all four alarm outputs, choose from the following items.

DO NOT CLEAR , CLEAR OUTPUTS

To select the output configuration for all four output lines, choose

from the following items.

LATCH ON FAIL , TRACK PASS/F

To configure the slope of all four output lines, choose from

the following items.

FAIL = HIGH , FAIL = LOW

•Remote Interface Operation: To clear the specified output lines (or to

clear all four lines), use one of the following commands.

OUTPUT:ALARM2:CLEAR Clear alarm output line 2

OUTPUT:ALARM:CLEAR:ALL Clear all four alarm outputs

To select the output configuration for all four output lines, use the

following command.

OUTPut:ALARm:MODE {LATCh|TRACk}

To configure the slope of all four output lines, use the following

command.

OUTPut:ALARm:SLOPe {NEGative|POSitive}

Falling Edge Rising Edge

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Using Alarms With the Multifunction Module

You can configure the instrument to generate an alarm when a specific

bit pattern or bit pattern change is detected on a digital input channel

or when a specific count is reached on a totalizer channel. These channels

do not have to be part of the scan list to generate an alarm. Alarms are

evaluated continuously as soon as you enable them.

•The digital input channels are numbered “s01” (lower byte) and “s02”

(upper byte), where s represents the slot number. The totalizer

channel is numbered “s03”.

•Alarms are evaluated continuously on the multifunction module,

but alarm data is stored in reading memory only during a scan.

•Each time you start a new scan, the instrument clears all readings

(including alarm data) stored in reading memory from the previous

scan. However, alarm data stored in the alarm queue from the

multifunction module is not cleared. Therefore, although the contents

of reading memory are always from the most recent scan, the alarm

queue may contain data that occurred during previous scans or while

the instrument was not scanning.

•Front-Panel Operation: To configure an alarm on a digital input

channel, choose from the following items and then set the desired

bit pattern. Set each bit to “0”, “1”, or “X” (don’t care). You can either

specify that an alarm will occur when certain bits change or when a

specific 8-bit pattern is read.

NOT PATTERN , PATTERN MATCH

To configure an alarm on a totalizer channel, select a high limit and

then set the desired count for the selected alarm.

HI ALARM ONLY

;%,1

Bit 7 Bit 0

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•Remote Interface Operation (Digital Input Channel): To assign the

alarm number to report any alarm conditions on the specified digital

input channels, use the following command.

OUTPut:ALARm[1|2|3|4]:SOURce (@<ch_list>)

To configure alarms on the specified digital input channel, use

the following commands (also see the example on the following page).

CALCulate

:COMPare:TYPE {EQUal|NEQual}[,(@<ch_list>)]

:COMPare:DATA <data>[,(@<ch_list>)]

:COMPare:MASK <mask>[,(@<ch_list>)]

Select EQUal to generate an alarm when the data read from the port

is equal to CALC:COMP:DATA after being masked by CALC:COMP:MASK.

Select NEQual (not equal) to generate an alarm when the data read

from the port is not equal to CALC:COMP:DATA after being masked by

CALC:COMP:MASK.

Use CALC:COMP:MASK to designate the “don’t care” bits. Bits that you

set to “0” in the mask are ignored.

To enable the specified alarm mode, send the following command.

CALCulate:COMPare:STATe ON [,(@<ch_list>)]

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Example: Configuring an Alarm on a Digital Input

Assume that you want to generate an alarm when a binary pattern of

“1000” is read on the upper four bits of port 1. Send the following

commands to configure the port for an alarm.

CALC:COMP:TYPE EQUAL,(@301)

CALC:COMP:DATA 128,(@301)

CALC:COMP:MASK 240,(@301)

OUTPUT:ALARM2:SOURCE (@301)

CALC:COMP:STATE ON,(@301)

Here are the calculations used to evaluate the alarm (assume that a

decimal 146 was read from the port):

Bit 7 Bit 0

10010010 Data read from port (decimal 146)

10000000 CALC:COMP:DATA command (decimal 128)

00010010 “X-OR” result

11110000 CALC:COMP:MASK command (decimal 240)

00010000 “AND” result (no alarm generated)

Since the calculations produce a non-zero result (decimal 16),

an alarm is not generated in this example.

•Remote Interface Operation (Totalizer Channel): To assign the alarm

number to report any alarm conditions on the specified totalizer

channels, use the following command.

OUTPut:ALARm[1|2|3|4]:SOURce (@<ch_list>)

To configure an alarm on a totalizer channel, specify the desired

count as the upper limit using the following command.

CALCulate:LIMit:UPPer <count>[,(@<ch_list>)]

To enable the upper limit on the specified totalizer channel, use the

following command.

CALCulate:LIMit:UPPer:STATe ON [,(@<ch_list>)]

ABX-OR

ABAND

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Digital Input Operations

The multifunction module (34907A) has two non-isolated 8-bit

input/output ports which you can use for reading digital patterns.

You can read the live status of the bits on the port or you can configure

a scan to include a digital read.

•The digital input channels are numbered “s01” (lower byte) and “s02”

(upper byte), where s represents the slot number.

•You can generate an alarm when a specific bit pattern or bit pattern

change is detected on an input channel. With the multifunction module,

the channels do not have to be part of the scan list to generate an alarm.

For more information, see “Using Alarms With the Multifunction Module”

on page 130.

•When you add a digital read to a scan list, that port is dedicated to

the scan. The instrument issues a Card Reset to make that port an

input port (the other port is not affected). While included in the scan

list, you can still perform low-level read operations on the port, but

you cannot perform write operations on the port.

•From the front panel, you can read data from only one 8-bit input

port at a time. From the remote interface, you can read both ports

simultaneously as a 16-bit word only if neither port is in the scan list.

If one or both ports are included in the scan list, you can read only

one 8-bit port at a time. However, if you have included both ports in

the scan list, the data will be read from both ports simultaneously

and will have the same time stamp. Therefore, you can externally

combine the two 8-bit quantities into a 16-bit quantity.

•From the front-panel only, you can specify whether you want to use

binary or decimal format (readings are always stored in memory in

decimal format). Once you have selected the number base, it is used

for all input or output operations on the same port.

•You can monitor a digital input channel even if the channel is not

part of the scan list (the internal DMM is not required either).

•A Factory Reset (*RST command), Instrument Preset (SYSTem:PRESet

command), and Card Reset (SYSTem:CPON command) from the

remote interface will reconfigure both ports as input ports.

Note that a from the front panel resets only the port currently

selected (both ports are not reset).

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•Front-Panel Operation: After selecting the port, press to read

the bit pattern (the least significant bit is on the right). The bit

pattern read from the port will be displayed until you press another

key, turn the knob, or until the display times out.

To add a digital read to a scan list, choose the following item.

DIO READ

From the front-panel only, you can specify whether you want to use

binary or decimal format.

USE DECIMAL , USE BINARY

•Remote Interface Operation: From the remote interface, you can read

an 8-bit byte from one port or a 16-bit word from both ports using the

following commands. If you are going to read both ports simultaneously,

you must send the command to port 01 and neither port can be

included in the scan list.

SENS:DIG:DATA:BYTE? (@302) Read port 02

SENS:DIG:DATA:WORD? (@301) Read both ports together

To redefine the scan list to include a digital read (8-bit read only),

send the following command.

CONF:DIG:BYTE (@302) Add port 02 read to scan list

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Totalizer Operations

The multifunction module has a 26-bit totalizer which can count TTL

pulses at a 100 kHz rate. You can manually read the totalizer count

or you can configure a scan to read the count.

•The totalizer channel is numbered “s03”, where s represents the

slot number.

•You can configure the instrument to count on the rising edge or

falling edge of the input signal.

•You can control when the totalizer actually records counts by providing

a gate signal (G and G terminals on the module). A TTL high signal

applied to the “G” terminal enables counting and a low signal disables

counting. A TTL low signal applied to the “G” terminal enables counting

and a high signal disables counting. The totalizer only counts when

both terminals are enabled. You can use either the G terminal, the G

terminal, or both. When a gate is not connected, the gate terminal

floats to the enabled state, effectively creating a “gate always” condition.

•Using the hardware jumper labeled “Totalize Threshold” on the

module, you can control the threshold at which an edge is detected.

Move the jumper to the “AC” position to detect changes through

0 volts. Move the jumper to the “TTL” position (factory setting)

to detect changes through TTL threshold levels.

Input Signal

(Rising Edge)

Add to Total

Totalizer Input

Gate Signal

(High True)

2.5 V Threshold (TTL)

0 V Threshold (AC)

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•The maximum count is 67,108,863 (226-1). The count rolls over to “0”

after reaching the maximum allowed value.

•You can configure the totalizer to reset its count after it is read

without losing any counts (TOTalize:TYPE RRESet command).

Then, if the totalizer is included in a scan list, the count will be reset

on every scan sweep. The count is also reset whenever it is read

directly by pressing from the front panel or when sending the

SENSe:TOTalize:DATA? command.

•You can configure the instrument to generate an alarm when a

specific count is reached on a totalizer channel. These channels do not

have to be part of the scan list to generate an alarm. Alarms are

evaluated continuously as soon as you enable them. For more

information, see “Using Alarms With the Multifunction Module”

on page 130.

•You can monitor a totalizer channel even if the channel is not part of

the scan list (the internal DMM is not required either). The count on a

totalizer channel is not reset when it is being monitored (the Monitor

ignores the totalizer reset mode).

•A Factory Reset (*RST command), Instrument Preset (SYSTem:PRESet

command), and Card Reset (SYSTem:CPON command) reset the count

to “0”.

•Front-Panel Operation: After selecting the totalizer, press

to read the count. If you have selected the READ + RESET mode,

the count is reset each time it is read. The count is displayed until

you press another key, turn the knob, or until the display times out.

To configure the totalizer reset mode, choose from the following items.

READ , READ + RESET

To configure the totalizer to count on the falling edge or rising edge of

the input signal, choose from the following items.

COUNT FALLING , COUNT RISING

To add a totalizer read to a scan list, choose the following item.

TOT READ

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•Remote Interface Operation: To read the count from the specified

totalizer channel, send the following command. The count may be

returned with time stamp, channel number, and alarm status

information depending on the FORMat:READing command setting

(see “Reading Format” on page 87 for more information).

SENS:TOT:DATA? (@303)

To configure the totalizer reset mode, send either of the following

commands (RRESet means “read and reset”).

SENSe:TOTalize:TYPE {READ|RRESet}[,(@<ch_list>)]

CONFigure:TOTalize {READ|RRESet} ,(@<scan_list>)

To configure the totalizer to count on the falling edge (negative) or

rising edge (positive) of the input signal, send the following command.

SENSe:TOTalize:SLOPe {NEG|POS} ,[(@<ch_list>)]

To immediately clear the count on the specified totalizer channel

(whether scanning or not), send the following command.

SENSe:TOTalize:CLEar:IMMediate [(@<ch_list>)]

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Digital Output Operations

The multifunction module (34907A) has two non-isolated 8-bit

input/output ports which you can use for outputting digital patterns.

•The digital output channels are numbered “s01” (lower byte)

and “s02” (upper byte), where s represents the slot number.

•You cannot configure a port for output operations if that port is

already configured to be part of the scan list (digital input).

•From the front panel, you can write to one 8-bit output port at a time.

From the remote interface, you can write to both ports simultaneously.

•From the front-panel only, you can specify whether you want to use

binary or decimal format. Once you have selected the number base,

it is used for all input or output operations on the same port.

•A Factory Reset (*RST command), Instrument Preset (SYSTem:PRESet

command), and Card Reset (SYSTem:CPON command) from the

remote interface will reconfigure both ports as input ports.

Note that a from the front panel resets only the port currently

selected (both ports are not reset).

•Front-Panel Operation: After selecting the output port, press

to edit the bit pattern or decimal value (the least significant bit is on

the right). Press again to output the bit pattern. To cancel an

output operation in progress, wait for the display to time out.

From the front-panel only, you can specify whether you want to use

binary or decimal format.

USE DECIMAL , USE BINARY

•Remote Interface Operation: From the remote interface, you can

output an 8-bit byte to one port or a 16-bit word to both ports

simultaneously using the following commands. You must specify a

decimal value (binary data is not accepted). If you are going to read

both ports simultaneously, you must send the command to port 01.

SOUR:DIG:DATA:BYTE 10 ,(@302) Write to port 02

SOUR:DIG:DATA:WORD 10327 ,(@301) Write to both ports

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DAC Output Operations

The multifunction module (34907A) has two low-noise analog outputs

capable of outputting calibrated voltages between ±12 volts with 16 bits of

resolution. Each DAC (Digital-to-Analog Converter) channel can be

used as a programmable voltage source for analog input control of other

devices.

•On the multifunction module, the DAC channels are numbered “s04”

and “s05”, where s represents the slot number.

•You can set the output voltage to any value between +12 Vdc and

-12 Vdc, in 1 mV steps. Each DAC is earth referenced; it cannot float.

•Each DAC channel is capable of 10 mA maximum output current.

Note: You must limit the output current to 40 mA total for all

three slots (six DAC channels).

•A Factory Reset (*RST command), Instrument Preset (SYSTem:PRESet

command), and Card Reset (SYSTem:CPON command) from the

remote interface will reset both DACs to 0 Vdc.

Note that a from the front panel resets only the DAC currently

selected (both channels are not reset).

•Front-Panel Operation: After selecting the desired DAC, press

to edit the output voltage. Press again to output the specified

voltage from the DAC channel.

•Remote Interface Operation: The following command outputs

+2.5 Vdc from the DAC on channel 05.

SOURCE:VOLT 2.5,(@305)

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System-Related Operations

This section gives information on system-related topics such as storing

instrument states, reading errors, running a self-test, displaying

messages on the front panel, setting the system clock, disabling the

internal DMM, reading the firmware revisions, and reading the relay

cycle count.

State Storage

The instrument has six storage locations in non-volatile memory to

store instrument states. The locations are numbered 0 through 5.

The instrument uses location “0” to automatically hold the state of the

instrument at power down. You can also assign a name to each of the

locations (1 through 5) for use from the front panel.

•You can store the instrument state in any of the six locations.

However, you can only recall a state from a location that contains

a previously stored state. You can use location “0” to store a sixth

instrument state. However, keep in mind that location “0” is

automatically overwritten when power is cycled.

•The instrument stores the state of all modules including all channel

configurations, scanning setups, alarm values, and scaling values.

•When shipped from the factory, storage locations “1” through “5” are

empty (location “0” has the power-on state).

•When shipped from the factory, the instrument is configured to

automatically recall the power-down state (state “0”) when power is

restored. You can change the factory configuration such that a

Factory Reset (*RST command) is issued when power is restored.

•Before recalling a stored state, the instrument verifies that the same

module types are installed in each slot. If a different module type is

installed, the instrument will perform the equivalent of a Card Reset

(SYSTem:CPON command) on that slot.

•You can assign a name to the storage locations (you cannot assign a

name to location “0”). You can name a location from the front panel or

over the remote interface but you can only recall a named state from

the front panel. From the remote interface, you can only recall a

stored state using a number (0 through 5).

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•The name can contain up to 12 characters. The first character must

be a letter (A-Z), but the remaining 11 characters can be letters,

numbers (0-9), or the underscore character (“ _ ”). Blank spaces are

not allowed. An error is generated if you specify a name with more

than 12 characters.

•A Factory Reset (*RST command) does not affect the configurations

stored in memory. Once a state is stored, it remains until it is

overwritten or specifically deleted.

•Front-Panel Operation:

NAME STATE , STORE STATE , RECALL STATE

After recalling a stored state, you will notice that a new choice

(UNDO RECALL) is added under RECALL STATE. This allows you to

cancel the last recall operation and revert to the previous state.

You can also select LAST PWR DOWN to recall the state of the

instrument at the power-down.

To configure the instrument to recall the power-down state or issue a

Factory Reset when power is restored, select from the following.

PWR ON LAST , PWR ON RESET

•Remote Interface Operation: Use the following commands to store

and recall instrument states (state “0” is the state of the instrument

at power down).

*SAV {0|1|2|3|4|5}

*RCL {0|1|2|3|4|5}

To assign a name to a stored state to be recalled from the front panel,

send the following command. From the remote interface, you can only

recall a stored state using a number (0 through 5).

MEM:STATE:NAME 1,TEST_RACK_1

To configure the instrument to automatically issue a Factory Reset

(*RST command) when power is restored, send the following command.

MEMory:STATe:RECall:AUTO OFF

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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 10 errors is stored in the instrument’s error queue. See chapter 6

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. Errors are cleared as you

read them. When you have read all errors from the queue, the ERROR

annunciator turns off and the errors are cleared. The instrument

beeps once each time an error is generated.

•If more than 10 errors have occurred, the last error stored in the

queue (the most recent error) is replaced with “Error queue overflow”.

No additional errors are stored until you remove errors from the

queue. If no errors have occurred when you read the error queue,

the instrument responds with “No error”.

•The error queue is cleared by the *CLS (clear status) command or

when power is cycled. The errors are also cleared when you read the

queue. The error queue is not cleared by a Factory Reset (*RST

command) or an Instrument Preset (SYSTem:PRESet command).

•Front-Panel Operation:

ERRORS

If the ERROR annunciator is on, press to view the errors. Use the

knob to scroll through the error numbers. Press to view the text of

the error message. Press again to increase the scrolling speed

(the final key press cancels the scroll). All errors are cleared when

you exit the menu.

•Remote Interface Operation:

SYSTem:ERRor? Read and clear one error from the queue

Errors have the following format (the error string may contain

up to 80 characters):

-113,"Undefined header"

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Self-Test

A power-on self-test occurs automatically when you turn on the

instrument. This limited test assures you that the instrument and

all installed plug-in modules are 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

20 seconds to execute. If all tests pass, you can have a high confidence

that the instrument and all installed plug-in modules are operational.

•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 34970A Service Guide for instructions on returning

the instrument to Agilent for service.

•Front-Panel Operation: To perform the complete front-panel self-test,

hold down as you turn on the instrument and hold down the key

until you hear a long beep. The self-test will begin when you release

the key following the beep.

•Remote Interface Operation:

*TST?

Returns “0” if the self-test is successful or “1” if it fails.

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Display Control

For security reasons or for a slight increase in scanning rates, you may

want to turn off the front-panel display. From the remote interface,

you can also display a 13-character message on the front-display.

•You can only disable the front-panel display by sending a command

from the remote interface (you cannot disable the front panel while in

local operation).

•When disabled, the entire front-panel display goes blank and all

display annunciators except ERROR are disabled. All keys except

are locked out when the display is disabled.

•The display is automatically enabled when power is cycled, after a

Factory Reset (*RST command), or when you return to local by

pressing .

•You can display a message on the front panel by sending a command

from the remote interface. The instrument can display up to

13 characters on the front panel; if you attempt to send more than

13 characters, an error is generated. You can use letters (A-Z),

numbers (0-9), and special characters like “@”, “%”, “*”, etc. Use the

“#” character to display a degree symbol ( ° ). Commas, periods, and

semicolons share a display space with the preceding character, and

are not considered individual characters. While a message is

displayed on the front panel, readings from a scan or monitor 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.

•Remote Interface Operation: The following command turns off the

front panel display.

DISPLAY OFF

The following command displays a message on the front panel and

turns on the display if disabled.

DISP:TEXT ’SCANNING ...’

To clear the message displayed on the front panel (without changing

the display state), send the following command.

DISPLAY:TEXT:CLEAR

Chapter 4 Features and Functions

System-Related Operations

144

Real-Time System Clock

During a scan, the instrument stores all readings and alarms with

the current time and date. The instrument stores the time and date

information in non-volatile memory.

•When shipped from the factory, the instrument is set to the current

time and date (U.S. Mountain Time).

•Front-Panel Operation:

TIME 03:45 PM

JUN 01 1997

•Remote Interface Operation: Use the following commands to set the

time and date.

SYST:TIME 15,45,00 Set time to 3:45 PM

SYST:DATE 1997,06,01 Set date to June 1, 1997

Internal DMM Disable

You can scan through the configured channels using either the internal

DMM or an external instrument. For externally-controlled scans,

you must either remove the internal DMM from the instrument or

disable it.

•For information on controlling a scan with an external instrument,

refer to “Scanning With External Instruments” on page 95.

•When shipped from the factory, the internal DMM is enabled.

When you change the state of the internal DMM, the instrument

issues a Factory Reset (*RST command).

•A Factory Reset (*RST command) or Instrument Preset (SYSTem:PRESet

command) does not affect the internal DMM configuration.

•Front-Panel Operation:

DMM ENABLED , DMM DISABLED

•Remote Interface Operation:

INSTrument:DMM {OFF|ON}

Chapter 4 Features and Functions

System-Related Operations

145

Firmware Revision Query

The instrument has three microprocessors for control of various internal

systems. Each plug-in module also has its own on-board microprocessor.

You can query the instrument and each module to determine which

revision of firmware is installed for each microprocessor.

•The instrument returns three revision numbers. The first number

is the firmware revision number for the measurement processor;

the second is the input/output processor; and the third is the

front-panel display processor. For each plug-in module, the

instrument returns one revision number for the on-board processor.

•Front-Panel Operation:

REV X.X-Y.Y-Z.Z

Turn the knob to read the firmware revision number for the module

installed in each of the three slots. If a slot does not contain a module,

EMPTY SLOT is displayed.

•Remote Interface Operation: Use the following command to read the

system firmware revision numbers (be sure to dimension a string

variable with at least 40 characters).

*IDN?

The above command returns a string in the form:

HEWLETT-PACKARD,34970A,0,X.X-Y.Y-Z.Z

Use the following command to read the firmware revision number of

the module in the specified slot (be sure to dimension a string

variable with at least 30 characters).

SYSTem:CTYPe? {100|200|300}

This command returns a string in the form:

HEWLETT-PACKARD,34901A,0,X.X

Chapter 4 Features and Functions

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146

Relay Cycle Count

The instrument has a Relay Maintenance System to help you predict

relay end-of-life. The instrument counts the cycles on each relay in the

instrument and stores the total count in non-volatile memory on each

switch module. You can use this feature on any of the relay modules and

the internal DMM.

•In addition to the channel relays, you can also query the count on

backplane relays and bank relays. Note that you cannot control the

state of these relays from the front panel but you can query the count.

For more information on channel numbering and layout, refer to

“Module Overview” starting on page 163.

•You can also query the state of the three relays on the internal DMM.

These relays are numbered “1”, “2”, and “3” (which correspond to

relays K102, K103, and K104 respectively). These relays open or close

when a function or range is changed on a module.

•The 34908A multiplexer contains 40 channels which are switched

(HI only) using only 20 relays. Each relay is used to switch HI on two

different channels (and only one channel can be closed at a time).

The channels are arranged such that channels 01 and 21 use different

contacts on the same relay. The remaining channels are also paired in

the same manner (channels 02 and 22, channels 03 and 23, etc.).

Therefore, when you query the relay count on a channel, the number

reflects the number of times that the relay was closed. For example,

the relay count will always be the same on channels 01 and 21.

•You can reset the count (allowed only from remote) but the instrument

must be unsecured (see “Calibration Overview” on page 155 to

unsecure the instrument).

•For more information on relay life and load considerations, refer to

“Relay Life and Preventative Maintenance” starting on page 399.

Chapter 4 Features and Functions

System-Related Operations

147

•Front-Panel Operation: To read the count on the active channel,

choose the following item and then turn the knob. To read the count

on the internal DMM relays, turn the knob counterclockwise beyond

the lowest numbered channel in the instrument. To read the “hidden”

backplane and bank relays, turn the knob clockwise beyond the

highest numbered channel in the current slot.

RELAY CYCLES

•Remote Interface Operation: To read the relay count on either the

internal DMM (all three relays) or the specified module channels,

send the following commands.

DIAG:DMM:CYCLES?

DIAG:RELAY:CYCLES? (@305,399)

To clear the count on either the specified internal DMM relay or the

specified module channels (the instrument must be unsecured),

send the following commands.

DIAG:DMM:CYCLES:CLEAR 2

DIAG:RELAY:CYCLES:CLEAR (@305,399)

Chapter 4 Features and Functions

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148

SCPI Language Version Query

The instrument complies with the rules and conventions of the present

version of SCPI (Standard Commands for Programmable Instruments).

You can determine the SCPI version with which the instrument 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 “YYYY” represents the

year of the version, and “V” represents a version number for that year

(for example, 1994.0). 4

Chapter 4 Features and Functions

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149

Remote Interface Configuration

This section gives information on configuring the instrument for remote

interface communication. For more information on configuring the

instrument from the front panel, see “To Configure the Remote Interface”

starting on page 46. For more information on the SCPI commands

available to program the instrument over the remote interface,

see chapter 5, “Remote Interface Reference” starting on page 179.

GPIB Address

Each device on the GPIB (IEEE-488) interface must have a unique

address. You can set the instrument’s address to any value between

0 and 30. The address is set to “9” when the instrument is shipped from

the factory. The GPIB address is displayed at power-on.

You can set the GPIB address from the front panel only.

•The address is stored in non-volatile memory, and does not change

when power has been off, after a Factory Reset (*RST command),

or after an Instrument Preset (SYSTem:PRESet command).

•Your computer’s GPIB interface card has its own address. Be sure

to avoid using the computer’s address for any instrument on the

interface bus. Agilent’s GPIB interface cards generally use address “21”.

•Front-Panel Operation:

ADDRESS 09

Chapter 4 Features and Functions

Remote Interface Configuration

150

Remote Interface Selection

The instrument is shipped with both an GPIB (IEEE-488) interface

and an RS-232 interface. Only one interface can be enabled at a time.

The GPIB interface is selected when the instrument is shipped from

the factory.

•The interface selection is stored in non-volatile memory, and does not

change when power has been off, after a Factory Reset (*RST command),

or after an Instrument Preset (SYSTem:PRESet command).

•If you select the GPIB interface, you must select a unique address for

the instrument. The GPIB address is displayed on the front panel

when you turn on the instrument.

•If you select the RS-232 interface, you must also set the baud rate,

parity, and flow control mode for the instrument. “RS-232” is

displayed on the front panel when you turn on the instrument.

•Front-Panel Operation:

HPIB / 488 , RS-232

•Remote Interface Operation:

SYSTem:INTerface {GPIB|RS232}

Chapter 4 Features and Functions

Remote Interface Configuration

151

Baud Rate Selection (RS-232)

You can select one of eight baud rates for RS-232 operation. The rate is

set to 57,600 baud when the instrument is shipped from the factory.

You can set the baud rate from the front panel only.

•Select one of the following: 1200, 2400, 4800, 9600, 19200, 38400,

57600 (factory setting), or 115200 baud.

•The baud rate selection is stored in non-volatile memory, and does not

change when power has been off, after a Factory Reset (*RST

command), or after an Instrument Preset (SYSTem:PRESet command).

•Front-Panel Operation:

19200 BAUD

Parity Selection (RS-232)

You can select the parity for RS-232 operation. The instrument is

configured for no parity with 8 data bits when shipped from the factory.

You can set the parity from the front panel only.

•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 also 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, after a Factory Reset (*RST

command), or after an Instrument Preset (SYSTem:PRESet command).

•Front-Panel Operation:

EVEN, 7 BITS

Chapter 4 Features and Functions

Remote Interface Configuration

152

Flow Control Selection (RS-232)

You can select one of several flow control methods to coordinate the

transfer of data between the instrument and your computer or modem.

The method that you select will be determined by the flow method used

by your computer or modem.

You can select the flow control method from the front panel only.

•Select one of the following: None (no flow control), XON/XOFF

(factory setting), DTR/DSR, RTS/CTS, or Modem.

•None: In this mode, data is sent and received over the interface

without any flow control used. When using this method, use a slower

baud rate (< 9600 baud) and avoid sending more than 128 characters

without stopping or reading a response.

•XON/XOFF: This mode uses special characters embedded in the

data stream to control the flow. If the instrument is addressed to

send data, it continues sending data until the “XOFF” character (13H)

is received. When the “XON” character (11H) is received, the instrument

resumes sending data.

•DTR/DSR: In this mode, the instrument monitors the state of the

DSR (data set ready) line on the RS-232 connector. When the line

goes true, the instrument sends data over the interface. When the line

goes false, the instrument stops sending information (typically within

six characters). The instrument sets the DTR line false when the

input buffer is almost full (approximately 100 characters) and

releases the line when space is available again.

•RTS/CTS: This mode operates the same as the DTR/DSR mode but

uses the RTS (request to send) and CTS (clear to send) lines on the

RS-232 connector instead. When the CTS line goes true, the instrument

sends data over the interface. When the line goes false, the instrument

stops sending information (typically within six characters).

The instrument sets the RTS line false when the input buffer is

almost full (approximately 100 characters) and releases the line when

space is available again.

Chapter 4 Features and Functions

Remote Interface Configuration

153

•Modem: This mode uses the DTR/DSR and RTS/CTS lines to control

the flow of data between the instrument and a modem. When the

RS-232 interface is selected, the instrument sets the DTR line true.

The DSR line is set true when the modem is on-line. The instrument

sets the RTS line true when it is ready to receive data. The modem

sets the CTS line true when it is ready to accept data. The instrument

sets the RTS line false when the input buffer is almost full

(approximately 100 characters) and releases the line when space is

available again.

•For more information on using the RS-232 interface, refer to

“RS-232 Interface Configuration” starting on page 270.

•The flow control selection is stored in non-volatile memory, and

does not change when power has been off, after a Factory Reset

(*RST command), or after an Instrument Preset (SYSTem:PRESet

command).

•Front-Panel Operation:

FLOW RTS/CTS

Chapter 4 Features and Functions

Remote Interface Configuration

154

Calibration Overview

This section gives a brief introduction to the calibration features of the

instrument and plug-in modules. For a more detailed discussion of the

calibration procedures, see chapter 4 in the 34970A Service Guide.

Calibration Security

This feature allows you to enter a security code to prevent accidental or

unauthorized calibrations of the instrument. When you first receive

your instrument, it is secured. Before you can calibrate the instrument,

you must unsecure it by entering the correct security code.

If you forget your security code, you can disable the security feature by

adding a jumper inside the instrument. See the 34970A Service Guide

for more information.

•The security code is set to “HP034970” when the instrument is

shipped from the factory. The security code is stored in non-volatile

memory on the mainframe, and does not change when power has

been off, after a Factory Reset (*RST command), or after an

Instrument Preset (SYSTem:PRESet command).

•The security code may contain up to 12 alphanumeric characters.

The first character must be a letter, but the remaining characters can

be letters, numbers, or an underscore ( _ ). You do not have to use all

12 characters but the first character must always be a letter.

Chapter 4 Features and Functions

Calibration Overview

155

To Unsecure for Calibration You can unsecure the instrument

either from the front panel or over the remote interface. The instrument

is secured when shipped from the factory and the security code is set to

“HP034970”.

•Once you enter a security code, that code must be used for both

front-panel and remote operation. For example, if you secure the

instrument from the front panel, you must use that same code to

unsecure it from the remote interface.

•Front-Panel Operation:

UNSECURE CAL

When you first enter the Utility menu, the calibration entries toggle

between CAL SECURED and UNSECURE CAL. To unsecure the

instrument, select UNSECURE CAL and press . After entering the

correct security code, press again. When you return to the menu,

you will see new choices CAL UNSECURED and SECURE CAL.

Note: If you enter the wrong secure code, NO MATCH is displayed

and a new choice, EXIT, is shown.

•Remote Interface Operation: To unsecure the instrument, send the

following command with the correct security code.

CAL:SECURE:STATE OFF,HP034970

Chapter 4 Features and Functions

Calibration Overview

156

To Secure Against Calibration You can secure the instrument either

from the front panel or over the remote interface. The instrument is

secured when shipped from the factory and the security code is set to

“HP034970”.

•Once you enter a security code, that code must be used for both

front-panel and remote operation. For example, if you secure the

instrument from the front panel, you must use that same code to

unsecure it from the remote interface.

•Front-Panel Operation:

SECURE CAL

When you enter the Utility menu, the calibration entries toggle

between CAL UNSECURED and SECURE CAL. To secure the

instrument, select SECURE CAL and press . After entering the

desired security code, press again. When you return to the menu,

you will see new choices CAL SECURED and UNSECURE CAL.

•Remote Interface Operation: To secure the instrument, send the

following command with the desired security code.

CAL:SECURE:STATE ON,HP034970

To Change the Security Code To change the security code, you must

first unsecure the instrument, and then enter a new code. Make sure

you have read the security code rules described on page 155 before

attempting to change the security code.

•Front-Panel Operation: To change the security code, first make sure

that the instrument is unsecured. Go to the SECURE CAL entry, enter

the new security code, and press (the instrument is now secured

with the new code). Changing the code from the front panel also

changes the code as seen from the remote interface.

•Remote Interface Operation: To change the security code, first

unsecure the instrument using the old security code. Then, enter the

new code as shown below.

CAL:SECURE:STATE OFF, HP034970 Unsecure with old code

CAL:SECURE:CODE ZZ007943 Enter new code

Chapter 4 Features and Functions

Calibration Overview

157

Calibration Message

The instrument allows you to store one message in calibration memory

in the mainframe. For example, you can store such information as the

date when the last calibration was performed, the date when the next

calibration is due, the instrument’s serial number, or even the name and

phone number of the person to contact for a new calibration.

•You can record a calibration message only from the remote interface

and only when the instrument is unsecured. You can read the

message from either the front-panel or over the remote interface.

You can read the calibration message whether the instrument is

secured or unsecured.

•The calibration message may contain up to 40 characters. From the

front panel, you can view 13 characters of the message at a time.

Press to scroll through the text of the message. Press again to

increase the scrolling speed.

•Storing a calibration message will overwrite any message previously

stored in memory.

•The calibration message is stored in non-volatile memory in the

mainframe, and does not change when power has been off, after a

Factory Reset (*RST command), or after an Instrument Preset

(SYSTem:PRESet command).

•Front-Panel Operation:

CAL MESSAGE

•Remote Interface Operation: To store the calibration message, send

the following command.

CAL:STRING ’CAL: 06-01-98’

Chapter 4 Features and Functions

Calibration Overview

158

Calibration Count

You can query the instrument to determine how many calibrations have

been performed. Note that your instrument was calibrated before it left

the factory. When you receive your instrument, be sure to read the

count to determine its initial value.

•The calibration count is stored in non-volatile memory in the

mainframe, and does not change when power has been off, after a

Factory Reset (*RST command), or after an Instrument Preset

(SYSTem:PRESet command).

•The calibration count increments up to a maximum of 65,535 after

which it rolls over to “0”. Since the value increments by one for each

calibration point, a complete calibration may increase the value by

many counts.

•The calibration count is also incremented with calibrations of the

DAC channels on the multifunction module.

•Front-Panel Operation:

CAL COUNT

•Remote Interface Operation:

CALibration:COUNt?

Chapter 4 Features and Functions

Calibration Overview

159

Factory Reset State

The table below shows the state of the instrument after a FACTORY RESET

from the Sto/Rcl menu or *RST command from the remote interface.

Measurement Configuration

Function

Range

Resolution

Integration Time

Input Resistance

Channel Delay

Totalizer Reset Mode

Totalizer Edge Detect

Scanning Operations

Scan List

Reading Memory

Min, Max, and Average

Scan Interval Source

Scan Interval

Scan Count

Scan Reading Format

Monitor in Progress

Mx+B Scaling

Gain Factor (“M”)

Scale Factor (“B”)

Scale Label

Alarm Limits

Alarm Queue

Alarm State

HI and LO Alarm Limits

Alarm Output

Alarm Output Configuration

Alarm Output State

Alarm Output Slope

Module Hardware

34901A, 34902A, 34908A

34903A, 34904A

34905A, 34906A

34907A

System-Related Operations

Display State

Error Queue

Stored States

Factory Reset State

DC Volts

Autorange

1⁄2 digits

1 PLC

10 MΩ (fixed for all DCV ranges)

Automatic Delay

Count Not Reset When Read

Rising Edge

Factory Reset State

Empty

All Readings are Cleared

All Statistical Data is Cleared

Immediate

Front Panel = 10 Seconds

Remote = Immediate

Front Panel = Continuous

Remote = 1 Scan Sweep

Reading Only (No Units, Channel, Time)

Stopped

Factory Reset State

Vdc

Factory Reset State

Not Cleared

Off

Alarm 1

Latched Mode

Output Lines are Cleared

Fail = Low

Factory Reset State

Reset: All Channels Open

Reset: Channels s11 and s21 Selected

Reset: Both DIO Ports = Input, Count = 0,

Both DACs = 0 Vdc

Factory Reset State

Errors Not Cleared

No Change

Chapter 4 Features and Functions

Factory Reset State

160

Instrument Preset State

The table below shows the state of the instrument after a PRESET from

the Sto/Rcl menu or SYSTem:PRESet command from the remote interface.

Measurement Configuration

Function

Range

Resolution

Advanced Settings

Totalizer Reset Mode

Totalizer Edge Detect

Scanning Operations

Scan List

Reading Memory

Min, Max, and Average

Scan Interval Source

Scan Interval

Scan Count

Scan Reading Format

Monitor in Progress

Mx+B Scaling

Gain Factor (“M”)

Scale Factor (“B”)

Scale Label

Alarm Limits

Alarm Queue

Alarm State

HI and LO Alarm Limits

Alarm Output Configuration

Alarm Output State

Alarm Output Slope

Module Hardware

34901A, 34902A, 34908A

34903A, 34904A

34905A, 34906A

34907A

System-Related Operations

Display State

Error Queue

Stored States

Preset State

No Change

Count Not Reset When Read

No Change

Preset State

No Change

All Readings are Cleared

All Statistical Data is Cleared

No Change

Stopped

Preset State

No Change

Preset State

No Change

Output Lines are Cleared

No Change

Preset State

Reset: All Channels Open

Reset: Channels s11 and s21 Selected

Reset: Both DIO Ports = Input, Count = 0,

Both DACs = 0 Vdc

Preset State

Errors Not Cleared

No Change

Chapter 4 Features and Functions

Instrument Preset State

161

Multiplexer Module Default Settings

The table below shows the default settings for each measurement

function on the multiplexer modules. When you configure a channel for

a particular function, these are the default settings.

Temperature Measurements

Temperature Units

Integration Time

Display Resolution

Thermocouple Type

Open T/C Detection

Reference Junction Source

RTD Type

RTD Reference Resistance

Thermistor Type

Channel Delay

Voltage Measurements

Range

Resolution

Integration Time

Input Resistance

AC Low Frequency Filter

Channel Delay

Resistance Measurements

Range

Resolution

Integration Time

Offset Compensation

Channel Delay

Frequency/Period Measurements

Range

Resolution

AC Low Frequency Filter

Channel Delay

Current Measurements

Range

Resolution

Integration Time

AC Low Frequency Filter

Channel Delay

Default Setting

°C

1 PLC

0.1°C

Type J

Off

Internal

α = 0.00385

0 = 100Ω

5 kΩ

Automatic Delay

Default Setting

Autorange

1⁄2 digits

1 PLC

10 MΩ (fixed for all DCV ranges)

20 Hz (medium)

Automatic Delay

Default Setting

Autorange

1⁄2 digits

1 PLC

Off

Automatic Delay

Default Setting

Autorange

1⁄2 digits (frequency), 61⁄2 digits (period)

20 Hz (medium)

Automatic Delay

Default Setting

Autorange

1⁄2 digits

1 PLC

20 Hz (medium)

Automatic Delay

Chapter 4 Features and Functions

Multiplexer Module Default Settings

162

Module Overview

This section gives a description of each plug-in module, including

simplified schematics and block diagrams. A wiring log is also included

to make it easy to document your wiring configuration for each module.

For complete specifications on each plug-in module, refer to the module

sections in chapter 9.

•34901A 20-Channel Multiplexer, starting on page 164

•34902A 16-Channel Multiplexer, starting on page 166

•34903A 20-Channel Actuator, starting on page 168

•34904A 4x8 Matrix Switch, starting on page 170

•34905A/6A Dual 4-Channel RF Multiplexers, starting on page 172

•34907A Multifunction Module, starting on page 174

•34908A 40-Channel Single-Ended Multiplexer, starting on page 176

Module Reference

Chapter 4 Features and Functions

Module Overview

163

34901A 20-Channel Multiplexer

This module is divided into two banks of 10 channels each. Two additional

fused channels are available for making direct, calibrated dc or ac

current measurements with the internal DMM (external shunts are not

required). All 22 channels switch both HI and LO inputs, thus providing

fully isolated inputs to the internal DMM or an external instrument.

When making 4-wire resistance measurements, the instrument automatically

pairs channel n with channel n+10 to provide the source and sense

connections. The module has a built-in thermocouple reference junction

to minimize errors due to thermal gradients when measuring thermocouples.

Reference

Junction

Sensor

Channel Switches

Shunt Switches

Fuse

Bank Switch

Backplane Switches

Internal

DMM Input

Internal

DMM Input

(4W Sense)

Internal

DMM Input

(Current)

Com (4W Sense)

Com

Com (Current)

NOTES:

• Only one of channels 21 and 22 can be connected to the internal DMM and/or Com at a time;

connecting one channel will close the other (thus shorting the input “I” to “LO”).

• If any channels are configured to be part of the scan list, you cannot close multiple channels;

closing one channel will open the previously closed channel.

• Connections to ac line are not recommended unless you provide external transient suppression.

Current Channels

Chapter 4 Features and Functions

34901A 20-Channel Multiplexer

164

Module Reference

WIRING LOG Slot Number: ❒ 100 ❒ 200 ❒ 300

Ch Name Function Comments

H COM

L COM

11 *

12 *

13 *

14 *

15 *

16 *

17 *

18 *

19 *

20 *

H COM

L COM

Current Channels Only :

I COM

L COM

* 4W Sense Channels are paired to Channel (n-10).

Refer to the diagrams on page 20 to connect wiring to the module.

Maximum Input Voltage: 300 V (CAT I)

Maximum Input Current: 1 A

Maximum Switching Power: 50 W

WARNING: To prevent electrical shock, use only wire

that is rated for the highest voltage applied to any channel.

Before removing a module cover, turn off all power to external

devices connected to the module.

Not Used

6 mm

20 AWG Typical

Chapter 4 Features and Functions

34901A 20-Channel Multiplexer

165

34902A 16-Channel Multiplexer

This module is divided into two banks of eight channels each. All 16

channels switch both HI and LO inputs, thus providing fully isolated

inputs to the internal DMM or an external instrument. When making

4-wire resistance measurements, the instrument automatically pairs

channel n with channel n+8 to provide the source and sense connections.

The module has a built-in thermocouple reference junction to minimize

errors due to thermal gradients when measuring thermocouples.

Channel Switches

Bank Switch

Backplane Switches

Internal

DMM Input

Reference

Junction

Sensor

Internal

DMM Input

(4W Sense) 97

Com (4W Sense)

Com

100Ω

NOTES:

• If any channels are configured to be part of the scan list, you cannot close multiple channels;

closing one channel will open the previously closed channel.

• Current measurements on this module will require external shunt resistors.

• Connections to ac line are not recommended unless you provide external transient suppression.

Chapter 4 Features and Functions

34902A 16-Channel Multiplexer

166

Module Reference

WIRING LOG Slot Number: ❒ 100 ❒ 200 ❒ 300

Ch Name Function Comments

H COM

L COM

09 *

10 *

11 *

12 *

13 *

14 *

15 *

16 *

H COM

L COM

* 4W Sense Channels are paired to Channel (n-8).

Refer to the diagrams on page 20 to connect wiring to the module.

Maximum Input Voltage: 300 V (CAT I)

Maximum Input Current: 50 mA

Maximum Switching Power: 2 W

WARNING: To prevent electrical shock, use only wire

that is rated for the highest voltage applied to any channel.

Before removing a module cover, turn off all power to external

devices connected to the module.

6 mm

20 AWG Typical

Chapter 4 Features and Functions

34902A 16-Channel Multiplexer

167

34903A 20-Channel Actuator

This module contains 20 independent, SPDT (Form C) latching relays.

Screw terminals on the module provide access to the Normally-Open,

Normally-Closed, and Common contacts for each switch. This module

does not connect to the internal DMM.

A breadboard area is provided near the screw terminals to implement

custom circuitry, such as simple filters, snubbers, and voltage dividers.

The breadboard area provides the space necessary to insert your own

components but there are no circuit board traces here. You must add

your own circuitry and signal routing.

NOTES:

• You can close multiple channels at the same time on this module.

• The channel CLOSE and OPEN commands control the state of the Normally Open (NO)

to COM connection on each channel. For example, CLOSE 201 connects the

Normally Open contact to COM on channel 01.

Chapter 4 Features and Functions

34903A 20-Channel Actuator

168

Module Reference

WIRING LOG Slot Number: ❒ 100 ❒ 200 ❒ 300

Ch NO NC COM Comments

NO = Normally Open, NC = Normally Closed

Refer to the diagrams on page 20 to connect wiring to the module.

Maximum Input Voltage: 300 V (CAT I)

Maximum Input Current: 1 A

Maximum Switching Power: 50 W

WARNING: To prevent electrical shock, use only wire

that is rated for the highest voltage applied to any channel.

Before removing a module cover, turn off all power to external

devices connected to the module.

6 mm

20 AWG Typical

Chapter 4 Features and Functions

34903A 20-Channel Actuator

169

34904A 4x8 Matrix Switch

This module contains 32 two-wire crosspoints organized in a 4-row by

8-column configuration. You can connect any combination of inputs and

outputs at the same time. This module does not connect to the internal

DMM. Each crosspoint relay has its own unique channel label

representing the row and column. For example, channel 32 represents

the crosspoint connection between row 3 and column 2 as shown below.

NOTES:

• You can close multiple channels at the same time on this module.

Row 1

Row 2

Row 3

Row 4

Col 8

Col 2Col 1

Channel 32

(Row 3, Column 2)

Chapter 4 Features and Functions

34904A 4x8 Matrix Switch

170

Module Reference

WIRING LOG Slot Number: ❒ 100 ❒ 200 ❒ 300

Row Name Comments

Column Name Comments

Example: Channel 32 represents Row 3 and Column 2.

Refer to the diagrams on page 20 to connect wiring to the module.

Maximum Input Voltage: 300 V (CAT I)

Maximum Input Current: 1 A

Maximum Switching Power: 50 W

WARNING: To prevent electrical shock, use only wire

that is rated for the highest voltage applied to any channel.

Before removing a module cover, turn off all power to external

devices connected to the module.

6 mm

20 AWG Typical

Chapter 4 Features and Functions

34904A 4x8 Matrix Switch

171

34905A/6A Dual 4-Channel RF Multiplexers

These modules consist of two independent 4-to-1 multiplexers.

The channels in each bank are organized in a “tree” structure to provide

high isolation and low VSWR. Both banks have a common earth ground.

This module does not connect to the internal DMM. You can connect

your signals directly to the on-board SMB connectors or to the

SMB-to-BNC cables provided with the module.

NOTES:

• The 34905A is used for 50Ω applications. The 34906A is used for 75Ω applications.

• You can close only one channel per bank at a time on these modules; closing one channel

in a bank will open the previously closed channel. One channel in each bank is always

connected to COM.

• This module responds only to the CLOSE command (OPEN does not apply). To OPEN a

channel, send the CLOSE command to another channel in the same bank.

Com1

Com2

Bank Switch 98

Bank Switch 99

Chapter 4 Features and Functions

34905A/6A Dual 4-Channel RF Multiplexers

172

Module Reference

WIRING LOG Slot Number: ❒ 100 ❒ 200 ❒ 300

Ch Name Comments

COM1

COM2

Refer to the diagrams on page 20 to connect wiring to the module.

Maximum Input Voltage: 42 V

Maximum Input Current: 700 mA

Maximum Switching Power: 20 W

SMB-to-BNC Cable

Ten color-coded cables are included with the module. To order

additional cables, use the following cable kit part numbers

(10 cables are included):

34905-60001 (50Ω cables)

34906-60001 (75Ω cables)

Chapter 4 Features and Functions

34905A/6A Dual 4-Channel RF Multiplexers

173

34907A Multifunction Module

This module combines two 8-bit ports of digital input/output, a 100 kHz

totalizer, and two ±12 analog outputs. For greater flexibility, you can read

digital inputs and the totalizer count during a scan.

Digital Input/Output

The DIO consists of two 8-bit ports with

TTL-compatible inputs and output. The open-

drain outputs can sink up to 400 mA. From the

front panel, you can read data from only one 8-bit

input port at a time. From the remote interface,

you can read both ports simultaneously as a

16-bit word only if neither port is in the scan list.

Totalize Input

The 26-bit totalizer can count pulses at a 100 kHz

rate. You can configure the totalizer to count on

the rising edge or falling edge of the input signal.

A TTL high signal applied to the “G” terminal

enables counting and a low signal disables

counting. A TTL low signal applied to the “G”

terminal enables counting and a high signal

disables counting. The totalizer only counts

when both terminals are enabled. Move the

Totalize Threshold jumper to the “AC” position to

detect changes through 0 volts. Move the jumper

to the “TTL” position (factory setting) to detect

changes through TTL threshold levels.

Analog Output (DAC)

The two analog outputs are capable of outputting

calibrated voltages between ±12 volts with 16 bits

of resolution. Each DAC channel is capable of

10 mA maximum current. You must limit the

DAC output current to 40 mA total for all three

slots (six DAC channels).

+IN

Gate

-IN

Gate

TOT

26 Bits Channel 03

DAC 1

16 Channel 04

16 DAC 2 Channel 05

Bit 0

DIO Bit 7

Bit 0

Bit 7

Port 1 (LSB)

Channel 01

Port 2 (MSB)

Channel 02

Chapter 4 Features and Functions

34907A Multifunction Module

174

Module Reference

WIRING LOG Slot Number: ❒ 100 ❒ 200 ❒ 300

Ch Name Comments

01 (DIO 1) Bit 0

Bit 1

Bit 2

Bit 3

Bit 4

Bit 5

Bit 6

Bit 7

GND

02 (DIO 2) Bit 0

Bit 1

Bit 2

Bit 3

Bit 4

Bit 5

Bit 6

Bit 7

GND

03 (Totalizer) Input (+)

Input (-)

Gate

04 (DAC 1) Output

GND

05 (DAC 2) Output

GND

Threshold Jumper Position: ❒ TTL ❒ AC

Refer to the diagrams on page 20 to connect wiring to the module.

Digital Input / Output:

Vin(L): <0.8V (TTL)

Vin(H): >2.0V (TTL)

Vout(L): <0.8V @ Iout = -400 mA

Vout(H): >2.4V @ Iout = 1 mA

Vin(H) Max: <42V with external open-drain pull-up

Totalizer:

Maximum Count: 67,108,863 (226 -1)

Totalize Input: 100 kHz (max)

Signal Level: 1 Vp-p (min), 42 Vpk (max)

DAC Output:

±12V, non-isolated

Iout: 10 mA max per DAC; 40 mA max per mainframe

Threshold

Jumper

6 mm

20 AWG Typical

Chapter 4 Features and Functions

34907A Multifunction Module

175

34908A 40-Channel Single-Ended Multiplexer

The module is divided into two banks of 20 channels each. All of the

40 channels switch HI only, with a common LO for the module.

The module has a built-in thermocouple reference junction to minimize

errors due to thermal gradients when measuring thermocouples.

NOTES:

• Refer to the diagrams on page 20 to connect wiring to the module.

• Only one channel can be closed at a time; closing one channel will open the previously

closed channel.

• This module cannot be used to directly measure current or any 4-wire measurements.

• When connecting thermocouples to the screw terminals on this module (not recommended

due to the common LO configuration), be sure to provide electrical isolation between

thermocouples to avoid current loops and subsequent measurement errors.

• Connections to ac line are not recommended unless you provide external transient suppression.

Maximum Input Voltage: 300 V (CAT I)

Maximum Input Current: 1 A

Maximum Switching Power: 50 W

WARNING: To prevent electrical shock, use only wire that is rated for the highest voltage

applied to any channel. Before removing a module cover, turn off all power to external devices

connected to the module.

Channel Switches

Bank Switch

Backplane

Switch

Internal

DMM Input

Reference

Junction

Sensor

Com

6 mm

20 AWG Typical

Chapter 4 Features and Functions

34908A 40-Channel Single-Ended Multiplexer

176

Module Reference

WIRING LOG Slot Number: ❒ 100 ❒ 200 ❒ 300

Ch Name Function Comments

H COM

L COM

Chapter 4 Features and Functions

34908A 40-Channel Single-Ended Multiplexer

177

178

Remote Interface

Reference

Remote Interface Reference

•SCPI Command Summary, starting on page 181

•Simplified Programming Overview, starting on page 201

•The MEASure? and CONFigure Commands, starting on page 207

•Setting the Function, Range, and Resolution, starting on page 214

•Temperature Configuration Commands, starting on page 219

•Voltage Configuration Commands, on page 223

•Resistance Configuration Commands, on page 224

•Current Configuration Commands, on page 224

•Frequency Configuration Commands, on page 225

•Scanning Overview, starting on page 226

•Single-Channel Monitoring Overview, starting on page 237

•Scanning With an External Instrument, starting on page 239

•Mx+B Scaling Overview, starting on page 244

•Alarm System Overview, starting on page 247

•Digital Input Commands, on page 255

•Totalizer Commands, starting on page 256

•Digital Output Commands, on page 258

•DAC Output Commands, on page 258

•Switch Control Commands, on page 259

•State Storage Commands, on page 261

•System-Related Commands, starting on page 264

•Interface Configuration Commands, on page 269

•RS-232 Interface Configuration, on page 270

•Modem Communications, on page 274

•The SCPI Status System, starting on page 275

•Status System Commands, starting on page 286

•Calibration Commands, starting on page 292

•Service-Related Commands, starting on page 294

•An Introduction to the SCPI Language, starting on page 296

•Using Device Clear, on page 302

If you are a first-time user of the SCPI language, you may want to refer to these

sections to become familiar with the language before attempting to program the

instrument.

180

SCPI Command Summary

Throughout this manual, the following conventions are used for

SCPI command syntax for remote interface programming:

•Square brackets ( [ ] ) indicate optional keywords or parameters.

•Braces ( { } ) enclose parameter choices within a command string.

•Triangle brackets ( < > ) enclose parameters for which you must

substitute a value.

•A vertical bar ( | ) separates multiple parameter choices.

Rules for Using a Channel List

Many of the SCPI commands for the 34970A include a scan_list

or ch_list parameter which allow you to specify one or more channels.

The channel number has the form (@scc), where s is the slot number

(100, 200, or 300) and cc is the channel number. You can specify a single

channel, multiple channels, or a range of channels as shown below.

•The following command configures a scan list to include only

channel 10 on the module in slot 300.

ROUT:SCAN (@310)

•The following command configures a scan list to include multiple

channels on the module in slot 200. The scan list now contains only

channels 10, 12, and 15 (the scan list is redefined each time you send

a new ROUTe:SCAN command).

ROUT:SCAN (@210,212,215)

•The following command configures a scan list to include a range of

channels. When you specify a range of channels, the range may

contain invalid channels (they are ignored), but the first and last

channel in the range must be valid. The scan list now contains

channels 5 through 10 (slot 100) and channel 15 (slot 200).

ROUT:SCAN (@105:110,215)

Chapter 5 Remote Interface Reference

SCPI Command Summary

181

Rules for Using scan_list and ch_list Parameters

Before you can initiate a scan, you must set up a scan list to include all

desired multiplexer or digital channels. Channels which are not in the

list are skipped during the scan. The instrument automatically scans

the list of channels in ascending order from slot 100 through slot 300.

•Commands which accept a scan_list parameter will reprogram

the scan list each time you send the command to the instrument.

The scan_list parameter is never an optional parameter.

•Commands which accept an optional ch_list parameter do not

reprogram the scan list when you send the command to the instrument.

If you omit the ch_list parameter, the command will be applied to the

channels in the active scan list.

•If a command specifies an illegal operation on a given channel,

the instrument will generate an error for each channel which is

illegal and the command will not be performed on any of the channels.

For example, the following command will generate an error on

channel 121 on the 34901A module since this channel is for current

measurements only.

CONFigure:VOLTage:DC (@101,121)

•If you select a range of channels in a command which specifies an

illegal operation on one or more channels, the instrument will skip

the illegal channels and will not generate an error. For example,

the following command will not generate an error on the 34901A

module even though channels 121 and 122 are for current

measurements only.

CONFigure:VOLTage:DC (@101:220)

However, if the illegal channel is one of the end points in the range,

the instrument will generate an error. For example, the following

command will generate an error on the 34901A module since channel

122 is for current measurements only.

CONFigure:VOLTage:DC (@101:122)

Chapter 5 Remote Interface Reference

SCPI Command Summary

182

Scan Measurement Commands

(see page 226 for more information)

MEASure

:TEMPerature? {TCouple|RTD|FRTD|THERmistor|DEF}

,{<type>|DEF}[,1[,{<resolution>|MIN|MAX|DEF}]] ,(@<scan_list>)

:VOLTage:DC? [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

:VOLTage:AC? [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

:RESistance? [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

:FRESistance? [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

:CURRent:DC? [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

:CURRent:AC? [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

:FREQuency? [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

:PERiod? [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

:DIGital:BYTE? (@<scan_list>)

:TOTalize? {READ|RRESet} ,(@<scan_list>)

Monitor Commands

(see page 237 for more information)

ROUTe

:MONitor (@<channel>)

:MONitor?

ROUTe

:MONitor:STATe {OFF|ON}

:MONitor:STATe?

ROUTe:MONitor:DATA?

This command redefines the scan list when executed.

Default parameters are shown in bold.

Chapter 5 Remote Interface Reference

SCPI Command Summary

183

Scan Configuration Commands

(see page 226 for more information)

ROUTe

:SCAN (@<scan_list>)

:SCAN?

:SCAN:SIZE?

TRIGger

:SOURce {BUS|IMMediate|EXTernal|ALARm1|ALARm2|ALARm3|ALARm4|TIMer}

:SOURce?

TRIGger

:TIMer {<seconds>|MIN|MAX}

:TIMer?

TRIGger

:COUNt {<count>|MIN|MAX|INFinity}

:COUNt?

ROUTe

:CHANnel:DELay <seconds>[,(@<ch_ list>)]

:CHANnel:DELay? [(@<ch_list>)]

:CHANnel:DELay:AUTO {OFF|ON}[,(@<ch_list>)]

:CHANnel:DELay:AUTO? [(@<ch_list>)]

FORMat

:READing:ALARm {OFF|ON}

:READing:ALARm?

:READing:CHANnel {OFF|ON}

:READing:CHANnel?

:READing:TIME {OFF|ON}

:READing:TIME?

:READing:UNIT {OFF|ON}

:READing:UNIT?

FORMat

:READing:TIME:TYPE {ABSolute|RELative}

:READing:TIME:TYPE?

ABORt

INITiate

READ?

This command redefines the scan list when executed.

This command applies to all channels in the instrument (Global setting).

Default parameters are shown in bold.

Chapter 5 Remote Interface Reference

SCPI Command Summary

184

Scan Statistics Commands

(see page 233 for more information)

CALCulate

:AVERage:MINimum? [(@<ch_list>)]

:AVERage:MINimum:TIME? [(@<ch_list>)]

:AVERage:MAXimum? [(@<ch_list>)]

:AVERage:MAXimum:TIME? [(@<ch_list>)]

:AVERage:AVERage? [(@<ch_list>)]

:AVERage:PTPeak? [(@<ch_list>)]

:AVERage:COUNt? [(@<ch_list>)]

:AVERage:CLEar [(@<ch_list>)]

DATA:LAST? [<num_rdgs>,][(@<channel>)]

Scan Memory Commands

(see page 235 for more information)

DATA:POINts?

DATA:REMove? <num_rdgs>

SYSTem:TIME:SCAN?

FETCh?

R? [<max_count>]

Chapter 5 Remote Interface Reference

SCPI Command Summary

185

Scanning With an External Instrument

(see page 239 for more information)

ROUTe

:SCAN (@<scan_list>)

:SCAN?

:SCAN:SIZE?

TRIGger

:SOURce {BUS|IMMediate|EXTernal|TIMer}

:SOURce?

TRIGger

:TIMer {<seconds>|MIN|MAX}

:TIMer?

TRIGger

:COUNt {<count>|MIN|MAX|INFinity}

:COUNt?

ROUTe

:CHANnel:DELay <seconds>[,(@<ch_ list>)]

:CHANnel:DELay? [(@<ch_list>)]

ROUTe

:CHANnel:ADVance:SOURce {EXTernal|BUS|IMMediate}

:CHANnel:ADVance:SOURce?

ROUTe

:CHANnel:FWIRe {OFF|ON}[,(@<ch_list>)]

:CHANnel:FWIRe? [(@<ch_list>)]

INSTrument

:DMM {OFF|ON}

:DMM?

:DMM:INSTalled?

This command redefines the scan list when executed.

This command applies to all channels in the instrument (Global setting).

Default parameters are shown in bold.

Chapter 5 Remote Interface Reference

SCPI Command Summary

186

Temperature Configuration Commands

(see page 219 for more information)

CONFigure

:TEMPerature {TCouple|RTD|FRTD|THERmistor|DEF}

,{<type>|DEF}[,1[,{<resolution>|MIN|MAX|DEF}]] ,(@<scan_list>)

CONFigure? [(@<ch_list>)]

UNIT

:TEMPerature {C|F|K}[,(@<ch_list>)]

:TEMPerature? [(@<ch_list>)]

[SENSe:]TEMPerature:TRANsducer

:TYPE {TCouple|RTD|FRTD|THERmistor|DEF}[,(@<ch_list>)]

:TYPE? [(@<ch_list>)]

[SENSe:]TEMPerature:TRANsducer

:TCouple:TYPE {B|E|J|K|N|R|S|T}[,(@<ch_list>)]

:TCouple:TYPE? [(@<ch_list>)]

:TCouple:CHECk {OFF|ON}[,(@<ch_list>)]

:TCouple:CHECk? [(@<ch_list>)]

[SENSe:]TEMPerature:TRANsducer

:TCouple:RJUNction:TYPE {INTernal|EXTernal|FIXed}[,(@<ch_list>)]

:TCouple:RJUNction:TYPE? [(@<ch_list>)]

:TCouple:RJUNction {<temperature>|MIN|MAX}[,(@<ch_list>)]

:TCouple:RJUNction? [(@<ch_list>)]

[SENSe:]TEMPerature:RJUNction? [(@<ch_list>)]

[SENSe:]TEMPerature:TRANsducer

:RTD:TYPE {85|91}[,(@<ch_list>)]

:RTD:TYPE? [(@<ch_list>)]

:RTD:RESistance[:REFerence] <reference>[,(@<ch_list>)]

:RTD:RESistance[:REFerence]? [(@<ch_list>)]

[SENSe:]TEMPerature:TRANsducer

:FRTD:TYPE {85|91}[,(@<ch_list>)]

:FRTD:TYPE? [(@<ch_list>)]

:FRTD:RESistance[:REFerence] <reference>[,(@<ch_list>)]

:FRTD:RESistance[:REFerence]? [(@<ch_list>)]

[SENSe:]TEMPerature:TRANsducer

:THERmistor:TYPE {2252|5000|10000}[,(@<ch_list>)]

:THERmistor:TYPE? [(@<ch_list>)]

[SENSe:]

TEMPerature:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

TEMPerature:NPLC? [{(@<ch_list>)|MIN|MAX}]

This command redefines the scan list when executed.

Default parameters are shown in bold.

Chapter 5 Remote Interface Reference

SCPI Command Summary

187

Voltage Configuration Commands

(see page 223 for more information)

CONFigure

:VOLTage:DC [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]

VOLTage:DC:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

VOLTage:DC:RANGe? [{(@<ch_list>)|MIN|MAX}]

VOLTage:DC:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

VOLTage:DC:RANGe:AUTO? [(@<ch_list>)]

[SENSe:]

VOLTage:DC:RESolution {<resolution>|MIN|MAX}[,(@<ch_list>)]

VOLTage:DC:RESolution? [{(@<ch_list>)|MIN|MAX}]

[SENSe:]

VOLTage:DC:APERture {<time>|MIN|MAX}[,(@<ch_list>)]

VOLTage:DC:APERture? [{(@<ch_list>)|MIN|MAX}]

[SENSe:]

VOLTage:DC:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

VOLTage:DC:NPLC? [{(@<ch_list>)|MIN|MAX}]

INPut

:IMPedance:AUTO {OFF|ON}[,(@<ch_list>)]

:IMPedance:AUTO? [(@<ch_list>)]

[SENSe:]

ZERO:AUTO {OFF|ONCE|ON}[,(@<ch_list>)]

ZERO:AUTO? [(@<ch_list>)]

CONFigure

:VOLTage:AC [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]

VOLTage:AC:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

VOLTage:AC:RANGe? [{(@<ch_list>)|MIN|MAX}]

VOLTage:AC:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

VOLTage:AC:RANGe:AUTO? [(@<ch_list>)]

[SENSe:]

VOLTage:AC:BANDwidth {3|20|200|MIN|MAX}[,(@<ch_list>)]

VOLTage:AC:BANDwidth? [{(@<ch_list>)|MIN|MAX}]

This command redefines the scan list when executed.

Default parameters are shown in bold.

Chapter 5 Remote Interface Reference

SCPI Command Summary

188

Resistance Configuration Commands

(see page 224 for more information)

CONFigure

:RESistance [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]

RESistance:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

RESistance:RANGe? [{(@<ch_list>|MIN|MAX}]

RESistance:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

RESistance:RANGe:AUTO? [(@<ch_list>)]

[SENSe:]

RESistance:RESolution {<resolution>|MIN|MAX}[,(@<ch_list>)]

RESistance:RESolution? [{(@<ch_list>)|MIN|MAX}]

RESistance:APERture {<time>|MIN|MAX}[,(@<ch_list>)]

RESistance:APERture? [{(@<ch_list>)|MIN|MAX}]

RESistance:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

RESistance:NPLC? [{(@<ch_list>)|MIN|MAX}]

[SENSe:]

RESistance:OCOMpensated {OFF|ON}[,(@<ch_list>)]

RESistance:OCOMpensated? [(@<ch_ list>)]

CONFigure

:FRESistance [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]

FRESistance:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

FRESistance:RANGe? [{(@<ch_list>)|MIN|MAX}]

FRESistance:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

FRESistance:RANGe:AUTO? [(@<ch_list>)]

[SENSe:]

FRESistance:RESolution {<resolution>|MIN|MAX}[,(@<ch_list>)]

FRESistance:RESolution? [{(@<ch_list>)|MIN|MAX}]

FRESistance:APERture {<time>|MIN|MAX}[,(@<ch_list>)]

FRESistance:APERture? [{(@<ch_list>)|MIN|MAX}]

FRESistance:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

FRESistance:NPLC? [{(@<ch_list>)|MIN|MAX}]

[SENSe:]

FRESistance:OCOMpensated {OFF|ON}[,(@<ch_list>)]

FRESistance:OCOMpensated? [(@<ch_ list>)]

This command redefines the scan list when executed.

Default parameters are shown in bold.

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SCPI Command Summary

189

Current Configuration Commands

(see page 224 for more information)

Valid only on channels 21 and 22 on the 34901A multiplexer module.

CONFigure

:CURRent:DC [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]

CURRent:DC:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

CURRent:DC:RANGe? [{(@<ch_list>)|MIN|MAX}]

CURRent:DC:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

CURRent:DC:RANGe:AUTO? [(@<ch_list>)]

[SENSe:]

CURRent:DC:RESolution {<resolution>|MIN|MAX}[,(@<ch_list>)]

CURRent:DC:RESolution? [{(@<ch_list>)|MIN|MAX}]

[SENSe:]

CURRent:DC:APERture {<time>|MIN|MAX}[,(@<ch_list>)]

CURRent:DC:APERture? [{(@<ch_list>)|MIN|MAX}]

[SENSe:]

CURRent:DC:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

CURRent:DC:NPLC? [{(@<ch_list>)|MIN|MAX}]

CONFigure

:CURRent:AC [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]

CURRent:AC:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

CURRent:AC:RANGe? [{(@<ch_list>)|MIN|MAX}]

CURRent:AC:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

CURRent:AC:RANGe:AUTO? [(@<ch_list>)]

[SENSe:]

CURRent:AC:BANDwidth {3|20|200|MIN|MAX}[,(@<ch_list>)]

CURRent:AC:BANDwidth? [{(@<ch_list>)|MIN|MAX}]

This command redefines the scan list when executed.

Default parameters are shown in bold.

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190

Frequency and Period Configuration Commands

(see page 214 for more information)

CONFigure

:FREQuency [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]

FREQuency:VOLTage:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

FREQuency:VOLTage:RANGe? [{(@<ch_ list>)|MIN|MAX}]

FREQuency:VOLTage:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

FREQuency:VOLTage:RANGe:AUTO? [(@<ch_list>)]

[SENSe:]

FREQuency:APERture {0.01|0.1|1|MIN|MAX}[,(@<ch_list>)]

FREQuency:APERture? [{(@<ch_list>)|MIN|MAX}]

[SENSe:]

FREQuency:RANGe:LOWer {3|20|200|MIN|MAX}[,(@<ch_list>)]

FREQuency:RANGe:LOWer? [{(@<ch_list>)|MIN|MAX}]

CONFigure

:PERiod [{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]

PERiod:VOLTage:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

PERiod:VOLTage:RANGe? [{(@<ch_ list>)|MIN|MAX}]

PERiod:VOLTage:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

PERiod:VOLTage:RANGe:AUTO? [(@<ch_list>)]

[SENSe:]

PERiod:APERture {0.01|0.1|1|MIN|MAX}[,(@<ch_list>)]

PERiod:APERture? [{(@<ch_list>)|MIN|MAX}]

This command redefines the scan list when executed.

Default parameters are shown in bold.

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Mx+B Scaling Commands

(see page 244 for more information)

CALCulate

:SCALe:GAIN <gain>[,(@<ch_list>)]

:SCALe:GAIN? [(@<ch_list>)]

:SCALe:OFFSet <offset>[,(@<ch_list>)]

:SCALe:OFFSet? [(@<ch_list>)]

:SCALe:UNIT <quoted_string>[,(@<ch_ list>)]

:SCALe:UNIT? [(@<ch_list>)]

CALCulate:SCALe:OFFSet:NULL [(@<ch_list>)]

CALCulate

:SCALe:STATe {OFF|ON}[,(@<ch_list>)]

:SCALe:STATe? [(@<ch_list>)]

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Alarm Limit Commands

(see page 247 for more information)

OUTPut

:ALARm[1|2|3|4]:SOURce (@<ch_list>)

:ALARm[1|2|3|4]:SOURce?

CALCulate

:LIMit:UPPer <hi_limit>[,(@<ch_ list>)]

:LIMit:UPPer? [(@<ch_list>)]

:LIMit:UPPer:STATe {OFF|ON}[,(@<ch_list>)]

:LIMit:UPPer:STATe? [(@<ch_list>)]

CALCulate

:LIMit:LOWer <lo_limit>[,(@<ch_ list>)]

:LIMit:LOWer? [(@<ch_list>)]

:LIMit:LOWer:STATe {OFF|ON}[,(@<ch_list>)]

:LIMit:LOWer:STATe? [(@<ch_list>)]

SYSTem:ALARm?

OUTPut

:ALARm:MODE {LATCh|TRACk}

:ALARm:MODE?

:ALARm:SLOPe {NEGative|POSitive}

:ALARm:SLOPe?

OUTPut

:ALARm{1|2|3|4}:CLEar

:ALARm:CLEar:ALL

STATus

:ALARm:CONDition?

:ALARm:ENABle <enable_value>

:ALARm:ENABle?

:ALARm[:EVENt]?

Ch 01

DIO (LSB) Ch 02

DIO (MSB) Ch 03

Totalizer Ch 04

DAC Ch 05

DAC

CALCulate

:COMPare:TYPE {EQUal|NEQual}[,(@<ch_list>)]

:COMPare:TYPE? [(@<ch_list>)]

:COMPare:DATA <data>[,(@<ch_list>)]

:COMPare:DATA? [(@<ch_list>)]

:COMPare:MASK <mask>[,(@<ch_list>)]

:COMPare:MASK? [(@<ch_list>)]

:COMPare:STATe {OFF|ON}[,(@<ch_list>)]

:COMPare:STATe? [(@<ch_list>)]

This command applies to all channels in the instrument (Global setting).

Default parameters are shown in bold.

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Digital Input Commands

(see page 255 for more information)

Ch 01

DIO (LSB) Ch 02

DIO (MSB) Ch 03

Totalizer Ch 04

DAC Ch 05

DAC

CONFigure:DIGital:BYTE (@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]DIGital:DATA:{BYTE|WORD}? [(@<ch_list>)]

Totalizer Commands

(see page 256 for more information)

Ch 01

DIO (LSB) Ch 02

DIO (MSB) Ch 03

Totalizer Ch 04

DAC Ch 05

DAC

CONFigure:TOTalize {READ|RRESet} ,(@<scan_list>)

CONFigure? [(@<ch_list>)]

[SENSe:]

TOTalize:TYPE {READ|RRESet}[,(@<ch_list>)]

TOTalize:TYPE? [(@<ch_list >)]

[SENSe:]

TOTalize:SLOPe {NEGative|POSitive}[,(@<ch_list>)]

TOTalize:SLOPe? [(@<ch_list>)]

[SENSe:]TOTalize:CLEar:IMMediate [(@<ch_ list>)]

[SENSe:]TOTalize:DATA? [(@<ch_ list>)]

This command redefines the scan list when executed.

Default parameters are shown in bold.

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Digital Output Commands

(see page 258 for more information)

Ch 01

DIO (LSB) Ch 02

DIO (MSB) Ch 03

Totalizer Ch 04

DAC Ch 05

DAC

SOURce

:DIGital:DATA[:{BYTE|WORD}] <data> ,(@<ch_list>)

:DIGital:DATA[:{BYTE|WORD}]? (@<ch _list>)

SOURce:DIGital:STATe? (@<ch_list>)

DAC Output Commands

(see page 258 for more information)

Ch 01

DIO (LSB) Ch 02

DIO (MSB) Ch 03

Totalizer Ch 04

DAC Ch 05

DAC

SOURce

:VOLTage <voltage> ,(@<ch_list>)

:VOLTage? (@<ch_list>)

Switch Control Commands

(see page 259 for more information)

ROUTe

:CLOSe (@<ch_list>)

:CLOSe:EXCLusive (@<ch_list>)

:CLOSe? (@<ch_list>)

ROUTe

:OPEN (@<ch_list>)

:OPEN? (@<ch_list>)

ROUTe

:CHANnel:FWIRe {OFF|ON}[,(@<ch_list>)]

:CHANnel:FWIRe? [(@<ch_list>)]

ROUTe:DONE?

SYSTem:CPON {100|200|300|ALL}

Default parameters are shown in bold.

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Scan Triggering Commands

(see page 228 for more information)

TRIGger

:SOURce {BUS|IMMediate|EXTernal|ALARm1|ALARm2|ALARm3|ALARm4|TIMer}

:SOURce?

TRIGger

:TIMer {<seconds>|MIN|MAX}

:TIMer?

TRIGger

:COUNt {<count>|MIN|MAX|INFinity}

:COUNt?

*TRG

INITiate

READ?

State Storage Commands

(see page 261 for more information)

*SAV {0|1|2|3|4|5}

*RCL {0|1|2|3|4|5}

MEMory:STATe

:NAME {1|2|3|4|5} [,<name>]

:NAME? {1|2|3|4|5}

MEMory:STATe:DELete {0|1|2|3|4|5}

MEMory:STATe

:RECall:AUTO {OFF|ON}

:RECall:AUTO?

MEMory:STATe:VALid? {0|1|2|3|4|5}

MEMory:NSTates?

This command applies to all channels in the instrument (Global setting).

Default parameters are shown in bold.

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System-Related Commands

(see page 264 for more information)

SYSTem

:DATE <yyyy>,<mm>,<dd>

:DATE?

:TIME <hh>,<mm>,<ss.sss>

:TIME?

FORMat

:READing:TIME:TYPE {ABSolute|RELative}

:READing:TIME:TYPE?

*IDN?

SYSTem:CTYPe? {100|200|300}

DIAGnostic

:POKE:SLOT:DATA {100|200|300}, <quoted_string>

:PEEK:SLOT:DATA? {100|200|300}

DISPlay {OFF|ON}

DISPlay?

DISPlay

:TEXT <quoted_string>

:TEXT?

:TEXT:CLEar

INSTrument

:DMM {OFF|ON}

:DMM?

:DMM:INSTalled?

*RST

SYSTem:PRESet

SYSTem:CPON {100|200|300|ALL}

SYSTem:ERRor?

SYSTem:ALARm?

SYSTem:VERSion?

*TST?

Default parameters are shown in bold.

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Interface Configuration Commands

(see page 269 for more information)

SYSTem:INTerface {GPIB|RS232}

SYSTem:LOCal

SYSTem:REMote

SYSTem:RWLock

Status System Commands

(see page 286 for more information)

*STB?

*SRE <enable_value>

*SRE?

STATus

:QUEStionable:CONDition?

:QUEStionable[:EVENt]?

:QUEStionable:ENABle <enable_value>

:QUEStionable:ENABle?

*ESR?

*ESE <enable_value>

*ESE?

STATus

:ALARm:CONDition?

:ALARm[:EVENt]?

:ALARm:ENABle <enable_value>

:ALARm:ENABle?

STATus

:OPERation:CONDition?

:OPERation[:EVENt]?

:OPERation:ENABle <enable_value>

:OPERation:ENABle?

DATA:POINts

:EVENt:THReshold <num_rdgs>

:EVENt:THReshold?

STATus:PRESet

*CLS

*PSC {0|1}

*PSC?

*OPC

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Calibration Commands

(see page 292 for more information)

CALibration?

CALibration:COUNt?

CALibration

:SECure:CODE <new_code>

:SECure:STATe {OFF|ON},<code>

:SECure:STATe?

CALibration

:STRing <quoted_string>

:STRing?

CALibration

:VALue <value>

:VALue?

Service-Related Commands

(see page 294 for more information)

INSTrument

:DMM {OFF|ON}

:DMM?

:DMM:INSTalled?

DIAGnostic

:DMM:CYCLes?

:DMM:CYCLes:CLEar (1|2|3}

DIAGnostic

:RELay:CYCLes? [(@<ch_list>)]

:RELay:CYCLes:CLEar [(@<ch_list>)]

*RST

SYSTem:PRESet

SYSTem:CPON {100|200|300|ALL}

SYSTem:VERSion?

*TST?

Default parameters are shown in bold.

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IEEE 488.2 Common Commands

*CLS

*ESR?

*ESE <enable_value>

*ESE?

*IDN?

*OPC

*OPC?

*PSC {0|1}

*PSC?

*RST

*SAV {0|1|2|3|4|5}

*RCL {0|1|2|3|4|5}

*STB?

*SRE <enable_value>

*SRE?

*TRG

*TST?

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Simplified Programming Overview

This section gives an overview of the basic techniques used to program

the 34970A over the remote interface. This section is only an overview

and does not give all of the details you will need to write your own

application programs. Refer to the remainder of this chapter and also

the application examples in chapter 7 for more details and examples.

You may also want to refer to the documentation provided with your

programming application for details on outputting command strings and

entering data.

The MEASure? and CONFigure commands provide the most straight-

forward method to program the instrument for scanning. You can select

the measurement function, range, and resolution all in one command.

All other measurement parameters are set to their default values as

shown in the table below.

Measurement Parameter

Integration Time

Input Resistance

AC Filter

Scan List

Scan Interval Source

Scan Count

Channel Delay

MEASure? and CONFigure Setting

1 PLC

10 MΩ (fixed for all DCV ranges)

20 Hz (medium filter)

Redefined when command executed

Immediate

1 Scan Sweep

Automatic Delay

When you configure a channel using MEASure? or CONFigure, it is

important to note that the previous configuration on that channel

is lost. For example, assume that a channel is configured for dc voltage

measurements. When you reconfigure that channel for thermocouple

measurements, the previous range, resolution, and other measurement

attributes are set to their default values.

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Using the MEASure? Command

The MEASure? command provides the easiest way to program the

instrument for scanning. However, this command does not offer much

flexibility. When you execute this command, the instrument uses

default values for the requested measurement configuration and

immediately performs the scan. You cannot change any measurement

attributes (other than function, range, and resolution) before the

measurement is taken. The results are sent directly to the instrument’s

output buffer but readings are not stored in memory.

Note: Sending MEASure? is functionally the same as sending

CONFigure followed immediately by a READ? command.

Using the CONFigure Command

For a little more programming flexibility, use the CONFigure command.

When you execute this command, the instrument uses the default

values for the requested measurement configuration (like the MEASure?

command). However, the scan is not automatically started and you can

change some measurement attributes before initiating the scan.

This allows you to incrementally change the instrument’s configuration

from the default conditions. The instrument offers a variety of low-level

commands in the ROUTe, SENSe, SOURce, CALCulate, and TRIGger

subsystems.

Note: Use the INITiate or READ? command to initiate the scan.

The INITiate command stores the readings in memory. Use the FETCh?

command to retrieve the stored readings from memory.

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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 also set the range parameter

to AUTO to select autoranging.

For frequency and period measurements, the instrument uses one

“range” for all inputs between 3 Hz and 300 kHz. The range parameter

is required only to specify the resolution. Therefore, it is not necessary

to send a new command for each new frequency to be measured.

Use the resolution parameter to specify the desired resolution for

the measurement. Setting the resolution also sets the integration time

for the measurement. The following table shows the relationship

between integration time, measurement resolution, number of digits,

and number of bits.

Integration Time Resolution Digits Bits

0.02 PLC

0.2 PLC

1 PLC

2 PLC

10 PLC

20 PLC

100 PLC

200 PLC

< 0.0001 x Range

< 0.00001 x Range

< 0.000003 x Range

< 0.0000022 x Range

< 0.000001 x Range

< 0.0000008 x Range

< 0.0000003 x Range

< 0.00000022 x Range

41⁄2 Digits

51⁄2 Digits

61⁄2 Digits

Specify the resolution in the same units as the measurement function,

not in number of digits. For example, for dc voltage measurements,

specify the desired resolution in volts. For resistance, specify the desired

resolution in ohms. For frequency, specify the desired resolution in hertz.

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Using the READ? Command

The READ? command changes the state of the scan trigger system from

the “idle” state to the “wait-for-trigger” state. Scanning will begin when

the specified trigger conditions are satisfied following the receipt of the

READ? command. Readings are then sent immediately to the instrument’s

output buffer. You must then enter the readings into your computer or

the instrument will stop scanning when the output buffer becomes full.

Readings are not stored in the instrument’s internal memory when

using the READ? command.

Note: Sending the READ? command is like sending the INITiate

command followed immediately by the FETCh? command, except the

readings are not stored in reading memory when using READ?.

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 first reading the

response. When you cannot avoid this situation, send a Device Clear

before sending the second query command.

Using the INITiate and FETCh? Commands

The INITiate and FETCh? commands provide the lowest level of

control (with the most flexibility) of scan triggering and reading retrieval.

Use the INITiate command after you have configured the instrument

for a scan. Scanning will begin when the specified trigger conditions are

satisfied following the receipt of the INITiate command. The readings

are placed in the instrument’s internal reading memory (up to 50,000

readings can be stored; if memory fills, new readings will overwrite the

first readings stored). Readings are stored in memory until you are able

to retrieve them.

Use the FETCh? command to transfer all of the readings from reading

memory to the instrument’s output buffer where you can read them into

your computer. Note that the FETCh? command does not clear memory.

You can send the FETCh? command any number of times to retrieve the

same data in reading memory.

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Example: Using MEASure?

The following program segment shows how to use the MEASure?

command to make a measurement on one channel. This example

configures the instrument for dc voltage measurements, internally

triggers the instrument to scan one channel, and then sends the reading

to the instrument’s output buffer.

MEAS:VOLT:DC? 10,0.003,(@301)

This is the simplest way to take a reading. However, you do not have

any flexibility with MEASure? to set the scan count, channel delay, etc.

All measurement parameters except function, range, and resolution are

preset for you automatically (see the table on page 201).

Example: Using CONFigure With READ?

The following program segment shows how to use the READ? command

with CONFigure to make an externally-triggered scan on one channel.

The program configures the instrument for a dc voltage measurement.

Using CONFigure does not place the instrument in the “wait-for-

trigger” state. The READ? command places the instrument in the

“wait-for-trigger” state, scans the channel once when the Ext Trig

terminal is pulsed on the rear panel, and sends the reading to the

instrument’s output buffer.

CONF:VOLT:DC 10,0.003,(@301)

TRIG:SOUR EXT

READ?

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Example: Using CONFigure With INITiate and FETCh?

The following program segment is similar to the previous example but it

uses INITiate to place the instrument in the “wait-for-trigger” state.

The INITiate command places the instrument in the “wait-for-trigger”

state, scans the specified channel when the Ext Trig terminal is pulsed

on the rear panel, and sends the reading to reading memory. The FETCh?

command transfers the reading from reading memory to the instrument’s

output buffer.

CONF:VOLT:DC 10,0.003,(@301)

TRIG:SOUR EXT

INIT

FETC?

Storing readings in memory using the INITiate command is faster

than sending readings to the output buffer using the READ? command.

The INITiate command is also an “overlapped” command. This means

that after executing the INITiate command, you can send other

commands that do not affect the scan. Note that the FETCh? command

will wait until the scan is complete to terminate. The instrument can

store up to 50,000 readings in internal reading memory.

Note: To stop a scan that has been started using the INITiate

command, send an ABORt command or Device Clear (see page 302).

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The MEASure? and CONFigure Commands

Both the MEASure? and CONFigure commands reset all measurement

parameters to their default values. For more information on the default

settings for these commands, see the table on page 201.

•For the range parameter, MIN selects the lowest range for the

selected function; MAX selects the highest range; AUTO or DEF

selects autoranging. For more information on autoranging, refer to

“General Measurement Configuration” starting on page 98.

•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 0.000003 x range (1 PLC).

For more information on resolution, see the table on page 203.

MEASure? Command Syntax

MEASure:TEMPerature?

TCouple,{B|E|J|K|N|R|S|T|DEF}

[,1[,<resolution>|MIN|MAX|DEF}]] ,(@<scan_list>)

Configure the specified channels for thermocouple measurements and

immediately sweep through the scan list one time. Note that this command

also redefines the scan list. The readings are sent directly to the

instrument’s output buffer but the readings are not stored in reading

memory. The default (DEF) transducer type is a J-Type thermocouple.

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MEASure:TEMPerature?

{RTD|FRTD},{85|91|DEF}

[,1[,<resolution>|MIN|MAX|DEF}]] ,(@<scan_list>)

Configure the specified channels for 2-wire or 4-wire RTD measurements

and immediately sweep through the scan list one time. Use “85” to

specify α = 0.00385 or “91” to specify α = 0.00391. Note that this command

also redefines the scan list. The readings are sent directly to the

instrument’s output buffer but the readings are not stored in reading

memory. The default (DEF) type is “85” (α = 0.00385).

For 4-wire RTD measurements (FRTD), the instrument automatically

pairs channel n with channel n+10 (34901A) or n+8 (34902A) to provide

the source and sense connections. For example, make the source

connections to the HI and LO terminals on channel 2 and the sense

connections to the HI and LO terminals on channel 12. Specify the

paired channel in the lower bank (source) as the scan_list channel.

MEASure:TEMPerature?

{THERmistor},{2252|5000|10000|DEF}

[,1[,<resolution>|MIN|MAX|DEF}]] ,(@<scan_list>)

Configure the specified channels for thermistor measurements and

immediately sweep through the scan list one time. Note that this command

also redefines the scan list. The readings are sent directly to the

instrument’s output buffer but the readings are not stored in reading

memory. The default (DEF) transducer type is a 5 kΩ thermistor.

MEASure:VOLTage:DC?

MEASure:VOLTage:AC?

[{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

Configure the specified channels for dc or ac voltage measurements and

immediately sweep through the scan list one time. Note that this command

also redefines the scan list. The readings are sent directly to the

instrument’s output buffer but the readings are not stored in reading

memory. For ac measurements, the resolution is actually fixed at

61⁄2 digits; the resolution parameter only affects the number of digits

shown on the front-panel.

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MEASure:RESistance?

MEASure:FRESistance?

[{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

Configure the specified channels for 2-wire or 4-wire measurements and

immediately sweep through the scan list one time. Note that this command

also redefines the scan list. The readings are sent directly to the output

buffer but the readings are not stored in reading memory.

For 4-wire measurements (FRES), the instrument automatically pairs

channel n with channel n+10 (34901A) or n+8 (34902A) to provide the

source and sense connections. For example, make the source connections

to the HI and LO terminals on channel 2 and the sense connections to

the HI and LO terminals on channel 12. Specify the paired channel in

the lower bank (source) as the scan_list channel.

MEASure:CURRent:DC?

MEASure:CURRent:AC?

[{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

Note: Current measurements are allowed only on channels 21 and 22

on the 34901A multiplexer module.

Configure the specified channels for dc or ac current measurements and

immediately sweep through the scan list one time. Note that this command

also redefines the scan list. The readings are sent directly to the

instrument’s output buffer but the readings are not stored in reading

memory. For ac measurements, the resolution is actually fixed at

61⁄2 digits; the resolution parameter only affects the number of digits

shown on the front-panel.

MEASure:FREQuency?

MEASure:PERiod?

[{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

Configure the specified channels for frequency or period measurements

and immediately sweep through the scan list one time. Note that this

command also redefines the scan list. The readings are sent directly to

the instrument’s output buffer but the readings are not stored

in reading memory. With no signal applied, “0” is returned.

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MEASure:DIGital:BYTE? (@<scan_list>)

Configure the instrument to read the specified digital input channels on

the multifunction module and immediately sweep through the scan list

one time. Note that this command also redefines the scan list. The readings

are sent directly to the instrument’s output buffer but the readings are

not stored in reading memory. The digital input channels are numbered

“s01” (LSB) and “s02” (MSB), where s represents the slot number.

Note that if you include both digital input channels in the scan list,

the instrument will read data from both ports simultaneously with the

same time stamp. This will allow you to externally combine the two

8-bit value into one 16-bit value.

MEASure:TOTalize? {READ|RRESet} ,(@<scan_list>)

Configure the instrument to read the count on the specified totalizer

channels on the multifunction module and immediately sweep through

the scan list one time. Note that this command also redefines the scan list.

The readings are sent directly to the instrument’s output buffer but the

readings are not stored in reading memory. The totalizer channel is

numbered “s03”, where s represents the slot number.

To read the totalizer during the scan without resetting the count, select

the READ parameter. To read the totalizer during the scan and reset the

count to “0” after it is read, select the RRESet parameter (this means

“read and reset”).

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CONFigure Command Syntax

CONFigure:TEMPerature

{TCouple},{B|E|J|K|N|R|S|T|DEF}

[,1[,<resolution>|MIN|MAX|DEF}]] ,(@<scan_list>)

Configure the specified channels for thermocouple measurements but

do not initiate the scan. Note that this command also redefines the scan list.

The default (DEF) transducer type is a J-Type thermocouple.

CONFigure:TEMPerature

{RTD|FRTD},{85|91|DEF}

[,1[,<resolution>|MIN|MAX|DEF}]] ,(@<scan_list>)

Configure the specified channels for 2-wire or 4-wire RTD measurements

but do not initiate the scan. Use “85” to specify α = 0.00385 or “91” to

specify α = 0.00391. Note that this command also redefines the scan list.

The default (DEF) type is “85” (α = 0.00385).

For 4-wire RTD measurements (FRTD), the instrument automatically

pairs channel n with channel n+10 (34901A) or n+8 (34902A) to provide

the source and sense connections. For example, make the source

connections to the HI and LO terminals on channel 2 and the sense

connections to the HI and LO terminals on channel 12. Specify the

paired channel in the lower bank (source) as the scan_list channel.

CONFigure:TEMPerature

{THERmistor},{2252|5000|10000|DEF}

[,1[,<resolution>|MIN|MAX|DEF}]] ,(@<scan_list>)

Configure the specified channels for thermistor measurements but

do not initiate the scan. Note that this command also redefines the scan list.

The default (DEF) transducer type is a 5 kΩ thermistor.

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CONFigure:VOLTage:DC

CONFigure:VOLTage:AC

[{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

Configure the specified channels for dc or ac voltage measurements but

do not initiate the scan. Note that this command also redefines the scan list.

For ac measurements, the resolution is actually fixed at 61⁄2 digits;

the resolution parameter only affects the number of digits shown on the

front-panel.

CONFigure:RESistance

CONFigure:FRESistance

[{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

Configure the specified channels for 2-wire or 4-wire measurements but

do not initiate the scan. Note that this command also redefines the scan list.

For 4-wire measurements (FRES), the instrument automatically pairs

channel n with channel n+10 (34901A) or n+8 (34902A) to provide the

source and sense connections. For example, make the source connections

to the HI and LO terminals on channel 2 and the sense connections to

the HI and LO terminals on channel 12. Specify the paired channel in

the lower bank (source) as the scan_list channel.

CONFigure:CURRent:DC

CONFigure:CURRent:AC

[{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

Note: Current measurements are allowed only on channels 21 and 22

on the 34901A multiplexer module.

Configure the specified channels for dc or ac current measurements but

do not initiate the scan. Note that this command also redefines the scan list.

For ac measurements, the resolution is actually fixed at 61⁄2 digits;

the resolution parameter only affects the number of digits shown on

the front-panel.

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CONFigure:FREQuency

CONFigure:PERiod

[{<range>|AUTO|MIN|MAX|DEF}

[,<resolution>|MIN|MAX|DEF}],] (@<scan_list>)

Configure the specified channels for frequency or period measurements

but do not initiate the scan. For frequency and period measurements,

the range parameter is ignored. Note that this command also redefines

the scan list.

CONFigure:DIGital:BYTE (@<scan_list>)

Configure the instrument to read the specified digital input channels

on the multifunction module but do not initiate the scan. Note that this

command also redefines the scan list. The digital input channels are

numbered “s01” (LSB) and “s02” (MSB), where s is the slot number.

Note that if you include both digital input channels in the scan list,

the instrument will read data from both ports simultaneously with the

same time stamp. This will allow you to externally combine the two

8-bit value into one 16-bit value.

CONFigure:TOTalize {READ|RRESet} ,(@<scan_list>)

Configure the instrument to read the specified totalizer channels on the

multifunction module but do not initiate the scan. Note that this command

also redefines the scan list. The totalizer channel is numbered “s03”,

where s represents the slot number.

To read the totalizer during the scan without resetting the count, select

the READ parameter. To read the totalizer during the scan and reset the

count to “0” after it is read, select the RRESet parameter (this means

“read and reset”).

CONFigure? [(@<ch_list>)]

Query the present configuration on the specified channels and return a

series of quoted strings. If you omit the optional ch_list parameter,

the instrument uses the active scan list. The command returns a series

of comma-separated fields as shown in the example below. Each field

contains the function, range, and resolution.

"FRES +1.000000E+02,+3.000000E-04" , "TEMP TC,K,+1.000000E+00,+3.000000E-06"

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Setting the Function, Range, and Resolution

See also “General Measurement Configuration” in chapter 4 starting

on page 98.

•For 4-wire measurements, the instrument automatically pairs

channel n with channel n+10 (34901A) or n+8 (34902A) to provide the

source and sense connections. Specify the paired channel in the lower

bank (source) as the ch_list channel.

•Current measurements are allowed only on channels 21 and 22

on the 34901A multiplexer module.

[SENSe:]FUNCtion "<function>"[,(@<ch_list>)]

Select the measurement function on the specified channels. The function

name must be enclosed in quotes in the command string (for example,

FUNC "VOLT:DC"). Specify one of the following strings to set the function.

TEMPerature

VOLTage[:DC]

VOLTage:AC

RESistance

FRESistance

CURRent[:DC]

CURRent:AC

FREQuency

PERiod

•Note that when you change the measurement function on a channel,

all of the other measurement attributes (range, resolution, etc.) are

set to their default values.

•You cannot set any function-specific measurement attributes unless

the channel is already configured for that function. For example,

you cannot set the ac filter unless that channel is already configured

for ac voltage or ac current measurements.

[SENSe:]FUNCtion? [(@<ch_list>)]

Query the measurement function on the specified channels and return

a quoted string. The short form of the function name is always returned

(for example, "VOLT").

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[SENSe:]

VOLTage:DC:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

VOLTage:AC:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

RESistance:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

FRESistance:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

CURRent:DC:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

CURRent:AC:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

FREQuency:VOLTage:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

PERiod:VOLTage:RANGe {<range>|MIN|MAX}[,(@<ch_list>)]

Select the measurement range for the function selected on the specified

channels. MIN selects the lowest range. MAX selects the highest range.

[SENSe:]

VOLTage:DC:RANGe? [{(@<ch_list>)|MIN|MAX}]

VOLTage:AC:RANGe? [{(@<ch_list>)|MIN|MAX}]

RESistance:RANGe? [{(@<ch_list>)|MIN|MAX}]

FRESistance:RANGe? [{(@<ch_list>)|MIN|MAX}]

CURRent:DC:RANGe? [{(@<ch_list>)|MIN|MAX}]

CURRent:AC:RANGe? [{(@<ch_list>)|MIN|MAX}]

FREQuency:VOLTage:RANGe? [{(@<ch_ list>)|MIN|MAX}]

PERiod:VOLTage:RANGe? [{(@<ch_list>)|MIN|MAX}]

Query the measurement range on the specified channels. Returns a

number in the form “+1.00000000E+01”.

[SENSe:]

VOLTage:DC:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

VOLTage:AC:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

RESistance:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

FRESistance:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

CURRent:DC:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

CURRent:AC:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

FREQuency:VOLTage:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

PERiod:VOLTage:RANGe:AUTO {OFF|ON}[,(@<ch_list>)]

Disable or enable autoranging on the specified channels. Autoranging

thresholds: Down ranges at <10% of range; Up range at >120% of range.

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[SENSe:]

VOLTage:DC:RANGe:AUTO? [(@<ch_list>)]

VOLTage:AC:RANGe:AUTO? [(@<ch_list>)]

RESistance:RANGe:AUTO? [(@<ch_list>)]

FRESistance:RANGe:AUTO? [(@<ch_list>)]

CURRent:DC:RANGe:AUTO? [(@<ch_list>)]

CURRent:AC:RANGe:AUTO? [(@<ch_list>)]

FREQuency:VOLTage:RANGe:AUTO? [(@<ch_list>)]

PERiod:VOLTage:RANGe:AUTO? [(@<ch_list>)]

Query the autorange setting on the specified channels. Returns “0” (OFF)

or “1” (ON).

[SENSe:]

VOLTage:DC:RESolution {<resolution>|MIN|MAX}[,(@<ch_list>)]

RESistance:RESolution {<resolution>|MIN|MAX}[,(@<ch_list>)]

FRESistance:RESolution {<resolution>|MIN|MAX}[,(@<ch_list>)]

CURRent:DC:RESolution {<resolution>|MIN|MAX}[,(@<ch_list>)]

Select the resolution for the function selected on the specified channels.

Specify the resolution in the same units as the measurement function,

not in number of digits. MIN selects the smallest value accepted for this

parameter, which gives the most resolution. MAX selects the largest

value accepted for this parameter, which gives the least resolution.

For more information on the relationship between integration time,

measurement resolution, number of digits, and number of bits, see the

table on page 203.

[SENSe:]

VOLTage:DC:RESolution? [{(@<ch_list>)|MIN|MAX}]

RESistance:RESolution? [{(@<ch_list>)|MIN|MAX}]

FRESistance:RESolution? [{(@<ch_list>)|MIN|MAX}]

CURRent:DC:RESolution? [{(@<ch_list>)|MIN|MAX}]

Query the resolution setting on the specified channels. Returns a

number in the form “+3.00000000E-05”.

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[SENSe:]

VOLTage:DC:APERture {<time>|MIN|MAX}[,(@<ch_list>)]

RESistance:APERture {<time>|MIN|MAX}[,(@<ch_list>)]

FRESistance:APERture {<time>|MIN|MAX}[,(@<ch_list>)]

CURRent:DC:APERture {<time>|MIN|MAX}[,(@<ch_list>)]

Select the aperture time for the function selected on the specified channels.

MIN selects the smallest value accepted for this parameter, which gives

the lowest resolution. MAX selects the largest value accepted for this

parameter, which gives the highest resolution.

For more information on aperture time, refer to “Custom A/D Integration

Time” in chapter 4 starting on page 103.

[SENSe:]

VOLTage:DC:APERture? [{(@<ch_list>)|MIN|MAX}]

RESistance:APERture? [{(@<ch_list>)|MIN|MAX}]

FRESistance:APERture? [{(@<ch_list>)|MIN|MAX}]

CURRent:DC:APERture? [{(@<ch_list>)|MIN|MAX}]

Query the aperture time setting on the specified channels. Returns a

number in the form “+1.66666700E-02”.

[SENSe:]

FREQuency:APERture {0.01|0.1|1|MIN|MAX}[,(@<ch_list>)]

PERiod:APERture {0.01|0.1|1|MIN|MAX}[,(@<ch_list>)]

Select the aperture time (or gate time) for frequency or period

measurements on the specified channels. Specify 10 ms (41⁄2 digits),

100 ms (default; 51⁄2 digits), or 1 second (61⁄2 digits). MIN = 0.01 seconds.

MAX = 1 second.

[SENSe:]

FREQuency:APERture? [{(@<ch_list >)|MIN|MAX}]

PERiod:APERture? [{(@<ch_list>)|MIN|MAX}]

Query the aperture time for frequency or period measurements on the

specified channels. Returns a number in the form “+1.00000000E-01”.

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[SENSe:]

TEMPerature

:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

VOLTage:DC

:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

RESistance

:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

FRESistance

:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

CURRent:DC

:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

Set the integration time in number of power line cycles (PLCs) on the

specified channels. The default is 1 PLC. MIN = 0.02. MAX = 200.

For more information on the relationship between integration time,

measurement resolution, number of digits, and number of bits, see the

table on page 203. For more information on integration time, refer to

“Custom A/D Integration Time” in chapter 4 starting on page 103.

[SENSe:]

TEMPerature:NPLC? [{(@<ch_list>)|[MIN|MAX}]

VOLTage:DC:NPLC? [{(@<ch_list>)|[MIN|MAX}]

RESistance:NPLC? [{(@<ch_list>)|[MIN|MAX}]

FRESistance:NPLC? [{(@<ch_list>)|[MIN|MAX}]

CURRent:DC:NPLC? [{(@<ch_list>)|[MIN|MAX}]

Query the integration time on the specified channels. Returns a number

in the form “+1.00000000E+00”.

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Temperature Configuration Commands

See also “Temperature Measurement Configuration” in chapter 4 starting

on page 106.

General Temperature Commands

UNIT

:TEMPerature {C|F|K}[,(@<ch_list>)]

:TEMPerature? [(@<ch_list>)]

Select the temperature measurement units on the specified channels.

The default is “C”. The :TEMP? query returns the temperature

measurement units currently selected. Returns “C”, “F”, or “K”.

[SENSe:]TEMPerature:TRANsducer

:TYPE {TCouple|RTD|FRTD|THERmistor|DEF}[,(@<ch_list>)]

:TYPE? [(@<ch_list>)]

Select the type of temperature transducer to use for measurements on

the specified channels. Select from TC (thermocouple), RTD (2-wire RTD),

FRTD (4-wire RTD), or THER (thermistor) . The default is TC. The

:TYPE? query returns the current temperature transducer type on the

specified channels. Returns “TC”, “RTD”, “FRTD”, or “THER”.

[SENSe:]TEMPerature

:NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)]

Set the integration time in number of power line cycles (PLCs) on the

specified channels. The default is 1 PLC. MIN = 0.02. MAX = 200.

For more information on the relationship between integration time,

measurement resolution, number of digits, and number of bits, see the

table on page 203. For more information on time, refer to “Custom A/D

Integration Time” in chapter 4 starting on page 103.

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Thermocouple Commands

[SENSe:]TEMPerature:TRANsducer

:TCouple:TYPE {B|E|J|K|N|R|S|T}[,(@<ch_list>)]

:TCouple:TYPE? [(@<ch_list>)]

Select the thermocouple type to use on the specified channels.

The default is a J-Type thermocouple. The :TYPE? query returns the

thermocouple type currently in use. Returns “B”, “E”, “J”, “K”, “N”, “R”,

“S”, or “T”.

[SENSe:]TEMPerature:TRANsducer:TCouple

:RJUNction:TYPE {INTernal|EXTernal|FIXed}[,(@<ch_list>)]

:RJUNction:TYPE? [(@<ch_list>)]

Thermocouple measurements require a reference junction temperature.

For the reference junction temperature, you can use an internal

measurement on the module, an external thermistor or RTD measurement,

or a known fixed junction temperature. The default is “INTernal”.

The :TYPE? query returns the source currently selected. Returns “INT”,

“EXT”, or “FIX”.

•If you select an external reference, the instrument automatically

reserves channel 01 on the multiplexer in the lowest slot as the

reference channel (thermistor or RTD measurement). If you have

more than one multiplexer installed, channel 01 on the module in the

lowest slot is used as the reference for the entire instrument.

•Before configuring a thermocouple channel with an external

reference, you must configure the reference channel (channel 01)

for a thermistor or RTD measurement. An error is generated if you

attempt to select the external reference source before configuring the

reference channel. An error is also generated if you change the

function on the reference channel after selecting the external

reference for a thermocouple channel.

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[SENSe:]TEMPerature:TRANsducer

:TCouple:CHECk {OFF|ON}[,(@<ch_list>)]

:TCouple:CHECk? [(@<ch_list>)]

Disable or enable the thermocouple check feature to verify that your

thermocouples are properly connected to the screw terminals for

measurements. If you enable this feature, the instrument measures the

channel resistance after each thermocouple measurement to ensure a

proper connection. If an open connection is detected (greater than 5 kΩ

on the 10 kΩ range), the instrument reports an overload condition for

that channel. The default is “OFF”. The :CHEC? query returns the

thermocouple check setting. Returns “0” (OFF) or “1” (ON).

[SENSe:]TEMPerature:TRANsducer:TCouple

:RJUNction {<temperature>|MIN|MAX}[,(@<ch_list>)]

:RJUNction? [(@<ch_list>)]

Set the fixed reference junction temperature for thermocouple

measurements on the specified channels. Specify a temperature

between -20 °C and +80 °C (always specify the temperature in °C

regardless of the temperature units selected). The default is 0 °C.

The :RJUN? query returns the fixed junction temperature (in °C)

currently selected. MIN selects -20 °C. MAX selects +80 °C.

[SENSe:]TEMPerature:RJUNction? [(@<ch _list>)]

Query the internal reference junction temperature on the specified

channels (useful only for an internal reference source). Returns the

reference temperature in °C regardless of the temperature units

currently selected. Returns a number in the form “+2.89753100E+01”.

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RTD Commands

[SENSe:]TEMPerature:TRANsducer

:RTD:TYPE {85|91}[,(@<ch_list>)]

:RTD:TYPE? [(@<ch_list>)]

:FRTD:TYPE {85|91}[,(@<ch_list>)]

:FRTD:TYPE? [(@<ch_list>)]

Select the RTD type for 2-wire or 4-wire measurements on the specified

channels. Use “85” to specify α = 0.00385 (ITS-90 software conversions)

or “91” to specify α = 0.00391 (IPTS-68 software conversions).

The default is “85”. The :TYPE? query returns the RTD type in use on

the specified channels. Returns “+85” or “+91”.

[SENSe:]TEMPerature:TRANsducer

:RTD:RESistance[:REFerence] <reference>[,(@<ch_list>)]

:RTD:RESistance[:REFerence]? [(@<ch_list>)]

:FRTD:RESistance[:REFerence] <reference>[,(@<ch_list>)]

:FRTD:RESistance[:REFerence]? [(@<ch_list>)]

Set the nominal resistance (R0) for RTD measurements on the specified

channels. Select a value between 49Ω and 2.1 kΩ. The default is 100Ω.

The :REF? query returns the nominal resistance (R0) in use on the

specified channels. Returns a number in the form “+1.00000000E+02”.

Thermistor Commands

[SENSe:]TEMPerature:TRANsducer

:THERmistor:TYPE {2252|5000|10000}[,(@<ch_list>)]

:THERmistor:TYPE? [(@<ch_list>)]

Select the thermistor type for measurements on the specified channels.

The default is a 5 kΩ thermistor. The :TYPE? query returns the

thermistor type in use on the specified channels. Returns “2252”, “5000”,

or “10000”.

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Voltage Configuration Commands

See also “Voltage Measurement Configuration” in chapter 4 starting on

page 113.

INPut

:IMPedance:AUTO {OFF|ON}[,(@<ch_list>)]

:IMPedance:AUTO? [(@<ch_list>)]

Disable or enable the automatic input resistance mode for dc voltage

measurements on the specified channels. With AUTO OFF (default),

the input resistance is fixed at 10 MΩ for all ranges. With AUTO ON,

the input resistance is set to >10 GΩ for the 100 mV, 1 V, and 10 V

ranges. The :AUTO? query returns the input resistance setting on the

specified channels. Returns “0” (OFF) or “1” (ON).

[SENSe:]

VOLTage:AC:BANDwidth {3|20|200|MIN|MAX}[,(@<ch_list>)]

VOLTage:AC:BANDwidth? [{(@<ch_list>)|MIN|MAX}]

Specify the lowest frequency expected in the input signal for ac voltage

measurements on the specified channels. The instrument selects the

slow, medium (default), or fast ac filter based on the frequency you

specify. MIN = 3 Hz. MAX = 200 Hz. The :BAND? query returns the

ac filter setting on the specified channels. Returns “3”, “20”, or “200”.

[SENSe:]

ZERO:AUTO {OFF|ONCE|ON}[,(@<ch_list>)]

ZERO:AUTO? [{(@<ch_list>)]

Disable or enable (default) the autozero mode. The OFF and ONCE

parameters have a similar effect. Autozero OFF does not issue a new

zero measurement until the next time the instrument goes to the

“wait-for-trigger” state. Autozero ONCE issues an immediate zero

measurement. The :AUTO? query the autozero mode. Returns “0”

(OFF or ONCE) or “1” (ON).

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Resistance Configuration Commands

See also “Resistance Measurement Configuration” in chapter 4 starting

on page 115.

[SENSe:]

RESistance:OCOMpensated {OFF|ON}[,(@<ch_list>)]

RESistance:OCOMpensated? [(@<ch_ list>)]

FRESistance:OCOMpensated {OFF|ON}[,(@<ch_list>)]

FRESistance:OCOMpensated? [(@<ch _list>)]

Disable or enable offset-compensation for resistance measurements.

Once enabled, offset compensation is applied to both 2-wire and 4-wire

resistance measurements. The default is “OFF”. The :OCOM? query returns

the offset compensation setting on the specified channels. Returns “0” (OFF)

or “1” (ON).

Current Configuration Commands

See also “Current Measurement Configuration” in chapter 4 starting on

page 116.

Note: Current measurements are allowed only on channels 21 and 22

on the 34901A multiplexer module.

[SENSe:]

CURRent:AC:BANDwidth {3|20|200|MIN|MAX}[,(@<ch_list>)]

CURRent:AC:BANDwidth? [{(@<ch_list>)|MIN|MAX}]

Specify the lowest frequency expected in the input signal for ac current

measurements on the specified channels. The instrument selects the

slow, medium (default), or fast ac filter based on the frequency you

specify. MIN = 3 Hz. MAX = 200 Hz. The :BAND? query returns the

ac filter setting on the specified channels. Returns “3”, “20”, or “200”.

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Frequency Configuration Commands

See also “Frequency Measurement Configuration” in chapter 4 starting on

page 118.

[SENSe:]

FREQuency:RANGe:LOWer {3|20|200|MIN|MAX}[,(@<ch_list>)]

FREQuency:RANGe:LOWer? [{(@<ch_list>)|MIN|MAX}]

Specify the lowest frequency expected in the input signal for frequency

measurements on the specified channels. The instrument selects a slow,

medium (default), or fast measurement timeout based on the frequency

you specify. MIN = 3 Hz. MAX = 200 Hz. The :LOW? query returns the

timeout setting on the specified channels. Returns “3”, “20”, or “200”.

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Scanning Overview

See also “Scanning” in chapter 4 starting on page 74.