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User Manual: KEI_196

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Model 196
System DMM
instruction Manual

Contains Operating and Servicing Information

WARRANTY
Keithley Instruments, Inc. warrants this product to be free from defects in material and tiorkmanship for a period of 1 year from date of
shipment.

Keithley Instruments, Inc. warrants the following items for90 days from the date of shipment: probes, cables, rechargeable batteries,
diskettes, and documentation.

During the warranty period, we will, at OUToption, either repair or replace any product that proves to be defective.~~

:

To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in Ct&e.land, Ohio. YOUwill
be given Prompt assistance and return instruciions. Send the product, transport&~ prepaid, to the indicated service facility. Repairs
will be made and the product returned, transportation prepaid. Repaired or replaced products are warranted for the balance of the original warranty period, or at least POdays.

LIMITATION OF WARRANTY
This warranty does not apply to defects resulting from product modification without Keithley’s express written consent, or misuse of
any product or part. This warranty also does not apply to fuses,~software, non-rechargeable batteries, damage from battery leakage,~or
problems arising~55Zi-incmii~l wear or failure to follow instructions.

THIS WARRANTY IS IN LIEU OF ALL OTtiERWARRANTIES,
EXPRESSED OR IMPLIED, INCLUDING ANY IMPLIED
WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PRO\IIDED HEREIN ARE
BUYER’S SOLE AND EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT, JNDIRECT, SPECIAL, INCIDENTALOR CONsE:QUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS JNSTRIJM.ENTS AND
SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF
SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED To: COSTS OFTREMOVAL
AND INSTALLATION, Lossm SUSTAINED As THE RESULT OF IN3URY TO ANY PERSON, OR DAMAGETO PROPERTY.

Model 196~ System DMM
Instruction Manual

01986, Keithley Instruments, Inc.
Test Instrumentation Group
All rights reserved.
Cleveland, Ohio, U.S.A.
Fourth PrintingJanuary 1992
Document Number: 196-901-01 Rev. 0

Safety Precautions
The following safety precautions should be observed befoE
using this product and any associated inshvmentation. Although some instruments and accessories would normally be
used with non-hazardousvoltages, therearesituatio~iis where
hazardous conditions may be present
This product is intended for use by qualiied personnel who
iecognize shock hazards and are familiar with the safety precautions required to avoid possible injury. Read the operating
information carefully before using the product.
Exercise extreme caution when a shock hazard is present. Lethal voittige may be present on cable connector jacks or test
f?xtures. The American National Standards Instih~te (ANSI)
states that a shock hazard exists when voltage levels greater
than 30V RMS, 42.4V peak, or 60VDC are present. A good
safety practice is to expect that hazardous voltage is present
in any unknown circuit before measuring.
Before operating an inskutient, make sure the line cord is
connected to a properly grounded power receptacle. Inspect
the connecting cables, test leads, and jumpers for possible
wear, cracks, or breaks before each use.
For maximum safety, do not touch the product, test cables, or
any other instruments while power is applied to the circuit
under test. ALWAYS remove power from the entire test systern and discharge any capacitors before: connecting or disconnecting cables or jumpers, installing or removing
switching cards, or making internal changes, such as installing or removing jumpers.
Do not touch any object that could provide a current path to
the common side of the circuit under test or power lie
(earth) ground. Always make measurements with dry hands
while standing on a ~JY, insulated surface capable of withstanding the voltage being measured.

Do not exceed the maximum signal levels of the instruments
and accessories, as defined in the specifications and operating
inform&ion, and a~ shown on the instrument or test fixture
rear panel, or switchiig card.
Do not connect switching cards directly to unlimited power
circuits. They are intended to be used with impedance limited sources. NEVER cbnnect switching cards directly to AC
tin.
When connecting sources to switching cards, install
$~~tive
devices to lit
fault current and voltage to the
card.
When fuses are used in a product, replace with same type and
rating for continued protection against fire hazard.
Chassis connections must only be used as shield connections
for measuring circuits, NOT as safety earth ground connections.
If you are using a test fxtwe, keep the lid closed while power
is applied to the device under test. Safe operation requires the
u.s$of a lid interlock.
Ifa @saew
ispresenton~hetest tixhm?,connectit tbsafety
earth ground using #18 AWG or larger wire.
The $ symbol on an instrument or accessory indicates that
1oOOVor more may be present on the terminals. Refer to the
product manual for detailed operahlng information.
Instrumentation and accessories should not be connected to
humans.
Maintenance should be performed by qualified service personnel. Before perfo&ng any maintenance, disconnect the
line cord~andall test cables.

SPECIFICATIONS
DC~VOLTS
6% Digits,

ANALOG SETTLING
of step change.

TIME:

lZOdB at dc, MHz or 6OHz (iO.O5%) with lkQ in either lead.
NMRR:

>M)dB at50Hz

RESPONSE:
CREST

or60Hz

(iO.0546).

Tiue root mean square,

FACTOR

~~

ac coupled.

(ratio of peak to rms)z Up to 3:l allowable.

NONSINUSOIDAL
INPUTS: For fundamental frequencies < -,
mest
factor ~3, add 0.25% of reading to specified accuracy for 3oomV and
3V ranges; add 0.6% of reading to specified accuracy for 30V and 3fXlV
ranges.
INPUT IMPEDANCE:
3dBBANDWIDTHz
MAXIMUM
whichever
SETTLING

3WkHzfypical.
INPUT:

’
3oOV -,

MAXIMUM
less.

ALLOWABLE

INPUT:

300V rms. 425” peak, whichever

is

TBMF’ERATURE COEFFICI@‘JT
(0=18”C & 28Y?,*C):
< i(O.l x app!icable accuracy specification)K
below 2OkHz,
f(0.2.x) for 2okHz to 1ook?iz.
CMRR:

>6OdB at 5OHz or 6OHz (*0.05%)

dB (Ref. = 1”):
INPUT

*OHa-~0gz

with IkR in either lead.

.4CC”RAcY *a
1 Year, IP-WC
?OW-?c!

-. P??LUnoN

’
425”

peak,

10’ VHz,

1 second to within 0.1% of change in reading.

WNETGURATION:
Automatic 2- or&,ire.
Offset compensationavai!ab~e
on 3wiXOkO ranges, requires proper zeroing. Allowable compensation
of ilOmV on 3OilQ range and ilWmV
on 3ktl and 3OkO ranges.
MAX, ALLOWABLE

deviation from a straight
line between the readings at zero and full range: 1Oppm of range for
~3V-3ooV ranges; 15ppm of range for 3OOmV range; at 23OC il°C.

lMlI shunted bv <12OoF.

ALLOWABLE
is less.
TIME:

LINEARI’IY Linearity is defined as the timurn

INPIJZ

3wV rms, 425V peak, whichever

is less.

OBN

CIRCUIT

VOLTAGE:

5.5V maxinwm.

JJNEARIlY
Linetity is defined as the madmum deviation from a &might
line between the readings at zero and full range: 20ppm of range for
SCO@3OkO ranges, at 23°C iYC.

tiAXIMUM READING RAT&
DCV,
10 n.4

3mA

conttn”ovs into
Internal Buffer

0.05 + 10

1ooP.A
0.05 +~
+ 10
3iE
1d
10 K.4
0.09 + 10
3 A
‘4wigit count error is 20. 3K-digit CO”“terror is 5.
MAXIMUMALLOWABLHINPUT:
OVERLOAD

PROTECTION:

DCA, ACV, ACA READINGS/SECOND

*

Extemal Rigger into
I”temd Buffer

Triggered via
IEEE488 Bus

v

3A, 250”.
3A fuse (25OV), accessible from reii~ panel.

TEMPERATURE
COEFFICIENT
c iCO.1 x applicable accumw

(O”-18’C & 2S”-500C):
svecification)PC.

~~~

1 For Sinewaveinputs >x.m EOuntS.For 4Vdigit accuracy,
divide cou*t error by
10. .%3lidigit
accuracy,
count errOI b 5. Jn 3vl- and 4K.digit modes,specificati‘J”d apply for stnew.we inputs ,200Hz.
RESPONSE:

True mot mean square,

ac coupled.

CREST FACTOR (ratio of peak to rms): Up to 3:l allowable at % full scale.
NONSINUSOIDAL
INPUTS: Spe&d
ctes lO’D paralleled by 4OOpF.

DATA MEMORY: 1 to 500 locations, programmable. Measurement
vals selectable from lms to 999999,&s or triggered.
BENCH READING
3COMtl ranges).

RATE: 5 readings/second

FILTER: Weighted average (exponential).
l/99.

(2lsecond

Programmable

inter-

on 30M8 and
weighting,

1 to

OPERATING ENVIRONMENT:
O”-500$ 0%.80% relative humidity up
to 35T; linearly derate 3% RH/“C, 35’C-5Ci’C (0%.60% RH up to 28OC
on 3oOMB range).

ENVIRONMENT:

-25”

to +65OC.

POWER: 105.125V or 210.UOV, rex panel switch selected, 5OHz or 6OHz,
30VA max. YO-1lOV and 18022OV versions available upon request.
DIMENSIONS,
WEIGHT: l27mm high x 216mm wide x 359mm deep
(5 in. x 8% in. x 14% in.). Net weight 3.7kg (8 Ibs.).
ACCBSSORIES
AVAILABLE:
Model lOlYA-1: 5%.in. Single Fixed Rack Mounting
Model
Model
Model
Model
Model
Model
Model
Model

lOlYA-2:
10195-1:
10195-2:
1651:
1681:
168s
1685:
1751:

Model
Model
Model
Model

1754:
5806:
7W7-I:
7007-2:

Model 7008.3:
Model 7008-6:

Kit

5’%-in. Dual Fixed Rack Mounting Kit
5’%-in. Single Slide Rack Mounting Kit
5X-b,. Dual Slide Rack Mounting Kit
5&Ampere Shunt
Clip-On Test Lead Set
RFPmbe
Clamp-On Current Pmbe
General Purpose Test Leads
Universal Test Lead Kit
Kelvin clip Leads
Shielded IEEE-488 Cable, lm
Shielded IEEE-488 Cable, 20,
IEEE-488 Cable, 3 ft. (O.Ym)
IEEE488 Cable, 6 ft. (1.8m)

Prices and specifications Subject to change without notice.

TABLE OF CONTENT!3
SECTION l-GENERAL
1.1
1.2
1.3
1.4
1.5~
:p7
1.8
1.9
1.10

INTRODUCTION. ...........................................................................
.~.-.~:.:
;~:~.~
.... .;.e:.;. .. .;. .......................................
FEAI-URES ......
.;. ................
WARRANTY INFORMATION .................................................................
; ..............................................................
MANUAL ADDENDA ..........
SAFETY SYMBOLS AND TFRMS ...............................................................
SPECIFICATIONS ............................................................................
. ....................................
INSPECTION ..............................................
USING THE MODEL 196 MANUAL ..........................................................
..~~...._~. ..~..:.. .;. .......
.; .........................
GE’JTMG STARED .............................
. :~.-;~; : .~:;~.........
ACCESSORIES ....................
.~:.~.~;~.~..~;~..~~.~;-;;~.‘;~.~.
.~;~;;:~.~..... : .... .;~;; .~~.-.:

SECTION 2-BASIC
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.3
23.1
2.3.2
2.33~
2.3.4
2.4
2.4.1
2.4.2
2.4.3
2.5
2.6
2.6.1
2.6.2
2.6.3
2.6.4
2.65
2.6;6
2.6.7
2.68
2.6.9
2.6.10
2.6.u.
2.7
27.1
2.7.2
2.7.3
2.%4
2.75
2.7.6
2.7.7
2.7.8
2.7.9

INFORMATION
l-1 ..
l-l
l-1
l-l
l-l
l-2
l-2
l-2
1-2
l-3

DMM OPERATIONS

2-l
INTRODUCTION ...........................................................................
2-l
_._.~..............................
..I.. .......................
POWER UP PROCEDURES .........
2-1
: .................................
Line rower ...................................................
2-l
Power-Up sequence. ............................................................................
2-l
Factory Default Conditions .................................................................
2-2
User Programmed Conditions .................................................................
2-2
FRONT PANEL FAMILIARIZATION ..........................................................
2-2
......................................................................
DisplayandIndicators
2-2
controls.. ........................................................................................
2-4
~1nputTermine.k .............................................................................
2-4
Calibration Enable Switch ...................................................................
__ ....
2-5
REAR PANEL FAMILIARIZATION .......................................................
2-5
Controls ...................................................................................
2-5
Connectors and Terminals ....................................................................
Z-6
Fuses.. ..... _. .......
. .............................................................................
~...~;. ... . ...... .;...:~;.=; ........ ;~~;~;::~2-6.
ERROR DISPLAY MESSAGES. ..~.;Z:..; .....................
2-6
BASIC MEASUREMENTS .....................................................................
2-7
WarmUpPeriod ...........................................................................
.........................................
2-7
Zero.........................~............~.~.......~
2-8
Filter .......................................................................................
.................
.~. ....
2-9
..: . ..*-. .......................
DCVolta eMeasurements.. ... ~.~~..~...=_
2-10
.Low-LeveHMeasurement Coiisiderations .....................................................
2-11
Resistan& Measurements ...................................................................
2-12
TRMS ACVoltageMeasurements ...........................................................
2-13
.I ...............................
Current Measurements (DC or TRMS~~AC).... ;. ...........
2-13
dBMeasurements .........................................................................
2-15
:TRMS Considerations ......................................................................
.: ................
:.~..........
:..~: ..............
. ........
2-17
~~dBApplications .......................
2-17
FRONT PANEL PROGRAMS ...................................................................
2-18
Program 0 (Menu) ........................................................................
2-18
Program2(Resolution) ....................................................................
2-18
Program4(MX+B)~. ...........................................................................
..............................................
2-19
Program5~/LO/Pass).....................;
2-20
Program 6 (Multiplexer, Auto/CAL) ..........................................................
..................................................
2-20
Program30(Save)..................~.....~
~2-21
Program 31 (IEEE Address). ..........................................................................
_. ...........
2-21
Program 32 (Lie Frequency) .......................................................
2-22
Program 33 (Diagnostic). .....................................................................

i

~~~

2.7.10
2.7.11
2.%x?
27.13
2.7.14
2.7.15
2.7.16
2.7x7
2.8
2.8.1
2.8.2
2.9
2.9.1
2.9.2
2.9.3

.,..... _~.... __....
Program 34 (MX+B Pammeters) ............................................
.,......
.,............................
Program 35 (HI/LO Limits) ..............................
Program36(Calibration) ...................................................................
.,.... __. .................
-. ............................
mgram 37 (Reset) ..................
Programn ................................................................................
.l~.
..............................
.I. .. . ... I~.~:.-...........
Program ZERO.. ..............
.: .~;:.~.~.
...................................................
.._.
..~.._~~
Program FILTER .................
_,_,_............................................
Program dB .................................
FRONT PANEL TRIGGERING .................................................................
.;.....
T. ..I. .............................
One-ShotTrigge~ring.. ........
I.~...;..~ ..................
.,..
.,.... __ .............................
Triggering Readings Into Data Store. .....................
_. ........................
EXTEEWAL TRIGGERING ...........................................
ExternalTrigger.. ..........................................................................
._ ....
.~._...._. .............
___~.........................
Voltmeter Complete ...................
~Trigering Example.. ......................................................................

SECTION 3-IEEE-488
3.1
3.2
3.3
3.4
3.5 ~~~,
3.6
3.6.1
3.6.2
3.7
3.7.1
3.%2
3.8
3.8.1
3.8.2
3.8.3
3.8.4
3.8.5
3.8.6
3.8.7
3.8.8
3.9 ~
3.9.1
3.9.2
3.9.3~
3.9.4
3.9.5
3.9.6
3.9.7
3.9.8
3.9.9
3.9.10
3.9.11
3.9.32
3.9.13
3.9.14
3.9.15
3.9.16
3.9.17
3.9.18

ii

2-22
2-22
2-23
2-23
2-24
2-24
2-24
2-25
2-25
2-25
Z-25
2-26
2-26
2-26
2-27

PROGRAMMING

...................
3-l
INTRODUCTION.. ........................................................
3-l
A SHORTCUT TO IEEE-488 OPERATION ........................................................
3-4
. . ..~.~_~..~_
............................................
BUS CONNECTIONS.. ...................
3-5
INTERFACE FUNCTION CODES ..............................................................
_...........
_ .........
3-6
PRJMARY ADDRESS SELECTION ......................................
~3-6
CONTROLLER PRO% RAMMING ........
_. ...................................................
3-7
Controller Handler Softwae ..................................................................
3-7
BASIC Interface Programming Statements. ....................................................
____ ,3-7
FRONT PANEL ASPECTS OF IEEE-488 OPERATION ..........................................
. 57
~..~..~...~;.~..............
FrontPanelErrorMessages..
... ~;.;~.~..:...:~~ ... . .......................
.~I. .... ._ .......
3-10
IEEE-488 Status Indicators and LOCAL Key ....................................
3-n
GENERAL BUS COMMAND PROGRAMMIN G ................................................
.,. 3-ll
REN (Remote Enable) .....................................................................
3Xl
__ _.,.............................................
IFC (Tnterface Clear) .......................
................
3-11
LLO (LocalLockout).......................................................~
3-12
GTL(GoToLocal).
........................................................................
3-12
DCL(Devi?e Clear) ........................................................................
3-13
1. _.~..... -. ...........
._..........................
~SDC Selective De& Clear), ..................
t. .................
3-n
-~.~.
........
GET tGroup Execute Trigger) ..................................
3-13
.-;. ........
.: ....................................
Se&d Polling (SPE,SPD). .1.. ................
.............................
_..:. . ;, .... .,.... 3-14
DEVICE-DEPENDENT COMMAND PRWWNG
3-17
.._. ...........................
Execute(x). .................................................
3-17
; ..............................................................
Fur&on (F) ................
3-18
.._ ......................................................
Range(R). ......................
3-18
..- .......................
zero(Z). .........................................................
.
Filter(P).......................~~............................................................3........
.........................................................................
3-19
Rate (S).
.;.
3-20
Trigger Mode Q ............................................................................
3-20
__ ..........................................
Reading Mode (B) .............................
3-20
Data Store Interval (Q) and Size (I) ..........................................................
3-22
Value (V) and Calibration (C) ...............................................................
.~:.... : 3-23
Default Conditions (L) ..............................................................
3-23
;~:. ...............
:I;.....;
.:. ........................
DataFormat(G).
.... . .............
3-24
SRQ Mask (M) and Serial Poll Byte Format ..................................................
3-26
EOI and Bus Hold-off Modes (K) ................................................................
:I!
_ ..........................................
Terminator(Y) ..............
~..~..~...~...l~.~
_. ........
status (u) ...................................................................................
3-29
Auto/Cal Multiplex (A). ....................................................................
331
Delay (W) ....................................................................................

3.9.19
3.9.20
3.9.21
3.9.22
3.10
3.10.1
3.10.2
3.10.3
3.108
3.10.5
3.10.6
3.10.7
3.10.8
3.10.9
3.11

.._. . .._. . .- .................
~Sem&~).
...................................................
~...~.~.~__
..
whit Button (H) ......................................................................
Display (D) ...............................................................................
lntemalFilter(N)
.........................................................................
._. .... -~.........
TRANSLATOR SOFIWARE ..................................................
_.,_~
.,. .,.......
Translator Format. .............................................................
. . c____. ... .._ .... ..............
WildCard($).
...............................................
I. ... ,:~. .........................
NEW and OLD .................
.;~,..~..~.~.......................
Combining Translator Words ..............
. ..................
_ ..............
.,_ ................
Combining Translator Words With Keithley IEEE-488 Commands ..............................
Executing Translator Words and Keithley IEEE Commands ....................................
1;:. ..........
;.~. .... ;...;.
SAVE.. .....................
~;~.~...~v................................
.: ........................
~LIST .........................
_.~.......
. .........................
FORGET .............
:.I; .......
.._ .....................
..~...................................
BUS DKC.4TRANSMISSION TIMES ..........................................................

SECTION 4-PERFORMANCE
4.1
4.2
4.3
4.4
4.5
4.5.1
4.5.2
4.5.3
4.5.4
4.5.5

VERIFICATION

INTRODUCTION ..............................................................................
41
_. .. _. ..................................
4-1
ENVIRONMENTAL CONDITIONS ............................
................
~.~_~.
...................
..-- ......
..-- ... 41
INITIAL CONDITIONS. ..... - _*_..._..__._
RECOMMENDEDTESTEQUIPMENT..
. .........
. ...............
41
................................
VERIFICAXION PROCEDURES. .................................................................
42
DC Volts Verification ........................................
____ _.______ ......................
4-2
4-2
..~.~......................~...I..~...........~.......~
..........
TRMS AC Volts Verification ......
. ._ .........
. .m
.,._ ...... ~.;;. ..... ;..~; ..:. .. .~..; ... 4-3
Ohms Verification .........
..~.._~:. ............
~:..... ~...~.;~;. ......
.~;~.~.-;.-;.......;.
4-4
DCCurrentVerification..
.... ;I;. .......
;~................
................
~_-_. ...............
4-5
TRMS AC Current Verification ..............................

SECTION 5-PRINCIPLES
5.1
5.2
5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.4
5.5
5.6
5.61
5.6.2
5.7

331
3-31
332
3-33
3-33
~3-34 ...
335
3-35~
3-35
3-36
3-36
3-37
3-37
3-37
3-37

OF OPERATION

........................................................
5-l
INTRODUCTION ...........
.___~.~_~.~.~._.
5-l
OVERALL FUNCTIONAL DESCRIPTION ...........................................................
. ..........
_:~.................
5-l
ANALOG CIRCUITRY.. ............................................
. .~;_. ................................
; ...........
5-l
Input Signal Conditioning. ....................
.~.~.~~-.
5-4
Multiplexer .................................................................................
5-7
. ....................
-. .... ~~~.~~:.~~.
.................
~+2.1V Reference Source ........... .............
.... .55
.: ............
Input Buffer Amplifier .........................................................
.._..~~.~_~_..................................~......_....._~
...
A/D CONVERTER ...............
5-8
CONTROL CIRCUITRY .......................................................................
;
DIGITAL CIRCUITRY
Microcomputer. ........................................................................................................................................................
5-9
..~._.......................~....................~
...........
Display Circuitry ................
5-9
..~.~...._..~
.............................................
POWER SUPPLIES ....................

SECTION B-MAINTENANCE
6.1
6.2
6.3
6.3.1
6.3.2
6.4
6.4.1
6.4.2

6-l
INTRODUCTION ..............................................................................
LINE VOITAGE SELECTION ..................................................................
..~~.~...~..-*~~
....
FUSE REPLACEMENT ....................................................
6-l
..................................................................................
Line Fuses
-;~
I,;;...;..;;.~....;.~~~:
.., ____.: .........
..._ ..__:.:
CurrentFuse
.
...................
........
..................
CALIBRKION ....................... ................ ... ..... .._....................~
RecommendedCalibrationEquipment
.................. ................................................................................. 2;;
.......................
.)
.~_.
Environmental Conditions.
iii

6.4.3
6.4.4
6.4.5
6.4.6
6.4.7
t%
6.4.10
6.4.11
6.4.72
6.5
6.6
6.7
6.7.1
6.7.2
67.3
6.7.4
6.7.5
6.7.6

. .............
6-3
Warn-UpPeriod..
..I... ... I......,: ..:. .... ..:.~:..:...~ ..; ...........
............
6-3
........................................................
CALENABLE Switch.. .................
6-3
_.-. ......
.,..... _. .......................................
Front Panel Calibration ...............
.. ~.~6-4
_ .......................
.._. __.__ _...................,
IEEE-488Bus~CaIibration.. ..............
__. _.. ,6,-4
Calibration Sequence .... ! ........
,.._._..:&.-. _. ...... ‘~-. ,_. ... .~_.............................
.._ ..........................................
DC V&s CaI’b
1 *alon..
t’
............................
6-5
6-6
Resistance Calibration. ..........
.I .... _,.......................................................
6-7
;~..._ .. :.:~:.~ ... . ...............................
TRMS~ACVtiltsCalibration.. ...................
.,. 6-9
_. ......... . __ ... ._. .....................................
DC Current Calibration .............
6-10
TRMS AC Currefit Calibration ................................................................
6-11
~...__._ . ,........I_ ..........
...............................
DISASSEMBLYINSi-RUCTIONS ..........
: ...... _I...~............
~&lZ
- ..l..:..........
SPECIAL HANDLING OF STATIC-SENSI’?IVE DEVICES ........
.,... 6-12
....................
.~:. ... .,.........................
TROUBLESHOOTING .............
.~I,~_.
6-14
-., .. ..I. ................
._,_ _~..,..__.......................
Recommended Test Equipment .........
6-14
.-~- ._.~_._...........
._~.~.~.~.~.~.~.
.,. ___., . .,......................
Power Up Self Test ..................
__. .............
6-14
._ .......
. _,...............
Program 33 - Self Diagnostic Program ................
6-15
.~.~_.__-...... .___“.,_. .............
_. .........................
Power Supplies ...................
_. .. 6-15
_. ....... ._. ........................
Signal COnditioning Check
.-. .. .:.:~~........ .~-.:~. .......
6-15
Digital and Display Circuitry Checks ........................................................

SECTION 74iEPLACEABLE
7.1
Z2
z3
%4
7.5

PAFITS

INTRODUCTION...~.~..~:~...;..;~..~.~..;
.._.....I....
_......_......................_.._......_
_.. 7-1
PARTS UST..............................................~....................~..~......-....
7-1
ORDFRINGINFORMATION ..,................,.
_.._ __...........
~-~. . . .~~.-- _..... ~-...1.~...~...-~~1~3~
FACTORY SERVICE . . . . . . . . ;..;.;....;...;;~-__.~.~-;;
._.. ~..__ . . . . . . . . . . . ...I_ . . . . . . . . f . . . _ . . .. . . . .. . . . ;rl
SCHEMp;TIC DIAGRAMS ps;rrj: COMPG&T
LOC&TIOti DRAWINGS . . .
. : .~.~.; __ . . .~.__. 7-l

APPENDIX

A

ASCII CHARACTER CODES AND IEEE-488 MULTILINE INTERFACE COMMAND MESSAGES..

APPENDIX

B

IBM PC/XT and MODEL 8573A PROGRAMMING

APPENDIX

..

k-1

.‘,

. .‘:. . .,. . . ::. .~.. __ . . . _. .~.. . . _ . .

. . . . , . . . . . :.

. . _. . C-l

D

IEEE-488 BUS OVERVIEW

iv

. __. . . . . . _. . . ____. _. . _ . ___.

C

CONTROLLER PROGRAMS.

APPENDIX

1. A-1~

.

. . . ._ . . . . . . . . . . . . . . . . _. . . _. , . _. . ___ _.

. . _.

. . . . . _. __. D-l

LIST OF TABLES
SECTION 2-BASIC
2-l
2-2
23
Et
2-6
2-7
2-8

DMM OPERATION

.~I. :. . : .; ... :~..................................................
Factory Default Conditions ......
..............
..~.......;-.....................,......................;
ErrorMessages ..........
. ............................................
............................
ResistanceRanges..
.:......
;~......
Corresponding Voltage +ferenceJev$@for
Impedance !7eference. .....................
Comparison of Average and TRMS Meter Readings .............................................
:.~. ..........
...... ~.:. .... . ..... :z.:. ... ~.:. ... .z.:..~ .:. .................
FrontPanelPrograms..
.,.. .__ .... _ .............................
Display Resolution ...........................
.............
. .............
~;;.;;~;;. ... i...;;.
.:~. ...............
. .......
......
ExampleMX+BReadings.:.

SECTION 3-IEEE-488
3-l
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-ll
3-12
3-13
3-14
3-35
3-16

PROGRAMMING

IEEE-488 Commands Used to Select Function and Range ........................................
i ......................................
~lEEE Contact Designation. ..............................
_. ... _. ........
Model 196 Interface Function Codes ............................................
1.. ...........
BASIC Statements Necessary to Send Bus Commands ...............................
..................
.. I...; ........
:I...............
l............
FrontPanelIEEE488Messages..
.~;. ...............
General Bus Commands and Associated BASIC Statements ;~..................
....... ;;...~.J:.:..~..:
... . .... -..I~;~.~1.. ............
FactoryDefaultConditiotis ....... ~~;I.~;.~~...;.;.~~;
._ ..........
Device-Dependent Command Summary ............................................
......................
:r:..~-..~.~ ..... ~..~i: ..%. ...........
-.!L.
Range Co~andSummary...~..,,:.
_......
_... _.. _ ................
Rate Command Summary ........................................
High Speed Data Store ..........................................................................
_ . __
_. ..........
SRQ Command Parameters ..................................................
__
._. .......
.~.~.:. ......
:. ............
Bus Hold-off Ties
............................................
_ ................
Translator Reserved Words and Chxacter ....................................
Translator Error Messages ... z ....................................................................
Trigger To Reading-Ready Times (DCV Funct&~n) ...............................................

SECTION 4-PERFORMANCE
41
4-2
22
45
46

5-1

3-3
35
3-6
3-7
3-8~
3-10
3-12
3-E
3-l$
3-19
3-22
3-25
3-26
3-33
3-34
3-37

VERIFICATION

................................................................
RecommendedTest
Equipment
Limits for DCV Volts Verification ................................................................
........
. .......
LimitsforTRMSACVoltsVerifibation..
MY..;.....................................
Limits for Ohms Verification ... .:~. ;~.~.~.
.......
;...~ ....................
.:. ......................
Limits for DC Current Verification .............................................................
t.. .... ~.I; ......................
Limits for AC CurretifVerification .......................

SECTION 5-PRINCIPLES

2-2
2-6
2-12
2-15
2-16
2-l7
2-18
2-19~

. ........

41
42
i-3
4-4
4-4
4-5

OF OPERATION

Input Buffer Amplifier (U35) Gain Co*gt&ation

. ...

. . ‘.

..

..

.‘; i . . . . ~. . . . . _~._ . _. 5-7

V

SECTION 6-MAINTENANCE
6-l
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
6-J.0
6-12
6-12
6-13
6-14

6-l
..L .........................................................
LineVoltage Selection ............
6-2
.......................................................................
LineFuseReplacement
6-2
_. ....... __. ......................
Current~Fuse Replacement ...................................
6-2
Recommended Calibration Equipment ..........................................................
6-5
..............................................
DCVoltsCalibration......................~.....6-6
ResistanceCalibration ........................................................................
6-7
_,.. _._...............................................
TRMS AC Volts Calibration. .................
6-10
.......................................
.~.....................
DC Current Calibration ............
6-11
_. .........................
TRMS AC Currefit calibration .......................................
6-14
Recommended Troubleshooting Equipment ....................................................
6-15
Model I.96 Troubleshooting Mode ..............................................................
_............
_..... .,.. .,., 6-18
Power Stipply Checks. ................................................
6-18
Digital Circuitry Checks. ........................................................................
6-19
_. ............................
.,.. __ .............
Display Circuitry Checks .....................

SECTION 7-REPLACEABLE
7-1
7-2
7-3
7-4

Display Board, Parts List.. .
. . . . . . . . . , . . . . __.-. .: . _ . _ :. . . . _:. . . . . _. . . . . . :. . . . .‘. . ._ _. 7-3
DigitalBoard,PartsList........................-~..............................................
7-S
AnalogBoard,Parts List . . . . . . . . . . . . . . . . . . . . ..~..............................................
719
7-33
Model196MiscellaneousParts
List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .._........................

APPENDIX
B-1

;;

Vi

B

BASIC Statements Necessary to Send Btis Co mmands...........................................

APPENDIX
D-l
D-2
D-3

PAFKS

B-1

D

............................................................
lEEE488Bus Command So
Hexadecimal and Decimal Command Codes ...................................................
Typical Addressed Command Sequence. .............................................
.; .....
Typical Device-Dependent Commiind Sequence .. ;~....................
_..... ; ....................................
IBEE Co mmaid Group ................

_ ..........
. .. .;~..~............
.,....... .,....

D-3
D-7
D-7
D-7
D-7

LIST OF ILLUSTRATIONS
SECTION 2-BASIC
2-l
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10

DMM OPERATION

.......
Model196FrontPanel................................................~.......~.......~.._ ........
Model 196 Rear Panel .............................................................
...
DCVoltageMeasurements
...........................
..~....~.....-...............~.-...~Two-Terminal Resistance Measurements .................................................
.,......
Four-Terminal Resistance Measurements ........................
.~.- ... _~_.~_
_,_..... _,__......
_. .~_....
TRMSACVoltageMeasuremement
....................................................................................................................................
Current Measurements.
External Trigger Pulse Specifications ..........................................................
I
.,
Voltmeter Complete Pulse Specifications
.._..............._
.....................................
...................................... .................
External Triggering Example .........

SECTION 3-IEEE-466
3-l
3-2
2
3-5
3-6
37
3-8
3-9
3-10

E
4-6

r
-.:-~. :;4j
~.y.:~I.T ._
TypicalProgramFlo~ Chart..
.................... ~.~--.~:~.~.~.
................................
..-........ ........................ .....
IEEE-488 Connector .. ................
.......
;;.~:3:
~.:.~
..;
;:
............................. . .
IEEE-488Connections~.
..*........~
...
.................
IEEE-488 Connector Location
................................... ... ....................... .......
3-5
Contact Assignments .........................................................................
3-23
_......................................................
~Generd Data Format ........................
. 3-24
SRQMask and Serial Poll Byte Fo~at.........................................~.....-...-..i;;:
UO Machine Status Word and Default V&es
.............................................................................................................
Ul Error Status Word .... .... ........
3-32
Hit Button Command Numbers ..............................................................

VERIFICATION

Conmctions ‘for DC Volts Verification ..........................................................
..!. .......
. ...................
_:. .........
CoMectionsforTRMSACVoltsVeriCication~
..... . ......
_. .........................
Connections for Ohms Verification (300%#$!
Range) ...............
Connections for Ohms Verification (3OOkn--3OOMQRanges) ......................................
Connections for DC Current Verification ........................................................
Connections for TRMS AC Cur&t Verification ._.....................................................

SECTION &PRINCIPLES
5-l
5-2
5-3
S-4
5-5
5-6

2-26
i;g

PROGRAMMING

SECTION 4-PERFORMANCE
41
42
43

2-3
2-5
2-10
2-11
2-p
$E

42
43
44
44
45
4-5

OF OPERATION

Overall Block Diagram. .......................................................................
Input Configuration During 2 and 4Terminal Resistance Measurement. ...........................
Resistance Measurement Simplified Circi&y ...................................................
.,...............................................
JFET Multiplexer
Multiplexer Phases.........................................................................................................
A/D Converter Simplified Schematic ...........................................................

5-2
5-3
5-4
;:
5-8

Vii

SECTION 6-MAINTENANCE
6-5
DC Volts Calibration Confii&on
(300mV ani ,y @nges) ......................................
6-5
DC Volts Calibration Confi~atio~
(3OV-300VRanges) ...........................................
6-6
Four-Wire Resistance Calibration Configuration (3000-3OkQ Ranges) ...............................
6-7
Two-Wire Resistance Calibration Configuration (300kO3OOMQRanges). ............................
6-8
Flowchart of AC Volts Calibration Procedure ....................................................
1. ... 6-8
TRMS AC Volts Calibration Configuration :.I .. ; ..................................................
6-9
TRMS~AC Volts Calibration Adjustments .......................................................
6-10
DC Current Calibration Configuration., .......................................................
6-U.
.........................................................
ACCurrent
CalibrationConfiguration
6-12~
.~.-i.. ..............
(. .........................................
Analog Board Conne~ors~. ..........
6-l3
....................................................................
Model196ExplodedViav

SECTION 7-REPLACEABLE
7-1
7-2
7-3
z
7-6

Display Board, Comporient Location Drawing, Dwg. No. 196-110. ..................................
Display Board, Schematic Diagram, Dwg. No. 196.XL6..............................................
;. .. ; . ~;; .......
Digital Board, Component Location Drawing, Dwg. No. 196-100 ....................
‘.‘~.
.........
Digital Board, Schematic Diagram, Dwg. No. 196-106. ...............................
Analog Board, Component Location Drawing, Dwg. No. 196.120 ..................................
Analog Board, Schematic Diagram, Dwg. No. 196-126 ...........................................

APPENDIX
D-l
D-2
D-3

viii

PARTS
~7-4
7-5
; . 7-12
: .. 7-13
7-24
7-25

D

......................................................................
tEEEBusCon@ration
;Y;~;..............................................
IEEE Handshake Sequence .......
CommandCodes ............................................................................

.;. .............

D-l
D-3
D-6

SECTION 1
GENERAL INFORMATION
1.1 INTRODU~ION

1.3 WARRANTY

The Keithley Model 196 System DMM is a five function
autoranging~digital multimeter. At 6% digit resolution, the
LED display can display ~*3,@0,1lOOcoo@s. The ran@ of
this analog-to-digital (A/D)converter is greater t+q the nor:
mal *l,999,999&tit~AAID converter used in many 6% &St
DMMs. The built-in IEEE-488~interface makes the instrument fully programmable over the IEEE-488 bus. The Model
196 can make the following basic measurements:

Warranty information may be found on the inside front
cover of this manual. Should it become necessary to exq
c@e the warranty, contact your Keithley represent&e or
the ~factory to determine the proper course of action.
Keithley Instruments maintains service facilities in the
United States, United Kingdom and throughout Europe.
Information concerning the application, operation or service of your instrument may be directed to the applications
engineer at any of these locations. Check the inside front
cover for addresses.

1.
2.
3.
4.
5.

DC voltage measurements from lOOnVto 3OOV.
Resistance measurements from lOOpI tb’3OOM62.
TRMS AC voltage measurements from 1pV to 300V.
DC current me&urements from lnA to 3A.
TRMS AC current measurements from lnA to 3A.

INFORMATION

1.4 MANUAL ADDENDA

In addition to the above~ mentioned measurement
capabilities, the Model 196 can make:AC dB voltage and
current measurements.

Information concerning improvements or changes to the
instrument which occur after the printing of this manual
will be found on an addendum sheet included with the
manual. Be sure to review these changes before attempting to operate or service the instrument.

1.2 FEATURES

1.5 SAFETY SYMBOLS AND TERMS

Some important Model 196 features include:

The following safety symbols and terms are used in this
manual or found on the Model 196.

10 Character Alphanumeric Display-Easy to read 14segment LEDs used for readings and front panel messages.
*High Speed Measurement Rate-l000 readings per
second.
l Zero-Used
to cancel offsets or establish baselines. A zero
value can be programmed from the front panel or over
the IEEE-488 bus.
l Filter-The
weighted average digital filter can be set from
the front panel or over the bus.
l Data Store-Can
stoti tip to 500 readings and is accessl%le
only over the bus.
l Digital Calibration-The
instrument may be digitally
calibrated from either the front panel or over the bus.
l User Programmable Default Condition&&y
inshument
measurement configuration can be established as the
power-up default conditions.
l Translator Softwze-User
defined words (stored in nonvolatile memory) can be used to replace standard command strings over the IEEE-488 bus.
l Offset Compensated Ohms-Used
to correct for small error voltages in the measurement circuit.
l

symbol on the instrument denotes that the user
The A
should refer tom
the -operating instruction iq this manual.
The I/y on the instrument denotes that a potential of
300V or more may be present on the terminal(s). Standard
safety practices should be observed when such dangerous
levels are encomitered.
The WARNING used in this manual explains dangers that
could result in personal injury or death.
The CAUTION used in this manual explains hazards that
could damage the instrument:

1.6 SPECIFICATIONS
Detailed Model 196 specifications may be found preceding
the 7hble of Contents oft &is manual. ~. ~~~~

l-l

1.7 INSPECTION

1.9 GETTING

The Model 196 System DMM was carefully inspected, both
electrically and mechanically before shipment. After unpacking all items from the shipping carton, check for any
obvious signs of physical damage that may have occurred
during transit. Report any damage to the shipping~agent.
Retain and use the original packing materials in case reshipment is necessary. The following items are shipped with
every Model 196 order:

The Model 196 System DMM is a highly sophisticated instrument with many capabilities. To get the instrument up
&id running quickly use the following procedure. For complete information on operating the Model 196 consult the
appropriate section of this manual.

Model 196 System DMM
Model 196 Instruction Manual
Safety Test Leads (Model 3751)
Additional accessories as ordered.

1. Plug the line cord intom~the
rear anel power jack and
plug the other end of the cordpinto an appropriate,
grounded power source. See paragraph 2.2.1 for more
complete information.
2. Press in the POWER switch to apply power to the inshument. The instrument will power up in the 3CW DC
*ange.

Jf an additional instruction manual is required, order the
manual package (Keithley Part Number 196-901-00). The
manual package includes an instruction manual and any
applicable addenda.

1.8 USING THE MODEL 196 MANUAL
This manual contains information necessrny for operating
and servicing the Model 196 System DMM. The information is divided into the following sections:
Section 1 contains general information about the Model
396includiig that necessary to inspect the instrument and
get it operating as quickly as possl%le.
l Section
2 contains detailed operating information on
using the front panel controls and programs, making connections and basic measuring techniques for each of the
available measuring functions.
l Section 3 contains the information necessary to connect
the Model 196 to the IEEE488 bus and program operating
modes and functions from a controller.
l Se&on
4 contains performance verification procedures
for the instrument. This information will be helpful if you
wish to verify that the instrument is operating in compliance with its stated specifications.
l Section 5 contains a description of operating theory.
Analog, digital, power supply, and IEEE-488 interface
operation is included.
0 Section 6 contains information for servicing the instrument. This section includes information on fuse replacement, line voltage selection,
calibration
and
troubleshooting.
l Section 7 contains replaceable parts information.
l

1-2

STARTED

Power up

Making Measurements
‘L Connect safety~shrouded testyleads to the front panel
VOLTS H.I and LO input terminals. Make sore the INPUT switch on the rear panel is in the in (FRONT)
position.
2. To make a voltage measurement, simply connect the input leads to a DC voltage source (up to 3OOV)and take
the reading from the display.
3. To change to a different measuring function, simply
press the desired function button. For -pie,
to
measure resistance, press the OHMS button.
Using Front P.&e1 Programs
Program selection is accomplished by pressing the PRGM
button followed by the button(s) eat corresponds to the
program number or name. For example, to select Program
31 (IEEE), press the PRGM button and then the 3 and 1
buttons. ‘Ihble 2-7 lists and briefly describes the available
front panel programs. Once a program is selected the
following general rules will apply:
1. A displayed program condition can be entered by pressi”p the ENTER button.
2. Program conditions that prompt the user with a flashing
digit can be modified using the data buttons (0 through
9 and i).
3. Programs that contain alternate conditions can be
displayed by pressing one ofthe range buttons. Each
press of one of these buttons toggles the display between
the two available conditions.

GENERALINFORMATION

4. A program will be executed when the ENTER button is
pressed.
5. A program can be exited at any time and thus not eyecuted, by pressing the PRGM button.
Paragraph 2.7 provides the detailed information for using
the front panel programs.

1.10 ACCESSORIES
The following accessories are available to enhance the
Model l96s, capabilities.
Models lOl9A and 1019s Rack Mounting Kits-The Model
~1019Ais a stationary rack mounting kit with two front
panels provided to enable either single or dual side-by-side
mounting of the Model 196 or other similar Wthley instruments. The Model 10195 is a similar rack mounting kit
with a sliding mount configuration.
Model X301 Temperature Probe-The Model 1301 is a rUgged low cost temperature probe designed to allow temperature measurements from -55 to I5O’C.
Model 16008 High Voltage Probe-The Model 16008 extends
DMM measurements to 40kV.
Model 165150Ampere Current Shunt-The Model 1651 is
an external 0.00161 +J% 4terminal shunt, which permits
current measurements from 0 to 50A AC or DC.
Model l&31 Clip-On Test Lead Set-The Model l68l’con
tains two leads, 1.2m (4 ft.) long terminated with banana
plugs and spring action clip probes.
Model 1682A RF Probe-The Model 1682A permits voltage
measurements from lOOkHato 25OMHz. AC to DC transfer
accuracy is *ldB from lOOkFIr to 25OhJH.z at IV, peak
responding, calibrated in RMS of a sine wave.
Model 1685 Clamp-On AC Probe-The Model 1685
measures AC current by clamping on to a single conductor. Interruption of the circuit is unnecessary. The Model
1685 detects currents by sensing the chsnglng magnetic field
produced by the current~flow.

Model 1754 Universal Test Lead Kit--The Model 1754 is a
12 piece test lead kit, with interchangeable plug-in accessories. Included in the kit is one set of test leads (l-red,
l-black), two spade lugs, two standard b-a
plugs, two
phone tips (0.06 DIA.), two hooks and miniature alligator
clips (with boots).
Model 5804 Test Lead Set-The Model 5804, used for
4terminal measurements, includes: two test probes with
spring-loaded plunger clip adapters to fit test probes, two
spring-loaded plunger test clips with in-line banana jacks,
and four solid copper alligator clips with insulator boots.
Model 5805 Kelvin Probes-The Model 5805 includes two
spring-loaded Kelvin test probes (one red, one black), with
48-inch banana plug cable assemblies. A set of eight replacement contacts for the Model 5805 Kelvin test probes
is also available (Keithley PIN CS-551).
Model 5806 Kelvin Clip Lead Set-The Model 5806 includes
~twoI+in clip test lead assemblies with banana plug termination (one red, one black). A set of eight replacement
rubber bands for the lviode1~5806is also available (Keithkey
PIN GA-22).
Model 7087 IEEE-&3 Shielded Cables-The Model 7007 connects the Model 196 to the IEEE-488 bus using shielded
cables to reduce electromagnetic interference (EMI). The
Model 7Ow-1is one meter in length and has a EMI shielded IEEE-488 connector at: each end. The Model 7007-2 is
identical to the Model 7007-1, but is two meters in length.
Model 7088 IEEE488 Cables-The Model 7008~connects the
Model 196 to the IEEE-488 bus. The Model 7008-3 is D.9m
(3 ft.) in length and has a~standard IEEE488 connector at
each end. The Model 7008-6 cable is identical to the Model
7008-3, but~is 1.8m (6 ft.) in length.
Model 8573A IEEE488 Interface--The Model 8573A is an
IEEE1188 standard interface designed to interface the IBM
PC or XT computers to Keithley instrumentation over the
~IEEE-488 bus. The interface system contains two distinctive parts an interface board containing logic~to perform
the necessary hardware functions and the handler software
(supplied on disk) to perform the required control functions. These two important facets of the Model 857ZA join
together to give the IBM advanced capabilities over
lXE-488 interfaceable instrumentation.

Model I751 Safety Test Leads-Finger gu$.s and shrouded
banana plugs help minimize the chance of making contact
with live circuitry.

l-311-4

SECTION 2
BASIC DMM OPERATION
2.1 INTRODUCTION
Operation of the Model 196 can be divided into two general
categories: front panel operation and IEEE-488 bus~operation. This section contains information necesssay to use the
instrument from the front panel. Theses functions can also
be programmed over the lEFE-488 bus, as described in Section 3.

2.2 POWER UP PROCEDURE

2.2.1 Line Power
Use the following procedure to connect the Model 196 to
line power and power up the instrument.
1. Check that the instrument is set to correspond to the
available line power. When the instrument leaves the factov, the internally selected line voltage is marked on the
rear panel. Ranges are 105W25V or 2kW!5OV 5016OHz
AC. If the line voltage setting of the instrument needs
to be changed, refer to Section 6, paragraph 6.2 for the
procedure. If the line frequency setting of the instrument
needs to be checked and/or changed, utilize front panel
Program 32 (see paragraph 2.7.8) after the instrument
completes the power up sequence.
2. Connect the female end of the power cord to the AC
receptacle on the rear panel of the instrument.~Connect
the other end of the cord to a grounded AC outlet.
WARNING
The Model 196 is equipped with a 3-wire power
cord that contains a separate ground wire and
is designed to be used with grounded outlets,
When proper connections are made, instrument
chassis is connected to power line ground.
Failure to use a gmunded outlet may result in
personal injury or death because of electric
shock.

CAUTION
Be sure that the power line voltage agrees with
the indicated range on the rear panel of the instrument. Failure to obsenre this precaution
may result in instrument damage.

2.2.2 Power Up Sequence
The instrument can be turned on by pressing in the front
panel POWER switch. The switch will be at the inner most
position when the instrument is turned on. Upon ower
up, the instrument will do a number of tests on itse 9 Tests
are performed on memory (ROM, RAM and ETROM). If
RAM or ROM fails, the instrument will lo& up. If ETROM
FAILS, the message ‘TINCAL!’ will be displayed. See paragraph 67.2 for a complete description of the power up self
test and recommendations to resolve failures.

2.2.3 Default Conditions
Default conditions can be defined as setup conditions that
the instrument will return to when a particular feature or
command is asserted. The Model 196 will return to either
factory default conditions or user saved default conditions.
Factory Default Conditions
Atethe factory, the Model 196 is set up so that the instrument is configured to certain setup conditions on the
initial power up. These factory default conditions are listed
in Tables 2-l and 37 (located in Section 3). If alternate setup
conditions are saved (see User Saved Default Conditions),
the instrument can be returned to the factory default conditions by running Program 37 (Reset). To retain the factory default condihons as power-up default conditions, run
Program 30 (Save} immediately after executing kograrn 37
(Reset).
Sending device-dependent comman d I.0 over the IEEE-488
bus is equivalent to running Program 37 (Reset) and then
Program 30 (Save).

2-l

Table 2-1. Factory Default Conditions
kfault Condition

Control/kahw

Zero value (rrogram ZERO)
dB
dB Reference Value
(program dB)
Filter
Filter Value (Program FILTER)
MX+B Status (Program 4)
MX+B Parameters (Program 34)
Multi lexer (Program 6) ‘-’
HI/LB /l’ASS~~(l’rogrsm
5)
HI/Lo Limits (Program 35)
Ohms Compensation (Program R1)

DCV
3cQV
6% Di ‘ts
Diiabgd
000.0000
Disabled
1.000000
Disabled
lo
Disabled
M=1.0OWOO~;~~
3=000.0000
Enabled
Disabled
+3.030000,
-3.o3clooo
Disabled

NOTE: The Model 196 is initially set for an IEEE address
of 7. The line frequency is set to 50 nor6OHz.
User Saved Default Conditions
Each function oft the Model 196 “remembers”~ the last
measurement configuration that it was set up for (such as
range, zero value, filter value, et+ Switching back and forth
between functions will not affect the unique tonfiguratioq
of each function. However, the instrument will “forget” the
configurations on power-down unless they are saved.
Unique setup conditions can be saved by running front
panel Program 30 (Save) or by sending device-dependent
command Ll aver the IEBE-488 bus. These~tiser saved
default conditions will prevsjl over the factory default conditions on power-up, or when a DCL or SDC is asserted
over the bus.
IEEE Address and Lie

Frequency

Any IEEE address and line frequency setting can be saved
as default conditions by running Program 30 (Save) or by
sending Ll over the bus. See paragraph 2.7 for complete
information on Programs 31 (IEEE Address) and 32 (Line
Frequency).

NOTE
An ‘TJNCAI!’ error will set the IEEE address to 7
and the line frequency to 6OHz.
2-2

2.3 FRONT PANEL FAMILIARIZATION
The front panel layout of the Model 196 is shown in Fiie
Z-l. The following paragraphs describe the various components of the front panel in detail.

2.3.1 Display and Indicators
Display-The 10 character, alphanumeric, LED display is
used to display numeric conversion data, range and function mnemonics (i.e. mv) and messages.
Function Indicators-The indicator that is on identifies
which of the five operating functions is currently selected.
Rsnge Jndicator-When the instrument is in autorange the
AUTO indicator light will be on.
Modifier Indicators-When the zero feature is enabled, the
ZERO indicator will torn on. When filter is enabled, the
FKTER indicator will turn on.
IEEE Status Indicators-These three indicators apply to instrument operation over the IEEE-488 bus. The RMT indicator shows when the instrument is in the IEEE-488
remote state. The TLK and LSN indicators show when the
instrument is in the talk and listen states respectively. See
Section 3 for detailed information on oueration over the
bus.

2.3.2 Controls
.&lI front panel co&ols, except the POWER and C%L
ENABLE switches, are momentary contact switches. Indicaton are located above certain buttons to show that they
are enabled. Some buttons have secondary functions that
are associated with front panel program operation. See
paragraph 2-7 for detailed information on front panel
prOg.3lllS.
El POWER-The POWER switch controls AC power to
the insbxment . Depressing and releasing the switch once
tams the power on. Depressing and releasing the switch
a second time turns the power off. The correct positions
footi\and off are marked on the front panel by the POWER

El FUNCTION GROUP
DCV-The DCV button places the instrument in the DC
volts measurement mode. The secondary function of this
button is to enter the i sign. See paragraph 2.6.4 for DCV
measurements.

BASIC DMM OPERATION

El

Figure 2-1. Model 196 Front Panel
ACV-The ACV button places the instrument in the AC volts
measurement mode. The secondary function of this button is to enter the number 0. See paragraph 26.7 for ACV
measurements.
&The fl button places the instrument in the ohms
measurement mode. The secondary function of this button is to enter the number 1. See paragraph 2.6.6~for
resistance measurements.
DCA-The DCA button places the instrument in the DC
amps measurement mode. The secondary function of this
button is to enter the number 2. See paragraph 26.8 for
DC4 measurements.
ACA-The ACA button places the instrument in the AC
amps measurement mode. The secondary function of this
button is to enter the number 3. See paragraph 2.6.8 for
ACA measurements.
!zl

RANGE GROUP

Manual-Each time the A button is pressed, the instrument will move up one range, while the V button will move

the instrument down one range each time its is
pressed. Pressing either of these buttons will cancel
autorange, if it was previous selected. The secondary functions of these buttons are tom
enter the number 4 (V) and
number 5 (A).
AUTO-The AUTO button places the instrument in the
autorange mode. While in this mode, the instrument will
go to the best range to measure the applied signal.
Autoranging is available for all functions and ranges.
Autoranging may be cancelled by pressing the AUTO button or one of the manual range buttons. The secondary
function of this button is to enter the number 6.

ZERO-The ZERO button turns on the ZERO indicator and
causes the displayed reading to be subtracted from subsequent readings. This feature allows for zero correction or
storage of baseline values. The secondary function of this
button is to select the ZERO program and enter the number
Z Refer to paragraph 2.62 for detailed information on the
zero feature.

2-3

SAS\C DMM OPERATION

FIUER-The FIWER button turns on the FIUEl7 indicator
and causes the instrument to start weighted averaging (1
to l/99) fhe readings. The factory default weighted average
is l/10,but may be changed using the PIITER program (see
paragraph 2.7.16). See paragraph 2.6.3 for filter operation.
Selectin the PILTEK rogiam is one of the secondary functionsof&isbutton.&eothersecondaryfunctionisto~nter
the number 8.
dB-The dB button places the inshument~~in the dB
measurement mode and may be used with the ACV and
ACA functions. Under factory default conditions, measurements are referenced to 1V or lmA. However, the dB program may be used to change the referqce @ell. ‘JTh$seconY
day function of this button is to select the dB program and
enter the number 9. See paragriph 2.6.9 for dB measurements.
El

CONTROL GROUP

PRGM-This button is used tom
enter the frontspanel program mode.

the LOCAL button will be inoperative. See Section 3 for
informa$on on operating the instnunent-over the IEEE488
bus.

2.3.3 Input Terminals

q

The ~inputterminals are intended to be used with safety
shrouded test leads to help minimize the possibility of contact with live cikuits. Note that the terminals sre duplicated
sideways on the rear panel and that the INPUT switch (also
located on the rear panel) determines which set of termin&
is Bctive.
VOLTS 0HMS~i-J.I akd LQ-l’he VOLTS OHMS Hl atid LO
terminals are used for making DC volts, AC volts and twowire resistance measurements.
AMPS and LO-The AMPS and LO terminals are used for
making DC current and AC cUrrent measurem&s.

OHMS SENSE HI and LO--The OHMS SENSE HI and LO
ENTER-This button is used to enter program parameters. terminals are used with the VOJXS OHMS HI and LO terThis button will also trigger a reading when the instruments minals to make four-wire resistance measurements.
is in a one-shot trigger mode.
El LQCA&When the instrument is in the IEEE-488
remote state (RM’I indicator on), the LOCAL button will
return the instrument to front panel operation. However,
if local lockout (LLO) was asserted over the IEEE-488 bus,

2-4

2.3.4 Calibration

Enable Switch

q

Calibration of the Model 196 can only be done if the CAL
ENABLE switch is in the enable position. See paragraph
6.4 for details.

BASIC DMM OPERATION

2.4 REAR PANEL FAMILIARIZATION

2.4.2 Connectors

and Terminals

The reax panel of the Model 196 is shown in Figure 2-2. ~~~pJ AC Receptacle-Power is applied through the supplied
power cord to the 3-terminal AC receptacle. Note that the
selected supply voltage is marked on the rear panel near
the line voltage switch.
2.4.1 Controls
ra

T TkTc TIC%TTA,-C

-t-L:-

a.r.2~L

-A,-~

the

hment

Iable lme voltage. see paragrapn 6.2 for the proset this switch.

L4INPUT-The

INPUT switch connects the instrument
to either the front panel input terminals or the rear panel
input terminals. This switch operates in same manner as
the power switch. The front panel input terminals are
selected when the switch is in the “in’ position and the
rear panel input terminals are selected when the switch is
in the “0uV position.

El
Input Terminals-The rear panel input terminals perform the same functions as the front panel input terminals.
Paragraph 2.3.3 contains the description of the input
terminals.

mu IEEE-488Carmector-This connector is used to connect the ins,e
nt to the IEEE-483 bus. IEEE interface
functions ym -rl-l
x5 14,&ed below the connector.

qEXTERNAL TRIGGER

Input-This BNC~connector is
used to apply pulses to trigger the Model 196 to take one
or more readings, depending on the selected trigger mode.

Figure 2-2. Model 196 Rear Panel

2-5

BASIC DMf.4OPERATION

I3 VOITMFXER COMPLETE Output-T% BNC output
connector provides a TTLcompatible negative-going pulse
when the Model 196 has completed a reading. It is useful
for triggering other inshumentation.

To optimize safety when measuring voltage in high energy
distribution circuits, read and use the directions in the
following warning.

2.4.3. Fuses
WARNING
Dangerous arcs of an explosive nature in a high
energy circuit can cause severe personal injury
or death. If the meter is connected to a high
energy circuit when set to a current range, low
resistance range or any other low impedance
range, the circuit is virtually shorted. Dangerous
arcing can also result when the meter is set to
a voltage range if the minimum voltage spacing
is reduced.

El LINE FUSE-The line fuse provides protection for the

AC power line input. Refer to paragraph 6.3.1 for the line
fuse replacement procedure.
El CURRENT FUSkhe
3A current fuse provides protection for the current measurement circoits of the instrument. Refer to paragraph 63.2 for the cwr$nt fuse replacement procedure.

2.5 ERROR DISPLAY MESSAGES
Table 2-2 lists and explains the various display messages
assodated with incorrect front panel operation of the Model
196.

When making measurements in high energy circuits use
test leads that meet the follcwing requirements:
l
l

Table 2-2. Error Messages
l

Message

Explanation

UNCAL

EIPROM failure on power up. See
paragraph 6.7.2.
Invalid entry while trying to select
program.
Overrange-Decimal point position
and mnemonics define function
and range (3kfl range shown).~Th:
number of characters in the
“OVERFLO” message defines the
display resolution (6Yzd resolution
shown).
Trigger received while still processing reading from last trigger.
Selecting dB with in&ument fitit
in ACV or ACA.
Pressing a range button while in
ACV dB or ACA dB.
196 in invalid state (i.e. dB function), when entering calibratioti
p*ogram.

NO PROGRAM
O.VERFLO KQ

TRIG-ERROR
AC ONLY
NO RANGE
CONFLICI

2.6 BASIC MEASUREMENTS
The following paragraphs describe the basic pwxdures for
making voltage, resJs@~ce, current, and~dBmeasurements.
2-6

Test leads should be folly insulated.
Only use test leads that can be connected to the circuit
(e.~,jz~~~~.clips,
spade lugs, etc.) for hands-off
Do not use test leads that decrease voltage spacing. This
diminishes arc protection and creates a hazardous
condition.

Use the following sequence when testing power circuits:
1. De-energize the circuit using the regular installed
connect-disconnect device such as the circuit breaker,
main switch, etc.
2. Attach the test leads to the circuit under test. Use appropriate safety rated lead~sfor this application.
3. Set the DMM to the proper function and range.
4. Energize the circuit using the installed connectdisconnect device and make measurenwnts without
disconnecting the DMM.
5. De-energize the circuit using the installed connectdisconnect device.
6. Disconnect the test~leads from the circuit under test.
WARNING
The maximum common-mode input voltage (the
voltage between inout LO and chassis around)
is 506J peak. Exceeding this value may create
s shock hazard.

BASIC DMM OPERATION

2.6.1 Warm Up Period
The Model 196 is usable immediately when it is first turned
on. However, the instrument must be allowed to warm up
for at least~two hours to achieve rated accuracy.

Example l-The instrument is set to the 3V DC range and
a maximum -3.03OOOOVis established as the zero value.
When -3.03OOOOVis connected to the input of the Model
196, the display will read O.OMlOOClV.
When +3.03OCEOVis
co.nnected to the input, the display will read +60600ooV.
Thus, the dynamic measurement range of the Model 196
is OV to 6.06V, which is 6060000 counts.

2.6.2 Zero
The zero feature serves as a means of baseline suppression
by aIlowing a stored offset value to be subtracted from
subsequent readings. When the ZERO button is pressed,
the instrument takes the currently displayed reading as a
baseline value. All subsequent readings represent~the difference between the applied signal level and the ~stored
baseline.
A baseline level can be established for any or all measurement functions and is remembered by each function. For
example, a 1OVbaseline can be established on DCV, a 5V
baseline can be established on ACV and a 1Okll baseline
can be established on OHMS. Theses levels will snot be
cancelled by switching back and forth between functioti.
Once a baseline is established for a measurement function,
that stored level will be the same regardless of what range
the Model 196 is on. For example, if 1V is established
as the baseline on the 3V range, then the baseline will also
be 1V on the 30V through 30lV ranges. A aem baseline level
canbeaslaigeasfullrange.
~~
NOTE
The followirg discussion on dynamic range is
based on a display resolution of 6% digits. At 5’/zd
resolution, the number of counts would be reduced
by a factor of 10. At 4Yzd resolution, counts would
be reduced by a factor of 100 and 3%d resolution
would reduce counts by a factor of 1000.
By design, the dynamic measurement range of the Model
196, at 6%-d@ resolution, is M)60000 counts.1 With zero
disabled, the displayed reading range of the instrument is
*303ooOO counts. With zero enabled, the Model 196 has
the capability to-display ~606OCOOcounts. This increased
display range ensures that the dynamic measurement range
of the instrument is not reduced when using a zero baseline
value. The following two examples will use the maximum
allowable zero values (3030000 counts and -3030008
counts) to show that dynamic measurement range wilI not
be reduced. It is important to note that the increased display
range does not increase the maximum allowable input level
to the instrument. For example, on the 3V range, the Model
196 will always overrange when more than k3.03V is connected to the input.

Example 2-Ihe instrument is still set to the 3V DC range,
but a maximum +3.03oOOOVia the zero level. When
+3.03oO~CGV
is connected to the input of the Model 196, the
display will read O.O@XtOOV
When Y3.0~
is connected
to the input, the display will read -6.06OOOCV.Thus the
dynamic measurements range of the instrument is -6.06V
to OV,which is still 6060000 counts.
Zero Correction-The Model 196 must be properly zeroed
when using the 3OOmVDC or the 3OOBrange in order to
achieve rated accuracy specifications. To use ZERO for zero
correction, perform the following steps:

z Disable zero, if presently enabled, by pressing the
2.
3.

4.
5.

ZERO button. The ZERO indicator will turn off.
Select the 3oOmVDC or the 30022 range.
Connect the test leads to the input of the Model 196 and
short them together.
If four-wire
resistance
measurements are to be made, connect and short all four
leads together. Allow any thermals to stabilize.
Note: At5% and 6%~digitresolution, low level measurement techniques need to be employed. Use Kelvin test
leads or shielded test leads. See paragraph 2.6.5 for low
level measurement considerations.
Press the ZERO button. The display will read zero.
Remove the short and connect thetest leads to the signal
or resistance to be measured.
Note: Test lead, resistance is also~compensated for when
zeroing the 3OO’Jrange with the above procedure.

Baseline Levels-Baseline values can be established by
either applying baseline levels to the instrument or by setting baseline values with the front panel ZERO program.
paragraph 27’15 contains the complete procedure for using
the ZERO program. To establish a baseline level by applying a level to the Model 196, perform the following steps:
1. Disable zero, if presently enabled, by pressing the ZERO
button. The ZERO indicator will turn off.
2. Sele&a function and range that is appropriate for the
anticipated measurement.
3. Chnect the desired baseline level to the input -of the
Model 196 and note that level on the display

2.7

BASIC DMM OPERATION

4. Press the ZERO button. The display will zero and the
ZERO indicator will be enabled. The previously
displayed reading will be the stored baseline. The rero
baseline value will also be stored in Program ZERO,
replacing the previous zero value.
WARNING
With ZERO enabled, a hazardous voltage
baseline level (rt4OV or more), not displayed,
may be present on the input terminals. If not
sure what is applied to the input, assume that
a hazardous voltage is present.

The factory default filter weighting is l/l@ but can be
changed to a weighting from 1 (l/l) to-1199 with the use
of the FILTER program. While in the program, the Model
196 will only display the denominator of the filter
Weighting. For example, if the current filter weighting is l/lo,
the FILTER program will display it as the value l0. Thus,
filter value as usecl in this discussion refers to the values
displayed by the Model 196 when in the FILTER program.
A falter value can be set for any or all measurement functions and is remembered by each function. For example,
a filter value of 20 can be set for DCV and a filter value of
53 can be set~for ACV These filter values will not be cancelled by switching back and forth between functions.

5. Disconnect the stored signal from the input and connect
the signal to be measured in its place. Subsequent~
readings will be the difference between the stored value An advantage of using the filter is to stabilize the reading
-ofa noisy input level. A consideration of filter usage is that
and the applied ‘signal.
the larger the weighting, the longer the response time of
the display. Perform the following procedure to use the
filter:
Notes:
1. Disablmg zero cancels the zero baseline value on that
selected function. However, since the zero value is
automatically stored in Program ZERO, the zero baseline
value can be retrieved by using the program as long as
the ZERO button is not ~againpressed (see paragraph
2.Xi5 for details). Pressing the ZERO button, thus enabling zero, will wipe out the previous baseline value in Program ZERO. Baselines established on other functions are
not affected.
2. To store a new baseline on a selected function, zero must
first be disabled and then enabled again. The new value
will be stored with the first triggered conversion. The
baseline value wi.lI also be stored as~the zero value in
Program ZERO, cancelling the previously stored value.
3. Setting the range lower than the suppressed value wi.lI
overrange the display; the instrument will display the
overrange message under theses conditions.
4. When the ZERO button is pressed to enable zero, the
ZERO indicator light will blink until an on scale reading
is available to use as a zero level.

2.6.3 Filter
The Model 196 incorporates two filters; a digital filter controlled from either the front panel or over the IEEE-438 bus,
and an internal filter controlled exclusively from over the
bus.
Digital Filter-The Model 196 utilizes a digital filter to attenuate excess noise present on input signals. This filter
is a weighted average type.

2-6

1. If it is desired to cb.eck and/or change the filter value,
utilize Program FIITER as explained in paragraph 27.16.
2. Press the FILTER button. The FILm indicator will turn
on.
Notes:
1. When the filter is enabled, readings will be filtered before
being displayed. See Digital Filter Theory.
2. Pressing the FILIER button a second time will disable
the filter.
3. After a reading is triggered (continuous or one-shot), the
FIITER indicator light will blink for three time constants.
A time constant is measured in readings. The number
of readings in one time constant is equal to the filter
value. For example, for a filter value of IO, one time constant~is equal to 10 readings and three time constants
would be equal to 30 readings. The blinking duration will
be shorter in the 3%d mode since that has the fastest
reading rate.
4. In a continuous trigger mode, a reading that is outside
the filter window wiIl cause the FILTER indicator to blink
for one time constant.
Digital Filter Theory-The mathematical representation of
the weighted average digital Elter is as follows:

AVG(t) = AVG(t-1) +

(new reading -AVG(t-I))
F

BASIC DMM OPERATION

displayed value will be the new reading, and weighted
averaging WilI start from this point. The step response was
one reding to tbis change. The window in the Model 196
filter is lO,OoOcounts for 6Yzd resolution, 1000 counts for
5Yzd, 7.00~
counts for 4Yzd and 10 counts for 31/2d.

where,
AVG(t) = displayed average
AVG(t-1) = old displayed average
F = weighting factor (filter value)
As with any filter, the Model 196 digital filter will affect
reading response time. The step response for this fiker~is
of the form:
step response = l-K’“+”
Where,

Internal Filter-In addition to the front panel digital filter,
an inter& running avenge digita~fiher & -cd when msking high ~oh$ion and high sensitivity rriek+reme$k qe
enable&able status of the filter is controlled over the IEEE
bus. However, under factory default conditions, the in&~ment powers up with the filter enabled. When enabled,
this filtering only occurs when the instniment is in the 5Yz
OI blh-digit resolution niode.

“K” is a constant based on the filter weighting~factor
Notes:

The step occurs when n=O. n=l is the first ream
the step, n=2 is the second reading, etc.

after

Therefore:
a+1
step response = l-

l- YF)
(

Example:
F=10
n=5

1. The front panel FILTER indicator light does not turn on
when the internal filter is activated. The indicator is only
used with the front~panel digital filter.
2. Contding
the internal filter (on/off) over the IEEE bus
is explained in paragraph 3.9.22.
3. In a one-shot trigger mode, the Model 196 will not output a reading until both filters have settled. Three time
constants are used to allow the filters to settle. A time
constant is measured in readings. The number of
readings in one time constant is equal to the filter value.
For example, for a filter value of lo,, three time constants
would be equal to 30 readings. If both the internal filter
and the front panel filter are in use, the time constant
is the sum of both filter values.
4. Filter windows for the internal filter function in the same
manner as the windows for the front panel filter.
However, the window sizes of the internal filter are much
bnaller than the front panel filter window sizes.

2.6.4 DC Voltage Measurements
The Model 196 can be.~used tommake DC voltage
measurements in the range oft-*XlOnV to k3OOV.Use the
following procedure to make DC voltage measurements.
Five readings sfter the step occurs, the display will be at
47% of the step change. After 10 readings (n=lO), the
display will be at 168% and after 20 readings, the display
wiU be at ~88%. The more the readings, the closer the
display will be to the step change.
To speed the response to large step changes, the Model 196
digital filter employs a “windo+ around the displayed
average. As long as new readings are within this window,
the displayed value is based on the weighted avemge equation. If a new reading is outside of this window, the

1. Select the DC volts fundion by pressing the DCV button.
2. Select a range consistent with the expected voltage or use
autorange.
3. Select the front or rear panel input terminals with the
INPUT switch.

NOTE

The 3oOmVDC range requires zero to be set in
order to achieve rated accuracy. The zero correction procedure can be found in paragraph 2.6.2.

2-9

BASIC DMM OPERATION

4. Connect the signal to be measured to the selected input
terminals as shown in Figure 2-3.
5. T&e the reading from the display

CAUTION:
MAXIFIUM INPUT = 300V RtlS. 425V PEAK
INPUT

RESISTANCE

= WJdiM:;Vs
300G: 10.llln

> IGIl

Thus, an e, of 0.635pV would be displayed at 6Yzd resolulion as an additional six diaits of noise on the Model 196.
To compensate for the dispgyed noise, use digital filtering
and then zero out the settled offset.
..~
.,
Shielding-AC voltages ‘Which &e extremely k&i cornpared with the DC signal may erroneously produce a DC
output. Therefore, if there is AC interference, the~~circuit
should be shielded with the shield connected to the Model
196 input Lo (particularly for low-level sources). Impropw
shielding can cause the Model 1% to behave in one or more
of the following ways:
1. Unexpected offset voltages.
2. Inconsistent readings between ranges.
3. Sudden shifts in reading.

To minimjze pick-up, keep-the voltage source and the
Model 196 away from strong AC magnetic sources. The
Figure 2-3. DC Voltage Measurements
voltage induced due to magnetic flux is proportional to the
area of the loop formed by the input leads. Therefore,
minimize the loop area of the input leads and connect each
m
signd at ody one point.
2.6.6 Low-Level Measurement Considerations
Accuracy Considerations-For
sensitive measurements,
other external considerations besides the Model I.96 will T&rmal EMFs-Thermal emfs (thermoelectric potentials)
affect the accumcy. Effects not noticeable wheti working are generated by thermal differences between the junction
with higher voltages sre significant in nanovolt and of dissimilar metals. These can be large compared to the
microvolt signals. The Model 196 reads only the signal signal which the Model 196 can measure. Thermal emfs can
received at its input; therefore, it is important that tb.is cause the following problems:
signal be properly bansmitted from the source. The following paragraphs indicate factors which affect accuracy noise, -1. Instability or zero offset is much higher than expected.
source resistance, thermal emfs and stray pick-up.
2. The reading is sensitive to (and responds to) temperature
changes. This can be demonstrated by touching the cirNoise and Source Resistance-The limit of sensitivity in
cuit, by placing a heat source near the circuit or by a
measuring voltages with the Model 196 is determined by
regular pattern of instability (corresponding to heating
the noise present. The noise voltage at the Model 1% inand air-conditioning systems or changes in sunlight).
put increases with sauce resistance.
3. To minim&e the drift caused by thermal emfs, use copper leads to connect the circuit to the Model 196. A
banana plug is generally suitable and generates just a
For high impedance sources, the generated ~noise can
few microvolts. A clean copper conductor such ss #lO
become significant when using the most sensitive mnge
bus wire is about the best for this application. The leads
(3COmV,6Yzd) of the Model 196. As an -pie
of deterto the input may be shielded or unshielded, as necessary.
mining e, (noise voltage generation due to Johnson noise
Refer to Shielding.
of the somce resistance), assume that the Model 196 is con4. Widely varying temperatwes within the circuit can also
nected to a voltage source with an internal resistance of
create thermal ends. Therefor& maintain Constant
lM0. At a mom temperature of 20°C, the p-p noise Voltage
temperatures to minimize these thermal ends. A cardgenerated over a bandwidth of lHz will be:
board box around the circuit under test also helps by
minimking air currents.
e, = 635xXP’~Rxf
5. The ZERO cOntro1can be used to null out constant offset voltages.
e, = 6.35 x lP
d/(1 x W) (1)
e, = 0.635fiV

2-10

BASICDMMOPERATION

2.6.6 Resistance

Measurements

The Model 196 can make resistance measurements from
lOO#-lto 3CGMtI.The Model 196 provides automatic selection of 2-terminal or 4terminal resistance measurements.
This means that if the ohms sense leads are not connected,
the measurement is done Zterminal. If the sense leads are
connected, the measurement is done 4terininaI. For
4terminal measurements, rated accuracy can be obtained
as long as the msximum lead resistance does not exceed
the values listed in Table 2-3. For best results on the 3008
3kQ and 3OkQranges, it is recommended that 4terminal
measurements be made to eliminate errors caused by the
voltage drop across the test leads which will occur when
2-terminal measurements are made. The Model 5806 Kelvin
Test Lead Set is ideal for low resistance 4terminal

especially the 3000 range. After offset-compep.sation is
enabled, the Model 1% should be properly zeroed.
To make resistance measurements, proceed as follows:
L Select the ohms function by pressing the Q button.
2. Select a range consistent with the expected resistance or

use autorange.
3. Select the f&t or rear panei input terminals using the
INPUT switch.
4. Turn offset-compensation on or off as needed, using Pmgram 0.

NOTE

Offset-Compensated Ohms-Offs&-compensated ohms is
used to compensate for voltage potentials (such as thermal
EMFs) across the device under test. This feature eliminates
errors due to a low level external voltage source configured
in series with the unknown resistor. Offsets up to KhnV
on the 3OOnrange and up to BlOmVon the other ranges
can be corrected with offset-compensation. This feature can
be used for both 2-terminal and 4terminal resistance
measurements up to 30k61.Offset-compensation is selected
through front panel Program !I (see paragraph 27.14).
During ohms offset compensated resistance measurements,
the Model 196 performs the following steps for each
conversion:
1. Makes a normal resistance meaS,mment of the device.
In general, this consists of sourcing a current thmu
the device, and measuring the voltage dmp acro~ tfz
device.
2. Turns off the internal -nt
source and again measures
the voltage drop across the device. This is the voltage
caused by an external source.
3. Calculates and displays the corrected resistance value.

If offset-compensatio~n is being used, the 3ooI1,
3ka and 3OkQranges require zero to be set in
order to achieve the best accuracy. The zero carrection procedure is located in paragraph 2.6.2.
5. For 2-terminal measurements connect the resistance to
the instnunent as shown in Figs 2-4. For 4terminal
measurements connect the resistance to the instrument
as shown in F&ire 2-5.

CAUTlON
The maximum input voltage between the HI
anti LO input terminals is 425V peak or 300V
RMS. Do not exceed these values or instrument damage may occur.
6. Take the reading from the’display.

SHKEf~D

n
w

Offset-Compensated ohms not only cowxts for small error voltages in the measurement circuit, but also compensates for thermal voltages generated withim the Model 196.
In normal ohms, these thermal EMF offsets are accounted
for during c&ration. Therefore, enabling offset-compensation wilI cause these offsets to appear in the’ readings,

NODEL 196

---

OPTIONAL SHIEY

I-

UNDER TEST

L---~-I

Figure 2-4. Two-Terminal Resistance Measurements

2-11

BASIC DMM OPERATION

OPTIONAL
-~~-

SHIELO
-

MODEL 196

Figure 2-5. Four-TerminalResistance Measurements

B.&rward bias the diode by connecting the red terminal
of the Model 196 to positive side of the diode. A good
diode will typically measure between 3OOnto IkQ.
C.Reverse bias the diode by reversing the connections
on the diode. A good diode will overrange the display.

Table 2-3. Resistance Ranges
Maximum Test Lead
6%d
Nominal
Resistance (Q) for
Range 1Resolutim I-Short 1 -3 Count Error (Wzd)
I
I
I

MODEL 196
CAUTION:
MAX I MUM INPUT = 300V RMS, 425V PEAK. 1O’V.H.
INPUT

IMPEDANCE = 1Hf-1SHUNTED BY < 120pF

Figure 2-6. TRMS AC Voltage Measurement
Notes:
1. With ohms compensation active (Progam a), the 61indicator light will blink when the ohms function is
selected.
2. Table 2-3 shows the current output for each resistance
range.
3. It helps to shield resistance greater than IOOkQto achieve
a stable reading. Place the resistance in a shielded
enclosure and electrically connect the shield to the LQ
input terminal of the instrument.
4. Diode Test-The 3kQ range can be used to test diodes as
MlOWS:
A. Select the 3kO range.

*5%d resolution only
NOTE: Typical open circuit voltage is 5V.

2.6.7 TRMS AC Voltage Measurements
The instrument can make TRMS AC voltage measurements
from l$I to 3OOV.To measwe AC volts, proceed as follows:
1. Select the AC volts function by pressing the ACV button.
2. Select a range con$stent with the expeqed voltage or use
autorange.
3. Select the front or rear panel input terminals using the
INPUT switch.

NOTE

There is a small amount of offset (typically 150
counts at 5%d) present when using the ACV function. Do not zero this level o-ut. Paragraph 2.6.10
provides an explanation of AC voltage offset.
4. Connecbthe signal to be measured to the selected input
terminals as shown in Figure 2-6.
5. Take the reading from the display.

2-12

BASIC DMM OPERATION

Clarifications of TRMS ACV Spedfications:

”

2.8.8 Current Measurements

Msximum Allowable Input-The following graph summarizes the maximum input based on ~the lWV*Hz
specification.

MAXIIIUH

INPUT

(DC or TRMS AC)

The Model 196 can m&e DC or TRW AC current measure:
ments from lnA (at 5Yrd resolution) to 34. Use the following procedure to make current measurements.
1. Select the DC current or AC current function by pressing the DCA or ACA button respectively.
I
2. Select a range consistent with the expected current or
use autorange.
3. Select the front or rear panel input terminals using the
INPUT switch.
4. Connect the signal to be measured to the selected input
terminals as shown in Figure 2-7.
5. Take the reading from the display.

TRt4S AC VOLTS

I

I

CAUTION:

FREOUENCY-HZ
~..-

MAXIMUM CONTINUOUS

INPUT=3A

_ ._..

Settling Time-lsec to within 0.1% of change in reading.
This the specification is for analog circuitry to settle and
does not in&de AID conversion time.
Notes:
1. See paragraph 26.10 for TRMS measurement conSid&
&iOllS.
2. When making TRMS AC voltage measurements below

45Hz, enable the front panel filter modifier to obtain
stable readings. A filter value of 10 is recommended.
3. To make low frequency AC mea%uenients in the range
of lOHz to 2oH.z:
A. The ACV function must be selected.
B. Digital filtering must be used to obtain a stable
reading.
C. Allow enough settling time before taking the reading.

Figure 2-7. Current Measurements

2.8.9 dB Measurements
The dB measurement mode makes it pocisible to compress
a large range of~measurements into a much smaller scope.
AC dB measurements can be made with the instrument in
the ACV or AC4 function. The relationship between dB
and voltage and currentxan be expressed by the followmg equations:

dB = 20 log

.%
0 Vw

2-13

At the factory the instrument is set up to be a dBV meter
when ACV dB is selected. dBV is defined as deciiels above
or below a 1V reference. The instrument will read OdBwhen
1V is applied to the input. The 1V reference is the factory
default reference. With ACA dS selected, the factory default
reference is lmA. The inskument will read OdBwhen lmA
is applied to the input.
Reference levels other than 1V and ImA can be established.
There are two methods that can be used to establish a dB
reference. One method is to use the zero feature. This
simply consists of applying a signal to the instrument and
pressing the ZERO button. That suppressed level& the dB
reference (OdBpoint). The alternate method is to utilize the
front panel dB program and enter the desired reference
value. An advantage of using the dB program is that-a
source is not needed to establish a reference.
The following procedure explains how to use the zero
feature to establish a reference:
1. Apply a voltage or current signal, that is to be used~as
the dB reference, to the input of the Model 196.
2. Press the ZERO button. The ZERO indicator will turn
on and the display will zero. The reference i?now
whatever the applied signal is.
3. Disconnect the signal from the instrument.
Program dB allows the user to check or change the dB
reference of the instrument. The recommended progmmmable voltage reference range is from lOpVto 9.99999v The
recommended programmabie current reference range is
from lOnA to 9.99999mA. Paragraph 27.77 contains the information needed for using the dB program.
AC dB Measurements-Perform
make dB measurements:

the following steps to

l. Select the ACV or ACA function.
2. Select the front or rear panel input terminals with the
INPUT switch.
3. Check and/or change the dB reference as previously
explained.
4. Connect the signal to be measured to the inputs of the
Model 196.

5. ktite,the

dB measurement mode by pressing the dB

6. Take the dB reading from the display.
WARNING
With dB enabled, a hazardous voltage baseline
level (~40V or more), not displayed, may be present on the input terminals. If not sure what is
applied to the input, assume that a hazardous
voltage is present.
dBm MeasurementiBm
is defined as decibels above or
below a lmW reference. dB~measurements can be made in
terms of impedance rather than voltage or current. Because
the instrument ~cannof directly establish impedance
referenws, a v&age reference must be calculated and
established for a particular impedance reference. Use the
following equation to calculate the voltage refenznce needed for a particular impedance reference:
For OdBm, V,., = JlmW

Z.,,

Example: Calculate the voltage reference needed to make
dBm measurements referenced to Mx)fi.
For OdBm, V,+ = ~O&lOlW:, 6OOQ
3 46

..,

= .77456v
Once the necessary voltage reference is known. it canbe
established in the Model 196 with the.dB program. Subsequent dBm readings will be referenced to the correspondin impedance reference. Table 2-4 lists the voltage
I 2 erences needed for some commonly used impedance
references.
dBW Measurements-dBW is defined as decibels above or
below a 1W reference. dBW measurements are made in the
same manner as dBm measurements; that is, calculate the
voltage reference for a particular impedance and set the instrument to it with the dB program. The only difference
between dBm and dBW is the reference point; ZmWvs 1W.
The following equation can be used to ca&Jate the voltage
reference:
For OdBW, V,, = dlW*Z,,

2-14

l

Table 2-4. Corresponding Voltage Reference Levels
for Impedance References
Reference
Impedance
(0
8
50
75
150
300
600
1000

Reference Voltage
Level for:
OdBm
OdBW
0.0894
0.2236
0.2739
0.3873
0.5477
0.7746
1.0000

V,f

for OdBm = -J lO?V*Z,

V,*t

for OdBW = 4 ZR,

2;828

2.6.10 TRMS Considerations
Most DMMs actually measure the average value of an input waveform but are calibrated to read its RMS equivalent.
This poses no problems as long as the waveform being
measured is a pure, low-distortion sine wave. For complex,
nonsinusodial waveforms, however, measurements made
with an averaging type meter can be grossly insccurafe.
Because of its TRMS measuring capabilities, the Model 196
provides accurate AC measurements for a wide variety of
AC input waveforms.
TRMS Measurement Comparison-The RMS value of a
pure sine wave is equal to 0.707 times its peak value. The
average value of such a waveform is 0.637 times the peak
value. Thus, for an average-responding meter, a correction
factor must be designed in. This correction factor, K can
be found by dividing the RMS valued by the average vsjue
as follows:
K = 0.707 / 0.637
= 1.11

resulting is no error in the average-type meter reading,
The situation changes with the half-wave rectified sine
wave. As before, the peak value of the waveform is IOV,
but the average value drops to 3.18V. The R&E value of
this waveform is 5V, but the average responding meter
wiUgiveareadingof35
(3.18xl.l~),~ealingan
MOT
of29.4%.
A similar situation exists for the rectified square wave,
which has an average value of 5V and an RMS value of 5.CW.
The average responding meter gives a TRMS reading of
5.55V (5 x Lll), while the Model 196 gives a TRMS reading
of 5V. Other waveform comparisons can be found in Table
2-5.
AC Voltage Offset-The Model 196, at 5%d resolution, will
typically display 150 counts of offset on AC volts with the
input shorted. This offset is caused by the offset of the
TRMS converter. This offset will not affect reading accuracy
and should not be zeroed out using the zero feature. The
following equation expresses how this offset (V,,) is added
to the signal input (V,.):
Disp1ayed reading = ’

@‘I=)’ + ‘V,,,)

Example: Range = 2VAC
Offset = I.50 counts (1.5mV)
Input = ZOOmVRMS
Display reading = 4 (2OOmV)’+ (1.5mV)
Lz J 0.04v + (2.25 x 10-v)
= .200005V
The offset is seen as the last digit which is not displayed
at5%d resolution. Therefore, the offset is negligible. If the
zero feature was used to zero the display, the I50 counts
of offset would be subtracted from Vj. resulting in an error
of 150 counts in the displayed reading.
Crest Factor-The crest factor of a waveform is the ratio of
its peak value to its RMS value. Thus, the crest factor
specifies the dynamic range of a TRMS instrument; For
sinusoidal waveforms, the crest is 1.414. For a symmetrical

By applying this correction factor to an weraged reading,
a typical meter can be designed to give the RMS equivalent.
This works fine as long as the waveform is a pure sine, butt square wave, the a& factor is unity
the ratios between the RMS and average values of different
waveforms is far from constant, and can vary considerably.
The crest factor of other waveforms will, of course, depend
on the waveform in question because the ratio of peak to
Table 2-5 shows a comparison of common types of RMS value will vsrj~ For example, the crest factor of a recwaveforms. For reference, the first waveform is an ordinary tang&u pulse is related to its duty cycle; as the duty cycle
sine wave with a peak amplitude of 1OVThe average value ~decreases, the crest factor increases. The Model 196 has a
of the voltage is 6.37V while its RMS value is ZO7V Jf we maximum crest factor of 3, which means the instrument
apply the 1.11 correction factor to the average reading, its will give accurate TRMS measurements of rectangular
can be seen thatboth meters will give the same reading,
waveforms with duty cycles as low as 10%.

2-15

BASIC DMM OPERATION

Table 2-5. Comparison of Average and TRMS Meter Readings

RMS

Value

Average
Responding
4&r Reading

,c Coupled
TRMS
Meter
Reading

Averaging
Meter
Percent Error

IOV

7.07v

7.07V

7.07V

0%

1ov

5.OOV

3.53v

5.oov

29.4%

Ul-Wave Rectified Sine

1ov

7.07v

7.07v

7.07v

0%

;quare

1ov

lO.ow

ll.lOV

lO.ooV

11%

1ov

5.cOv

5.55v

5.OOV

11%

Yaveform
iine
+,p------

ic Coupled
Peak
Value

0
0
la&Wave Rectied

+10-0

Sine

-?I-

Rectified Square Wave

~~~

IOV

Triangular Sawtooth

1ov

,ov
lfi

5.77v

ll.lV*

5.55v

q

1ov

lfi

5.77v

:.11fi-I)

3.6%

x 100

BASIC DMM OPERATION

Table 2-6. Front Panel Programs

2.6.11 dB Applications
Measuring Circuit Gain/Loss-Any poimin a circuit can
be established as the OdB point. Measurements in that circuit are then referenced to that point expressed in terms
of gain (+dB) or loss (-dB). To set the zero dB point proceed as follows:
1. Place the Model 196 in ACV and dB.
2. Connect the Model 196 to the desired location in then
circuit.
3. Press the ZERO button. The display will read OdB.
4. Gain/loss measurements can now be made referenced
to the OdB point.
Measuring Bandwidth-The Model 196 can be used to
determine the bandwidth of an amplifier as follows:
1. Connect a signal generator and a frequency counter to
the input of the amplifier.
2. Set the Model 196 to ACV and autorange.
3. Comect the Model 196 to the load of the amplifier.
4. Adjust the frequency of the signsI generator until a peak
AC voltage reading is measured on the Model 196. This
is the center frequency.
5. Press the dB button and then press the ZERO button.
The OdB point is now established.
6. Increase the frequency input~until the Model 196 reads
-3.OOdB. The frequency measured on the frequency
counter is the high-end Emit of the bandwidth.
7. Decrease the frequency input until the dB reading again
falls to -3.OOdB. The frequency measured on the signal
generator is the low-end limit of the bandwidth.
Note: The bandwidth of the Model 196 is typically 3oOkHz.
Do not use this application to check amplifiers that exceed
the bandwidth of the Model 196.
Determining Q-The Q of B tuned circuit~can be determined as follows:
1. Determine the center frequency and bandwidth as explained in the previous application (Measuring
Bandwidth).
2. Calculate Q by using the following formula:
Q ‘= Center Frequency/Bandwidth

2.7 FRONT PANEL PROGRAMS
There are I.7 programs available from the front panel of the
Model 196. These ~tiroamms are Listed in Table 26. The
following paragraphs describe and explain the operation
of each program.

Program
0 (Menu)
2 (Resolution)
4 (MX+B)
5 (HlILo/Pass)

Description
I

Display software level and list
available front panel
Programs
Change display resolution
(3Yzd, 4%d, 5%d or 6%d).
Enable MX+B program.
Enable/disable HI/LO/Pass

~~%lsaskus,
enable/disable
~multiplexer.
Save currem instrmnent set
3O(Save)
up.
Recall/modify IEEE address.
31 (IEEE Address)
Recall/modify line frequency
32 (Line Frequency)
setting (50/6OHz).
Enter self-test program.
33 (Self Test)
34 (MX+B Parameters; Recall/modify MX+B program
values.
Recalllmodify HI/LO limits.
3.5 (HI/Lo Liits)
Enter digital calibration
36 (Calibration)
mode.
Returns 196 to factory default
37 (Reset)
conditions.
n
Recall status, enable/disable
offset ~comoensation.
ZERO
Recall/modify zero value.
FluER
RecaWmocbfy falter value.
dB
Recall/modify dB reference
value.
6

W-9

Program Selection--Program selection is accomplished by
pressing the PRGM button followed by the button(s) that
corresponds to the program number or name. For example, to select Program 31 (IEEE Address), press the PRGM
button and then the “3” and ‘7” buttons.
Data Entry--Program data is applied from the front panel
using the data buttons. The data buttons consist of the but-~
t ons~labeled with the +-oolaritv sipn and numbers 0
through~9.~Data entry is &bmpl&hed”by pressing the appropriate number button at each cursor location. Cursor
location is indicated by the bright, flashing display digit.
The cu%or moves one digit to the right every time a number
is entered. After entering a number at the least significant
display digit, the cursor will move back to the most significantdiait; Polarity fi button) can be changed with the cmsor at &y display character.‘I’lus (+) is &plied and thus,
not displayed,

2-17

Once a program is selected, the following general Mes wiu
=PPlY:
1. A displayed program condition can be entered by pressim the ENTER button.
2. P&gram conditions that prompt the user with a flashing
digit (cursor) can be modified using the data buttons (0
through 9). Polarity (i button) can be changed with the
msor on any character. Plus (+) is implied and thus,
not displayed.
3. Program.5 that contain alternate conditions can be
display:d by pressing one of the range buttons. Each
press of one of these buttons toggles the display between
the two available conditions.
4. A program will be executed when the pressed ENTER
button causes the instrument to exit the program.
5. A program can be exited at any time and thus not executed, by pressing the PRGM button.

1.~Set the in+ument to the desired fun@iqn and range.
2. Press the PRGM button. The following prompt will be
displayed:
PROGRAM ?
3. Enter the number 2 by pressing the “2” button. The current resolution status will then be displayed. For example, if the selected function is currently set for 6% digits
of resolution, the following message v+l be displayed:
6% d
4. If an altered resolution is desired, use the manual Range
buttons to display the resolution. The V Range button
decreases resolution, while the A Range but&n increases resolution.
5. With the desired resolution displayed, press the ENTER
button. The instrument will return to the previously
selected function and range.

2.7.1 Program 0 (Menu)
Table 2-7. Display Resolution

This program displays the software revision levelsof the
Model 196 and lists the available front panel progr-.
Perform the following steps to use this program:
1. Press the PRGM button. The following prompt-will be
displayed:
PROGRAM ?
2. Enter the number 0 by pressing the “0” button. The software level of the instrument will be displayed, For example, if the software level is Bl, the following message
will be displayed:

Range

Available
Resolution

DCV

All

31/2d,4%d, 5Hd, 61hd

ACV

AU

3%d, 4%d, 5%d

Function

SOFTREV 81
3. Use the manual Range buttons to scroll through the front
panel programs. The A range button scmlls forward
while the y range button scrolls backward.
4 To exit from the menu, press the PRGM button. The instrument will retnrn to the previous operating state.

2.7.2 Program 2 (Resolution)
Program 2 selects the number of display resolution digits.
The resolution available is dependent on function and
range. Table 2-7 lists the display resolution availabie for the
various function/range combinations. Display resolution
can be set for each function and is remembered by each
function as long as the instrument remains powered up.
Resolution can be remembered after power-down by running Program 30 (Save). To change the display resolution,
perform the following procedure:

2-16

DCA

IAll
I

I AcAI-

( 3%d, 4%d, 5Yzd
I
3%d, 4Hd, Shd

2.7.3 Program 4 (MX+B)
This program allow3 the operator to automatically multiply
normal display readings (X) by a constant (M) and add a
constant (B). The result (Y) will be &played in accordance
with the formula, Y=MX + B. This program is useful when
slope calculations are required for a series of measurements.
The values of M and B can be char&
by utilizing Program 34. Perform the following steps to enable the MX t
B feature:
1. Set the Model 196 to the desired function and range.
2. Connect the signal to be measured (x) tvthe input of
the Model 196.

I

BASIC DMM OPERATION
,,
3. If the values of M and B need to be checked or changed,
do so using Program 34.
4. Press the PRGM button. The following prompt will be
displayed:

Table 2-8. Example MX + B Readings

PROGRAM ?

lzooomc

5. Enter the number 4 by pressing the “4” button. The current status of the MX+B program will be displayed. For
example, if the MX+B is currently disabled, the following message will be displayed:
MX+B OFF
6. Any range button will to&e the display to the alternate
MX+B status. Therefore, press a Range button and the
following message will be displayed:
MX+B ON
7. With the message “MX+B ON” displayed, press the
ENTER button to enable MX+B. The ins&rnent will
return to the function initially set.
8. AUsubsequent readings cr) wiJ.lbe the result of the equation: Y=MX+B.
Notes:
1. The hIX+B feature can be disabled by again running Program 4. While in the progxwn, press a range button until the message “MX+B OFF” is displayed and then press
the ENTER button.
2. Once h4X+B has been enabled, the Model 196 will show
the value of Y. If the value of Y is larger than can be
handled by the particular range, the overrange message
will be displayed, indicating the instrument must beswitched to a higher range.
3. User selected values of M and B will be stored within
the Model 196 until the power is turned off (unless saved
by Program 30). These constants will be used whenever,
X+B is enabled. Note however, that the value of B is
scaled according to the range in use. Example: A value
of 19.00000 entered for B is actually 19.0000OVwith the
instrument on the 30V range and 19O.OOOOV
with the instrument on the 3OO.oMxxT
range.
4.An example of readings that will be obtained when
MX+B is enabled is shown in Table 2-8. Each of the obtained values for Y assumes the following constants:
M=+1.5; B=+5.

~-2.5OOOOvDc
14.4500OVAC
11.00000kQ
*where M = +1.5 and B = +5.

2.7.4 Program 5 (HI/LO/Pass)
Program 5 is used to enable the HI/LO/PASSprogram. With
this program, the Model 196 will indicate whether or not
a specific reading falls within a prescribed range. The factory defa&L.Q limit is a negative full scale reading, with
the actual value depende~ntron function and range. Conversely, the factory’default y limit is a positive full scale
reading. With these f full scale limits, the Model 196 will
display the HI or Lo message for overrange readings and
the PASS message for oh-range readings. The HI and LO
limits can be set to any on-range value with Program.35
(HI/Lo Limits).
This feature is especially useful for component evaluation,
where certain component tolerances must be observed.
Once the limits are programmed into~the instrument, the
operator need only monitor the display messages to determine the integrity of the device. perform the following proceduIe to enable Program 5:
1. Select the desired function and range, and zero the inshument, if desired. These operating parameters cannot be changed once the program is active without exiting the program.
2. If the limits need to be checked or changed, do so using
Program 35.
3. Press the PRGM button. The following prompt will be
displayed:
PROGRAM ?
4. Enter the number 5 by pressing the “5” button. The
following message will be displayed briefly:
HI LO PAS5

2-19

BASIC DMM OPERATION

5. At this point, the instrument will run the program. No
numeric readings wilI be displayed. Instead, one of the
following messages will be displayed:
A. If the measured value is less than the low limit, the
following message will be displayed:

MUX ON
3. If the alternate multiplexer status is desired, press one
of the range buttons. The alternate status will be
displayed as follows:
MUX OFF

Lo
B. If the measured value is greater than the Mgh limit,
the following message will be displayed:

4. To enter the displayed multiplexer status, press the
VENTER button. The instrument will return to the
previous operating state.

HI
C. If the measured value falls within the high and low
limits, the following message will be displayed:
PASS
6. To disable the program, press the function button that
has the indicator light on. This will disable the~prZ@am
without changing the measurement parameters (i.e.
function, range, etc.) of the instrument.
~~~~
~~~>)

Notes:

1. L&its can be set using Program 35 with or without Program 5 enabled.
2. User selectable values of L and H will be stored within
the Model 196 until the power is turned off (unless saved
by Program 30). These constants will be used whenever
HI/LO/PASSis enabled. Note however, that the value of
L and H are scaled according to the range in use.
3. Pressingany ofthe front panel controls, &cept dB (unless
in AC), ENTER, and LOCAL, will disable the program
and select the feature associated with that button.

2.7.5 Program 6 (Multiplexer,

Auto/Cal)

The multiplexer autoical routines may be defeated by run-~
ning Program 6. Using the Model 196 with the auto zerokal
defeated increases measurement speed and is useful for
making high impedance DC voltage measurements which
can be affected by the input multiplexing. Perform the
-.
following steps to run this program:
1. Press the PRGM button. The following prompt will be
displayed:
PROGRAM ?
2. Enter the number 6 by pressing the “6”button. The current multiplexer status will then be displayed. For example, if the multiplexer is on, the following message~~*
be displayed:
~;~

2-20

NOTE
with the auto/Calmultiplexer disabled, the internal
zero and calibration are affected by changing the
nominal inout level. esneciallv on ohms and the
3OOVDCrange. WheneGer the’applied input level
changes, press the selected function button to perform an auto/Cal routine, otherwise substantial
errors will result. Zero and calibration may also be
affected by time. Thus, it is recommended that the
selected function button be pressed periodically.

2.7.6 Program 3O~(Save)
Program 30 saves current instrument conditions set up by
the user. These user programmed conditions will then
replace the previously saved default conditions on power
up. Also, an SDC or DCL asserted over the IEEE-488 bus
will return the instrument to these saved conditions.
The following instrument operating parameters are saved
by this program:
Function
Range
Resolution
Zero status (on/off) and value
Filter status (on/off) and value
ACdB status (on/off) and reference value
IEEE ~address ~.~
Line frequency setting
MX+B status (on/off) and values
HI&O limits
Ohms compensation status (on/off)
Perform the following procedure to use the save program:
1.~Sethup the instrument as desired or~run Program 37
(Reset) to return the instrument to the factory default
conditions.

BASIC DMM OPERATION

2. Press the PRGM button. The following prompt will be
displayed:
PROGRAM ?
3. Enter the number 30 by pressin
tons. The following message &

the “3” and “0” butbe displayed briefly:

SAVE
4. The following message will then be displayed:
ENTBR?
5. To save the instrument set up conditions, press the
ENTER button. The following message v$k~displayed
L..z^cL..
BNTBRBD
6. The instrument wi!.l return to the conditions set up in
step 1 and will now power up to those conditions.
Notes:

3. Ifit is desired to retain the displayed status value, proceed
to~step 4. To change the status value, enter the address
number (0 to 30).
4. With a valid status disulaved, mess the ENTER button.
The instrument will %rn to the previously defined
,stam
Notes:
1. If an invalid number is entered, the instrument wiIl exit
zrn@t$ program with the IEEE primary address being
2.To change the default address of the instrument, select
the desired IEEE address using this program and then
Program 30 (or Ll over the IEEE bus) to save it. Cvchng
power, Program 37 (Reset), or an SDC, DCL or Lb sen?
over the bus will not have any affect on the new default
address.
3. If the JEBE address is changed but not saved:
A. 2 cl&power will return the insmument to the default
B
.
B. Program 37 (Reset), or an SDC or DCL sent over the
bus wiB not have any affect on the current address.
C. Sending LO over the bus will not change the current
IEEE address, and will save that address as the power
up default address.
4, An /mCAfJ’ error d default the IEEE address to 7 and

1. TO exit the program without changing the previous
default conditions, press any front panel button except
the ENTBR button. The instrument will return to the
operating states set up in step 1.
the line frequency setting to 6OHz.
2. To return the instmment to the factory power up default
conditions, use Program 37 (Reset) and save the conditions using Program 30.
~~
2,7.8 Program 32 (Lht? Frequency)
3. When using this program, make sure that the rest~ofthe
instrument is in the desired operating state.
The Model I.96 does not automatically detect the power line
frequency upon power up.~~Thisprogram aLlowsthe user
to check the line frequency set
2.7.7 Program 31 (IEEE Address)
to select the alternate fmquenc$K&%e&Z%Z~~~
to either 5OH.zor 6oHz. Perform the folloxjng steps to check
Program 31 allow? the user to check and/ormodify the ad- and/or change the line frequencysetting of the yodel 196.
dress of the IEEE&B interface. The interface can be set to
address from 0 to 30 Detailed information on 1. Press the PRGM button. The following prompt will be
displayed.
bus rs prowded m Section 3. Perform the
!!Zo%g%ps
to use this program:
PROGRAM ?
1. Press the PRGM button. The following prompt will be
2. Enter the number 32 by pressing the “3” and “2” butdisplayeyed:
tons. The current line frequency setting will then be
displayed. J.f the instrument is currently set to 6OH.2,the
PROGRAM ?
following message @I be displayed:
2. Enter the number 31 by pressing the “3” and “1” butPRBQ=6OHz
tons. The IEEE address value will be displayed. Exampie: If the current primary address of the instrument is
7, the following message will :be displayed:
07

IE

2-21

BASIC DMM OPERATION

3. If the displayed frequency setting matches the available
line frequency, proceed to step 4. If the alternative line
frequency setting is needed, press one of the Range buttons. The display will toggle to the alternate frequency
setting as shown:
FREQ=5OHz
4. With the correct frequency setting displayed, press the
FJITER button. The instrument will return to the previous operating state.
Notes:
1. To change the default line frequency setting of the ins&~ment, select the desired setting using this prog;&% and
then Program 30 (or Ll over the IFEE bus) to save it. Cycling power, Program 37 (Reset), or an SDC, DCL or I.0
sent over the bus will not have any affect on the new
default setting.
2. If the line frequency setting is changed but not saved:
A. Cycling power, x~rsending an SDC~or DCL over the
bus will return the instrument to the default.s&&.
8. Program 37 (Reset) will not have any affect on the current setting.
C. Sending Lo over the bus will not change the current
line frequency setting, and will save that setting as
the default setting.
3. An “UNCAE’ error will default the IEEE address to 7 and
the line frequency setting to 6OHz.

2.7.9 Program 33 (Diagnostic)
Program 33 is a diagnostic program designed to switch on
tious switching PET’s, relays and logic levels to allow signal tracing through the instrument. Also, tests on the display and memcry are performed. Refer to paragraph 6.7.3 in
the maintenance section to use this program to troubleshoot
the instrument.

2.7.10 Program 34 (MX+B

Parameters)

This prqpm allows the operator to check/change the M
and B values for the MX+B feature (Program 4) of the
Model 196. The factory ower up default value of M is
lBOOOOO
and the value of i. 1s OOOOCKX.
To check/change the
values of M and B, proceed as follows:
1. Press the PRGM button. The following prompt will be
displayed:
PRO&AM

2-22

?

2. Enter the number 31 by pressing the “3” and ‘+I”buttons.
The current value of M will now be diip1ayed.X thefactory default value is the current value of M, then the
following message will be-displayed:
l.OLlONOM
3. If it is desired to retain the displayed M value, proceed
to step 4. If it is desired to modify the M value, do so
causingthe data buttons. Note that valid M values are in
the range of -9.999999 to +9.999999.
4. With a M value displayed, press the ENTER button.
5. The ctit%t~B value will now be displayed. If the factory
defualt~value is the current B value, the following
message will be displayed:
0000.000 B
Decimal point~position is determined by the mnge that
the instrument was on when t&s program was selected.
6. If it is desired to retain the displayed B value, proceed
to step Z If it is desired to modify the value of M, do
so usin the data keys. Notesthat the B value range is
fmm f %.ooolxlo-~ to i9999.999 (in&ding zero).
7. With a valid B value displayed, press the ENTER button. The instrument will return to the previously defmed state of operation.
Notes:
1. User se&ted &&s of M and B will be~st&ed &thin
the Model 196 until the power is turnedoff (unless saved
by Program 30). These constants will be used whenever
MX+B is enabled. Note however, that the value of B is
scaled according to the range in use. Example: A value
of 19.00000 entered for B is actually 19.O0XOVwith the
instrument on the 3OVrange and 19O.OOC0V
with the instrument in the 300V range.
2. The user can set the values for M and B as the power
up default values by running Program 30.

2.7.11 Program 35 (Hi/LO Limits)
Program 35 is used to set the high and low limits for t&
HI/LO/PASS program (l’rogram 5). The fa~ctorydefault
limits are +303X03 counts (Hl limit) and -3030300 counts
(LO limit). The actual value of the limits is dependent on
the range. For example, the factory default HI limit on the
3V ran e is 3.03OOoW,while the factory default HI limit ori
the3c8 range 1s 30.3ooo(N.Perform the following procedure
to~set HI and Lo limits:

BASIC DMM OPERATION

1. Place the Model 196 in the function and range that the
HI/LO/PASSprogram (Program 5) will be used.
2. Press the PRGM button. The folIowing prompt will be
displayed:
PROGRAM ?
3. Enter the number 35 by pressing the “3” and “5” buttons. The current LO limit wiII be displayed. For example, if the I.0 limit is the factory default value, the following message will be displayed:
-303.0000 Lo
Decimal point position is determined by the range that
the instrumentwas on when this program was selected.
4. If it is desired to retain the dis layed LO limit, proceed
to step 5. Otherwise, modify tKe &splayed value using
the data buttons. The IO limit must be in the range of
-3030000 to +3030000 counts.
5. With the desired LO lit
displayed, press the ENTFR
button. The current HI limit will be~dis la ed. For example, if the LO lit
is the factory d&I?
a t value, the
following message will be displayed:
303.0000 HI
Decimal point position is determined by the ran e that
the instrument was on when this program was seHe&d.
6. If it is desired to retain the displayed HI limit, proceed
to step 7. Otherwise, modify the displayed value using
the data buttons. The HI limit must be in the~range of
-3030000 to +3030ooo counts.
7. With the desired HI limit displayed, press the ENTER
button. The instrument will return to the previous
operating state.
Notes:
1. Userselected limits wiil be stored in the Model.196 until
power is turned off (unless saved by Program 30). These
constants
will be used whenever Program 5
@I/IAX?~SS) is enabled.
2. Limits set by the user will become the power up default
limits by running Program 30 (Save).
3. Entering an invalid value will result with the instrument
using the power up default limit.

2.7.12 Program 36 (Calibration)
The user can easiIy perform front panel digital calibration
by applying accurate calibration signals using Program 36.
The calibration signals can be either prompted default
values or numbers entered from the front panel. Paragraph
6.4.5 descriis the basic steps for using this program, while
paragraphs 6.4.7 through 6.4.12 provide the complete front
panel calibration procedure.

2.7.13 Program 37 (Reset)
Program 37 resets instrument set up parameters back to factory default conditions. The factory default conditions are
listed in Tables 2-l and 3-T’.Perform the following steps to
run this program.
1. Press the PRGM button. The following prompt will be
displayed:
PROGRAM ?
2. Enter the number 37 by pressing the “3” and “7” buttons. The following message will be displayed briefly:
RESET
3. The following promptwill then be displayed:

4. Press the ENTER button. The following message will be
displayed briefly and the instrument~will return to the
factory default conditions.
ENTERED
Notes:
1. Prwgram 37 (Reset) can be aborted by pressing any front
panel button, except the ENTER button, when the
prompt “ENTER?” is displayed. The instrument will
return to the previous operating state.
2. Once the instrument is reset to the factory default conditions with this program, Program 30 must be run if
it is desired to have the factory default conditions on
subsequent power ups.
3. Program 37 (Reset) will have no aifect on the current ISEE
address and line frequency setting.

2-23

SASIC DMM OPERATION

2.7.14 Program L!

the ranges. Example: If 1V DC is set to the zero value of
the 3V DC range, the zero value in the program wiil be
displayed as 1.000000. On the 30V DC range the zero value
will still be 1V DC, but will be expressed as 01.00000 in the
program.

The ohms offset compensation program is used to compensate for voltage potentials (such as thermal EMFs) across
the resistance to be measured. This feat&s can be used for
both 2-terminal and 4-terminal resistor measurements up
to 3OkR. Additional information on ohms offset compensation can be found in paragraph 2.6.6. Perform the following steps to use the ohms offset compensatron program:

Perform the following procedure to implement Program
ZERO.

1. Press the PRGM button. The following prompt wilJ be
displayed:

1. Press the PRGM button. The following prompt will be
displayed:

PROGRAM ?

PROGRAM ?

2. Press the Q button. The current status of ohms compen- 2. Press the ZERO button. The current zero value will then
be displayed. Example: If the instrument is on the 3OV
sation wiIl be dis layed. For example, if compensation
DC
range and the current zero value is +3V DC the
is currently disaEled, the following messages will bee
following
message will be displayed:
displayed:
COMPOFF
3. If the alternate status is desired ,gressoneoftheRange
buttons. The alternate status will e displayed as fo!.lows:
COME’ ON
4 With the desired compensation status displayed, press
the ENTER button.
A. If ohms offset compensation was enabled, the instrument will be placed in the ohms function with the
0 indicator light flashing.
B. If ohms offset compensation was disabled, the insnument will return to the previous 0 eraling state. When
light
the ohms function is selected, tKe B mdrcator
.’
will not flash.

03.00000 z

-~

3. If it is desired to retain the displayed zero value, press
the ENTER button. The instrument will return to the
previous operating state with the zero modifier enabled.
The displayed reading will reflect the entered zero value.
4. To modifythe zero value, enter the new value and press
the ENTER button. The instrument will return to the
previously defined state with the zero modifier enabled
using the newly entered zero value.
Note: The factory default power up zero value is OCKKICO.
If it is desired to have a different zero value displayed
on power up, modify the zero value using Program
ZERO followed by Program 30 to save it.

2.7.16 Program FILTER
Notes:
1. The lT iridicator~light reveals the status of ohms offset
compensation. With the ohms function selected, a
flashing 0 light indicates that compensation is enabled,
and conversely, a non-flashing Q light indicates that compensation is disabled.
2. The status of ohms offset compensation can be saved as
a power up default condition by running Program 30.

2.7.15 Program ZERO
Program ZERO allows the user to check or modify the,,zero
value. A complete explanation of the zero modifier can be
found in paragraph 2.6.2. Once a zero v&e is set on a
measurement function, that zero level is the same on all

2-24

Program FILTER allows the user to modjfy~the weighting
of the digital filter. Valid filter values are from 1 to 99. More
information concerning the filter can be found in paragraph
2.6.3.
Perform the following steps to check and/or modify the
filter value.
1. Select the desired function.
2. Press the PRGM button. The following prompt will be
displayed:
PROGRAM ?

BASIC DMM OPERATION

3. Press the FIITER button. The current filter value will then
be displayed. Example: If the filter value is 5, the following message wilI be displayed:
05

F

4. If it is desired to retain the displayed filter value, proceed to step 5. If it is desired to modify the filtervalue,
do so using the data buttons.
5. With the desired filter value displayed, press the ENTER
button. The instrument will return to the previously
defined state when the filter is enabled.
6. To check or change the filter value of another function,
select the function and repeat steps 2 through 5.
Notes:

referencepn power up, modify the reference using Program dB followed by Program 30 to save it.

2.8 FRONT PANEL TRIGGERING
With the instrument properly configured over the IEEE-488
bus, readings can be triggered from the front panel using
the ENTER button. The following paragraphs provide
general procedures for one-shot front panel triggering and
front panel triggering into data store.

NOTE

The procedures in this section require IEEE-488 bus
programming. Refer to Section 3 particukxly
paragraphs 3.9.7 (Triggering) and 3.9.9 (Data Store)
fx$t&
on progrsmming the instrument over the

l.The factory default power up filter value is 10. If it is
desired to have a different filter value on power up,
change the filter value using Program FILTER followed
by Program 30 to save it.
2. Entering a filter value of 00 wilI default the filter value
back to the previous value and return the instrum~ent~to
On power up, the instrument is in the continuous trigger
the previously defined state with the filter disabled.
mode with the conversion rate determined by the internal
time base. To lace the instrument in a state where each
press of the Ed
OR button wilI trigger one reading, perXJTE
2.7.17 Program dB
form the following general procedure:
Program dB allowsthe user to check and/or modify~the dB
reference. The programmable voltage reference can be up
to 9999999V and the rogr-able
current referencescan
be up to 9.99Y999mA. ?I et&d information on dB messurements is provided in paragraph 2.6.9. Perform the following steps to use this program:
1. Press the PRGM button. The following promptwiIl be
displayed:
PROGRAM ?
2. Press the dB button. The current reference level will be
displayed. Example: If the reference is 1V or lmA, the
following message wilI be displayed:
1.oocmoodB

1. ~Placethe instrument in the desired function and range.
2. mace the instrument in “one-shot on external trigger” by
sending ‘I7 over the IEEE-488 bus.
3. Press the LOCAL button to return control to the front
pill-d.
4. Each press of the ENTER button will trigger one reading.

2.8.2 Triggering Readings into Data Store
The front panel ENTER button can be used to trigger
reading into data store. In the one-shot trigger mode, each
ress of the ENTERbutton wilI store one readin in the
Euffer In the continuous trigger mode, the ENTE lf button
will start the storage process at the rate that was programmed over the IEEE-488 bus. Performthe following general
procedure to trigger readings into data store from the front
panel:

3. Modify, if desired, the dB reference level and press the
ENTER button. The recommended reference mnge is
lo/# to 9.999999V and l!lnA to 9999999mA. The ins&u-~ 1. Place the instrument in the desired function and range.
ment wilI return to the previously defined state.
2. place the instrument in the appropriate trigger mode:
A. To store one reading in the buffer after each press of
ENTERED
the ENTER button, send T7 (one-shot on external trigger) over the bus.
Note: The factory default power up voltage reference is
B. To store a series of readings in the buffer after the
1.OOOOOOV
with the instrument in ACV and 1M)OOOOmA
ENTER button is pressed, send~T6~(continuouson CCwith ACA selected. If it is desired, to have a~different
ternal trigger) over the bus.
2-25

3. Configure the storage interval and buffer size of the data
store by sending the appropriate Qn and I commands
over the bus (see paragraph 3.9.9).
4. Press the LOCAL button to return control to the front
panel.
5. Press the ENTER key to either store one reading in the
buffer or to start storage of a series of readings.

2.9 EXTERNAL

External

1. Connect the external trigger soum to the rear panel BNC
EXTERNAL TRIGGER INPUT ccinnector. The shield
(outer) part of the connector is connected to digital common. Since an internal pull-u ~re.?.istor is used, a
mechanical switch ma be used. ate however that debcmncing circuitry wiEyprobablyl! required to avoid improper &&e&g.

TRIGGERING

The Model 1% has two external BNC connectors on the
rear panel associated with instrument triggerinp. The EXTERNAL TRIGGER IiWUT connector allows the instrument to be triggered by other devices, while the
VOLTMETER COMPLETE OUTPUT connector allows the
instrument to triggerother devices.

2.9.1

To use the external trigger, proceed as follows:

Trigger

The Model 196 may be triggered on a continous~or oneshot basis. For each of these modes, the trigger stimulus
will depend on the selected trigger mode. In the continuous
trigger mode, the instrument takes a continuous series of
readings. In the one-shot mode, only a single reading is
taken each time the instrument is triggered.

CAUTION
Dq not exceed 30V between digital common and
chassis ground, or instrument damage may
occur.
2. Place the instrument in the “one-shot on external trigger” (T7) or “continuous on external trigger’ (T6) as explained in paragraph 3.9.7.
3. To trigger the instrument, apply a pulse to the external
trigger input. The instrument twill process a single
reading each time the pulse is applied (one-shot), or start
a continuous series of readings.
Note: External triggering can be used to control the fill rate
in the data store mode with the data store enabled and oneshot mode selected, each trigger will cause a reading to be
stored.

The external trigger input requires a fallin edge pulse at
‘ITL logic levels, as shown in Figure 2-8. Ebb
omaections to
the rear nanel !?XTERNAL TRIGGER INPUT iack should 2.9.2 Voltmeter Complete
be made with a standard BNC connector. If thei&rument
is in the external trigger mode, it will be triggered to take The Model 196 has an available output pulse that can be
readings while in either a continuous or one-shot mode used to trigger other instrumentaticm. A single TTL
when the negative-going edge of the external trigger pulse, compatible negative-going pulse (see Figure 2-9) will apOCCUIS.
pear at the VOLTMETER COMPLETE OUTPUT jack each
time the instrument completes a reading. To use the
voltmeter complete output, proceed as follows:
TRIGGERS ON
LEADING EDGE

1. Cmnect the Model 196 to the instrument to be triggered
with a suitable shielded cable. Use a standard BNC connector to make the connection to the Model 196.
CAUTION
Do not exceed 30V between the VOLTMETER
COMPLETE common (outer ring) and chassis
ground or instrument damage may occur.

Figure 2-8. External Trigger Pulse Specifications

2-26

BASIC DMM OPERATION

Figure 2$X Usesshielded cables with BNC connectors.
The Model 196~YOLTMETERcoMrmouTr~jack
should be connected to the Model 705 EXTERNAL TRIG
GER INPUT jack. The Model 196 EXTEXNALTRIGGEE
INPUT jack should be connected to the Model 7Ki
CHANNEL READY OUTPUT. Additional connections,
which are not shown on the diagram, will also be
necessary to apply signal inputs to the scanner cards,
~~~ as well as for the signal lines between the wanner and
the Model 196.
2. Place the Model 196 in “one-shot on external trigge~”0
as explained in paragraph 3.9.7.
3.
Program the Model 705 scan parameters such as first and
1’
last channel as required. Place the instrument in the
single scan mode.
4. lnstdl the desired scanner cards and make the re uired
input and output signal connections. See the MOi el705
Instruction Manual for details.,
5. Begin the measurement sequence by pressing the Model
705 START/STOPbutton. The Model 705 will close the
first channel and trigger the Model 196 t0 t&e a reading.
When the Model 196 completes the reading, it will higger the Model 705 to go to the next channel. The process repeats until all programmed channels have been
scanned.

2. Select the desired function, range, trigger mode, and
other operating parseters,
as desired.
3. In a continuous trigger mode, the ins@unent will output pulses at the conversion rate; each pulse will occur
after the Model I% has completed a conversion.
4. In a one-shot trigger mode, the Model 196 will output
a pulse once each time it is higgered.

REA?&JG

BEGIN NEXT
CONVERSION

LS TTL LOU 1
(025V TYPICAL)
I

1
I

Figure 2-9. Voltmeter Complete Pulse
Specifications

2.9.3 Triggering Example
As an example of using both the external trigger input and
the meter complete output, assume that the Model 196 is
to be used in conjunction with a Keithley Model 705 Scanner to allow the Model 196 to measure a number of different signals, which are to be switched by the scanner. The
Model 705 can switch up to 20 2-pole channels (20 singlepole channels with special cards such as the low-current
card). In this manner, a single Model 196 could monitor
up to 20 measurement points.

I /I

\I
MOOEL 705

I

By connecting’the triggering inputs of the two instruments
L__..,- ~~~
cogerner, a complete automatic measurement sequence”
could be performed. Data obtained from each measurement
point could be stored using the data store of the Model 196.
Once the Model 705 is programmed for its scan sequence,
the measurement procedure is set to begin. When the
Model 705 closes the selected channel, it triggers the Model
705 to scan to the next channel. The process repeats until
all channels have been scanned.

II

(I
To use the Model 1% with the Model 705, proceed as
follows:
1. Connect the Model 196 to the Model 705 as shown in

MODEL 196

Figure 2-10. External Triggering Example
2-271248

SECTION 3
IEEE-488 PROGRAMMING
3.1 INTRODUCTION

3.7

This section contains information on programming the
Model 196 over the IEEE-488 bus. Detailedinstructions fork
all programmable functions are included; however, infor3.8
mation concerning operating modes presented elsewhere
is not repeated here.
Additional IEEE-488 information is provided in the following appendices:
Appendix A-ASCII character codes and multiline interface command messages.

Appendix D-A detailed overview of the IEEE488 bus.
Also, a tear out card listing the device-dependent commands follows the appendices.
S&ion
3.2

3 contains the following infonnation:~

~_~~~~:

A Short-cut to IEEE-488 Operation: Gives a
simple step-by-step procedure for g+ng on the bus
as quickly as possible.

General Bus Command Programming: Outlines
methods for sendingg&&al bus commands to the
instrument.

3.9~

Device-Dependent Commands: Contains descrip-~
tions of most of the programmjng commands used
to control the instrument over the bus.

3.10

Using the Translator Mode: Describes an alternate
Prow naming method of using easily recognized
user-defined words in place of device-dependent
xommands.

3.11

Bus Data Transmission Times: Lists typical times
when accessing instrument data over the bus.

Appendix B-Progmmning information for using the FM
PC/XT computer with the Model 8573A interface.
Appendix C-Saniple programs using a variety of ef!rent
controllers with the Model 196.

Front Panel Aspects of- IEEE-488 Operation:
Describes the operation of the LOCAL key and bus
status indicators, and summarizes front panel
messages that may occur during bus operation.

3.2 A SHORT-CUT TO IEEE-488 OPERATION
The paragraphs below will take you through a step-by-step
procedure to get your Model 196 on the bus as quickly as
possible and program basic operating modes. Refer to the
remainder of S&ion 3 for detailed information on IEEE-488
operation and programming.
Step 1: Connect Your Model I96 to the Controller
With power off, connect the Model 196 to the IEEE-488 interface of the controller using a standard interface cable.
Some controllers such as the HI-85 include an integral
cable, while others require a separate cable. Paragraph 3.3
discusses bus connections in more detail.

3.3

Bus Connections: Shows typical methods for connecting the instrument to the bus.

34

Interface Function Codes: Defies IEEE standard
codes that apply to the instrument.

3.5

Primary Address Selection: Tells how to program
the instrument for the correct primary address.

Step 2: Select the Primary Address

3.6

Controller Programming: Demonstrates simple
programming techniques for a typical IEEE-488
controller.

Much like your home address, the primary address is a way
for the controller to refer to each device on the bus individually. Consequently, the primary addres~s of your
Model 196 (and any other devices on the bus, for that mat-

3-l

IEEE-488 PROGRAMMING

ter), must be the same as the primary address specified
in the controlletis programming language, or you will not
be able to program instrument operating modes and obtain data over the bus. Keep in mind that each device on
the bus must have a different primary address.
The primary address of your Model 196 is set to 7 at the
factory, but you can program other values between 0 and
30 by pressing PRGM, 3, 1, and then using the data en*
keys to change the primary address. Once the desired value
is displayed, press ENTER to program the value.
More detailed information on primary address selection is
located in paragraph 3.5.
Step 3: Write Your Program

OPERATING

REQUEST

DATA

Even the most basic operations will require that you write
a simple program to send commands and read back data
from the instrument. Figure 3-l shows a basic flow chart
that a typical simple program will follow. The programming
example below follows this general sequence. This program
will allow you to type in command strings to program the
instrument and display data on the computer CRT.
HP85 Progra mming Example-Use the simple program
below to send programming commands to the Model 196
and display the data string on the computer CRT.

PROGRAM

COMMENTS

10 REMOTE707
Send remote enable.
26 DISP L LCOMMAND’
’ j Prompt for command
string.
30 INPUT CB
Input the command string.
40 UUTPUT707;
CB
Send command string to
196
50ENTER707;

60 DISP A8
70 GOTO 20
80 END

3-2

A$

Get a r&ding from the
inshument.
~Diiplay the reading.
Repeat.

0

END

Step 4: Pmgram Model I.96 Operating Modes

Step 5: Get Readings from the Model I96

You can program instrument operating modes by sending
the appropriate command, which is made up of an ASCII
letter representing the command, followed by one or two
numeric parameters separated by commas for the corn-~
mand option. Table 3-l summarizes the commands used
to select function and range.

Usually, you will want to obtain one or more readings from
the Model 196. In the example program abcwe, a single
reading is requested and displayed after each command.
In other cases, you may wish to program the instrument
configuration& the beginning of your program, and then
obtain a whole series of measurements.

A number of commands can be grouped together in one
string, if desired. Also, you must terminate the command
or command string with the X character in order for the
instrument to execute the commands in question.

The basic reading string that the Model 196 sends over the
bus is in ASCII characters of the form:

If you are using the programming example from Step 3
above, simply type in the command string when prompted
to do so. Some example strings are given below.

where: N indicates a normal reading (0 tiould indicate an
overflow),
DCV shows the function in effect (in this case, DCV)
-1.234567 is the mantissa of the reading data,
E?-0~represents the exponent.

F3X: select DCA function.
FORZX: select DCV function, 3V range.

Table 3-1. IEEE-488 Commands

NDCV-l234567E+O

Used to Select Function

and Range

:ommandI
X

Execute other device-dep$w~commands.

FO
Fl

DC volts
AC volts
ohms
DC current
AC current
ACV dB
ACA dB
Offset compensated ohm.~~-

E
E
F6
F7

WY
RO
E
R3
R4
R5

Aa’

~~!lF!K

ACA

Ohms

Auto
Auto
Auto
300mV 3oOmV 3OOfi
3v
30
300
300
300
300

V
v

3v

30 V
300

v

V 300 V
V 300 V
V 300 V

Auto
Auto
300~2% 300 0
3mA
3mA
3k0
3OmA 30mA
30 kQ

3oomA

3 A
3 A
3 A

3ooti-TLiO~kQ

3 A
3Mfl
3 A
3OM!l
3 A 3OOMfl

ACV dB,

&CA dB

Auto
Auto
Auto
Auto

Auto
Auto
Auto
Auto
A&o
Auto
Auto
Auto

Auto

Auto
Auto
Auto

Offset Compensated
Ohms
Auto
300

I-i

3kt-l
3Ok’2

30 lit-l
30 kfl
30 kQ

30, kQ

3-3

3.3 BUS CONNECTIONS
The Model 196 is intended to be connected to the IEEE-488
bus through a cable equipped with standard IEEE-488 connectors, an example of which is shown in Figure 3-2. The
connector is designed to be stacked to allow a number of
parallel connections at one instrument;~~Twoscrews are
located on each connector to ensure that connections remain secure. Current standards call for metric threads,
which are identified with dark colored screws. Earlier versions had different screw& which were silver colored. Do
not attempt to use these type~~ofconnectors tin the Model
196, which is~aesigned for metric threads.

INSTRWENT

INSTRUMENT

CONTROLLER

Figure 3-3. IEEE-488

Connections

Connect the Model 196 to the IEEE-488 bus as follows:

Figure 3-2. IEEE-488

Connector

A typical connecting scheme for a multiple-instrument test
set up is shown in Figure 33. Although any number of connectors can be stacked on one instrument, it is recommended that you stack no more than three connectors on any
one unit to avoid possible mechanical damage.

3-4

1. Lime up thecable connector with the connector located
on the rear panel of the instrument. The connector is
designed so that it will fit only one way. Figure 3-4 shows
the location of the IEEE-488 connector on the instrument.
2. lighten the saew securely, but do not overtighten them.
3. Add additional connectors from other instruments, as
required.
4. Make certain that the other end of the cable is properly
connected to the controller. Most controllers are
equipped with an IEEE-488 style connector, but a few
may require a different~type of connecting cable. Consult the instruction manual for your controller for the
..
_..
proper connectmg metnoa.

IEEE-488 PROGRAMMING

Table 3-2. IEEE Contact Designation

contact

Number
1

ADDRES3ENTEREDWiTH
FRONT PANEL PROGRAM 31

;
4
7
i
lo
11
tz
14
FIgure 3-4. IEEE-488

Connector

Location

NOTE
The FEE-488 bus is limited to a maximum of 35
devices, incluiing the controller. The maximum
cable length is 20 meters, or 2 meters times the
number of devices, which ever is less. Failure to
observe these limits may result in erratic bus
operation.
Custom cables may be constructed by using the informafiOn in Table 3-2 and Figure 3-5. Bble 3-2 Ii& the COntad
assignments for the bus, and Figure 3-5 shows the contact

E
17
l8
19
20
ii
23
24

IEEE-488
Designation
DIOl
D102
D103
DI04
N-RFD
NDAC
ATN
SHIELD
DI05
D106
D107
DI08

Gnd,
Gnd,
Gnd,
Gnd,
Gnd.

*Numbersin parentheses refer to signal ground rehrn
of reference-d contact number. EOI and REN signal
lines return On contact 24.
3.4 INTERFACE

CAUTION
IEEE-488 common is connected
ground and cannot be floated.

r

CONTACT 12
-7

t

CONTACT 241

CONTACT I

FUNCTION

CODES

The interface function codes, which are part of the IEEE-488
standards, define an instmment’s ability to support various
interface functions, and they should not be confused with
programming commands found elsewhere in this manual.
Interface function codes for the Model 196 are listed in Table
3-3 and are listed for convenience on the rear panel adjacent to the IEEE488 connector. The codes define Model 196
capabilities as follows:
SH (Source Handshake)-SHl
defines the ability of the
Model 196 to properly handshake data or command bytes
when the unit is acting as a source.

I

I

to chassis

(8)*
(9)
(lo)*
(ll)*
LOGIC

Tyge
Data
Data
Data
Data
Management
Handshake
Handshake
Handshake
Management
Management
Management
Ground
Data
Data
Data
Data
Management
Ground
Giounii
Ground
Ground
Ground
Ground
Ground

\
L

J
CONTACT 13

Figure 3-5. Contact Assignments

AH (Acceptor Handshake&AH1 defines the ability of the
Model 196 to properly handshake the bus when it is acting as an acceptor of data or commands.
T (Talker)-The ability of the Model 196 to send data over
the bus to other devices is defined by the T function. Model
196 talker capabilities exist only after the instrument has
been addressed to talk.
3-5

L (Listener)-‘he L function defines the ability of the Model
196 to receive device-dependent data over the bus. Listener
capabilities exist only after the instrument has been addressed to listen.
SR (Service Request)--The SR function defies the ability
of the Model 196 to request services from the controller.
RL (Remote-Local)-The RL function defies the capabiligofe;vz Model 196 to be placed in the remote or local
PP (Parallel Poll)-I’he Model 196 does not have parallel polling capabilities.

3.5 PRIMARY

ADDRESS

SELECTION

The Model 196 must receive a listen cornman dbeforeitwill
respond to addressed co mmands over the bus. Similarly,
the instrument must receive a talk command before it will
transmit its data. These listen and talk commands are derived from the primary address of the instrument, which
is set to 7 at the factory. Until you become more familiar
with your instrument, it is recommended that you leave
the address at this value because the programming I+
amples in this manual assume the instrument is p10grammed for that address.

Model 196 does not have controller

The primary address can be programmed for any value between 0 and 30. However, each device on the bus must have
a unique primary address-- a factor that should be kept in
mind when setting the primary address of the Model 796.
Most controllers also use a primary address; consult the
controller instruction manual for details. Whatever address
is used, it must be the same as the value specified as part
of the controll& programming language.

TE (Extended Talker)-The Model 196 does not have extended talker capabilities.

To check the presently programmed primary address, or
to change to a new one, proceed as follows:

DC (Device Clear)-The DC function defines the ability of
the Model 196 to be cleared (iitialized).
DT (Device Trigger)-The ability for the Model 196 to have
its readings triggered is defined by the DT function.
C (Controller)-The
capabilities.

LE (Extended Listener)-The Model 196 does not have SC- 1. Press PRGM, 3,l. The current primary address will be
tended listener capabilities.
displayed. For example, if the current address is 7, the
following message will be displayed:
E (Bus Driver Type)-The Model 196 has open-colle$or bus
drivers.
07
IE
Table 3-3. Model 196 Interface

Function

Codes

Interface Function
Source Handshake cauabilitv
Acceptor Handshake capab&y
Talker (Basic talker, Serial poll, Unaddressed
to talk on LAG)
Listener (Basic listener, Unaddressed to listen
on TAG)
Service Request capability
Remote/Local capability
No Parallel Poll capability
Device Clear capability
Device Trigger capability
No Controller capability
Open Collector Bus Drivers
No Extended Talker capabilities
No Extended Listener capabilities-

3-6

2. To modify the address, key in a new value (O-30) with
the numeric data buttons.
3. With the desired address value displayed, press the
ENTER button. The address will be programmed and
the instrument wiUreturn to the previous operating state.
4. To store the address as the power up address, run Program 30.
Note: For detailed information on using Programs 30 and
31, refer to paragraph 2.7.

3.6 CONTROLLER

PROGRAMMING

A number of IEEE-188 controllers are available, each of
which has its-own programming language. In th$ section,
we will discuss the programming language for the HewlettPackard W-85.

IEEE-488 PROGFlAMMlNG

NOTE
amming
information
for using the IBM PC/XT
p=w
equipped with a Model 8573A IEEE-488 interface
is contained in Appendix 8.

3.6.1 Controller

Some~of the statements have two forms, with the exact configuration depending on the command to be sent over the
bus. For example, CLEAR 7 sends a DCL command over
the bus, while CLEAR 707 sends the SDC command to a
device with a primary address of 7.

Handler Software

a specific controller can be used over the IEEE-488
bus, it must have IEEE-488 handler software installed. With
some controllers like the HP-85, the software is located in
an optional I/O ROM, and no software installation is
necessary on the part of the user. In other cases, software
must be loaded tiooma diskette and initialized, as is the
case with the Model 8573A interface.
Before

Other small computers that can be used as IEEE-488 controllers may not support all IEEE488 functions. With some,
interface pro* amming may depend on the particulsx interface being used. Many times, little “tricks” are necessary
to obtain the desired results.
From the preceding discussion, the message is clear: make
sure the proper software is being used with the interface.
Often the user may incorrectly suspect that the hardware
is causing a problem, when it was the software all along.

3.6.2 BASIC Interface Programming
Statements
The progmmmin g instructions covered @ this section include examples written in HP-85 BASIC. This computer was
chosen for the examples because of its versatility in controlling the IEEE-488 bus. A partial list of statements for the
HP-85 is shown in Table 3-4.
HP-85 statements have a one or three digit argument~that
must be specified as part of the statement. The first digit
is the interface select code, which is set to 7 at the factory.
The last two digits of those statements requiring a 3-digit
argument specify the primary address. k the examples
shown, the default Model 196 address (7) is shown. For a
different address, you would of course change the corresponding digits in the programming statement.

Table 3-4. BASIC Statements Necessary to Send
Bus Commands

Action

1 HP-85 Statement
I

Transmits string to device 7.
Obtain string from device Z
Send GTL to device Z
Send SDC to device Z
Send DCL to all devices.
Send remote enable.
Cancel remote enable.
Serial poll device Z
Send Local Lockout.
Send GET to device.
Send IFC.

OUTPUT707;
A$
ENTER707;
A$
LUCAL 707
CLEAR 7’37
CLEhR 7
REMOTE 7
LrJCAL 7
SPOLL<707>
LOCAL LOCKUUT
TRIGGER787
ABURTIO 7

3.7 FRONT PANEL ASPECTS OF IEEE-488
OPERATION
The following paragraphs discuss aspects of the front panel
that are part of IEEE488 operation, including front panel
error messages, IEEE-488 status indicators, and the LOCAL
key.

3.7.1 Front Panel Error Messages
The Model 196 has a number of front panel error messages
associated with IEEE-488 programming. These messages
are intended to inform you of certain conditions that may
occur when sendine device-deuendent commands to the
instrument, as summarized in Table 3-5.
I

The following paragraphs discuss each of these messages
in detail. Note that the instrument may be programmed
to generate an SRQ (paragraph 3.9.X3), and the Ul error
word can be checked for specific error conditions
(paragraph 3.9.16) if any of these errors occur.

3-7

IEEE-488 PROGRAMMlNG

Table 3-5. Front Panel IEEE-488 Messages

Note that the NO REMOTE Errol message is briefly
displayed when the second statement above is executed.

IDDC

Instrument programkd Wifh REN
false.
Uegal Device-dependent Command
IDDC
Illegal Device-dependent Command
IDDCO
Option
TRIG ERROR Instrument triggered while it is still
urocessinc a urevious triczer.
SHORT TIME &xume~t c&-mot Store G&dings at
programmed interval. Readings will
be stored as fast as the instrument
can run.
BIG STRING
Programmed display message exceeds 10 characters.
CAL LOCKED Calibration command sent with
calibration switch in the disable
position.
I
Data Store-Instrument cannot store
CONFLICT
readmgs at a high speed interval (1
to 14ms) while in an invalid state.
Storage will not occur.

ilIIega.I Device-Dependent Command) Error

NO REMOTE

Calibration-Calibration com&tid is
ignored when instrument is~in a+ invalid state (i.e. dB function).
NOTE: Error messages associated with translator software
are located in paragraph 3.10.

An IDDC error ocCtis when the unit receives an invalid
command over the bus. For -pie,
the command string
EIX includes an illegal command because the letter E is not
part of the inshwmenl% programming language. When an
illegal command is received, the instrument will briefly
display the following enor message:
IDDC
To correct the error condition, send only valid commands.
Refer to paragraph 3.9 for device-dependent command pmgmmming details.
HP-85Rog? amming Fxampl~To demonstrate an IDDC error, use the following statements:
REMOTE 707
OUTPIJT 707;

* ‘ElXI

’

Note that the IDDC error message is briefly displayed when
the second statement above is executed.
IDDCO (Illegal b&ice-Dependent
Error

Cmnman d Option)

No Remote Error
A no remote error will occur if the instrument receives a
device-dependent command and the REN (Remote Enable)
line is false. In this instance, the following error message
will be displayed on the front panel:
NO REMOTE

Sending the instrument a legal command with an illegal
option that cannot be automatically scaled within bounds
will result in the following front panel error message:
IDDCO

The error condition can be corrected by placing the REN
line true before attempting to ~programthe instrument.

For example, the command WX has an iIlegal option (9)
that is not paruf ~theinstrument’s programming language.
Thus, aleough~ the cq$rna$ (Y) itseg is valid, the option
(9) is not, and the IDDCO err01 will result.

HP-85 Programming Example--To demonstrate the NQ
REMOT!Z error message, type in &e following lines:

To correct this error condition, use only valid command oplions, as discussed in paragraph 3.9.

LOCAL i
OUTPUT 707i

3-8

L ( RiX’

’

HP-85 Pm gmmming Example-Demonstrate an IDDCO error with the following statements:

IEEE-488 PROGRAMMlNG

REMOTE 707
OUTPUT 797; r r Y9X’ ’

Note that the IDDCO error message is briefly displayed
when the second statement above is executed.

Cd Locked Error
A cal locked error occurs when trying to calibrate the instrument over the bus with the front panel calibration
switch in the disable position. Calibration commands will
be ignored and the following message will be displayed
briefly:
CAL LOCKED

Trigger Ovemm Error
A trigger overrun error occurs when the instrument receives
a trigger while still processing a reading from a previous
trigger. Note that orily the overrun triggers are ignored.
These overrun triggers will not affect the instrument except to generate the message below. When a trigger overrun occurs, the foLIowing front panel message will be
displayed for approximately one second:

Short Time Error
A short time error occurs when the instrument cannot store
readings in the data store at the programmed interval (Q
tiriunand). However, the instrument will continue to store
readings as fast as itscan run. The following message is
displayed briefly when a short time error occurs:

TRIG ERROR
HP-85 Programming Example-To demonstrate~~~a
trigger
overrun error, enter the following statements into the W-85
keyboard:
REMOTE 707
OUTPUT 707; 6 ‘ T3X’ ’

SHORT TIME
HP-85 Pmgramming Example--To demonstrate a short time
error, enter the following statements into the computer:
REMOTE 707
OUTPUT707;~rQ100F2T2X”
TRIGGER707

TRIGGERi07iZTRIGGER707

Note that the trigger overrun message is displayed after the
END LINE key is pressed a third time.

When END LINE is pressed the thiid time, the instrument
wiU start storing readings in the buffer. However, since the
instroment cannot make resistance measurements (FZ) at
the selected interval (QlOO),short period errors will occur.

Big String Error
A big string error occurs when trying to &splay a message
(using the EDcommand) that exceeds 10 characters. Blank
display digits used in the message count~ascharacters. The
invalid message is ignored and the following message is
displayed briefly when a big string error occurs:
BIG STRING

Conflict Error
A conflict error occurs when trying to store readings at a
high speed interval (lms to 14ms) while the instrument is
in an invalid state. After sending a command string that~
contains the interval command(Q), the following message
is displayed briefly when a conflid error occurs:
CONFLICI

HP-85 Progr amming Example-Enter the following state:
ments into the computer to demonstrate a big string qror:
REMOTE 707
OIUTPUT 707; r r DH0U@ARECYOU?X~ ’

When END LINE is pressed the second time the big string
error will occur because the message is made up oft I2
characters.

The entire command string will be ignored and the data
store will not start.
Mid instrument states for high speed data storage are listed
in Table 3-U

3-9

A conflict error also occurs when trying to send a calibration command over the bus while the instrument is in an
invalid state, such as the dB function. The entire command
string is ignored when a conflict error occurs.
HP-85 Programming Example-Enter
the following
statements into the computer to demons&ate a CONFLXT
error:
REMOTE 707
OIJTPUT 707;

r LQlWX

s

When END LINE is pressed the second time, a conflict er-

ror will occur because data cannot be stored at the high
speed interval of lms (Ql) with the instrument in the ohms
function (F2). The entire command string will be ignored.

3.7.2 IEEE-488
Key

Status indicators and LOCAL

The TLK, RMT, and LSN indicators show the present
IEEE-488 status of the instrument. Each of these indicators
is briefly described below.

RHT LSN
0
Cl
LOCAL

0

LISTEN-The LSN indicator will be on when the Model 196
is in the listener active state, which is activated by addressing the instrument to listen with the correct MLA (My
Listen Address) command. LSN will be off when the unit
is in the listener idle state. The unit can be placed in the
listener idle state by sending UNL (*ten),
addressing
it to talk, or by sending JFC (Interface Clear) over the bus.
LOCAJJYhe LOCAL key cancels the remote mode and
restores local operation of the instrument;

Note that the LOCAL key will also be inoperative if the LLO
(Local Lockout) command is in effect.

HP-85
Statement

Affect on Model 196
I

REMOTE 7
ABORT10 7
LOCALLOCKOUT
LOCAL 707
CLEAR 7
CLEAR 707
TRIGGER707

3-10

REMOTE-The RMT indicator shows when the instrument
is in the remote mode. Note that RMT does not necessarily
indicate the state of the REN line, as the instrument must
be addressed to listen with REN true before the RMT indicator will turn on. When the instrument is in remote, all
front panel keys except for the LOCAL key will be locked
out. When RMT is turned off, the instrument is in the local
mode.

Since all front panel keys except LOCAL are locked outs
when the instrument is in remote, thii key provides a convenient method of restoring front panel operation. Pressing LOCAL will also hum off the RMT indicator and return
the display to the~normal mode if user messages were
previously displayed with the D command.

STATUS INDICATORS
T‘K
El

TALK-The TLK indicator will be on when the instrument
is in the talker active state. The unit is placed in thii state
by addressing it to talk with the correct MTA (My Talk Address) command. TLK will be off when the unit is in the
talker idle state. The instrument is placed in the talker idle
state by sending it-an UNT (Untalk) ~command, addressing it to~listen, or with the IFC (Interface Clear) command.

Goes into remote when next addressed.
Goes into talker and listener idle states.
Front panel controls locked out.
Cancel remote.
Returns to default conditions.’
Returns to default conditions.
Trigsem reading in T2 and T3 modes.

3.8 GENERAL BUS COMMAND
PROGRAMMING
General bus commands are those commands such as DCL
that have the same general purpose regardless of the instrument. Cbmmands supported by the Model 196 are
summarized in Table 3-6, which lists HP-85 statements
necessary to send each command. Note that commands
requiring a primary address assume that~the Model 196
primary address is set to 7 (its factory default~addr&s).

3.8.1 REN (Rem’ote Enable)

Model 196 in the talker and listener idle states; The unit
wilI respond to the IFC comman d by cancelling front panel
TALK or LISTEN lights, if the instrument was previously
placed in one of those modes.
To send the IFC co nunand, the controller need only set the
EC line true for a minimum of 100pec.
HP-85 Pmgrammi ng Example-Before demonstrating the
LFCcommand, place the instrument in the talker active state
with the following statements:
REMOTE 707

REN is a uniline command that must be asserted by the
controller to place the Model 196 in the remote mode.
Simply setting REN true will not actually place the in&ument in remote; instead, the units must be addressed to
listen after REN is set true.
Generdly, remote enable should be asserted before attempting to program the instrument over the bus. Once the instrument is in r¬e, all front panel controls except
LOCAL will be inoperative. Normal front panel operation
can be restored by pressing the LOCAL key.
To place the Model 196 in the remote mode, the controller
must perform the following sequence:
1. Set the REN line true.
2. Address the Model 196 to listen.
HP-35 Programming Example-Place the Model 196 in
remote with the following statement:

ENTER 707; A$

At this point, the RMT and TLK indicators should be on.

The lFC command can be sent by typing in the following
statement:
FlEORTIU 7

Note that the TLK indicator hnns off when the Eb!D LINE
key is presse-d.

3.8.3 LLO (Local Lockout)
The LLQ conunand is used to lock out operation of the
LOCAL key, thereby completely locking outs front panel
operation of the instrument (recall that the remaining controls are locked out when the instrument is placed in
remote).

REMOTE 787

When the END LINE key is pressed, the Model 196 should
be in the remote mode as indicated by the RMT annunciator light. If not, check to see that proper bus connections are made, and that the instrument is programmed
for the correct primary address (7).
Note that all front panel controls except~LOCAL (and, of
course, POWER) are inoperative while the instrument is
in remote. You can restore normal front panel operation by
pressing the LOCAL button.

3.8.2 IFC (Interface

Clear)

The IFC command is sent by the controller to place the

To send the LLO comniand, the controller must perform
the following steps:
1. Set .4lN tie.
2. Place the LLQ command byte on the data bus.
To cancel local lockout and return control to the front panel,
REN must be set false by sending the LOCAL 7 command
to the instrument.
HP-85 Progr amming Example-To verify LLO operation,
enter the following statements:
REMOTE 707
LOCALLOCKOUT

3-11

After the second statement is executed, the LOCAL key will
be locked out.

it does not set RBN false.
HP-85 Programming Example-Place the instrument in the
remote modes with the following statement:

To cancel LLO, type in the following statement:
LOCAL 7

REMott

When END LINE is pressed, control to the front panel will
be restored.

707

Verify that the instrument is in remote.
Send GTL as follows:

3.8.4 GTL (Go To Local)

LOCAL 7M7

The GTL command is used to take the instrument out of
the remote mode and restore operation of the front panel
keys.

Note that the instrument goes into the local mode, and that~
operation of the front panel keys has now been restored.

TO setid GTL, the controller must perform the following
sequence:

3.8.5 DCL (Device Clear)

1. Set KIN true.
2. Address the Model 196 to listen.
3. Place the GTL command byte on the data lines.
TheGTLco nunand wi!.lnot cancel LLO (local lockout) since

The DCL cormnand may be used to clear the Model 196
and return it to its default conditions. Note~that the DCL
command is riot an addressed command, so ail instruments
equipped to implement DCL will do so simultaneously.
When the Model 196 receives a DCL command, it-will
r&urn to either the factory default conditions listed in Tables
2-l and 3-7 or to the user saved default conditions.

Table 3-7. Factory Default Conditions
Mode
Multiplex
Reading
Function
Data Format
Selflrest
EOI

SRQ

Internal Digital Filter
Filter
Data Store Interval
Data Store Size
R=w
Rate

3-12

1Command
I
Al
BO

JO
Kil

MO
Nl

status

Enabled
A/D converter
DC volts
Send prefix with reading
Clear
Enable EOI and bus hold-off on X
Disabled
Enabled
Disabled
One-shot~into buffer
One reading
3ocN

6%d, line cycle integration
Continuous on external trigger
No delay
CR LF
l&a&d

IEEE-488 PROGRAMMING

To send the DCL command, the controller must perform
the following steps:

When the above statement is executed, the instrument
retums to the default configuration.

1. Set ATN true.
2. Place the DCL conuixmd byte on the data bus.

3.8.7 GET (Group Execute Trigger)

Notes:
1. DCL will return the instrument to the default line frequency setting.
2. DCL will not have any affect on the -nt
IEEE address:
HP-85 Programming Example-Place the unit in an operating mode that is not a default xondition. Now enter the
following statement into the I-Jl’-85 keyboard:
CLEAR 7

When the END LJN!? key is pressed, the inslnnnent w
to the default conditions.

3.8.6 SDC (Selective

GET may be used to initiate a Model 196 measurement sequence if the instrument is placed in the appropriate trigger mode (see paragraph 3.9). Once triggered, the i&ument~~will
perform the measurement sequence in accordance with previously selected rate and sample parameters.
To send GET, the controller must perform the following
sequence:
1. set !irN low.
2. Address the Model 196 to listen.
3. Place the GET command byte on the data bus.
HP-85 Programming Example--Type in the following
statements to place the instrument in the correct trigger
mode for purposes of this demonstration:

Device Clear)

The SDC command is an addressed command that performs essentially the same function as the DCL command.
However, since each device must be individuslly addressed, the SDC command provides a method to clear only a
single, selected instrument instead of clearing all instruments simultaneous1 as is the case with DCL. When
the Model 196 receives tite SDC command, it will return
to either the factory default conditions listed in Tables 3-7
and 2-1 or to the user saved default conditions.
To transmit the SDC command, the controller must perform the following steps:
1. Set ATN true.
2. Address the Model 196 to listen.
3. Place the SDC command byte-on the data bus.
Notes:

REMOTE~707
OCITFILIT
707; L* T3X’ ’
Now trigger the measurement sequence by sending GET
with the following statement:
TRIGGER707
When the END LINE key is pressed, the measurement sequence will be triggered.

3.8.8 Serial Polling (SPE,SPD)
The serial polling sequence is used to obtain the Model 196
serial poll byte. The serial poll byte contains important information about internal functions, as desoibed in
paragraph 3.9.13. The serial polling sequence can also be
used by the controller to determine which instxument on
the bus has asserted SRQ (Service Request).

1. SDC will return the instrument to the default line frequency setting.
2. SDC will not have any affect on the current IEEE address.

F~,rial

HP-85 Programming Example-Using several front~panel
controls, alter instrument states from the default wnfiguration. Send SDC with ~thefollowing statement:

1. The controller sets KiW true.
2. The controller then places the Sl’E (Serial Poll Enable)
command byte on the data bus. At this paint;~~allactive
devices are in the serial poll enabled mode and waiting
to be addressed.

CLEQR 707

polling sequence is generally conducted as

3-13

IEEE-488 PROGRAMMING

3. The Model 196 is then addressed to talk.
4. The controller sets Al-N false.
5. The instrument places its serial poll byte on the data bus
to be read by the controller.
6. The controller then sets ATN true and places the SPD
(Serial Poll Disable) command byte on the data bus to
end the serial polling sequence.
Once instruments are in the serial poll mode, steps 3
through 5 above can be repeated by sending the correct talk
address for each instrument.

Commands that affect instrument operation will trigger a
reading when the command is executed. These-bus commands affect the Model 196 much like the front panel controls. Note that commands are not necessarily executed in
the order received; instead, they will be executed in
alphabetical order. Thus to force a particular command sequence, you would follow each command with the execute
character(X), as in the example string, Upcnx, which will
reset the instrument to factory default conditions and then
select the ohms function.
Device-dependent comman ds can be sent either one at a
time, or in groups of sweral commands within a single
string. Some examples of valid command strings include:

HP-85 Programming Example-The HP-85 SPOLL statement automatically performs the sequence justmdescn%ed. FOX-Single command string.
TO demonstrate serial polling, type in the following
FOKlPOROX-Multiple command string.
statements:
T6 X-Spaces &e ignored.
AEllOTE 707
S= SPOIL (797)

DISP s

Typical invalid command strings include:

When the above statements are executed, the Model 196
is serial polled, and the decimal value of the serial poll byte
is displayed on the computer CRT.

ElX-Invalid command, as E is ndt one of the instrument
commands.
=X-Invalid
co nunand option because 15 is not an option
of the F command.

3.9 DEVICE-DEPENDENT
PROGRAMMING

If an illegal COmIMnd @DC), illegal command option
(IDDCO), is sent, or if a command string is sent with REN
false, the string will be ignored.

COMMAND

IEEE-488 device-dependent commands are used with the
Model 196 to control various operating modes such as function, range, trigger mode and data format. Each command
is made up of a single ASCII letter followed by a number
representing an option of that command. For example, a
command to control the measuring function is programmed
by sending an ASCII “F” followed by a number representing the function option. The IEEE-488 bus actuall treats
these commands as data in that ATN is false when ;I e commands are transmitted.
A number of commands may be grouped together in one
s&in . A command strin is usually terminated with an
AS cl3 “Y character, whx3-l tells the instrument to execute
the command string. Cornman ds sent without the execute
character will not be executed at that time, but they will
be retained within an internal command buffer for execution at the time the X character is received. If any errors
occur, the instnunent will displa a propriate front panel
error messages and generatesan J8R If programmed todo
so.

3-14

Device-dependent commands that control the Model 196
are listed in lkble 3-8. These commands are covered in detail
in the following paragraphs. The associated programming
scamples show how to send the commands with the HP-%
NOTE
Programming examples assume that the Model
196 is at its factory default- value of 7.
In order to send a device-dependent-command,
troller must perform the following steps:
1.
2.
3.
4.

the con-

Set MN true.
Address the Model 196 to listen.
set MN false.
Send the command string over the bus one byte at a
time.

IEEE-488 PROGRAMMING

Table 3-8. Device-Dependent Command Summery

Auto Auto Auto Auto
3wmv390mv300&4m+4
3v3v3mA3mA
3ov3GmY3onA3GmA

so

hfger

Mode

3’hd

3’/ld

3’hd

3Md

Sl

4Hd

4’hd

4%d

4Md

::

5Vtd
6Hd

5’hd
5’hd

5Hd
5’hd

5Hd
5Md

To
E
-I3
T4
T.5
T6
77

hto

300 n

5’hd

5’hd

5’hd

5Md

5’hd

5’hd

5’hd
5Md

5%d
5Yzd

5Yzd
6’hd

3ol n
3M
3okn

3%d(Rl-4)
5w=-Rn
4%d@l-R4)
5’/zd@S-I(7
5’hd
6Hd(Rl-R6)
5Md(R7j

Integration period: 3Yzd=3l&sec, 4%d=ZS9nwec,
3%d and 6%d=Liie cycle
Cmtinuous on Talk
One-shot on Talk
Continuous on GET
One-shot on GET
Continuous on X
One-shot on X
Continuous on External Trigger
One-shot on External Trigger

3.9.7

3-15

IEEE-488 PROGRAMM,ING

Table 3-8. Device-Dependent
Mode
Reading Mode

Command
BO

Data Store Size
Data Store Interval
Value
Calibration
Default Conditions
Data Format

In
QO
Qn
Vjnn.nnnn 01
V+n.nnmqnE+
2
Lo
Ll
:;
G2
2
G5

SRQ

MO
Ml
E
M32

EOI and Bus Hold-of;

E
E

Terminator

SthLS

m
Yl

Y2
n
uo
ii

u3
U4
u5
U6

Multiplex

3-16

E
A0
Al

Command

Summary (Cont.)

Description
Readings from A/D converter
Readings from data store
Continuous data store mode
Data store of no(n=l to 500)
One-shot into buffer
n=intend in milliseconds (lmsec to 999999msec)
Calibration value, zero value
Calibrate first point using value (V)
Calibrate second point using value (V)~
Restore factory default conditions and save (Ll)
Save present machine states as default conditions
Readings with prefixes.
Reading without~prefixes.
Buffer readitlgs with prefixes and buff& locations.
Buffer readings without prefues and with buffer locations.
Buffer readings with prefixes and without buffer locations.
Buffer read&s without orefues and without buffer
1
locations.
“~~
Disable
Reading overflow
Data store full
Data store half full
Reading done
Ready
Error
Enable EOI and bus hold-off on X
Disable EOI, enable bus hold-off on X
Enable EOI,, disable bus hold-off on X
Disable both EOI and bus hold-off on X
CR LF
4F_CR~

Parag
3.9.8
3.9.9
3.9.9
3.9.10
3.9.10
s9.11
3.9.12

3.9.13

3.9.14

3.9.15

CK
LF

Send machine status word
Send error conditions
Send translator word
Send buffer size
Send average reading in buffer
Send lowest reading in buffer
Send highest reading in buffer
Send current value
Send input switch status (front/rear)
Auto/Cal multiplex disabled
Auto/Cal multiplex enabled

3.9.16

3.9.17

IEEE-488 PROGRAMMING

Table 3-8. Device-Dependent
Command
wn
JO

Mode
Delay
self-test
Hit Button
Display

I-h
Da
D

Exponential Filter

E.

Summary

(Cont.)

Desqiption
n=delay period in milliseconds, (Omsec to 6OOOOqsec)
Te&ROM, RAM, E’PROM
Hit front panel button munber n
Display up to 10 character message. a=character
Cq@
display mode
Internal filter off
Internal filter on

NOTE
REN must be true when sending device-dep~+nt
commands to the instrument, or it will ignore the
command and display a bus error message.
General HP-85 Pmgramming Example-Device-dependent
commands may be sent from the HP-85 with the following
statement:
OUTf’UT707;AB

A!$in this case contains the ASCII characters representing
the command string.

3.9.1 Execute

Command

(X)

The execute command is implemented by sending an ASCn
“X” over the bus. Its purpose is to direct the Model 196 to
execute other device-dependent commands such as F (function) or R (range). Usually, the execute character is the last
byte in the comrn+nd.string (a r+mber of commands may
k FTC!
together mto one strmg); bowever, there may
amumstmces where it is desrable to send a command string at one time, and then send the execute
character later on. Command strings sent without the execute character will be stored within an internal command
buffer for later execution. When the X character is finally
transmitted, the stored comman ds will be executed, assmning that alI commands in the previous string were valid.
HP-85 Pmgramming E%%nple-Enter the following statements into the HZ-85 keyboard:

Paragraph
3.9.18
3.9.19
3.920
3.9.21
3.9.22
;,.

X character will be transmitted to the instrument. No mode
changes will OCCUI
withH~$ example because no other comman& were sent. Note that the instrument remains in the
listener active state after the command is transmitted.

3.9.2

Function

(F)

The function command allows the user to select the type
of measurement made by the Model 196. When the instrument responds to a function command, it will be ready to
take a reading once the front-end is set u The function
may be programmed by sending one oP the following
commsrlds:
FO = DC Volts
Fl = AC Volts
FZ=Ohms
F3 = DC Current
F4 = AC Client
F5 = ACV dB
F6 = AC4 dB
F7 = Offset Compensated Ohms
Upon power up, or after the instrument receives a DCL or
SDC command, the Model 196 will return to the default
condition.
HP-85 Programming Example-Place the instrument in the
ohms function by pressing the OHMS button and enter the
following statements into the HP-85 keybq%d:
REMOTE 707

REMOTE 707

OUTPUT707i”F0X”

UUTPUT~707;“X”

When the END LINE key is pressed the second time, the

When END LINZ is pressed the second time, the instrument changes to DC volts.

3-17

\EEE-488 PROGRAMMING

3.9.3 Range

ZO = Zero disabled.
Zl = Zero enabled.
22 F Zero enabled using a zero value (V).

(R)

The range command gives the user control over the sensitivity of the instrument. This command, and its options,
erform essentialI the same functions as the front anel
kge
buttons. &nge commands parameters an$ the Sending Zl has the same effect as pressing the ZERO butrespective ranges for each measurings functjon are~sum_ ton. Zero will enable, and the display will zero with the
marized in Table 3-9. The instrument wiil be ready to take mput signal becoming the zero baseline level. The baseline
a reading after the range is set up when responding to a wih be stored in Program ZERO.
range command.
Upon power up, or after the instrument receives a DCL or
SDC co mmand, the Model 196 will return to the default
condition.
HP-35 Programming Example-Make sure the instrument
is in the autorange mode and then enter the following
,statements into the HP-85:
REMOTE 707
OUTPUT 707; ’ ‘R3X’

The 22 command is used when a zero value, using the V
command, has already been established. When the 22 command is sent, subsequent readings represent the difference
between the input signal and the value of V. Also, the value
of V is stored in Program ZERO. For example, with 0.5V
on the in ut, sending the command strings V2XZ2X will
result WIIi zero being enabled and the instrument reading
-1.5v (0.5 -2.0 = -1.5).
Sending the 22 comman d without a V value established
is the same as sending the Zl command. See paragraph
3.9.10 for more information on using the V command.

9

When the END LINE key is pressed the second time, the
instrument cancels the autorange mode, and enters the R3
range instead.

3.9.4 Zero (if)
Over the bus, the zero modifier can be controlled in the
same way that it is controlled from the front panel. Refer
to paragraphs 2.6.2 and 2.7.15 Qro rogram) for a complete
description of the zero modifier. TE e zero modifier is controlled
by sending one of the folkowingzero comman dsover
.. .

Upon power up or after the instrument receives a DCL or
SDC command, the Model 196 %ill return to the default
condition. The value of V will reset to zero.
HP-85 Programming Example-Set the instruments to the
3V DC range. With the front panel ZERO button disable
th e zero mode, if enabled, and enter the following
stat ements into the HP-85 kevbosrd:
REMOTE 707
OUTPUT707;‘1111Xy’

the bUS:

OUTPUT 707; ’ ‘ZZX’

Table 3-9. Range Command

I
3-18

Summary

Range

Command DCV
Ro
Auto
Rl
3oomv
E
R4

3

3i ::
300 v

ACV
DCA
ACA
Auto
Auto
Auto
3oOnN 300 /LA 300 @A

Ohms
Auto
300 0

ACV dB
Auto
Auto

ACA dB
Auto
Auto

3: ::
300 v

303kil
m
300 kbl

Auto
AU&J

Auto
Auto

322
3oomA

3;s
3oomA

Offset Compensated
Ohms
Auto
300 0
303kS
kD
30 kQ

IEEE-488 PROGRAMMING

After the END LINE key is pressed the third time, the
ZERO indicator will turn on with a zero baseline level of
1V DC. The zero value will also be stored in Pmgram ZERO.

When the END LINE key is pressed the second-&ne,,the
falter will turn on and have a filter value of 20.

3.9.6 Rate (S)
3.9.5 Filter (P)
The filter command controls the amount of filtering applied
to the input signal. The Model 196 filters the signal by
taking the weighted average of a number of suicessive
reading samples. Since noise is mostly random in nature,
it can be largely cancelled out with this method.~The
number of readings averaged (filter value) can be from 1
to 99. The filter value can be programmed by sending one
of the following commands:
PO = Filter disabled.
Pn = Filter on with a value of n. Where n can be from 1
to 99.
Upon power up or after the instrument receives a DCL or
SDC command, the Model I96 will return to the default
condition.
Notes:
1. A filter value sent over the bus is stored in Program
FIUER, replacing the previous filter value.
2. Keep in mind that each function can have its own
unique filter value.
Ew85Rogr amming BxamphGWnh the front panel FKFER
indicator off, enter the following statements into the HF-85:

The rate command controls the integration period and the
usable resolution of the Model 196. lhble 3-10 lists the usable
resolution on each function for the four S modes. The integration period is dependent-on usable resolution as
follows:
3Yzd resolution
4Md resolution
5Yzd resolution
6Yzd resolution

=
=
=
=

3l8psec
259msec
Line cycle*
Lime cycle*

“20msec for 5OH2, l6.6msec for 6OHz.
Upon power up or after the instrument receives a DCL or
SDC command, the Model 196 will return to the default
condition.
HP-85 Programming Example-From the front panel, Seth
the display of the Model 1% for DCV at 6Yzd resolution.
Now enter the following statements into the HP-85
REMOTE 707
OUTPUT707;“S1X3’

When END LINE is pressed the second time, the Sl rate
will be selected.

REMOTE707
OlJTPUT707;“PZOX”

Table 3-10. Rate Command Summary

L
Command
so

DCV
3Yzd

ACV
3%d

DC4

ACA

LCV dB

3Yzd

3Yzd

5Yzd

AC4 dB
5%d

Sl

4Yzd

4Yzd

4Yzd

4Yzd

5Yzd

5Yzd

5Yzd

zi

5Yzd
6%d

5%d
5%d

5Yzd
5Yzd

5Yzd
5r/zd

5Yzd
5Yzd

5Yzd
5Yzd

5Yzd
6Yzd

Integt

m perilId:

[

bd=259msec,

5Y’a ana bYza=Lme
cycle.
,~~
,.v.

.

3.19

IEEE-488 PROGRAMMING

3.9.7 Trigger Mode (T)
Triggering provides a stimulus to begin a reading conversion within the instrument. Triggering may be done in two
basic ways: in a continuous mode, a single trigger command is used to start a continuous series of readings; in
a one-shot trigger mode, a separate trigger stimulus is required to start each conversion. The Model 196 @eight
trigger commands as follows:
TO = Continuous on Talk
Tl~ = One-shot on Talk
T2 ~= Continuous on GET
I3 = One-shot on GET
T4 = Continuous on X
T5 = One-shot on X
T6 = Continuous on External Trigger
T7 = One-shot on External Trigger

In this example, the ENTER statement addresses the Model
196 to talk, atewhich point a single reading is triggered.
When the reading has been processed, it is sent out over
to the bus to the computer, which then displays the result.

3.9.8 Reading Mode (B)
The reading mode command parameters allow the selection of the source of data that is transmitted over the
IEEE-488 bus. Through this comman d, the user has a choice
of data from the A/Dmv%ter (normal DMM readings)
or the buffer (data store).~Thereading mode commands are
as follows:
BO = A/D converter readings
Bl = Data Store readings

~ ~~~~~

The trigger modes are paired according to the type of
stimulus that is used to trigger the instrument. In the ‘IO
and~Tl niddes, t+iggering is performed by addressing the
Model 196 to talk. In the T2 arid T3 modes, the IEEE-488
multiline GET command performs the trigger function. The
instrument execute (X) character provides the triggeT
stimulus in the T4 and T5 modes. External trigger pulses
provide the trigger $imuhrs in the T6 ,and T7 modes.
Upon power up or after the instmment receives a DCL or
SDC cbmmtid, the Model 196 will return to the default
condition.
NOTE
With the instrument in the T6 and T7 trigger
modes, the front panel ENTER button can be used to trigger readings. See paragraph 2.8 fqordetails.

Upon power up or after the instrument receives a DCL or
SDC command, the Model 196 wiIl return to the default
condition.
When in BO, normal A/D reading+ will be sent~.In a continuous trigger mode, readings will be updated atethe conversion rate. The Bl command is used to access readings
from the buffer. When the Bl command is sent, subsequent
readings will be taken from consecutive buffer locations
beginning with the first memory location (001). Once all
readings have been requested, the unit will cycle back and
begin again.
HP-85 Programming Example-Enter
the following
statements into the computer to send a reading over the
bus and display it on the computer CRT.
REMOTE 707
OUTPUT 707~; ’ ’ EnXI ’
ENTER 707 i A$
DISP A9

HP-85 Pmgmmming Exampl+Place the instrument in the
one-shot on talk mode with the following statements:
REMOTE 707
OLlTPUT707j~“Tl:x:”

One reading can now be triggered and the resulting da@
obtained with the following statements:
ENTER 787; A4:
DISP A$

3-20

The second statement above sets the instrument to the AID
converter reading mode. The third and fourth statements
acquire the reading and display it~~onthe CRT.

3.9.9 Data Store Interval (Q) and Size (I)
The data store is controlled by the interval command (Q).
and the size command (I).

IEEE-488 PROGRAMMING

J.nterval

With the Q comman d, the user can select the interval that
the instrument will store readings or select the one-shot
mode. In one-shot, one reading will be stored each time
the instrument is triggered. The Q cmnman d is in the
following form:
QO=Oneshot into buffer.
Qn=Set storage interval in millisec (lmsec to 999999tiec).
To use the data store in the one-shot mode (QO), the instrument must be in a one-shot trigger mode (cc n, T5
or T7). In the QOTl mode, one reading will be stored each
lime the instrument is addressed to talk. In the QClI3mode,
each GET co mmand will cause one reading &qbe store&
ln the QOT5 mode, each instrument execute character (X)
will cause a reading to be stored. Fmally, in the Qm mode,
each external trigger pulse will cause a r&ling to be stored.
If the instrument is in a continuous trigger mode (To, T2,
T4 or T6), anyIDDC error will occur.
NOTE
With the instrument in the T7 trigger mode, the
front uanel ENTER button can be used to manuallv
store’readings into the buffer. Each press of thk
ENTER button wilI store one reading in t&e buffer.
See paragraph 2.8 for details.
To store readings at a selected interval (Qn), the instrument
must be in a continuous trigger mode f,lU,T2, X, T6). &en
the selected trigger occurs, the storage process will
commence.
NOTE
With the instrument in the T6 trigger mode, the
front panel ENTER button can be used to start a
series of readings to be stored in the buffer. The
storage interval and buffer size are determined by
the Qn and I co mmands respectively. See
paragraph 2.8 forkdetails.

IO=Continuous storage mode.
In=Set data store size to n (1 to 500).
In the continuous data storage mode (IO), storage will not
stop after the buffer is filled (500 readings), but will proceed back to~thefirst memory location and start oven&kg
data. V+h the Innn command, the storage process will stop
when the defined number of readings have been stored.
In this case the buffer is cdnsidered to be fuli.’
Notes:
1. When the Q or I command is sent, ‘c---i’ will be
displayed until the first trigger occurs.
2. The data store can be disabled by sendine: the F command. Storage will again resume’when &appropriate
trigger occurs.
The instrument must be in a valid operating state (see
%ble 3-11) in order to use the high speed data store
capabilities. The high speed intervals are lmsec through
lknsec. The instrument display will blank while the instrument is storing readings at high speed. If the ins&ument~is not in a valid operating state for high speed
storage, a conflict error will be displayed briefly and
storage will not occur.
The short time error message indicates that the in&umentcannot store readings at the programmed interval
rate. Instead, readings will be stored as fast as the instrument can run.
With S2 or 53 asserted, the fastest valid storage interval
(I) is 3lmsec and 35msec respectively. A shorter interval will result in a short time error when the storage pmc&s is started. Readings will be stored as fast as the instrument can run.
Either during or after the storage process, readings may
be recalled by using the Bl command as described in
the previous paragraph. Also, the highest, lowest and
average reading in a full buffer can be recalled by sending the ,appropriate U commands. See paragraph 3.9.16
for information on using the U commands.~
Upon power up or after the instrument receives a DCL of
SDC command, the Model 196 will return to the defaults
condition.

siie
The size of the data store can be controlled by one of the
following I commands.

~Hp-85Programming Example-Enter the program below
to enable data store operation and obtain and display 100
readings on the computer CRT:

3-21

PROGRAM
10DItlA8C25l
20 REMOTE 70.7
30 OUTPUT 707;

‘1T2~3001100X”

40TRIGGER707
50 OUTPUT 707:

s ‘BiGBX”
60FORI=lTO100
70ENTER707iR8

00 DISPA$
30 NEXT I
100 END

COMMENT3 _.__.._-_-. .~ ,.$ @is example, note that only as many significant digits
as necessary need be sent. In this case, the exact value is
assumed to be 3OMxxx)even though only the first two digits
were adually sent.
Send remote enable.
Set trigger mode, and
Digital Calibration-When performing digital c&ration,
storage parameters.
two points must be caliiated on each range. The first
Start storage process.
caliiation
value should be approtiately
full range and
Set read mode to data
the
second
calibration
value
should
be
approximately
zero.
StOK?.
After the second calibration value is sent over the bus, perSet counter for 100
manent storage of the two values will occur.
loops.
Get a reading.
In order to send calibration values over the btxs, the caliiaDisplay reading.
tion command (C) must be sent after the value command
toop back for next
(V) is sent. The calibration command takes on the followreading.
mg form:
cO=Calibrate first point using value (V)
Cl=Calibrate second point using value Iv)
,

After entering the program, press the HP-85 RUN key. The
program will set the store size to IOO(line 30), enable the
data store (line 4O), turn on the data store output (line 50),
and then request and display all 100 readings (lines 6O-l.OO). The following example first sends a caliiration value of 3
and then a calibration of 0.

3.9.10 Value (V) and Calibration

WXCOX
VOXCIX

(C)

Otie ;Idvanced feature of the Model 196 is its digital c&bration capabilities. Instead of the more difficult method of
adjusting a number of potentiometers, the user need only
apply an appropriate calibration signal and send the caliiration value over the bus.
The V command is also used to program a zero value (see
paragraph 3.9.4).
Fhy

command may take on either of the following

VM.mlNm
Vn.nnnnnnE+n

If the calibration value is greater than 3030000 counts (at
61Adresolution) an lDDC0 error message will be displayed
on the Model 196.
CAUTION
Precision calibration signals must be connected
to the instrument before attempting calibration,
otherwise instrument accuracy will be affected.
See Section 6 for complete details on calibrating
the instrument either from the front panel or over
the bus.

Thus, the following two comman ds would be equivalent:
WI
V3.OE+l
Table 3-11. High Speed Data store
. .

Data Store Valid Reading
Interval
Rate

Valid
FundiOnS

.~.

Valid Valid Date
Ranges* Store Site*

QL Q2

so

FO, FYLF3, F4

Rl-R7

Il-I500

Q3-Q14

so, Sl

FO, F-l, F3, M

Rl-R7

Il-I500

*Data store size IO (continuous) and Ro (autorange) cannot be used in
the high speed data store mode.
3-22

IEEE-488

3.9.11 Default Conditions

(L)

The LOcotiand
allows the user to return the instrument
to the factory default conditions. Factory default conditions
are set at the factory and are listed in Tables 3-7 and 2-l.
The imtmment wiIl power up to these default conditions.
The current IEEE address and line frequency setting of the
instrument are not affected by the M command.
The Ll command is used to save the current instrument
conditiO116.
The ir!StrUment
wiu then power up t0 these
default conditions.

PROGRAMMING

Thus, the current IEEE address and line frequency setting are saved by IJ.
2. Sending Ill is equivalent to running Program 37 (Reset)
and then Program 30 (Save), thus:
A. User saved defaults will be lost since fact&y default
conditions will be saved.
B. M will not change the current IEEE address and line
frequency setting, and will save them as the default
conditions.
~&&j fiogmmming E-@-&t
the Model 196 to the
ohms function, and enable zero and filter. Now, enter the
following statements into the computer:

Any of the options of the following device-dependent commar& can be saved as the default conditions:

REMOTE

787

CIUTPIJT~~~;“L~X”

A (multiplex), F (function), N (internal filter), P (digital
filter), Q ad 1 (data Store h-ttemd and Sue), R (ra%d, s
(rate), W (delay), and Z (zero).

After pressing END LINE the second time, cycle power on
the Model 196 and note that the hmment
retins to the
conditions initially set in this example.

The L command options are as follows:

3.9.12 Data Format (G)

L&Restore instrument to factory default conditions and
save (Ll).
Ll=Save present machine states as the default conditions.
Notes:

The G comman d controls the format of the data that the
instrument sends over the bus. Readings may be sent with
or without prefixes. Prefixes are the mnemonics preceding
the reading and the buffer memory location. Figure 3-6 further clarifies the general data format. The G comniands are
as follows:

1. Sending Ll is equivalent to running program SAVE.

pREFIx~~A~~“~A
+NONE’NO
DATA

READINGS
STORE

‘:

D’G”s~~~~~R,,~O~~~~~~N

IN
NDCV

+I.234567

E + 1 .ESOO

1
DCV=OC
VOLTS
ACV=AC
VOLTS
OHH=OHMS
OCO=OFFSET
COMPENSATED
DCI=DC
AMPS
ACI=AC
ANPS
dBV=AC
dB VOLTS
dBI=AC
dB AMPS

CR LF

L7”;;;;g!yR
EXPONENT

OHNS

Figure

3-6.

General Data Format

3-23

IEEE-408 PROGRAMMlNG

GO = Send single reading with prefixes. Examples:
NDCV-1.234567E+D (A/D reading)
NDCV-1234567E+O,BOOl (buffer reading)
Gl = Send single reading without pwfixes. Etim$es:
-1234567E+O (A/D reading)
-1234567E+0,001 (buffer reading)
G2 = Send alI buffer readings, separated by co-s,
with
prefixes and buffer memory locations. Examples:
NDCV-l.Z34567E+O,BOOl,NDCV-1.765432E+
O,BOO2,etc.. .
G3 = Send aII buffer readings, separated by commas,
without prefixes and with buffer memory locations.
Example: -1.2X!WE+O,IX?~-1.765432E+O,M?2, etc...
G4 = Send alI buffer readings, separated by commas, with
reading prefixes and without~memory buff&r locations. Example:
NDCV-1.234567E+O,NDCV-1.765432E+O,etc...
G5 = Send all buffer readings, separated by co-s,
without reading prefixes and without buffer memory
locations. Example:
-1234567E+O,-1.765+0,
etc...
Upon power up or after the instrument receives a DCL or
SDC ~command, the Model 196 will return to the default
CO*diti0*.

Notes:

HP-85 Programming Example-To place the instrument in
the Gl mode and @@n a reading, enter the following
statements into the m-85 keyboard:
REMOTE787

When the second statement is exerted, the instrument wilI
than e to the Gl mode. The last two statements acquire
data fr om the instiment and display the reading string
on the CRT. Note that no prefii or suffix appears on the
da@ string.

3.9.13 SRQ Mask (M) and Serial Poll Byte
Format
The SRQ command controls which of a number of conditions within the Model 196 wiU cause the instrument to request service from the controller by asserting an SRQ. Once
an SRQ is generated, that serial p* byte can be checked to
determine if the Model 1% was the instrument that asserted
the SRQ and if so, what conditions can be checked by using
the Ul command, as described in paragraph 3.9.33.

1. The B command affects the source of the data. In the The Model 196 can be programmed to generate an SRQ
BOmode, the bus data wiIl come from the A/Dconverter. under one or more of the following cqncjitions:
In the Bl mode, the data wiIl come from the buff&
2. The Bl command must be asserted when using the G2 1. When a reading is completed or an overrange condition
oaxrs.
through G5 modes.
3. Pro~ammed terminator and EOI sequences appear at 2. If a bus error occurs.
the&d of each reading in the GO and Gl mddes, but 3.~When the data store is full.
are transmitted only at the end of the buffer in the G2 4, men the data store is yz full.
through G5 modes. No terminator is sent if in G2 5. If a trigger overrun error occurs.
through G5 modes while in BO (data from A/D). ~‘~
~~~
6;~When the bus is ready.

BIT
POSITION
VALUE
DECIMAL
WEIGHTING
I=SRQ BY 196 (STATUS

BYTE ONLY)

I=READING

I=ERRDR

I= BUFFER FULL

I-READY

l=BUFFER
I’READING

Figure 3-7. SRQ Mask and Serial Poll Byte Format
3-24

OVERFLOW

HALF FULL
DONE

IEEE-488 PROGRAMMING

Upon power up or after a DCL or SDC co~%id
ceived, SRQ is disabled.

is re-

SRQ Mask--The Model 196 uses an internal mask to determine which conditions will cause an SRQ to be generated.
Figure 3-7 shows the general format of this mask.
SRQ can be programmed by sending the ASCII letter “M”
followed by a decimal number tomset the appropriate bit
in the SRQ mask. Decimal values for the various bits are
summarized in Table 3-12. Note that the instrument may
be programmed for more than one set of conditions
simultaneously. To do so, simply add up the decimal bit
values for the required SRQ conditions. For example, to
enable SRQ under reading overflow and buffer full conditions, send M3X. To disable SRQ, send MOX.This command
wi!.l clear all bits in the SRQ mask.

Table 3-12. SRQ Command

Parameters

Command ( Cond#qn to Generate SRQ
I
Disable
MO
Reading overflow
Ml
Data store full
Data store half full
iii
Reading done
Ready
ibE3
Error
M32

Bit 5 (Error)-Set when one of the following errors have
occurred:
1. Trigger Error
2. Short Tie
3. Big String
4. UncaGxated
5. Cal Locked
6. Conflict
7. No Remote
8. IDDC
.~~
9. IDDCO

10. Translator

The nature of the error can be determined with the Ul command asexplained in paragmph 3.9.16. An explanation of
each error can also be found in paragraph 3.9.X
Bit 6 [SRQ)-Provides a means to determine if an SRQ Was
asserted by the Model 196. Jf this bit is set, service was requested by the instrument.
Bit-7-Not

.-~~

Serial Poll Byte Format-The serial poll byte contains information relating to data and error conditions with@ the
instrument. The general format of the serial poll byte
(which is obtained by using the serial polling sequence, as
described in paragraph 3.88) is shown k Figure 3-7.

_

used and always set to zero.

Note that the status byte should be read to clear the SRQ
line once the instroment~has generated an SRQ. All bits
in the status kyte will be latched when the SRQ is
generated. Bit 6 (RQS) will be cleared when the status byte
is read.
I-IF-85 Programming Example-Enter
gram into the m-85:

COMMENTS

PROGRAM
10 REMUTE 797 @ CLEAR 7

The bits in the serial poll byte have the following meanings:
Bit 0 (Reading Overtlow)-Set
applied to the inshument.

when an overrange input is

Bit 1 (Buffer Full)-Set when the defied buffer size is full.
Bit 2 (Buffer YzFull)-Set when half the defined buffer size
isfoll.
Bit~3 (l%adirg Done)-Set when the instrument has completed the present reading conversion.
Bit 4 (Ready)-Set when the instrument has processed all
previously received commands and is ready to accept additional commands over the bus.

the following pro-

20 UIJTPUT 707; r r M32X’ y
30 OIJTPLIT 7M7; 8 ‘KSX’ ’
40 S=SFOLL<707:)

Set up for remote

operation, clear
instrument;~~~
Promm for SRQ on

Ipwo.

Attempt to program
ille@bptioti.
Serml poll the
insbxment.

WaitforSRQemor.
B6 B5 E4 B3 BZ Identify the bits.

~~IF~OTEIT(SIS)THEN~~

50 DISF “B7
El RQ”

60 FOR I=7 TOM STEF~-1
~BDISFEITV~U35

R26
Loozkn
n

4)

REF

1

REF

LO

(3oon.
a3

LO

( 30kn
n

,

a13

HI

>TO
U24A OF
MULTIPLEXER

3kn I

TO U240
>WJ‘TIPLEXER

OF

u220

ai1

INPUT

n REF
(300kn

E HI

> TO

a30

OF

>TO

U22B

(Vn

SENSE

LO

- soonn

TO a34 OFT
I

>wJLTIPLEXER

tlULTIPLEXER

RX
\
/

\
/

II SENSE

INPUT
LO

LO

RX =

RREF.

vn REF

Figure 5-3. Resistance

5.3.2

HI

HI -

RULTIPLEXER

-

Multiplexer

Figure 5-5 shows the general switching phases for the
various signals. During each phase, an integration is per-

Vn

vn REF

Measurement

The multiplexer circuitry selectsamong the var+us signals
that xe part of the Model 196 measurement cycle and connects them to the input~buffer amplifier. Figure 5-4 shows
a simplified schematic of the multiplexer circuitry The
Front/Rear INPUT switch detector TJ75B is not part of a
measurement cycle.

5-4

OF

SENSE

LO)

LO

Simplified

Circuitry

formed by the A/D converter, and the resultant data is
used by the microprocessor to calculate the fiial reading.
The precharge amplifier (UZOB)is momentarily selected by
Q31 just before signal FET 430 is activated. The purpose
of the precharge amplifier is to get the signal seen by the
_
mput buffer amplifier closer to the actual input~~atsignal
FET Q30: The precharge ampliier also provides the drive
to keep the FE% on until turned off by the control circuitry.

PRINCIPLES OF OPERATION

SIGNAL

Q30

(SOOsdOC. 3VDC)

II SENSE HI
031

PRECHARGE

.

SIGNAL

1

U24E
lo

(DCA)

il REF LO (3Okn)

II SENSE LO
U22A
Ia

ZERO (3OV)

033

,

n REF Lo (3ook-3ootm)

SIGNAL

03s

( BOVDC, 300VDC)

n REF HI

012

Figure 5-4. JFET Multiplexer

5-5

PFilNClPLES OF OPERATION

II

REFERENCE
PHASE

REF
HI
PHASE

XL
xl/

L

fT REF
LO
PHASE

SIGNAL
PHASE

.L

II SENSE
PHASE

J/

ZERO
PHASE

HI

XL

II SENSE
PHASE

J/

CALCULATE
A READING

LO

\1

CALCULATE
A READING

A.

TYPICAL
CURRENT

YDLTAGE
YOLTAGE
AND
HEASUREflENlS

8.

TYPICAL

Figure 5-5. hlutliplexer

5-6

RESISTANCE

Phases

MEASUREMENTS

PRINCIPLES OF OPERATION

5.3.3 +2.1V Reference

Source

5.4 AID CONVERTER

Voltage and current measurements are based on comparing the unknown signal with an internal +&lV reference
voltage source. During each measurement cycle, the
unknown signal is sampled and then compared with signal
common and the +2.1V reference values.
U34 provides a highly stable +6.95V reference, while Ul3
and RlO provide a constant current to minimize zener
voltage variations. R36 and R37 divide down the +6.95V
value to the final +t.lV reference voltage.

5.3.4 input Buffer Amplifier
The input buffer
buf
amplifier provides isolation between the
input signal and
ana the
tne A/D
x/u converter. 441
u41 provides
pro\
the low
noise, high impedance FET input for amplifier
amplif
U35. The
amplifier can be configured for Xl or X10 gain with R41 and
R42 acting as the feedback network. When
Whel Xl gain is
selected by the mipprocessor, feedback is 101
routed through
pin 12 of the analog switch U44A. At Xl0 gain,
ga
feedback
is routed through pin I3 of~themultiplex switch.
switc Amplifier
gain configurations for the various functions
function tid ranges
are listed in Table 5-l.

Table 5-1. Input Buffer Amplifier (U35) Gain

Range
3oomv
3-300V
All
3k-E&*
All
All

;ain
==I

The Model 196 uses a tionstant~frequency, variable pulse
width, analog-to-dig@ converter. A simplified schematic
of t~he~A@ used in &heModel 196 is shown in Figure 5-6.
The charge balance phase begins when~the input enable/
disable line is set high. This occurs at the end of a softwaregenerated delay period thatallows the signal to settle after
the appropriate multiplexer FET is turned on. Once the input + Fabled, the sign+ from the buffer amplifier is added
to the level shift current applied through RllC and RllD
or RllC only. In this manner, the i3.03V bipolar signal from
the buffer amplifier is converted to a unipolar signal that
can be integrated.
The integrator is made up of Ql, Ul9 and C32. When the
input to the integrator is applied, the integrator output
ramps up until its voltage is slightly higher than the voltage
applied to the inverting input of ~theduty cycle comparator
(U5A). The charge balance current, whose duty cycle is pro-~
portional to the input, is fed back to the integrator input
through R8 and Q4. Since the charge balance current-is
much larger than the sum of the input and level shift-currents, the integrator output now ramps in the negative
direction until 0 of LJ8B eoes low. The VJA then counts
the total numb& of oul& that occur during the charze
balance phase.
*
At the end of the charge balance phase, the output of the
integrator is resting at some positive voltage. Since the integrator output is connected to the non-inverting~input of
the final-slope comparator (U5B), the final-slope cornpar&o+ output remains high until the integrator output
ramps in the negative direction. During fin@-slope, Q4 is
huned off and the feedback is fed through U16 back to the
integrator input;The fmal-slope comparator output is then
gated with the 3.84MH.z clock and counted. Once the comparator output goes low, the VJA stops counting and the
reading can be computed.

5-7

PRINCIPLES OF OPERATION

.,

..,

U43D

3.84NHz

CLOCK

> IO

lJ88
-ii

-0

1102

FINAL
SLOPE
COMPARATOR
RllF

U7.

CURRENT

W

DUTY
CYCLE
COMPARATOR

us4
FEEDBACK
CONTROL
CIRCUIT

Figure 5-6. AID Converter Simplified Schematic
5.5 CONTROL

CIRCUITRY

The signals for the circuitry that provides control of the
” arious FETs, relays, analog switches and logic levels are
supplied by the shift store registers U.29, U30, U31, and U32
(see schematic 196-126, page 3). CLOCK, DATA and
!ZROBE signals are sent from the VIA (U109) across the
pulse transformers T103, T104 and TlO5 (see ~schematic
196-106). The pulse transformers provide 5OOVisolation between the analog and dig&J sqtions of~tlw~nstrument.
DKIYAis serially loaded into the shift store registers and a
STROBE pulse causes the registers to simultaneously~~utput the appropriate logic levels to the FET, analog switch
and relay drivers.

5-8

5.6 DIGITAL CIRCUITRY
The Model 196 is controlled by an internal microcomputer.
This section briefly desoibes the operation of the
microcomputer and associated digital circuitry. Refer to
schematic diagram number 196-106 ftir circuit details.

5.6.1 Microcomputer
The microcomputer centers around the 8-bit 68809
microprocessor. The MPU has direct control over the
display, front panel switches, AID converter, IEEE488 bus,

PRINCIPLES OF OPERATION

as welI as the VOLTMETER COMPLETE Output and the 5.6.2 Display Circuitry
FXTERNAL TRIGGER Input. Timing for the microprocessor is accomplished by the use of X01; an SMH!z The display information is sent through display latches UllO
crystal. Internally, this frequency is divided~down by four and Ulll. Upon each display update, new segment~inforto obtain a bus operating frequency ofZMHz.
mation is presented to the display latches and a clock pulse
is sent on l”. The clock pulse to U4 and U5 (see schematic
196-116) shifts a digit enable bit to the next digit to be
Instrument operation software is stored in EPROMs U105 enabled. Every 10 times the display is updated, a digit
and U106. The revision level of this software is displayed enable it is generated at PA1 and goes to the data input of
by Program 0 (Menu). Calibration constants, Translator the shift register. Ul28 through Ul.31 are the drivers for the
words and instrument set up conditions ati ~stti*d in LED segments of the display digits tid the LED indicators.
E*I’ROM (UlO8). Ul!l7 is the RAM. Partial address decoding
is use~din this system. The function selected is d&en-n%
ed by the state of All, Al2, Al?, Al4 and Al5 address lines.
5.7 POWER SUPPLIES
These address lines determine which is selected by the
decoders (U101). Only one device WOM, RAM, VIA, etc)
The main power supplies of the Model 196 are located on
will have access to the data bus at any one time.
sheet 1 of 2 of schematic drawing number 196-106.Fuse FlOl
is the line fuse which is accessible from the rear panel. 5102
The heart of the IEEE-488 circuiixy is the GPIBA (Ull2). The is the POWER ON/OFF switch and SlOl selects ll5V or
GPIBA is capable of performing aII IEEE talker-listener pro- 230V operation by placing the transformer primary windtocols. The bidirectional data lies DON
through D7 permit ings in parallel or series. The power transformer, TlOl, has
the transfer of data between the microprocessor and the three secondary windings; one for the +5V digital supply,
GPISA. The transceivers Ull3 and Ull4 are used to drive one for the +5V analog supply and one for the kl5V analog
the output. Data is buffered by Ull3 and U114 and iS supply. CRlOl, CR102 and CR103 provide fullwave rectification for the three supplies, while VRlOl through VR104 protransmitted to the bus via connector Jl5.
vide the regulation.

5-9/5-10

SECTION 6
MAINTENANCE
6.1 INTRODUCTION
This section contains information necessary to maintain,
calibrate, and troubleshoot the Model 196. Fuse replacement
and line voltage selection procedures are also included.
WARNING
The procedures included in this section are for
use onlv bv aualiffed service oersonnel. Do not
perform the& procedures unless qualified to
do so. Many of the steps in this section may expose you to potentially lethal voltages that
could result in personal injury or death if normal safety precautions are not observed.

Table 6-1. Line Voltage Selection
Line
Voltage
105v-lzv
21Ov-25Ov

Line
Frequency
5OHz--6OHz
50Hz-6OHz

Switch
Setting
lO5v-lz5v
21ov-25Ov

6.3 FUSE REPLACEMENT
The Model 196 has two fuses for protection in case of
overload. The line fuse protects the line power input of the
instrument and the current fuse protects the current function from excessive current. The fuses may be replaced by
using the procedures found in the following paragraphs.

6.2 LINE VOLTAGE SELECTION
The Model 196 may be operated from either lll5-l25V or
210~25OV50 or 6OHz power sources. The instrument was
shipped from the factory set for an operating voltage
marked on the rear panel. To change the line voltage, proceed as follows:

WARNING
Disconnect the instrument fmm the power line
and from other equipment before replacing
fuses.

6.3.1 Line Fuse
WARNING
Disconnect the line cord and all other equipment from the Model 196.
1. Place the line voltage switch, located on the rear panel,
in the desired position. See Table 6-l for the correct
position.
2. Install a power line fuse consistent with the line voltage.
See paragraph 6.3.1 for the fuse replacement procedure.
CAUTION
The correct fuse type must be used to maintaln proper instrument protection.
3. Mark the selected line voltage on the rear panel for future
reference (to avoid confusion, erase the old mark).

To replace the line fuse, proceed as follows:
1. Turn off the power and disconnect the line cord and all
other test cables from the instrument.
2. Place the end of a flat-blade screwdriver into the slot in
the line fuse holder on the rear panel. Push in and rotate
the fuse carrier onequarter turn counterclockwise.
Release pressure on the holder and its internal spring
will push the fuse and the carrier out of the holder.
3. Remove the fuse and replace it with the proper type
using Table 6-2 as a guide.
CAUTION
Do not use a fuse with a rating higher than
specified or instrument damage may occur. If
the instrument repeatedly blows fuses, locate
and correct the cause of the trouble before
replacfng the fuse.
4. Install the new fuse and the carrier into the holder by
reversing the above procedure.

6-l

MAINTENANCE

Table 6-2. Line Fuse Replacement
I

Line
I
Voltage 1 Fuse %e
9OV-125V
1/4A, 25OV, Slo-Blo, 3AG
18OV-250V
1 /SA. 250V. Slo-Blo. 3AG

6.3.2

Current

I Keithlev
~~~~~
I p=cY6
Fu-I7
m-20

Fuse

6.4 CALIBRATION
Calibration should be performed every 12 months, or if the
performance verification procedures in Section 4 show that
the Model 196 is out of specification. If any of the calibration procedures in this section cannot be performed properly, refer to the troubleshooting information in this section. If the problem persists, contact your Keithley representative or the factory for further informatxon.

The current fuse protects the 3CQA through 3A ranges from
an input current greater than 3A. To replace the current
fuse, perform the following steps:

NOTE
Check that the instrument is set to the proper line
frequency before proceeding with calibration.

1. Tuin off the power and disconnect the power line and
test leads.
2. Place the end of a flat-blade screwdriver into the slot in
the fuse holder on the rear panel. Press in slightly and
rotate the fuse carrier onequarter turn counterclockwise.
Release pressure and remove the fuse carrier and the
fuse.
3. Remove the defective fuse and replace it~usingTable 6-3
as a guide.

~~ entjre &brafion procedure may be performed without
having to make any internal adjustments if high frequency
(701612) has been verified, as explained in paragraph 6.4.10,
step 5. Calibration can be performed from the front panel
(Program 36) or over the IEEE-488 bus.

CAUTION
Use only the recommended fuse type. If a fuse
with s higher current rating is installed, instrument damage may occur.
4. To replace the fuse carrier with the fuse, reverse the procedure in step 2.
Table 6-3. Current Fuse Replacement
Fuse Type
3A, 25OV, 3AG,~Normal-Blo

=I

Description
DC Voltage Calibrator -’
AC Voltage Calibrator
AC Power Amplifier

Current Calibrator

6-2

6.4.1

Recommended

Calibration

Equipment

Table 6-4 lists recommended calibration equipment. Alternate equipment may be used as long as eqGp&ent accurxy
is at least as good as the specifications listed in the table.

/ Keithley Part No.
/
Fu-82
Table 6-4. Recommended

M
Fluke
Fluke

NOTE
A ~“CONFLICT” error will be displayed, and the
CONFLfCT error bit in 

?

MESSAGES

ML‘52

MLA 3
MLA4
MLA 5~
MLA6

MLA~24
MLA 25
ML.4 26
MLA2.7
MLA 28
MLA 29
~MLA 30
UNL

* Message sent or received with KIN true.~Numbers shown represent primary address resulting
in ML4 (My Listen Address).

A-2

APPENDIXA

ASCII CHARACTER CODES AND IEEE-488 MULTILINE INTERFACE COMMAND MESSAGES
Decimal

Hexadecimal

ASCII

40
41

@

:

:

it
46
47
:
4.4
4E
4c
4D
4E
4F
50
51
52
53
54
55
56
57

95

58
59
5A
5B
5c
5D
5E
5F

IEEE=488 Messages*

A

D
z
G
H
I

MTA6

Es’
MTA9
MTA 10
ilK%i
MTAl3

MT.4 14
ml5

S
T
U

MIX 16
MTN.7
MT.418
MT.4 19
MTA 20
Mm 21

z

EE

x

MT.4 24

tEz
MT.427

MTA 28
MT4 29
MT4 30
UNT

* Message sent or received with ATN true. Numbers shown are primary address resulting in MTA
(My Xlk Address).

A-3

APPENDIXA

ASCII CHARACTER CODES AND IEEE-488 MULTILINE INTERFACE COMMAND MESSAGES
Decimal

Hexadecimal

96
97
98
99

60

ii:
102
103

65
66
67

lo4

68
69 ~” -~
6A
68
6C
6D
6E
6F

E
107
lO8
lo9
110
111
ll.2

70
n
~72

115
116

73

ll.7
1X3

119

124
125
126
127

ASCII

h
i
k

MSA
MSA
MSA
MSA
MSA
MSA
MSA
MSA

0,PPE
1,l’l’E
2,PPE
3;PpE
4,PPE
5,PPE
6,IT’E
7,l’l’E

MSA
MSA
MSA
MSA
MSA
MSA
MSA
MSA

S,PPE9,PPE
10,l’l’E
11,PPE
l2,l’PE
l3;PPE
14,l’PE
l5,I’PE

:

MSA l6,PPD
MSA lX’I?D
MSA 18,l’l’D
MSA 19,PPD
MSA 20,Pl’D
MSA 21.l’PD
MS?%22,iTD
MSA 23,ppD

74
75
76
77

7c
7D
7E
7F

IEEE-488 Messages*

MSA 24J’PD
MSA 25,PrD
MSAi6,PPD
MSA 27,PPD
MSA 28,PPD
MSA 29,PPD
MSA 30,I’l’D
IJEL

*Message send or received with ATN hue. Numbers represent secondary address values resulting
in MSA (My Secondary Address).

A-4

APPENDIX

6

IBM PC/XT and MODEL 8573A PROGRAMMING

INTRODUCTION

SOFTWARE

This appendix contains general programming information
needed to control the Model 196 using the IBM PUG personal computer via the Keithley Model 8573A IEEE-488 interface. Refer to the Model 8573A Instruction Manual for
complete programming information;

Before~usingthe Model 8573A, you mustconfigure the software by using the procedure below. Note that the binary
handler fde called Gl’lB.COM and the system ~onfiguration file called CONFIG.SYS must be present on the DOS
bootydisk, as described in the Model 8573A Instruction
Mamlal.

CONTROLLER

1. Boot up your system in the usual manner and enter
BASICA. ~~~
2; Place the Model 8573A software disk into~the default
drive and load the program called “DECL. BAS’! Modify
the program by changing the XXXXX values in lines 1
and 2 to l6Ci30.
3. Add the fojlowing lines to the declaration file:
: #*EL i Gp~IBMI5~: CALL IEFIN~IN178~,~XHDU%j

HANDLER

SOFTWARE

Before a specific tiontroller can be used over the IEEE-488
bus, it must have the appropriate IEEE-488~handler software installed. For the IBM computer, the necessary
handler software is provided on diskette, along with the
Model 85734 interface.

INTERFACE
BASIC
STATEMENTS

8 t.tcI$=L ‘DEW3 ’ CALL IXFI~HD~NW~Mi96%:~
9 II%=7:mLL
IEPfmItli96%rU:+~>

PROGRAMMING

This section covers the Model 8573A statements that are
essential to Model 196 operation. A partial list of programming statements are listed in Table B-l. Each of these
statements uses the IBM BASIC CALL statement, with
various variables as shown in the table. The command
words such as IBCLR (Interface Bus Clear) and IBSRE (Interface Bus Send Remote Enable), are in fact BASIC
variables themselves, which must be initialized at the start
of each BASIC program.
Table B-l. BASIC Statements
ActlOll
Transmit string to device Z
Obtain string from device Z
Send GTL to device Z
Send SDC to device 7.
Send DCL to all devices.
Send remote enable.
Cancel remote enable.
Serial poll device 7.
Send Local Lockout.
Send GET to device.
Send LFC.

CONFIGURATION

4. Now save the modified declaration file for future use.
Remember that you must load and nm this short program before programming the Model 196 over the bus.
Also; do not use the BASIC~CLEAR or NEW command
after running this program.
Note: An example program using the IBM PC/XT and the
Model 8573A can be found in Appendix C.

Necessary

to Send Bus Commands

Model 8573A &+ame+
CALL IBl.tRT ‘:Eii%::r

CMDBI~

B-IIB-2

APPENDIX

C

CONTROLLER PROGRAMS

The following programs have been supplied as a simple aid to the user and are not intended to
suit specific needs. Each progrm~allows you to send a device-dependent command string to the
instrument and obtain and display an instrument reading string.
Programs for the following controllers are iqcluded:
IBM PC or XT (with Keithley Model 8573A IEEE-488 Interface)
Apple II (equipped with the Apple II IEEE-488 Interface)
l Hewlett-Packard Model 85
l Hewlett-Packard Model 9816
l HewlettJ’ackxd
Model 9825A
. DEC LSI 11
. l’ET/CBM 2001
l

l

APPENDIX

C

IBM PC OR XT (KEITHLEY MODEL 8573A INTERFACE)
The following program sends a command string to the Model 196 from an IBM PC or XT cornputer and displays the instrument reading string on the CRT. The computer must be equipped
with the Keithley Model 8573A IEEE-488 Int&ace and the DOS 2.00 oper+ing system. Model 8573A
software must be installed and configured as described in the instruction manual.
DIRECTIONS
1. Using the front panel program feature, set the primary address of the Model 196 to 7.
2. With the power off, connea~the Model 196 to the IEEE-488 interface installed in the IBM
computer.
3. Type in BASICA on the computer keyboard to get into the IBM interpretive BASICSlanguage.
4. Place the interface software disc in the default drive, type LOAD”DECI?, and press the return key.
5. Add the lines below to lines l-6 which are now in memory. Modify the address in lines 1 and
2, as descried in the Model 8573A Instruction Manual.
6. Run the program and typein the desired~~commandsting. For example, to place the instrument in the ACV function and autoiawe, tvue in FlROX and press the return kev.
7. The instrument reading string will then appear on the display. l&r example, the display might
show NDCV+O.OOOOO(IE+O.
8. To exit the program, type in EXIT at the command prompt and press the return key.
I.

PROGRAM

I_

CwMENTs
Clear screen.
Find board descriptor.
Find instrument descriptor.
Set primary address to 7.
Set timeouts.
Set REN true.
Prompt for command.
Se& if program is to be halted.
check for null input.
YAddress 196~to listen, send string.
Defme reading input buffer.
Address 196 to talk, get reading.
Display the string.
Repeat.
Close the instrument file.
Close the board file.

NOTE: For conversion to numeric variable, make the following changes:
130 RD=VHL,~tlIDBiRDB~5~
135PRINTRD

14jj

APPENDIXC

APPLE II (APPLE II IEEE-488 INTERFACE)
The following program sends a command string to the Model 196 from an Apple II computer
and displays the instrument reading string on the computer CRT.
The computer must be equipped with the Apple II IEEE-488 Interface installed in slot 3.
DIRECTIONS
1. Using the front panel program feature, set the primary address of the Model 196 to 7.
2. With the po-wer off, connect the Model 196 to the IEEE-488 interface installed in the Apple II
computer.
3. Enter thenlines in the program below, using the RETURN key after each line.
4. Run the program and typein the desired cotimand string at the command prompt. For example, to place the instrument in ACV and autorange; ~tipe in FlROX and press the return key.
5. The instrument reading string will then appear on the CRT A typical display is:
NDCV+O.OOOOOOE+O.
COMMENTS

PROGRAM

4E1 It4#3
50 PI?1 NT r LRA’ ’
60 PRINT ‘ r MT7 ’ I i ZB.; ES:
7@FRINT rrLFi”
~~F’RIt~T~~RDG’~;2$j:It~FCITrr
90 PRINT <
2 CONTINUE
CRLL IBSTER115rS:n
WLL IBTIM~O~:120~
CALLIETERM
CtiLL IRREN
4 T’iPE 5
5 FORWT < 1X, r ENTER ADDRESS : ’ 3 BZ’
ACCEPT 10sPRIADR
10 FURMAT <12:)
12 TYPE 15
i5FORMATr.iX~LTE!~TSETUP:‘~5:~
CALL GETSTR (53 NSG, 72)
CALL IESEOI
IMfG, -1sPRIADHj
1E: I=IEREC!J (INPCIT, 80, PRIADR:l
INPCIT II+13
=0
CALL PIJTSTR 177 INPUT, 80’ >
CQLL IBUNT
GOT0 12
END

-

COMMENTS

Turn off IB etiors.
Allow

5 error 15’s.

Allow 1 second bus timeout.
Set line feed as terminator.
Turn Ofi remote.
Input primary address.

Prompt for command string.
Frogran instruments
Address 196 to listen, send string.
Get data from instrument.
Untalk the 196.
Repeat.

G7

PETICBM 2001
The following program sends a co mmand string to the Model 196~from a l%T/CBM 2001 computer and displays the instrument reading string on the computer CRT. As the PB UCBM cornputer has a standard IEEE-488 interface, no additional equipment is necessary.
DIRECTIONS
1.
2.
3.
4.

Using the front panel program feature, set the primary address of the Model 196 to Z
With the power off, connect the Model 196 to the PETlCBM IEEE-488 interface.
Enter the lines of the program below, using the RETURN key after each line is typed.
TypeRUN and press the RETURN key. Type in the desired command string at the command
prompt. For erample, to place the instrument in ACV and autorange, typesin FlROX and press
the RETURN key.
5. The instrument reading string will then appear on the CRT. A typical display is:
NDCV+O.OOOOOOE+O.
COMMENTS

PROGRAM
18OPEN ir7
30 PRINT#lrE$
40 INPLlT#i I A$
59 IF ST=2 THEN40

Open file 1, primary address Z
Prompt for, input command string.
Address 196 to listen, send string.
Address 196 to talk, input data.
If bus timeout, input~~~again.

60 PRINT

Epldl

20 INPUT’

r CCMliWD

A$

70 GOTO20

STRING’

F ;EB

reading

string.

P

NOES:
1. If conversion to numeric variable is required, modify the program as follows:

2. The PET terminates on commas in the data string. To avoid problems, program the Model 196
for the BOG0 or BOG1 data format to eliminate commas.

G8

APPENDIX

D

IEEE-488 BUS OVERVIEW

BUS DESCRIPTION
The IEEE-488 bus, yhich is also frequently referred to as
the GPIB (General Purpose Interface Bus), was designed
as a parallel transfer medium to optimize data transfer with
a minimum number of bus lines. In keeping with this goal,
the bus has eight data lines that are used both for data and
many commands. Additionally, the bus has~five management lines, which are used to control bus operation, and
three handshake lines that are used to control the data byte
transfer sequence.

TO OTHER DEVICES
h
,
\

A typical configuration for controlled bus op&tion is
shown in Figure D-l. A typical system will have one controller and one or more devices to which commands are
given and, in most cases, from which data is received.
Generally, there are three categories that describe device
operation: controller, talker, and listener.
The controller does what its name implies: it con&cJ.sother
devices on the bus. A talker sends data (usually to the controller), and a listener receives data. Depending on the instrument, a particular device may be a talker only, a listener
only, or both a talker and a listener. The Model 196 has
both talker and listener capabilities.
There are two categories of controllers: system c+rolIer
and basic controller. Both are able to control other devices,
but only the system controller has absolute authority in
the system. In a system with more than onesco&r&r, only
one controller may be active at any given time. Certain
command protocol allows control to be pa&d from OS
controller to another.
MANAGEMENT

The bus is limited to I5 devices, including the controller.
Thus, any number of devices may be present on the bus
at one time. Although several active listeners may be present simultaneously, only one act& t$kFr may be present
on the bus, or communications would be scrambled.

Figure D-l. IEEE Bus Configuration

D-1

A device is placed in the talk or listen mode from the controller by sending an appropriatetalk or listen command.
These talk and listen commands are derived from an instrument’s primary address. The primary address may
have any value between 0 and 30 and is generally set bye
rear panel switches or programmed in from the front ~pairel
(as in the case of the Model 196). The actual listen command value sent over the bus is derived by ORing the
primary address with $20 (the $ symbol preceding the
number designates a hexadecimal, or base 16 value). For
example, if the primary address is 7 (the default Model
196 value), the actual listen command byte value is $27 ($07
+ 520 = $27). In a similar manner, the talk command byte
is derived by ORing the primary address with 540. With
a priniaty address of 7, the actual talk command byte
would be 547 (540 + 507 = 547).
The IEEE-438 standards also include another addressing
mode called secondary addressing. Secondary address
byte values lie in the range of $60-$7F. Note, however, that
many devices, including the Model 196, do not use secondary addressing.
Once the device is properly addressed, bus transmission
sequences are set to take place. For example, if an instrument is addressed to talk, it will usually outputs its-data
string on the bus one byte at a~time. The listening device
(frequently the controller) will then read this information
as transmitted.

BUS LINES
The signal lines on the IEEE488 bus are grouped into three
categories: data lines, management lines, and handshake
lines. The eight data lines handle bus data and many commands, while the management and handshake lines ensure orderly bus operation. Each bus line is active low with
approximately zero volts representing logic 1 (true). The
following paragraphs briefly describe the operation of
these lines.

Data Lines
The bus uses eight data lines tom
transmit and receive ~data
in bit-parallel, byte serial fashion. These lines use the convention DIOI-DI08 instead of the more common DO-D7
DIOl is the least significant bit, while D108 is the most
significant bit. The data lines are bidirectional (with most
devices), and, as with the remaining bus lines, low is considered to be true.

D-2

Bus Management

Lines

The five bus management limes ensure proper interface
control and management. These lines are used to send
uniline commands.
ATN (Attention)-The state of ATN determines how information on the data lines is to be interpreted.
IK (Interface Clear)-lFC allow the clearing of active
talkers or listeners from the bus.
REN (Remote Enable)-REN is used to places devices in
the remote mode; Usually, devices must be in remote
before they can be programmed over the bus.
EOI (End Or Identify)-EOI is used to mark the end of
a multi-byte data transfer sequence. EOI is also used along
with !XN, to send the IDY (identify) message for parallel
polling.
SRQ (Service RequestGSRQ is used by devices to request
service from the controller.

Handshake

Lines

Three handshake lines that operate in an interlocked sequence are used to ensure reliable data transmission
regardless of the transfer rate. GeneraLly, data transfer will
occur at a rate determined by the slowest active device on
the bus. These handshake lines are:
DAV (Data ValidPThe source (talker) controls the state
of DAV to indicate to any listeners when ~datais valid.
NRFD Orot Ready For Data)-The acceptor (listener) controls the state of NRFD. It is used to signal the transmitting device to hold off the byte transfer sequence until the
accepting device is ready.
NDAC (Not Data Accepted)-NDAC is also controlled by
the accepting device. The state of NDAC tells the source
whether or not the device has accepted the data byte.
Figure D-2 shows the basic handshake sequence for the
transmission of one data byte. This sequence is used to
transfer data, talk and listen addresses, as well as multiline
commands.

APPENDIX

D

BUS COMMANDS

DATA

SOURCE

DATA

SOURCE

II
I
I
I
I

NDAC

OA’TA
TRANSFER
BEGINS

UniIine Commands--Thesecommands are %serted by setting the associated bus line true. For example, to assert
REN (Remote Enable), the REN line would be~set low
(true).
I
ACCEPTOR

Sequence

Table D-l. IEEE-488

Unilille

Multiline
UlliVersal

Addressed
Unaddressed
Device-dependent

Multiline Commands-General bus commands which are
sent over the data lines with the Al’N line true.
Device-dependent Commands-Comman ds whose meanings depend on the device in question. These commands
are transmitted via the data lies while ATN is false.

DATA
TRANSFER
ENDS

Figure D-2. IEEE Handshake

Command Type

Cdtimands associated with the IEEE-488 bus can be
grouped into~the following three general categ@s. Refer
to Table D-l.

Command
REN (Remote Enable)
EOI
IFC (Interface a4
ATN (Attention)
SRQ
LLQ (Local Lockout)
DCL (Device Clear)
SPE (Serial Enable)
SPD Serial PoII Disable)
SDC (selective Device Clear)
GTL (Go To Local)
GET (Group Execute Trigger)
UNL (Unlisten)
IJNT (Untalk)

Bus Command

Summary

State of
ATN Line* Comments
Sets up devices for remote operation.
X
X
Marks end of transmission.
clears Interface.
X
Defines data bus contents.
Low
X
Controlled by external device.
Low
Law
Law
Low
Low
Low
Low
Low
Low
High

Locks out local operation.
Returns device to default conditions.
Enables serial polling.
Disables serial polliig.
Returns unit to default conditions.
Returns device to local.
Triggers device for rea$ing.
Removes all listeners from bus.
Removes any talkers from bus.
Programs Model 196 for tious
modes.

*Don’t Care.

D-3

Uniline Commands
The five uniline commands include REN, EOI, lFC, Al’N,
and SRQ. Each comman d is associated with a dedicated
bus lie, which is set low to assert the command in
question.
REN (Remote Enable&EN
is asserted by the controller
to set up instruments on the bus for remote operation.
When REN is true, devices will be removed from the local
mode. Depending on device configuration, ail front panel
controls except the LOCAL button (if the device is so
equipped) may be locked out when REN is true. Generally REN should be asserted before attempting to program
instruments over fhe bus.
EOI (End or Identify)-EOI may be asserted either by the
controller or by external devices to identify the last byte,
in a multi-byte transfer sequence, allowing data words of
various lengths to be transmitted.
IFC (Interface Clear)-IFC is asserted by the controller to
clear the interface and return all devices to the talker and
listener idle states.
ATN (Attention)-The controller asserts KIN while sending addresses or multiline commands.

SPD (Serial Poll Disable)-SPD is used by the controller
to remove all devices on the bus from the serial poll mode
and is generally the last command in the serial polling
sequence.

Addressed

Multiline Commands

Addressed multiliie conunan ds are those commands that
must be preceded by an appropriate listen address before
the instrument will respond to the command in question.
Note that only the addressed device will respond to the
command. Both the command and the address preceding
it ilIe sent with .KlYJ true.
SDC (Selective Device Clear)-The SDC command performa essentially fhe same function as DCL except that only the addressed device responds. Generally, instruments
return to their power-up default conditions when responding to SDC.
GTL (Go To Local)-GTL is used to remove instruments
from~theremote mode and place them in local. With many
instruments, GTL may also n?store operation of front panel
controls if previously locked out.

SRQ (Service Request)-SRQ is asserted by a device on
the bus when it requires service from the controller.~

GET (Group Execute Trigger)-GET is used to bigger
devices to perform a specific action that will depend on
device con@uration (for ~ple,
perform a measurement
sequence). Although GET is an addressed command,
many devices may respond to GET without addressing.

Universal Multiline Commands

Address Commands

Universal multiline commands are those uxnmands that
required no addressing as part of the command sequence.
Ail devices equipped to implement these commands will
do so simultaneously when the commands are transmitted. As with all multiline commands, these commands are
transmitted with ATN true.

Addressed co remands include two primary command
groups, and a secondary address group. ATN is true when
these conman ds are asserted. These commands include:

LI.0 (LncaI Lockout)-LLO is Sent to instruments to lock
out front panel or local operation of the instrument.
DCL (Device Clear)-DCL is used to return instruments
to some default state. Usually, devices return to their
power-up conditions.
SPE (Serial Poll Enable)-SPE is the first step in the serial
polling sequence, which is used to determine which device
on the bus is requesting service.

D-4

LAG (Listen Address Group)-These listen commands are
derived from an instrument’s primary address and are
used to address devices to listen. The actual command byte
is obtained by ORing the primary address with $20.
TAG (TaIk Address Group)-The talk co-nds~
are derived from the plimary address by ORing the address with
$40. Tdk commands are used to address devices to talk.
SCG (Secondary Command Group)-Commands in this
group provide additional addressing capabilities. Many
devices (icluding the Model 196) do not use thes~e
commands.

APPENDIX

Unaddress Commands
The two unaddress~commands are used by the controller
to remove any talkers or listeners from the bus. ATN is true
when these commands are asserted.
UNL Wnlis&n)-Listeners
state by UNL.

are placed in the listener idle

UNT @Jntalk)-Any previously commanded talkers will
be placed in the talker idle state by LINT.

Device-Dependent

Commands

D

are sent as one or more ASCII characters that command
the device to perform a specific action. For example, the
command string ROXis used to control the measurements
mnge of the Model 196.
The IEEE-488 bus treats these commands as data in thatch
ATN is false when the commands are transmitted.

Command Codes
Command codes for the various commands that use the
data lines are s-tied
in Figure D-3. Hexadecimal and
and decimal values for the various commands are listed
in Table D-2.

The purpose of device-dependent commands will depend
on instrument configuration. Generally, these commands

D-5

APPENDlX G

D-6

I

Ix/

I

I

i i i i i i i I

Codes

El I I I I I I I I I I I I I I I
~I-I-I-I~I-I~I>I~I~I-I~I-I..I-III~
1

11

Figure D-3. Command

1

APPENDIX

Table D-2. Hexadecimal
Codes
Command
GTL
SDC
GET
LLO
DCL
SpE
SPD

Typical

and Decimal Command

Table D-4. Tvaical Device-Dependent
Sequence
.
I

Hex Value
01
04
08
11
14
18
19
ZO-3F
406F
60-7F
3F
5F

I

I

Step Command ATN Stz$e
1 I UNL ISetlow

8
17
20
24
25
32-63
64-95
96-W

Command

I
ASCI
?
I

IEEE Command Groups
Command groups supported by the Model 196 are listed
in Table D-5. Device-dependent commands are not included in this list.

Command Sequences

For the various multiline commands, a specific bus sequence must take place to properly send the command.
In particular, the correct listen address must be sent to the
insment
before it wiJ.lrespond to addressed commands.
Table D-3 lists a typical bus sequence for sending an addressed m&line command. In this instance, the SDC
command is being sent to the instrument. UNL is generally
sent as part of the sequence to ensure that no other active
listeners are present. Note that ATN is true for both the
listen command and the SDC conimand byte itself.
Table D-3. Typical Addressed Command Sequence

Table D-5. IEEE Command

Group

HANDSHAKE COMMAND GROUP
DAC=DAZlXACCEFTED

WD=READYFORD.UA

DAV=DXlA VALID
UNIVERSAL COMMAND GROUP
ATN=xKl-I’ENTION
DCL=DEVICE CLEAR
JFC=INTERFACE CLEAR
LLO=LOCAL LQCKOUT
REN=RFMOTE ENABLE

~PD=~~~ALIJOLLD~~AB~

4

St&s low
Retqw high

D

EOT

04
I

4
I

*Assumes primary address = Z
%ble D-4 gives a typical device-dependent~command sequence. In this instance, XI’N is true while the instrument
is being addressed, but it is set high while sending the
device-dependent command string.

SPE=SERIAL POLL ENABLE
ADDRESS COMMAND GROUN
LISTEN: LAG=LISTEN ADDRESS GROUP
MLA=MY LISTEN ADDRESS
UNL=UNLISTEN
TALK: TAG=TALK ADDRESS GROUP
M’C4=MY TALK ADDRESS
UNT=UNTALK
oTA=OTHER TALK ADDRESS
ADDRESSED COMMAND GROUP
ACG=ADDRESSED COMMAND GROUP
GET=GROUP EXECUTE TRIGGER
GTL=GO TO LOCALS
SDC=SELEClWE CLEAR
STATUS COMMAND GROUP
RQS=REQUEST SERVICE
SRQ=SERIAL POLL REQUEST
STB=SWS
BYTE
EOI=END

D-7/D-8

Auto

Auto

Auto

Auto

300mV3CGmV3WpA3CGpA
3v3v3mA3m4
3ov3omv3omA3amA
3&l

v3al

vmmA3mmA

AlltO
300

II

AlltO

AUtO

Auto

Auto

AUtO

Auto

3kn

Auto

AUtO

3kll

3okn

Auto

Auto

3okn

300 ktl

Auto

Auto

3okn

3Md(R1-R4)

5Yzd

5Hd

5Yzd

4Hd(RI-R4)
5%d(R55-R7

5Yzd

Shd

5%d

5Y2d

5’hd

5Kd

5Md

5Yzd

5’hd

6Yzd

Zero disabled

3Yid

3%d

3Hd

3’hd

5Md(R5-W)
41hd

4’hd

4%d

444d

5%d

5Vtd

5’hd

5Yzd

6Hd

5Yxd

5Md

5Vld

ontmuous on
One-shot on Talk
Continuous on GET
One-shot on GET
Continuous on X
One-shot on X

6Kd@l-R6)

Device-Dependent

Command

Data store full

Summary

(Cont.)

Service Form
Date

.Serial No.

Model No.
Name atid Telephone No.
Company

List all control settings, describe problem and check boxes that apply to problem.

Cl Intermittent

a

Analog output follows display

a

Particular range or function bad; specify

0
a

0 Obvious problem on power-up
m All ranges or functions are bad

0
0

Batteries and fuses are OK~
Checked all cables

IEEE failure
Front panel operational

Display or output (clwk one)
0 Drifts
m Unstable
0 Overi&d
0

Calibratiofi only

0

Data required

(attach any additional sheets as necessary)
Show a block diagram of your measurements :ystem including all instruments connected (whether power is turned on or not).
Also, describe signal source.

Where is the measurement being performed? (factory, controlled laboratory, outdfdoors,

Ambient temperature?

What power line voltage is tied?~
Relative humidity?

etc.)

Other?

Any additional information. (If special tiodifications have been made by the user, please describe.)

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