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Model 192
Instruction Manual
Contains Operating and Servicing Information for
Model 192 Programmable DMM and Model 1910 AC Option




Publication Date: June 1984
Document Number: 30983 Rev. C
WARRANTY

Keithley instruments, Inc. warrants this product to be free from defects
in material and workmanship for a period of 1 year from date of ship-
ment. During the warranty period, we will, at our option, either repair
or replace any product that proves to be defective.

To exercise this warranty, write or call your local Keithley represent-
ative, or contact Keithley headquarters in Cleveland, Ohio. You will be
given prompt assistance and return instructions. Send the instrument,
transportation prepaid, to the indicated service facility. Repairs will be
made and the instrument returned, transportation prepaid. Repaired
products are warranted for the balance of the original warranty period,
or at least 90 days.
LIMITATION OF WARRANTY
This warranty does not apply to defects resulting from unauthorized
modification or misuse of any product or part. This warranty also does
not apply to fuses, batteries, or damage from battery leakage.
This warranty is in lieu of all other warranties, expressed or implied, in-
cluding any implied warranty of merchantability or fitness for a par-
ticular use. Keithley Instruments, Inc. shall not be liable for any indirect,
special or consequential damages.


STATEMENT OF CALIBRATION

This instrument has been inspected and tested in accordance with
specifications published by Keithley Instruments, Inc.
The accuracy and calibration of this instrument are traceable to the
National Bureau of Standards through equipment which is calibrated at
planned intervals by comparison to certified standards maintained in
the Laboratories of Keithlev Instruments, Inc.




Keithley Instruments, Inc. I instruments Division
28775 Aurora Road i Cleveland, Ohio 44139 , ".`%A
Phone: (216) 248-0400 / Telex: 98.5469
Instruction Manual
Model 192
Programmable DMM




01982, Keithley Instruments, Inc.
Cleveland, Ohio, U.S.A.
Document Number: 30983
SPECIFICATIONS
DC VOLTS
TABLE OF CONTENTS

PARAGRAPH TITLE PAGE

SECTION l-GENERAL INFORMATION
1.1 Introduction ................................................................................... 1-l
1.2 Features ....................................................................................... l-l
1.3 WarrantyInformation ........................................................................... l-l
1.4 ManualAddenda ............................................................................... 1-l
1.5 SafetySymbolsandTerms ....................................................................... l-l
1.6 Unpackingandlnspection ........................................................................ l-l
1.7 Specifications. ................................................................................ l-l
1.8 Preparation for Use ............................................................................ l-l
1.9 Line Power .................................................................................... 1-2
1.10 Line Voltage Selection .......................................................................... l-2
1.11 LineFrequencySelection ................................................................... .~,~ 1.2
1.12 Repackingforshipment ......................................................................... 1-2

SECTION Z-ACCESSORIES
2.1 Introduction ................................................................................... 2-l
2.2 RackMountingKits ............................................................................. 2-1
2.2.1 Model1019ARackMountingKit ................................................................ 2-l
2.2.2 Model1019SRackMountingKit ................................................................ 2-1
2.3 Model1600AHighVoltageProbe ................................................................. 2-l
2.4 Model1641KelvinTestLeadSet..............................................................~~ 2-1
2.5 Model165150AmpereShunt................................................................~ ... 2-l
2.6 Model1681Clip-OnTestLeadSet.............................................................~ 2-l
2.7 Model1682ARFProbe......................................................................~ ... 2-2
2.8 Model 1683 Universal Test Lead Kit. .......................................................... .. 2-2
2.9 Model 1685 Clamp-On AC Current Probe ........................................................ 2-2
2.10 Model1901CurrentAdapter ...................................................................... 2-2
2.11 Model1910ACVoltageOption...............................................................~ .. 2~3
2.12 Model1920TRMSACVoltOption ................................................................ 2-3
2.13 Model19231EEE-488lnterface...............................................................~~~~ 2-3
2.14 Modal1924RearlnputAdapter..............................................................~.~~ 2-3
2.15 Model7008IEEE.488Cable.. .................................................................. 2-3

SECTION 3-FRONT AND REAR PANEL CONTROLS
3.1 Introduction ................................................................................... 3-1
3.2 Front Panel .................................................................................... 3-l
BenchModeofOperation ........................................................................ 3-l
Bench Programming Mode of Operation. ......................................................... 3-l
SystemModeofOperation ....................................................................... 3-l
RearPanel ..................................................................................... 3-2

SECTION 4-BASIC DMM OPERATION
4.1 Introduction ................................................................................... 4-l
4.2 Powerup....................................................................................~ 4-1
4.3 Operating Instructions ........................................................................... 4-l
4.4 zero ......................................................................................... 4-l
4.5 Overrangelndication ............................................................................ 4-2
4.6 Filter ......................................................................................... 4-2
4.7 DCVoltageMeasurement ........................................................................ 4-3
4.8 ResistanceMeasurement ...................................................................... ., 4-3
4.9 Four-Wire Ohms Measurement ................................................................... 4-4
4.10 AC Voltage Measurement (1910AC Option). ........................................................ 4-4
4.11 AC Voltage Measurement l192OTRMS Optionl, .................................................... 45
TABLE OF CONTENTS (CONT.1

TITLE PAGE
PARAGRAPH

SECTION `&FRONT PANEL PROGRAMS
5.1 Introduction 5-1
5.,
5.2 Program Notes....................................................................................................................................................................
5.3 P,og,a,"OC,~~, ................................................................................ ;I;
5.4 Programl.Resolution ........................................................................... 5-4
5.5 ProgramZ.Filter 5-4
5.6 .........................................................................................................................................................
Program3.Dffset/Scale
5.7 Program4. Percent Deviation.. ................................................................... z:E
5.8 Program5,Min/Max ............................................................................ 5-J
5.9 Program&HI/LO/PASS 5-B
;:;(: Program7.DataLogger .................................................................................................................................................
lEEEBufferOpmt,on ........................................................................... ;I;
5.12 ProgramB.ServiceProgram ......................................................................

SECTION 6-PERFORMANCE VERIFICATION
6.1 Introduction ................................................................................... E:;
6.2 Environmental Conditions ........................................................................
6.3 RecommendedTestEquipment ................................................................................................................................................... E:i
6.4 InitialConditions
6.5 Performanceverification ......................................................................... 6-l
6.5.1 DC Voltage Accuracy Check 12OV to 12OOV ranges) ............................................. 6-l
6.5.2 DC Voltage Accuracy Check (.2V to2V ranges1 ................................................. .. ;I:
6.5.3 AC Voltage Accuracy Check (With Model 1910 AC Voltage Option Installed) ...........................
6.5.4 Resistance(R)AccuracyCheck ................................................................. 6-2

SECTION 7-THEORY OF OPERATION
7.1 Introduction ................................................................................... 7-l
7.2 Overall Functional Description .................................................................... 7~1
7.3 Analog Circuit Description ....................................................................... 7-3
7.3.1 InputMultiplexer ............................................................................. 7-3
7.3.2 DCVoltage Measurement ............................................................................................................................................ ;:;
7.3.3 ResistanceMeasurement
7.3.4 ACVoltageMeasurement ............................................................................................................................................... ;I:
7.3.5 InputBufferAmplifier
7.3.6 AIDConverter ............................................................................... 7-7
7.4 Digital and Display Circuit Description .............................................................. ;:;
7.4.1 Microcomputer (Refer to Schematic 309750) .....................................................
7.4.2 Memon/ .............................................................................................................................................................. ;:;;
7.4.3 AddressDecoder..
7.4.4 Reset ...................................................................................... ;:;;
7.4.5 FrontPanelSwitchPort .......................................................................
7.4.6 LineFrequency .............................................................................. 7.11
7.5 AIDControl .................................................................................. 7.11
7.5.1 ClockCircuit ;I;:
7.6 DisplayCircuit .................................................................................................................................................................
7.7 PowerSupply ................................................................................. 7.14

SECTION E-MAINTENANCE
6.1 Introduction ................................................................................... B-l
6.2 Calibration ..................................................................................... 8.1
6.2.1 RecommendedTestEquipment ................................................................. B-l
8.2.2 Environmental Conditions ...................................................................... B-1



ii
TABLE OF CONTENTS (CONT.)

PARAGRAPH TITLE PAGE
8.2.3 Warmup ................................................ ...... 8-l
8.2.4 Calibration Adjustments ................................... ...... ai
8.3 Troubleshooting Set-Up Procedures ........................... ...... 8-2
8.3.1 Line Power Fuse iFlO1) Replacement ........................ ...... 8-2
8.3.2 Line Voltage Selection ..................................... ...... 8-4
8.3.3 Disassembly ............................................. ...... 8.4
8.3.4 Special Handling of Static Sensitive Devices .................. ...... 8-5
8.4 Troubleshooting Procedure ................................... 8-5
8.4.1 Line Power .............................................. 8-6
8.4.2 A/D Converter and Display ................................. 8-6
8.4.3 ACConverter ............................................ 86
8.4.4 DC Attenuator and Ohms Sources and Resistors. .............. 86
8.4.5 DigitalBoard ............................................. 86

SECTION B-REPLACEABLE PARTS
9.1 lntrodution ................................................ ..................... 9-1
9.2 Parts List .................................................. ...................... 9-1
9.3 Ordering Information ........................................ ...................... 9-1
9.4 Factory Service ............................................. ...................... 9-l
9.5 Schematic Diagrams and Component Location Drawings ......... .... .... ..... ...... 9- 1




iii
LIST OF ILLUSTRATIONS

FIGURE TITLE PAGE

l-l Instrument Packaging ........................................................................... l-2
2-1 Model1019RackMountingKit .................................................................... 2-1
2-2 Model1600AHighVoltageProbe ................................................................. 2-l
2-3 Model 1641 Kelvin Test Lead Set .................................................................. 2-1
2-4 Model165150AmpereShunt .................................................................... 2-1
2-5 Model1681Clip-OnTestLeadSet ................................................................. 2-2
2-6 Model1682ARFProbe..........................................................~......~ ........ 2-2
2-7 Model 1683 Universal Test Lead Kit ................................................................ 2-2
2-8 Clamp-OnACCurrentProbe ...................................................................... 2~2
2-9 Model1901CurrentAdapter.............................................................~ ........ 2-3
2-10 Model1910ACVoltageOption .................................................................... 2-3
2.11 Model 1920 TRMS AC Voltage Option ............................................................. 2~3
2-12 Model 1923 IEEE-488 Interface ..................................................... ..... ..... 2-3
2-13 IEEE-488Connector....................................................................~..~ ..... 2~3
2.14 Model1924RearlnputAdapter ................................................................. 2-J
3-l Modell92FrontPanel.............................~.............................~.~ ............. 3~:~
3-2 Model192RearPanel .......................................................................... 3-2
4-1 Effect of Zero Function on Dynamic Range of Measurements ....................... ................ 4~'
4-2 InputFilterFiesponseGraph ...................................................................... 4~2
4-3 DCVoltageMeasurements ..................................................................... 4~3
4-4 ResistanceMsasurements................~..........................~............~......~...~ .. 44
4-5 Four-Wire Resistance Measurement .............................................. .. 4~i
4-6 ACVoltage Measurements ........................................................... ~, ... 4~4
5-1 Front Panel Program Buttons ................. .................... ....... .. .. 52
6-l TestCircuit,2mVand2V............~ ......................................................... 6-2
7~1 Basic Block Diagram .................................................................... ,., 7~1
7-2 Simplified Multiplexer Schematic. .................................. ........... ..... 7~2
7-3 DCVoltage Measurement .................................................... ., ., ..... 7~3
J-4 FET Switching Sequence for DC Voltage Measurement (Bench Mode of Operation) .. ...... .. .. 7-4
7-5 DC Voltage Measurement FET Switching Sequence (System Mode of Operation1 ..... .. .. .. .. .. 7~4
Resistance Measurement Simplified Circuit ....... ~, .................. ...... .... ... 7~5
7-6
J-7 FETSwitchingSequenceforOhmsMeasurement ................................ `~6
J-8 Affect of Lead Resistance in 2.Terminal Ohms Measurements. ................ .. M
7-9 Affect of Lead Resistance in 4.Terminal Ohms Measurements. .......................... .... .. .... 7Yz
7-10 Block Diagram AC Volts Operation ...... ..... ............... ... .......... J-7
7-11 ACVoltsOperationFlowChart..~ .................................... ~,.,~ ...... ~.~.~,, ..... 7~8
7-12 Simplified Input Buffer Schematic .............. ..................... 7-9
7.13 Simplified A/D Converter Schematic ............. ...................... ... .. .... ..... .... 7-9
7-14 AID Converter Integrator Output Waveform ....... .................................... ... .. 7.10
7.15 Microcomputer Block Diagram .................................................................. 7~12
7-16 ChargeBalanceTimming ..................................................................... 7~:3
7.Ii SingleSlopePhase.........~.........................................................~ ........ 7-14
J-18 Simplified Schematic of Latch .............................................................. .... 7-15
7-19 Simplified Oscillator/Divider Diagram .................................. .......................... 7-15
7-20 Display Schematic ................................................................. ........... 7-16
8-l Adjustment Locations .............................................. ................. .......... 8-3
9-1 Exploded View With Mechanical Parts ............................................................. 9-2
9-2 AC Converter, Component Location Drawing ...................................................... 9.11
9-3 MotherBoard,ComponentLocationDrawing ...................................................... 9-13
9-4 Analog Board, Component Location Drawing ...................................................... 9-17
9-5 Display Board, Component Location Drawing ...................................................... 9-21




iv
LIST OF ILLUSTRATIONS (CONT.)

FIGURE TITLE PAGE
9-6 AC Converter, Schematic Diagram g-23
9-7 MotharBoard.SchematicDiagram............................................................... 9.25
9-a Analog Board, Schematic Diagram g-29
9-9 Display Board, Schematic Diagram g-33


LIST OF TABLES

TABLE TITLE PAGE

4-l LineVoltagaSalection ........................................................................... 4-l
4-2 MaximumInput ............................................................................... 4-1
4-3 ResistanceRanges ............................................................................. 4-3
4-4 Maximum Four-Wire Test Lead Resistance. ............................................ ..... 4-4
5-l FrontPanalProgramSummary ................................................................... 5-l
52 Data Point Times .................................................................. ....... 5-9
6-l Recommended Test Equipment for Performance Verification ...................................... .. 6-l
6-Z DC Voltage Performance Check (2OV to 12OOV Rangel ......................................... .. 6-2
6-3 ACVoltageAccuracyChack ..................................................................... 62
6-4 ZeroReading .................................................................................. 6-3
6-5 ResistanceAccuracyChack ..................................................................... 6-3
7-1 SenlingDelays.SNontoTurnonoflntegrator.. ......................................... ........ 7-8
7-2 MamoryByteLocations...............................................................~..~ .... 7-10
7-3 FunctionsofLatchOutputs .................................................................... 7-13
7-4 Power Supply Component Identification. .............................................. ..... 7-15
6-l Recommended Test Equipment for Calibration .................................................... 6-l
6-2 CalibrationProcaduras.................................................................~~~ ...... a-2
8-3 Fuse Replacement ............................................................................. 6-4
9-4 LineVoltagaSalaction................................................................~~~~ ..... 6-4
86 TestNumberSummarization ..................................................................... 6-6
6-5 Static Sensitive Devices ......................................................................... 8-5
a-7 Program 8 A/D Test-FET Switching Sequence ......................................... ....... ... 6.7
a8 LinePowarChecks................................................................~...~ ....... a-a
a-9 AIDConvarterChacks ..................................................................... .~~ 6.6
a10 Display Checks.. ............................................................................. 6.9
6-11 ACConvartarCheckslModel1910) ................................................................ 6.9
6-12 DCAnanuatorChacks.....................................................................~ .... 6.10
El3 Ohms Source and Resistors Checks. .............................................................. 9-l 1
6-14 DigitalBoardChecks....................................................................~..~.~ 6-11
9-1 Modal192DrawingPackage..............................................................~..~..~ 9-1
9-2 AC Converter PC-496, Parts List ............................................................ ..... 9-3
9-3 MotharBoardPC-559,PartsList........................................................~~ ...... 9.4
9-4 Analog Board PC-560. PartsList ............................................................ .. 9.6
9-5 Display Board PC-530, Parts List ................................................................ 9-9




v/vi
SECTION 1
GENERAL INFORMATION

1.1 INTRODUCTION the proper action to be taken. Keithley maintains service
facilities in the United States, West Germany, Greet Britain,
This instruction manual contains complete operating in- France, the Netherlands, Switzerland, and Austria. Informa-
structions for the Keithley Model 192. Detailed descriptions tion concerning the application, operation or service of your
of the available options for the Model 192 are provided instrument may be directed to the applications Engineer at
lseperate instruction manuals are supplied with the Model any of the above locations. Check the inside Front Cover of
1920 and Model 19231, along with a theory of operation, this manual for addresses.
calibration and service instructions for maintaining the in-
strument. A complete parts list with schematics and compo- 1.4 MANUAL ADDENDA
nent layouts is also provided at the end of this manual.
Improvements or changes to this manual will be explained
The Model 192 is a 6'h digit, 2,000,OOO count, fast on an addemdum attached to the inside back cover.
autoranging DMM. With the IEEE-468 interface option
(Model 1923). the Model 192 becomes fully programmable. 1.5 SAFEN SYMBOLS AND TERMS
DC Volts and Ohms functions are standard. Measurements
of l&V to 12OOV are attainable on 5 voltage ranges, and Safety symbols used are as follows:
Z-and 4-terminal messurements of 1mD to ZOMR are at-
tainable on 6 resistance ranges. With the addition of the The symbol A on the instrument denotes that
Model 1910 AC Voltage Option, the Model 192 will provide the user should refer to the operating instructions.
readings from 1OrV to 1OOOVAC on 4 ranges. True Root
Mean Square ITRMS) AC voltages can also be attained with The symbol i, on the instrument denotes that
the use of the Model 1920 TRMS ACV Option. Because the 1OOOV or more may be present on the terminal(sl.
Models 1910, 1920, and 1923 are easily field installed, these
options can be added at any time. The WARNING used in this manual explains dangers that
could result in personal injuy or death.
1.2 FEATURES
The CAUTION used in this manual explains hazards that
The Model 192 includes the following features: could damage the instrument.
Front Panel Programs-The internal programs in the
Model 192 are accessible from the front panel. Descrip- 1.6 UNPACKIrdG AND INSPECTION
tions of these programs can be found in the detailed spe-
cifications which precede this Section and in Section 5. The Model 192 was carefully inspected both mechanically
Data Storage- Registers for storing 100 readings are pro- and electrically before shipment. Upon receiving the Model
vided in the basic Model 192. These storage registers are 192, unpack all items from the shipping container and check
utilized by Front Panel Program 7. Data Logger (see for any obvious damage that may have occurred during
Section 51. transit. Report any damage to the shipping agent. Retain
and use the original packaging materials if reshipment is
Multiple Inputs-Multiple inputs provide access to DCV.
necessan/. The following items are shipped with all Model
ACV, and Ohms terminals simultaneously. This enables
systems designers to optimize their switching matricies 192 orders:
for the parameter being measured. In addition, in some l Model 192 Programmable DMM
simple systems, switching can be eliminated altogether. l A Model 192 instruction Manual
For systems that require only one input, the Model 1924 l Installed or separate optional accessories, as ordered
Rear Panel Input Adapter is available as an option.
One Button Zero-The front panel zero is activated by 1.7 SPECIFICATIONS
pushing one button. The zero offset is automatically scal-
ed when a new range is selected. Unique offset settings For Model 192 detailed specifications, refer to the specifica-
are saved for each function. tions that precede this section.

1.3 WARRANTY INFORMATION 1.8 PREPARATION FOR USE

Warranty information is given on the inside front cover of The Model 192 is shipped ready for use on the line voltage
this manual. If there is a need to exercise the warranty, con- marked on its rear panel. The line frequency 150 to 400Hzl is
tact the Keithley representative in your area to determine selected automatically by the Model 192 during power up. If



l-l
the Model 1923 IEEE Interface is installed it will be set to the
Addressable mode and et Address 8.
CARDBOARD STRIP
1.9 LINE POWER
NSTRUCTION MANUAL
The Model 192 is provided with a J-wire line cord which
mates with a third wire earth grounded receptacle. The in-
strument will operate on two of four voltage ranges listed in
Table B-4. These ranges may be selected by positioning an
internal slide switch and installing the appropriate fuse for
that range. An optional line voltage range of SO to 110 volts
is available by special order. Instruments with this range use
a different transformer.

1.10 LINE VOLTAGE SELECTION

Refer to Section 6 Maintenance to select the proper line
voltage settings.

1.11 LINE FREQUENCY SELECTION MODEL 192

Line frequency is sensed automatically by the Model 192
during power up. The instrument will operate at 50 to 400Hz
end will display F60 at 60Hz or F50 at either 50Hz or 400Hz.

1.12 REPACKING FOR SHIPMENT
PROTECTIVE
The Model 192 should be packed in its original carton using CARDBOARD
the packaging method shown in Figure l-l. Before packag- BOTTOM
ing, wrap the instrument in plastic. After it is placed in the
box, surround the instrument with styrofoam packaging
material.

If the Modal 192 is to be returned to Keithley Instruments for
calibration or rapair, include the following:
l AlTENTION REPAIR DEPARTMENT on the address label
l Warranty status of the instrument ARDBOARD STRlP
l Completed service form




PACKAGING MATERIAL
L 1

Figure l-l. Instrument Packaging




1-2
SECTION 2
ACCESSORIES

2.1 INTRODUCTION

This section describes the various accessories and options
available for use with the Model 192 OMM.

2.2 RACK MOUNTING KITS

2.2.1 Model 1019A Rack Mounting Kit
Figure 2-2. Model 16OOA High Voltage Probe
The Model 1019A is a universal rack mounting kit for the
Model 192. Two different front panels &we provided to allow
left, right, or dual Iside-by-side) installation. ISee Figure 2.4 MODEL 1641 KELVIN TEST LEAD SR
2-1.1
The Model 1641 test leads (Figure 2.3) are used in making
4-terminal measurements. The test leads I1 pair1 are twin-
lead cables 1.2m 146 inches1 long. Each cable is terminated
by a twin-banana plug and a spring-clip Kelvin contact. Plug
the twin banana plugs into the DMM horizontallv (HI to HI
and LO to LO).




Figure 2-3. Model 1641 Kelvin Test Lead Set

2.6 MODEL 1661 66 AMPERE SHUNT
Figure 2-1. Model 1019 Rack Mounting Kit
The Model 1651 (Figure 2-4) allows current measurements
2.2.2 Model 1019s Rack Mounting Kit
to be made from 0 to 50 amperes DC and up to 50 amperes
Model 1019s slide rack mounting kit enables one or two half AC with AC Voltage option. It is a 0.001 ohm + 1%
rack size instruments to be rack mounted with the added 4-terminal shunt. A 50 ampere current will correspond to
feature of sliding the instrumentls) for easy access. The 50mV.
dimensions are 133mm x 463mm (5% x 19 inl.


2.3 MODEL WOOA HIGH VOLTAGE PROBE

The Model 1600A (Figure 2-2) extends the DMM measure-
ment capabilities to 40kV. It has a 1M)O:l division ratio I1 Figure 24. Model 1661 M Ampere Shunt
lolt on the DMM corresponds to 1 kilovolt).
2.6 MODEL 1681 CLIP-ON TEST LEA0 SET

The Model 1661 (Figure 2-6) contains two leads 1.2117146in. I
long, terminated with banana plug and spring-action clip-on
probe.


2-l
Figure 2-7. Model 1663 Universal Test Lead Kit

Figure 2-6. Model 1661 Clip-On Test Lead Set 2.9 MODEL 1666 CLAMP-ON AC CURRENT PROBE

The Model 1666 (Figure 2-8) measures 60Hz and 60Hz AC
current by clamping onto a single conductor. Interruption of
2.7 Model 1682A RF Probe the current path is unnecessary. The Model 1685 detects
current by sensing magnetic field produced by current.
The Model 1662A is en RF probe that permits measure-
ments of AC voltages at frequencies from 1OOkHz to
250kHz. Connect the probe to the input terminals of the
DMM. Select the DCV function and the appropriate range.
The Model 1662A will give en output of one volt for an input
of one volt rms when usad with instruments having an input
impedance of 10MlI. ISee figure 2-6.)




Figure 24. Clamp-On AC Current Probe

2.10 MODEL 1901 CURRENT ADAPTER

The Model 1901 (Figure 2-91 allows the DMM to read DC
Figure 2-6. Model 1662A RF Probe current from lnA/digit to 2000mA. With the Modal 1910
AC voltage option it reads from lOnA/digit to 2000mA. The
Model 1901 plugs into the INPUT terminals of the Model
192. Maximum allowable continuous voltage drop (full scale
2.6 MODEL 1663 UNIVERSAL TEST LEA0 KIT input voltage burden) is 200mV. Shunt resistors are con-
nected to eliminate contact resistance errors. Use the Model
The Model 1663 consists of two test leads 1.2m (48in. l long 192 200mVDC range and 2VAC range for DC current and
with 12 screw-in tips, 2 banana plugs, 2 spade lugs, 2 AC current respectively. Input voltage burden can be reduc-
alligator clips with boots, 2 needle tips with chucks, and 4 ed by selecting the lowest shunt that provides the necessary
heavy-duty tip plugs. (See Figure 2-7.) resolution.




2-2
2.13 MODEL 1923 IEEE-466 INTERFACE

The Model 1923 is a microprocessor-based IEEE Standard
466-1976 interface that provides the logic and control
necessary to interface the Model 192. In the Talk Only mode
the Model 192 can send data to one or more listeners with-
out the use of a controller. In the Talk/Listen mode the
Model 192 can send or receive data over the IEEE Bus when
addressed by a systems controller. (See Figures 2-12 and
2-13.) Also provides status output and external trigger con
nector to rear panel.


2.11 MODEL 1910 AC VOLTAGE OPTION

The Model 1910 (Figure 2-10) is a factory or field installable
option which allows the DMM to read AC volts from
lO@/digit to 1OOOV. The Model 1910 is internally installed
in the Modal 192. It is important to note that field installation
or removal/replacement of the Modal 1910 requires Figure 2-12. Model 1923 IEEE-466 lnterfsce
recalibration of the Model 1910. Refer to the instructions ac-
Refer to the Model 1923 IEEE-468 Interface Instruction
information. Manual for operation and installation procedures.




Figure 2-10. Model 1910 AC Voltage Option
Figure 2-13. IEEE-466 Connector
2.12 MODEL 1920 TRMS AC VOLT OPTION

The Model 1920 is a True Root Mean Square ITRMSI AC
plug-in option for the Model 192 (Figure Z-11). The Model 2.14 MODEL 1924 REAR INPUT ADAPTER
1920 enables the Model 192 to measure the TRMS value of
an AC signal. When the Model 1920 is installed, an AC + DC The basic Model 192 has multiple inputs on the front panel.
function is available. The Model 1920 has four ranges on The Model 1924 Rear Input Adapter provides multiple rear
which an AC signal can be measured. It is field installable. inputs without the Model 1923 IEEE option. (See Figure
Refer to the instructions accompanying this option for 2-14.1 The IEEE option must be installed with the Model
operation and installation information. It is important to 1924 to use the single rear input on the Model 1924.
note that field installation or removal/replacement of the
Model 1920 requires recalibration of the Model 1920. Necessav switching signals for the Model 1924 Input op-
tion are obtained through the status port connector which is
located on the rear panel. The status port is an integral part
of the IEEE ootion.


2.15 Model 7008 IEEE-466 CABLE

The Model 7008 is a 6ft l2m) IEEE-488 Digits Cable. The
cable has 24 stranded wire conductors and is terminated
Figure 2-11. Model 1920 TRMS AC Voltage Option with IEEE Standard 488 connectors.




2-3
STATUSPORT
CONNECTOR

FRONT PANEL
INPUT CONNECTOR




WHITE W,RE



Figure Z-14. Model 1924 Rear Input Adapter




2-4
SECTION 3
FRONT AND REAR PANEL CONTROLS


3.1 INTRODUCTION Display-The utilization of Front Panel PROGRAM 1 in-
creases resolution to 6% digits (see paragraph 5.41.
This section describes the Model 192 front and rear panel
controls. Refer to Figures 3-1 and 3-2. IEEE-466 Bus Indicator-The indicators (Talk, Listen and
Remote) are used during remote operation of the Model
3.2 FRONT PANEL 192. They can be disregarded during the Bench mode of
operation.
The Front panel features are explained under the following
modes of operation: Input Terminals-There are separate connections for DCV.
ACV, and Ohms with the use of five-way bindinq posts.
l Bench Mode of Operation
l Bench Programming Mode of Operation
l System Mode of Operation PROGRAM $ through PROGRAM 5-The number 0
.through 5 and the sign I-l to the left of the Range push but-
3.3 BENCH MODE OF OPERATION tons are used to select their corresponding programs or
enter data.
Power ON/OFF Button-Power is ON with button IN;
power is OFF with button OUT. PROGRAM 7 through PROGRAM g--The number 7,8. and
9 at the left of the Function push buttons are "sed to select
Display-Display is direct reading in AC and DC volts. Ohms their corresponding program or enter data,
is read in kfl, except the 20MR range which is read in
megohms. 5'h digits of resolution is standard in the Bench PROGRAM 6-The number 6 at the left of the Zero push
mode. button is used to select front panel PROGRAM 6 or enter
data.
IEEE-488 Bus Indicator-The indicators (Talk, Listen and
Remote1 are used during remote operation of the Model Programming Push Buttons-PRGM-This button enables
192. They can be disregarded during the Bench mode of the selection of front panel programs. RECALL-This butt
operation. ton has three function levels or uses. The first function level
(RECALL) displays the currant program along with data, if
Input Terminals-There are separate connections for DCV, any. The second function level (ENTI is used to enter pro-
ACV, and Ohms with the use of five-way binding posts. gramming data. The third function level is a trigger for the
System mode.
Range Push Buttons-These seven momentary switches
are used to select range. The annunciators indicate which 3.5 SYSTEM MODE OF OPERATION
range the instrument is in, and if it is in Manual or Auto
ranging. Power ON/OFF Switch-Power is ON with button IN;
power is OFF with button OUT.
Function Push Buttons-These three push buttons select
either DCV, ACV lif the option is installed), or kR. Display-In the System mode, the Model 192's resolution is
determined by the conversion rata. Refer to IEEE-469 Bus
Zero Push Buttons-This button controls the internal Zero Operator Manual.
program (See paragraph 4-41. An illuminated annunciator
indicates Zero function is enabled.