Keithley 1910, 192 Service manual
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 shipment. 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, including any implied warranty of merchantability or fitness for a particular 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
DC
SPECIFICATIONS
VOLTS
TABLE OF CONTENTS
PARAGRAPH TITLE PAGE
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
1.11
1.12
2.1
2.2
2.2.1
2.2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
2.10
2.11
2.12
2.13
2.14
2.15
SECTION l-GENERAL INFORMATION
Introduction ...................................................................................
Features .......................................................................................
WarrantyInformation
ManualAddenda
SafetySymbolsandTerms
Unpackingandlnspection
Specifications.
Preparation for Use
Line Power
Line Voltage Selection
LineFrequencySelection
Repackingforshipment
SECTION Z-ACCESSORIES
Introduction
RackMountingKits
Model1019ARackMountingKit
Model1019SRackMountingKit
Model1600AHighVoltageProbe
Model1641KelvinTestLeadSet..............................................................~~
Model165150AmpereShunt................................................................~
Model1681Clip-OnTestLeadSet.............................................................~
Model1682ARFProbe......................................................................~
Model 1683 Universal Test Lead Kit. ..........................................................
Model 1685 Clamp-On AC Current Probe
Model1901CurrentAdapter ......................................................................
Model1910ACVoltageOption...............................................................~
Model1920TRMSACVoltOption
Model19231EEE-488lnterface...............................................................~~~~
Modal1924RearlnputAdapter..............................................................~.~~
Model7008IEEE.488Cable..
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1-l
l-l
l-l
1-l
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l-l
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l-l
1-2
l-2
1.2
1-2
2-l
2-1
2-l
2-1
2-l
2-1
2-l
2-l
2-2
2-2
2-2
2-2
2~3
2-3
2-3
2-3
2-3
3.1
3.2
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
SECTION 3-FRONT AND REAR PANEL CONTROLS
Introduction
Front Panel
BenchModeofOperation
Bench Programming Mode of Operation.
SystemModeofOperation
RearPanel
SECTION 4-BASIC DMM OPERATION
Introduction
Powerup....................................................................................~
Operating Instructions
zero .........................................................................................
Overrangelndication
Filter .........................................................................................
DCVoltageMeasurement
ResistanceMeasurement
Four-Wire Ohms Measurement ...................................................................
AC Voltage Measurement (1910AC Option).
AC Voltage Measurement l192OTRMS Optionl,
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3-1
3-l
3-l
3-l
3-l
3-2
4-l
4-1
4-l
4-l
4-2
4-2
4-3
.,
4-3
4-4
4-4
45
TABLE OF CONTENTS (CONT.1
PARAGRAPH
SECTION ‘&FRONT PANEL PROGRAMS
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
Introduction
.................................................................................................................................................................... Program Notes
P,og,a,“OC,~~, ................................................................................
Programl.Resolution
ProgramZ.Filter
Program3.Dffset/Scale
Program4. Percent Deviation.. ...................................................................
Program5,Min/Max
5.9
;:;(: Program7.DataLogger
5.12 ProgramB.ServiceProgram
6.1
6.2
Program&HI/LO/PASS
lEEEBufferOpmt,on
SECTION 6-PERFORMANCE VERIFICATION
Introduction ...................................................................................
Environmental Conditions ........................................................................
6.3
6.4
6.5
6.5.1
6.5.2
6.5.3
6.5.4
7.1
7.2
7.3
7.3.1
7.3.2
7.3.3
RecommendedTestEquipment
InitialConditions
Performanceverification
DC Voltage Accuracy Check 12OV to 12OOV ranges)
DC Voltage Accuracy Check (.2V to2V ranges1
AC Voltage Accuracy Check (With Model 1910 AC Voltage Option Installed)
Resistance(R)AccuracyCheck
SECTION 7-THEORY OF OPERATION
Introduction
Overall Functional Description
Analog Circuit Description
InputMultiplexer .............................................................................
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DCVoltage Measurement
ResistanceMeasurement
7.3.4 ACVoltageMeasurement
7.3.5
7.3.6
7.4
7.4.1
7.4.2
7.4.3
7.4.4
7.4.5
7.4.6
7.5 AIDControl ..................................................................................
7.5.1 ClockCircuit
7.6 DisplayCircuit
7.7
InputBufferAmplifier
AIDConverter ...............................................................................
Digital and Display Circuit Description
Microcomputer (Refer to Schematic 309750)
Memon/
AddressDecoder..
Reset ......................................................................................
FrontPanelSwitchPort
LineFrequency
PowerSupply
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PAGE
5-1
5.,
;I;
5-4
5-4
z:E
5-J
5-B
;I;
E:;
E:i
..
;:;;
;:;;
7.11
7.11
;I;:
7.14
6-l
6-l
;I:
6-2
7-l
7~1
7-3
7-3
;:;
;I:
7-7
;:;
SECTION E-MAINTENANCE
6.1 Introduction ...................................................................................
6.2 Calibration
6.2.1 RecommendedTestEquipment
8.2.2 Environmental Conditions
ii
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...................................................................... B-1
B-l
8.1
B-l
TABLE OF CONTENTS (CONT.)
PARAGRAPH
8.2.3
8.2.4
8.3
8.3.1
8.3.2
8.3.3
8.3.4
8.4
8.4.1
8.4.2
8.4.3
8.4.4
8.4.5
9.1
9.2
9.3
9.4
9.5
Warmup ................................................
Calibration Adjustments ...................................
Troubleshooting Set-Up Procedures
Line Power Fuse iFlO1) Replacement
Line Voltage Selection .....................................
Disassembly .............................................
Special Handling of Static Sensitive Devices
Troubleshooting Procedure ...................................
Line Power ..............................................
A/D Converter and Display .................................
ACConverter ............................................
DC Attenuator and Ohms Sources and Resistors.
DigitalBoard
SECTION B-REPLACEABLE PARTS
lntrodution ................................................
Parts List ..................................................
Ordering Information ........................................
Factory Service
Schematic Diagrams and Component Location Drawings
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TITLE
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PAGE
8-l
ai
8-2
8-2
8-4
8.4
8-5
8-5
8-6
8-6
86
86
86
9-1
9-1
9-1
9-l
9- 1
iii
LIST OF ILLUSTRATIONS
FIGURE
l-l
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2.11
2-12
2-13
2.14
3-l
3-2
4-1
4-2
4-3
4-4
4-5
4-6
5-1
6-l
7~1
7-2
7-3
J-4
7-5
7-6
J-7
J-8
7-9
7-10
7-11
7-12
7.13
7-14
7.15
7-16
7.Ii
J-18
7-19
7-20
8-l
9-1
9-2
9-3
9-4
9-5
TITLE
Instrument Packaging
Model1019RackMountingKit ....................................................................
Model1600AHighVoltageProbe
Model 1641 Kelvin Test Lead Set
Model165150AmpereShunt
Model1681Clip-OnTestLeadSet
Model1682ARFProbe..........................................................~......~ ........
Model 1683 Universal Test Lead Kit
Clamp-OnACCurrentProbe ......................................................................
Model1901CurrentAdapter.............................................................~ ........
Model1910ACVoltageOption ....................................................................
Model 1920 TRMS AC Voltage Option
Model 1923 IEEE-488 Interface
IEEE-488Connector....................................................................~..~ .....
Model1924RearlnputAdapter
Modell92FrontPanel.............................~.............................~.~ .............
Model192RearPanel
Effect of Zero Function on Dynamic Range of Measurements
InputFilterFiesponseGraph
DCVoltageMeasurements
ResistanceMsasurements................~..........................~............~......~...~
Four-Wire Resistance Measurement
ACVoltage Measurements
Front Panel Program Buttons
TestCircuit,2mVand2V............~
Basic Block Diagram
Simplified Multiplexer Schematic.
DCVoltage Measurement
FET Switching Sequence for DC Voltage Measurement (Bench Mode of Operation)
DC Voltage Measurement FET Switching Sequence (System Mode of Operation1
Resistance Measurement Simplified Circuit
FETSwitchingSequenceforOhmsMeasurement
Affect of Lead Resistance in 2.Terminal Ohms Measurements.
Affect of Lead Resistance in 4.Terminal Ohms Measurements.
Block Diagram AC Volts Operation
ACVoltsOperationFlowChart..~ ....................................
Simplified Input Buffer Schematic
Simplified A/D Converter Schematic
AID Converter Integrator Output Waveform
Microcomputer Block Diagram
ChargeBalanceTimming
SingleSlopePhase.........~.........................................................~ ........
Simplified Schematic of Latch
Simplified Oscillator/Divider Diagram
Display Schematic
Adjustment Locations
Exploded View With Mechanical Parts
AC Converter, Component Location Drawing
MotherBoard,ComponentLocationDrawing
Analog Board, Component Location Drawing
Display Board, Component Location Drawing
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~.~.~,,
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PAGE
l-2
2-1
2-l
2-1
2-1
2-2
2-2
2-2
2~2
2-3
2-3
2~3
2-3
2~3
2-J
3~:~
3-2
4~’
4~2
4~3
44
4~i
4~4
52
6-2
7~1
7~2
7~3
7-4
7~4
7~5
‘~6
M
7Yz
J-7
7~8
7-9
7-9
7.10
7~12
7~:3
7-14
7-15
7-15
7-16
8-3
9-2
9.11
9-13
9-17
9-21
iv
LIST OF ILLUSTRATIONS (CONT.)
FIGURE
9-6
9-7 MotharBoard.SchematicDiagram............................................................... 9.25
9-a
9-9
AC Converter, Schematic Diagram g-23
Analog Board, Schematic Diagram
Display Board, Schematic Diagram
TITLE
PAGE
g-29
g-33
LIST OF TABLES
TABLE
4-l
4-2
4-3
4-4
5-l
52
6-l
6-Z
6-3
6-4
6-5
7-1
7-2
7-3
7-4
6-l
6-2
8-3
9-4
86
6-5
a-7
a8
a-9
a10
6-11
6-12
El3
6-14
9-1
9-2
9-3
9-4
9-5
TITLE
LineVoltagaSalection
MaximumInput
ResistanceRanges .............................................................................
Maximum Four-Wire Test Lead Resistance.
FrontPanalProgramSummary
Data Point Times
Recommended Test Equipment for Performance Verification
DC Voltage Performance Check (2OV to 12OOV Rangel
ACVoltageAccuracyChack
ZeroReading ..................................................................................
ResistanceAccuracyChack .....................................................................
SenlingDelays.SNontoTurnonoflntegrator..
MamoryByteLocations...............................................................~..~
FunctionsofLatchOutputs ....................................................................
Power Supply Component Identification.
Recommended Test Equipment for Calibration
CalibrationProcaduras.................................................................~~~
Fuse Replacement .............................................................................
LineVoltagaSalaction................................................................~~~~
TestNumberSummarization .....................................................................
Static Sensitive Devices .........................................................................
Program 8 A/D Test-FET Switching Sequence
LinePowarChecks................................................................~...~
AIDConvarterChacks .....................................................................
Display Checks..
ACConvartarCheckslModel1910) ................................................................
DCAnanuatorChacks.....................................................................~
Ohms Source and Resistors Checks. ..............................................................
DigitalBoardChecks....................................................................~..~.~
Modal192DrawingPackage..............................................................~..~..~
AC Converter PC-496, Parts List
MotharBoardPC-559,PartsList........................................................~~
Analog Board PC-560. PartsList
Display Board PC-530, Parts List
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.... 6.10
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4-l
4-1
4-3
4-4
5-l
6-l
6-2
6-3
6-3
7-8
7-10
7-13
7-15
6-l
a-2
6-4
6-4
6-6
8-5
6.7
a-a
6.9
6.9
9-l 1
6-11
9-1
9-3
9.4
9.6
9-9
v/vi
SECTION 1
GENERAL INFORMATION
1.1 INTRODUCTION
This instruction manual contains complete operating in-
structions for the Keithley Model 192. Detailed descriptions
of the available options for the Model 192 are provided
lseperate instruction manuals are supplied with the Model
1920 and Model 19231, along with a theory of operation,
calibration and service instructions for maintaining the instrument. A complete parts list with schematics and component layouts is also provided at the end of this manual.
The Model 192 is a 6’h digit, 2,000,OOO count, fast
autoranging DMM. With the IEEE-468 interface option
(Model 1923). the Model 192 becomes fully programmable.
DC Volts and Ohms functions are standard. Measurements
of l&V to 12OOV are attainable on 5 voltage ranges, and
Z-and 4-terminal messurements of 1mD to ZOMR are attainable on 6 resistance ranges. With the addition of the
Model 1910 AC Voltage Option, the Model 192 will provide
readings from 1OrV to 1OOOVAC on 4 ranges. True Root
Mean Square ITRMS) AC voltages can also be attained with
the use of the Model 1920 TRMS ACV Option. Because the
Models 1910, 1920, and 1923 are easily field installed, these
options can be added at any time.
1.2 FEATURES
The Model 192 includes the following features:
Front Panel Programs-The internal programs in the
Model 192 are accessible from the front panel. Descriptions of these programs can be found in the detailed specifications which precede this Section and in Section 5.
Data Storage- Registers for storing 100 readings are provided in the basic Model 192. These storage registers are
utilized by Front Panel Program 7. Data Logger (see
Section 51.
Multiple Inputs-Multiple inputs provide access to DCV.
ACV, and Ohms terminals simultaneously. This enables
systems designers to optimize their switching matricies
for the parameter being measured. In addition, in some
simple systems, switching can be eliminated altogether.
For systems that require only one input, the Model 1924
Rear Panel Input Adapter is available as an option.
One Button Zero-The front panel zero is activated by
pushing one button. The zero offset is automatically scaled when a new range is selected. Unique offset settings
are saved for each function.
the proper action to be taken. Keithley maintains service
facilities in the United States, West Germany, Greet Britain,
France, the Netherlands, Switzerland, and Austria. Information concerning the application, operation or service of your
instrument may be directed to the applications Engineer at
any of the above locations. Check the inside Front Cover of
this manual for addresses.
1.4 MANUAL ADDENDA
Improvements or changes to this manual will be explained
on an addemdum attached to the inside back cover.
1.5 SAFEN SYMBOLS AND TERMS
Safety symbols used are as follows:
The symbol
A
on the instrument denotes that
the user should refer to the operating instructions.
The symbol
i,
on the instrument denotes that
1OOOV or more may be present on the terminal(sl.
The WARNING used in this manual explains dangers that
could result in personal injuy or death.
The CAUTION used in this manual explains hazards that
could damage the instrument.
1.6 UNPACKIrdG AND INSPECTION
The Model 192 was carefully inspected both mechanically
and electrically before shipment. Upon receiving the Model
192, unpack all items from the shipping container and check
for any obvious damage that may have occurred during
transit. Report any damage to the shipping agent. Retain
and use the original packaging materials if reshipment is
necessan/. The following items are shipped with all Model
192 orders:
l
Model 192 Programmable DMM
l
A Model 192 instruction Manual
l
Installed or separate optional accessories, as ordered
1.7 SPECIFICATIONS
For Model 192 detailed specifications, refer to the specifications that precede this section.
1.3 WARRANTY INFORMATION
Warranty information is given on the inside front cover of
this manual. If there is a need to exercise the warranty, contact the Keithley representative in your area to determine
1.8 PREPARATION FOR USE
The Model 192 is shipped ready for use on the line voltage
marked on its rear panel. The line frequency 150 to 400Hzl is
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.
1.9 LINE POWER
The Model 192 is provided with a J-wire line cord which
mates with a third wire earth grounded receptacle. The instrument 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.
CARDBOARD STRIP
NSTRUCTION MANUAL
1.11 LINE FREQUENCY SELECTION
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
The Model 192 should be packed in its original carton using
the packaging method shown in Figure l-l. Before packag-
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
l
Completed service form
MODEL 192
PROTECTIVE
CARDBOARD
BOTTOM
ARDBOARD STRlP
1-2
PACKAGING MATERIAL
L
1
Figure l-l. Instrument Packaging
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
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
2-1.1
Figure 2-2. Model 16OOA High Voltage Probe
2.4 MODEL 1641 KELVIN TEST LEAD SR
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 2-1. Model 1019 Rack Mounting Kit
2.2.2 Model 1019s Rack Mounting Kit
Model 1019s slide rack mounting kit enables one or two half
rack size instruments to be rack mounted with the added
feature of sliding the instrumentls) for easy access. The
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
lolt on the DMM corresponds to 1 kilovolt).
Figure 2-3. Model 1641 Kelvin Test Lead Set
2.6 MODEL 1661 66 AMPERE SHUNT
The Model 1651 (Figure 2-4) allows current measurements
to be made from 0 to 50 amperes DC and up to 50 amperes
AC with AC Voltage option. It is a 0.001 ohm + 1%
4-terminal shunt. A 50 ampere current will correspond to
50mV.
Figure 24. Model 1661 M Ampere Shunt
2.6 MODEL 1681 CLIP-ON TEST LEA0 SET
The Model 1661 (Figure 2-6) contains two leads 1.2117 146in. 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
2.7 Model 1682A RF Probe
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 2-6. Model 1662A RF Probe
2.6 MODEL 1663 UNIVERSAL TEST LEA0 KIT
The Model 1663 consists of two test leads 1.2m (48in. l long
with 12 screw-in tips, 2 banana plugs, 2 spade lugs, 2
alligator clips with boots, 2 needle tips with chucks, and 4
heavy-duty tip plugs. (See Figure 2-7.)
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
the current path is unnecessary. The Model 1685 detects
current by sensing magnetic field produced by current.
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
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
input voltage burden) is 200mV. Shunt resistors are connected to eliminate contact resistance errors. Use the Model
192 200mVDC range and 2VAC range for DC current and
AC current respectively. Input voltage burden can be reduc-
ed by selecting the lowest shunt that provides the necessary
resolution.
2-2
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
recalibration of the Model 1910. Refer to the instructions ac-
information.
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.
Figure 2-12. Model 1923 IEEE-466 lnterfsce
Refer to the Model 1923 IEEE-468 Interface Instruction
Manual for operation and installation procedures.
Figure 2-10. Model 1910 AC Voltage Option
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
1920 enables the Model 192 to measure the TRMS value of
an AC signal. When the Model 1920 is installed, an AC + DC
function is available. The Model 1920 has four ranges on
which an AC signal can be measured. It is field installable.
Refer to the instructions accompanying this option for
operation and installation information. It is important to
note that field installation or removal/replacement of the
Model 1920 requires recalibration of the Model 1920.
Figure 2-11. Model 1920 TRMS AC Voltage Option
Figure 2-13. IEEE-466 Connector
2.14 MODEL 1924 REAR INPUT ADAPTER
The basic Model 192 has multiple inputs on the front panel.
The Model 1924 Rear Input Adapter provides multiple rear
inputs without the Model 1923 IEEE option. (See Figure
2-14.1 The IEEE option must be installed with the Model
1924 to use the single rear input on the Model 1924.
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
with IEEE Standard 488 connectors.
2-3
FRONT PANEL
INPUT CONNECTOR
Figure Z-14. Model 1924 Rear Input Adapter
STATUSPORT
CONNECTOR
WHITE W,RE
2-4
SECTION 3
FRONT AND REAR PANEL CONTROLS
3.1 INTRODUCTION
This section describes the Model 192 front and rear panel
controls. Refer to Figures 3-1 and 3-2.
3.2 FRONT PANEL
The Front panel features are explained under the following
modes of operation:
l
Bench Mode of Operation
l
Bench Programming Mode of Operation
l
System Mode of Operation
3.3 BENCH MODE OF OPERATION
Power ON/OFF Button-Power is ON with button IN;
power is OFF with button OUT.
Display-Display is direct reading in AC and DC volts. Ohms
is read in kfl, except the 20MR range which is read in
megohms. 5’h digits of resolution is standard in the Bench
mode.
IEEE-488 Bus Indicator-The indicators (Talk, Listen and
Remote1 are used during remote operation of the Model
192. They can be disregarded during the Bench mode of
operation.
Input Terminals-There are separate connections for DCV,
ACV, and Ohms with the use of five-way binding posts.
Range Push Buttons-These seven momentary switches
are used to select range. The annunciators indicate which
range the instrument is in, and if it is in Manual or Auto
ranging.
Function Push Buttons-These three push buttons select
either DCV, ACV lif the option is installed), or kR.
Zero Push Buttons-This button controls the internal Zero
program (See paragraph 4-41. An illuminated annunciator
indicates Zero function is enabled.
Programming Push Buttons-These two momentary switches are used during tha Bench Programming mode of
operation. They can be disregarded during the Bench mode.
Tilt Bail-The tilt bail is used as a handle and also to elevate
the front of the instrument for better Viewing.
3.4 BENCH PROGRAMMING MODE OF OPERATION
Display-The utilization of Front Panel PROGRAM 1 increases resolution to 6% digits (see paragraph 5.41.
IEEE-466 Bus Indicator-The indicators (Talk, Listen and
Remote) are used during remote operation of the Model
192. They can be disregarded during the Bench mode of
operation.
Input Terminals-There are separate connections for DCV.
ACV, and Ohms with the use of five-way bindinq posts.
PROGRAM $ through PROGRAM 5-The number 0
.through 5 and the sign I-l to the left of the Range push buttons are used to select their corresponding programs or
enter data.
PROGRAM 7 through PROGRAM g--The number 7,8. and
9 at the left of the Function push buttons are “sed to select
their corresponding program or enter data,
PROGRAM 6-The number 6 at the left of the Zero push
button is used to select front panel PROGRAM 6 or enter
data.
Programming Push Buttons-PRGM-This button enables
the selection of front panel programs. RECALL-This butt
ton has three function levels or uses. The first function level
(RECALL) displays the currant program along with data, if
any. The second function level (ENTI is used to enter programming data. The third function level is a trigger for the
System mode.
3.5 SYSTEM MODE OF OPERATION
Power ON/OFF Switch-Power is ON with button IN;
power is OFF with button OUT.
Display-In the System mode, the Model 192’s resolution is
determined by the conversion rata. Refer to IEEE-469 Bus
Operator Manual.
IEEE-466 Bus Indicator-These indicators (Talk. Listen and
Remote) identify the present status of the IEEE Bus.
Input Terminal-There are separate connections for DCV.
ACV, and Ohms with the use of five-way binding posts.
Range Push Buttons-These seven momentary switches
are used to select range. The annunciators indicate which
range the instrument is in, and if it is in Manual or Auto
Range.
Power ON/OFF Button-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 k0.
3-1
Zero Push Buttons-This button controls the internal Zero
program ISee paragraph 4.4). An illuminated annunciator
indicates Zero function is enabled.
3.6 REAR PANEL
The following information describes Model 192 rear panel
controls.
Power Connector-The instrument will operate on four
voltage ranges of 50 to 400Hz AC power Isee paragraph 1.9
and 1.10).
Fuse-See paragraph 8.5.1 for the proper fuse replacement.
Status Output’ and External Trigger-Six active low out-
puts and the external trigger input are available through the
Status Output Connector. Three of the outputs are funtion
(ACV, DCV, kR). The remaining outputs are PASS, LOW,
HIGH which are used with the internal program
HI/LO/PASS. The function outputs are continuously
active, the PASS, LOW, HIGH outputs are active only when
utilizing the HI/LO/PASS program. The external trigger requires a 0 to 5V logic signal and is recognized only when in
system mode.
IEEE-488 Interface Connector’-This is the IEEE-488 con“action to the Modal 192.
Address Switches*-These switches are used to set up the
Model 1923 IEEE-488 interface.
Accessory Mounting Holes-These are threaded mounting
holes for the rear input adapter,
l
These functions are present when the Model 1923 option
is installed.
\ - \‘IWU. 1m1*..
.
1 /
Figure 3-1. Model 192 Front panel
Figure 3-2. Model 192 Rear Panel
I”“*Y) i-
,i
\
1
3-2
SECTION 4
BASIC DMM OPERATION
4.1 INTRODUCTION
This section contains procedures for connecting and
operating the Model 192.
4.2 POWER UP
Plug the instrument into the proper power receptacle in ac-
cordance with Table 4-l.
Table 4-l. Line Voltage Selection
Input
Voltage
105-125VAC
210-250VAC 230VAC
90-IlOVAC’ 115VAC
195235VAC’ 230VAC
‘For instruments equipped with a low voltage transformer,
lmmediatley after turning on the Model 192 via the POWER
switch, the Display will indicate the following:
1. This is a display test. The operator can note inoperative
display segments by comparing the Model 192’s display
with the figure above.
2. In addition, the push button and GPIB annunciators will
illuminate. All annunciators will illuminate simultaneously
if operating correctly.
After the display test is completed the Model 192 will display
the integration period and software level. For example;
when the following is displayed:
1. The Model 192 senses the power line frequency and sets
the A/D conversion rate.
2. The F60 indicates that the integration time has been set
for 16.6 milliseconds.
3. The C4 is a code that identifies the software revision that
is installed in the Model 192.
4. If the following is displayed the F50 indicates that the integration time has been set for 20 milliseconds.
4.3 OPERATING INSTRUCTIONS
Basic operation of the Modal 192 is presented in the following paragraphs. The upper three binding posts are used for
voltage input connections. The lower four binding posts are
used for ohms connections. The LO binding posts for
ACV, DCV and 0 are wired together.
Switch Setting
s102
115VAC
rlzKm?q
-1-6
-1-5
CAUTION
Do not apply voltages between the LO
binding posts. Instrument damage may
OCC”r.
WARNING
Maximum floating voltage is 1400VDC
or peak AC at < 5 x 106V.H~. Do not exceed the maximum floating voltage
ratings. Destruction of insulation could
present e shock hazard.
The LO inputs may be floated at voltages up to 1.4kV at
5x 106V*Hz. with reference to chassis ground. Chassis
ground is connected to earth ground with the line power
cord and an appropriately grounded three-wire receptacle.
WARNING
Hazardous voltages may be present on
the LO input terminals. Any voltage that
is applied to LO will also be present at
the DLO terminals.
CAUTION
Do not exceed maximum input limits
given in Table 4-2.
DC voltage sources. AC voltage sources, and Resistance
values may be connected to the input termtnals
simultaneously with consideration for possible ground loops
and noise. Refer to Table 4-2.
Table 4-2. Maximum Input
Function
4.4 ZERO
The Zero control serves as a baseline suppression subtract-
ing a stored offset or measured value from a subsequent
measurement. When the Zero control is enabled, the Zero
LED will light. All readings displayed while in the Zero mode
are the difference between the stored baseline and the
actual voltage level. The baseline obtained while the Zero
control is enabled represents a specific level or quantity of
volts or ohms. For example, if 1OOmV is zeroed. then,
1OOmVDC represents the specific level of the Zero baseline.
One hundred millovolts will then be automatically sub-
tracted from readings on any DCV range. The value for the
[ Ranga
Maximum Input
1200VDC or Peak AC
1OOOV rms sins or DC,
2x 10’V’Hz
360V peak or 250V rms
4-l
baseline can be as little as a few microvolts or as large as
999 volts. This capacity enables the user to zero a wide
range of voltages. For example:
4.6 OVERRANGE INDICATION
Overrange is indicated by the following display:
Displayed Push
offset Zero Input Result
Example #l 1.23000 .ooooo
Example #2 .23000 .ooooo
Note
Setting range lower than the zero baseline
value, will overrange display.
WARNING
The voltage present on the input may be
greater than the displayed reading when
the instrument is Zeroed.
Example: 1OOV = stored baseline
lSOV=actual voltage to be
measured
SOV = displayed reading
One baseline can be stored for each of the functions (DC
Volts, AC Volts, and Ohms). For example, 20mVDC can be
stored for DC volts, 1OVAC volts and 50 can be stored for
ohms. Proceed as follows:
1. To store a zero value for DC volts, select the DC Volts
function. Press the ZERO Button. The reading on the
Model 192 display will be stored as the zero value. The
zero control can be disabled by pressing the ZERO button
again.
2. To store a zero value for AC volts, select the AC volts
function. Press the Zero button. The reading on the
Model 192 display will be stored as the zaro value. The
zero control can be disabled by pressing the ZERO button
again.
3. To store a zero value for Ohms, select the Ohms function. Press the ZERO button. The readina on the Model
192 display will be stored as the zero value. The zero con-
trol can be disabled by pressing the ZERO button again.
4. The Model 192 will retain these zero values. If the func-
tion is changed the Model 192 will recall the value of zero
that was set for that function. To replace an earlier stored
zero value, simply press the ZERO button twice. The
reading that was on the Model 192 will be stored as the
new zero value.
It is important to note that the use of zero reduces the
dynamic range of measurement. For instance, if
+ l.OOOOOVDC is the zeroed value, input voltages greater
than 2V would still overload the AID converter (200,000
counts). even though overrange would occur at approximately 100,000 counts displayed. Readings less than -lV
would cause overrange (2V less than + 1Vl because of the
maximum display reading of 199,999 counts. This reduction
in the dynamic range of the measurement is illustrated in
Figure 4-1. In DCV function, both the Displav dvnamic
range and the Input dynamic range can be &wed& and
thus, both can limit the dynamic range of the measurement.
Apply
1 .ooooo - .23000
1 .ooooo .77000
Displayed
If the overflow is negative then a minus I-) prefix will
precede the displayed OFLO.
\
Figure 4-l. Effect Of Zero Function on Dynamic Range
of Measurement
4.6 FILTER
The Model 192 employs digital filtering techniques. There
are three internal filter routines. Figure 42 shows the filter
response curves. In the Bench mode of operation, the internal computer automatically selects the filter. Filter 1 is
selected on 5’S digit readings and filter 2 on 6% digit
readings.
An exception to this is a 20 digit window selected on the
20MIl range in the 5H digit mode of operation. In the 6%
mode a 60 digit window (filter 2) is selected, similar to other
6% digit modes.
When a large input change is sensed, the microprocessor
disables the digital filter. This permits a fast response to the
input (as noted by A in Figure 4-2). When the reading nears
its final value, the filter is turned on (as noted by 6 in Figure
4.2). This permits low noise senling to the final value.
A third filter, filter 3, is available through the front panel pro-
gram number two. Filter routines 1, 2, and 3 can be programmed through the IEEE programming option. Refer to
the IEEE-466 Instruction Manual for Bus operation.
Figure 4-2. Input Filter Response Graph
9
,HPllT O”~lWC PAHW
/
4-2
4.7 DC VOLTAGE MEASUREMENT
The Model 192 reads DC voltage from 1aV to 1200V. DC
volts are measured as follows:
CAUTION
Do not exceed the 1ZOOVDC maximum
allowable input voltage rating. Instru-
ment damage may occur.
1. Turn power ON by pressing the POWER ON/OFF button.
If the instrumc?t is within 0°C to 50°C. it is useable immediately, but a two hour warmup is required to obtain
rated accuracy.
2. Press DCV button. The Model 192 will enter the DCV
mode automatically at power up.
3. Zero instrument on the .2V range. Zero must be set with
the Zero function for rated accuracy. Zeroing is necessary
to compensate for thermal EMFs generated by the connections to the circuit to be measured. These voltages
may be only a few microwIts or several tens of
microvolts. Set Zero as follows:
A. Set the output of test circuit for zero volts or discon-
nect the test leads at the circuit and short them.
B. Set the Model 192 on the .2V range.
C. Press the ZERO button.
D. Select range from the five ranges available. The
decimal point is positioned by the Range button. The
1200V range is selected by the 2000 button. If the
20MR is inadvertently pressed when in the DCV function, the Model 192 will set the range to 1200V.
4. Connect input between the DCV and LO (see figure 43).
The binding posts accept wires, spade lugs, or banana
plugs for ease of connecting the potential to be
measured. Low thermal cabling atid connections are
recommended for measurements on the .2V range.
CAUTION
Do not exceed the 1200VDC maximum
allowable input voltage rating; Instrument damage may occur.
5. Take readings by observing the displayed digits and
decimal Point locations. All ranges are direct reading in
volts.
4.6 RESISTANCE MEASUREMENTS
The Model 192 DMM measures resistance from lm$figit to
20Mn. The Model 192 provides automatic 2.wire or 4.wire
ohms operation (see paragraph 4.9 for d-wire ohms
measurements). Measure resistance as follows:
1. Turn on power by pressing the POWER ON/OFF button.
2. Press kR button.
3. Select range from the six ranges available lor autorangei.
The decimal point is positioned by the Range button.
4. Connect input between n and LO Isee Figure 4-4).
5. Accomplish Zero for a 2.wire or 4.wire measurement on
the .2kQ range. Zero must be set with the Zero function
to obtain rated accuracy. Zeroing is necessav to cornpensate for test lead resistance on 2.wire measurements
and for thermal EMFs on 2. and 4.wire measurementS.
set zero as follows:
A. Disconnect the test leadsat the circuit to be measured
and short them.
B. Press the “ZERO” button.
C. Reconnect the test leads.
6. Take reading.
CAUTION
Maximum allowable input voltage lall
ohms rangesl: 38OV peek, 250V rms. Do
not exceed maximum voltage. Instrument damage may occur. Table 4-3
lists the maximum outputs for all the
resistance ranges.
Table 4-3. Resistance Ranges
INPUT IMPEDANCE:
Figure 4-3. DC
1OOOMD on 2V-20V ranges
1OMn on 2OOV-1200V ranges
Voltage Measurements
Range
Setting I (Shorted1
* HI binding post Ired) is negative.
** Zero must be set to obtain rated accuracy~
Maximum Outputs*
!
i
v IOpen) ~
4-3
Figure 4-4. Resistance Measurements
Figure 4-5. Four-Wire Resistance Measurement
4.10 AC VOLTAGE MEASUREMENT II910 AC Option)
4.9 FOUR-WIRE OHMS MEASUREMENT
For 4-wire measurements. connect the sense leads to the
circuit to be measured and to the fi SENSE terminals on the
Model 192 (see Figure 4-5). This arrangement eliminates the
error due to the voltage drop ecross the current-carrying
leads. Accurate, high resolution ohms measurements are
obtained using 4wire connections.
Four-wire ohms measurements are recommended when
utilizing the .2k. 2k. or 20k0 range. Maximum test lead
resistance for 4-wire ohms measurement is given in table
4-4.
Table 4-4. Maximum Four-Wire Test Lead Resistance
Lead
Range
.2k
2k
20k
200k
2000k
20M
Resistance+
70
220
700
2200
7oon
22000
“Maximum resistance per lead for en additional 1 digit error
et 6K digits.
With the Model 1910 option, the Model 192 reads AC
volteges from 1OpV digit to 1OOOV. The instrument is
average responding and is calibrated to the root mean
sauare value of e sine weve. with a freauencv span of 20Hz
to 100kHz.
INPUT IMPEDANCE: 2MR shunted
by less than
5OpF
Figure 4-6. AC Voltage Measurements
CAUTION
Do not exceed maximum allowable input voltage. Instrument damage may
occur. Maximum input is both the
voltage and voltage hertz product. If
maximum ratings ara exceeded, instrument damage will occur.
It is recommended that measurements greater than 150
volts and 2OkHz be made in the Manual ranging mode to
pravant autoranging to an incorrect range. This is due to the
decreased accuracy specified above 20kHz.
Accuracy is specified for 1000 counts and above. The maximum reading is 199999 at 5’h digits. Overrange is indicated
by OFLO. Maximum allowable input is 1OOOV rms or DC;
2x lOW*Hz. Measure AC voltage as follows:
1. Turn power ON by pressing POWER ON/OFF button.
2. Press ACV button.
NOTE
The Model 192 will display “NO AC” if AC is
selected without an AC option installed.
3. Select range from the four ranges available. The decimal
point is positioned by the Range button. The 1OOOV
range l75OV range if the Model 1920 is intalledj is
selected with the 2000 button. If the 20MQ button is inadvertently pressed when in ACV function, the Model
192 will set the range to 1OOOV.
4. Zero OFF unless measurements are to be made as deviations from a preset value.
NOTE
Do not use the ZERO button to zero the AC
function. A small residual voltage is normal
lapproxiamtely 200rV). If ZERO is used, the
reading will be low by the amplitude of the
zeroed residual voltage.
5. Connect input to be measured between the ACV and LO
binding posts (see Figure 4-61.
6. Take reading.
4.11 AC VOLTAGE MEASUREMENT (1920 TRMS
Option)
A separate manual is provided with the Model 1920 containing installation, operation and calibration instructions.
6514.6
SECTION 5
FRONT PANEL PROGRAMS
5.1 INTRODUCTION
This section contains information and instructions
necessary for operating the nine internal programs of the
Model 192. These programs are run by depressing the front
panel PRGM button, along with the button representing the
appropriate program number. Some of the programs require
numerical constants that must be entered from the front
panel by using the numbered buttons. Other programs will
display appropriate messages. Program examples are provided when necessary to instruct the operator in practical
applications. For basic operation of the front panel buttons,
refer to Section 4. The programs, which are summarized in
Table 5-l. are explained in detail in the following paragraphs. Refer to Figure 5-1 for front panel details.
5.2 PROGRAM NOTES
1. Most of the front panel buttons serve a dual purpose.
The Range, Function, end Zero buttons are numbered in
sequence. These numbered buttons are used when a
program number or numerical constant is to be entered.
2. Each program is entered by depressing the PRGM but-
ton followed by the desired program number.
3. PROGRAM$is used to cancel all other programs except
PROGRAMS 1 end 2. An appropriate clear message is
displayed when this program is entered.
4. PROGRAM 1, which controls the display resolution, and
PROGRAM 2, which controls the internal filter, may
both be used with any other program.
5. PROGRAMS 3 through 7 are mutually exclusive; only
one of these programs may be used at any one time.
6. New programs may be entered without clearing a program that is presently running. To do so, depress the
PRGM button, followed by the desired program
number.
7. Anempting to enter an invalid program number will
result in the following error message:
B. The numerical constants used for each program are
stored separately and will not change unless entered at
the appropriate point in each program. Constant values
will be lost if the power is turned off.
9. Constants are to be entered when the operator is
prompted to do so by the instrument. When entering a
numerical constant:
A. The constant is entered by depressing the numoereo
buttons in the desired sequence.
B. The decimal point is automatically placed in accor-
dance with the allowable range of the constant.
C. Data is entered into the digit whose “c” segment is
fleshing by pressing the desired numbered button.
The “c” segment of a display digit is shown below:
E-8, ,,
c segment
As each digit is entered, the blinking segment will
move one place to the right until all the necessary
digits have been entered.
D. Only a 0 or 1 may be entered as the first digit for any
of the constants.
Table 6-l. Front Panel Program Summary
Program
Number Operation
0
1
2
3
4
:
7
B
‘The Service Program is intended for use only by qualified personnel. See Section 8
of this manual for complete details.
Clears PROGRAMS 3-7
Display Resolution
Filter Mode
Offset/Scale
Percent Deviation
Min/Max
High/Low/Pass
Data Logger
Service’
Required
Constant
None
None
None
S (scaling factor)
b (offset)
n (comparison constant1
None
LOL (low limit)
HIL (high limit)
r (time interval1
None
6-l
192 PROGRAMMABLE DMM
Y--c71 n n 17 17
DCV AC”
qo
6-2
A
MINUS 1-l
B
NUMBERS 0 THROUGH 5
C
NUMBERS 6 THROUGH 9
D
PRGM
E ENT/RECALL
Figure 6-l. Front Panel Program Buttons
E. Only es many significant digits es necessary need to
be entered. The Model 192 will complete the constant with trailing zeroes where necessary.
F. Invalid keys will be ignored. If an invalid key is
depressed, the blinking “c” segment will remain at
the current digit.
G. If an incorrect digit is entered, the complete constant
must be reentered. The new value may be entered by
cycling the display around to the beginning by
repeatedly depressing one of the number buttons.
H. A neoative constant mev be entered bv deoressina
I~ I
the front panel minus (-I button. The display will the;
show a negative number. This mey be done at any
point in the numeric input sequence. Depressing the
minus button a second time will restore the constant
to s positive value.
If too many digits are entered, the display will begin
again et the first digit on the left. All the digits in the
constant must then be entered again.
Once all the digits of the desired constant are shown
on the display, the constant is entered into the program by depressing the front panel ENT button.
The number of significant digits to be entered for s
constant will depend on the display resolution mode
in use. In the 5 H digit mode, only five digits after the
leadingfi or 1 may be entered. In the 6 !4 mode, up to
six digits in addition to the leading 0 or 1 may be
entered.
10. PROGRAMS 3 through 7 will be terminated if the Model
192 receives a Remote Enable command over the
IEEE-488 bus. PROGRAM&through 2 are not affected
by the Remote Enable command.
Note
If it becomes necessary to exit a program in
progress (for example, to change resolution
with PROGRAM 1, or change the filter mode
with PROGRAM 21, readings will be missed
while the instrument waits for the operator
to enter the desired program number.
11. When the front panel PRGM button is pressed, the
instrument will prompt the operator to enter the desired
program number by displaying the following message:
Note that the question mark on the display will blink
until a program number is entered. Depressing en invalid
button at this point will result in the following message,
which will be displayed for K second:
[no]
gram, the following message will be displayed for H
second:
j-z-T-q
13. While PROGRAMS 3 through 7 era being run, the front
panel PRGM indicator light will be on. This light will go
off if the program is cancelled. either by using PROGRAM 8: or if the Remote Enable command is received
over the IEEE-488 bus.
14. The front panel PRGM button will be inoperative if the
IEEE REMOTE indicator light is on. Once the instrument
is in the Remote mode, the following IEEE command
sequence must be sent to restore front panel program-
ming operation: GTL (Go to Local); DCL (Device Clear).
For more information on IEEE commands. refer to the
Model 1923 Instruction Manual. Alternately. the instrument may be turned off and then powered-up again to
restore programming operation. Of course. any con-
stants previously stored will be lost, and the instrument
will return to the power-on default conditions.
15. When PROGRAMS 3 through 7 are entered, the AUTO
range will be cancelled. The instrument will stay on the
present range when one of these programs is entered
6.3 PROGRAM 0. CLEAR
PROGRAMtimey be used to cancel PROGRAMS 3 through
7. This program is entered by depressing the PRGM switch
followed by the 0 button es follows:
1. Press PRGM. The instrument will display the following,
indicating it is waiting for s program number:
r-Fzi-71
2. Press 0. The following message will be displayed for approximately % second:
[ml
3. Immediately following the program number indication.
the following message will be displayed for Ih second:
4. PROGRAMS 3 through 7 will be cancelled. and the
Model 192 will return to the normal operating mode by
displaying readings. The operation of the Function.
Range, and Zero buttons will be restored after PRO-
GRAM 0 is entered.
5. Depressing the RECALL button after PROGRAM fi has
been run will cuese the following message to be dis-
played for H second:
12. The Range, Function, and Zero buttons are locked out
while PROGRAMS 3 through 7 sre in progress. The operator must exit the program if these parameters are to
be changed. If en invalid key is pressed durinp a pro-
6-3
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