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
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.
