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Keithley 2700 Service Manual

Data acquisition system
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Model 2700 Multimeter/
Data Acquisition System
Service Manual
Contains Servicing Information

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Summary of Contents for Keithley 2700

  • Page 1 Model 2700 Multimeter/ Data Acquisition System Service Manual Contains Servicing Information...
  • Page 2 AGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR DAMAGE TO PROPERTY. Keithley Instruments, Inc. • 28775 Aurora Road • Cleveland, OH 44139 • 440-248-0400 • Fax: 440-248-6168 • http://www.keithley.com BELGIUM: Keithley Instruments B.V.

  • Page 3: Service Manual

    Model 2700 Multimeter/Data Aquisition System Service Manual ©1999, Keithley Instruments, Inc. All rights reserved. Cleveland, Ohio, U.S.A. Second Printing, February 2000 Document Number: 2700-902-01 Rev. B...
  • Page 4 Revision A (Document Number 2700-902-01) ............November 1999 Revision B (Document Number 2700-902-01) ............. February 2000 All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc. Other brand names are trademarks or registered trademarks of their respective holders.

  • Page 5: Safety Precautions

    As described in the International Electrotechnical Commission (IEC) Standard IEC 664, digital multi- meter measuring circuits (e.g., Keithley Models 175A, 199, 2000, 2001, 2002, and 2010) are Installation Category II. All other instruments’ signal terminals are Installation Category I and must not be connect- ed to mains.
  • Page 6 To maintain protection from electric shock and fire, replacement components in mains circuits, including the power transformer, test leads, and input jacks, must be purchased from Keithley Instruments. Standard fuses, with applicable national safety approvals, may be used if the rating and type are the same. Other components that are not safety related may be purchased from other suppliers as long as they are equivalent to the original component.

  • Page 7: Table Of Contents

    Restoring factory defaults ............1-5 Performing the verification test procedures ....... 1-6 Verification test summary ........... 1-6 Test considerations .............. 1-7 Model 2700 verification ............. 1-8 Verifying DC voltage ............1-8 Verifying AC voltage ............1-9 Verifying DC current ............1-11 Verifying AC current ............
  • Page 8 Calibration Introduction ................2-2 Environmental conditions ............2-2 Warm-up period ..............2-2 Line power ................2-2 Calibration considerations ............2-3 Calibration code ................2-4 Front panel calibration code ..........2-4 Remote calibration code ............2-4 Comprehensive calibration ............2-5 Calibration cycle ..............2-5 Recommended equipment ...........
  • Page 9 Troubleshooting Introduction ................4-2 Repair considerations ..............4-2 Power-on self-test ............... 4-2 Front panel tests ................. 4-3 KEY test ................4-3 DISP test ................4-3 Principles of operation ............... 4-4 Power supply ............... 4-4 Display board ..............4-6 Digital circuitry ..............4-7 Analog circuitry ..............
  • Page 10 Specifications Accuracy calculations .............. A-12 Calculating DC characteristics accuracy ......A-12 Calculating AC characteristics accuracy ......A-12 Calculating dBm characteristics accuracy ......A-13 Calculating dB characteristics accuracy ......A-13 Additional derating factors ..........A-14 Optimizing measurement accuracy ......... A-14 DC voltage, DC current, and resistance: ......A-14 AC voltage and AC current: ..........
  • Page 11 Manufacturing calibration commands ........B-15 :AC:STEP<14|15> ............B-15 :DC:STEP0 ..............B-15 Model 7700 calibration commands ......... B-16 :CODE ................B-17 :COUNt? ................B-17 :DATE? ................B-18 :INIT ................B-18 :LOCK ................B-19 :LOCK? ................B-19 :RCOunt ................B-19 :SAVE ................B-20 :STEP0 ................
  • Page 12 List of Illustrations Performance Verification Figure 1-1 Connections for Model 2700 DC volts verification ....1-8 Figure 1-2 Connections for Model 2700 AC volts verification ....1-9 Figure 1-3 Connections for Model 2700 DC current verification ...1-11 Figure 1-4 Connections for Model 2700 AC current verification ...1-12...
  • Page 13 Troubleshooting Figure 4-1 Power supply block diagram ........... 4-4 Figure 4-2 Digital circuitry block diagram ..........4-6 Figure 4-3 Analog circuitry block diagram ..........4-9 Calibration Program Figure C-1 Model 2700 calibration program ........... C-3...
  • Page 14 List of Tables Performance Verification Table 1-1 Recommended verification equipment ........1-4 Table 1-2 DCV reading limits ..............1-9 Table 1-3 ACV reading limits ...............1-10 Table 1-4 DCI limits ................1-11 Table 1-5 ACI limits ................1-12 Table 1-6 Limits for resistance verification ...........1-14 Table 1-7 Thermocouple temperature verification reading limits ..1-16 Table 1-8...
  • Page 15 Replaceable Parts Table 6-1 Model 2700 motherboard parts list ......... 6-3 Table 6-2 Model 2700 display board parts list ........6-8 Table 6-3 Model 2700 connector board parts list ........6-9 Table 6-4 Model 2700 miscellaneous parts list ........6-10 Table 6-5 Model 7700 parts list ............

  • Page 17: Performance Verification

    Performance Verification...

  • Page 18: Introduction

    Model 7700 verification: Discusses procedures to verify accuracy of measurement made through the Model 7700 20-Channel Multiplexer. Note that the same general pro- cedures can be used to verify measurement accuracy of other Model 2700 plug-in mod- ules that have similar functions. For specific information about the individual modules,...

  • Page 19: Verification Test Requirements

    A relative humidity of less than 80% unless otherwise noted. Warm-up period Allow the Model 2700 to warm up for at least two hours before conducting the verification procedures. If the instrument has been subjected to temperature extremes (those outside the ranges stated above), allow additional time for the instrument’s internal temperature to stabilize.

  • Page 20: Recommended Test Equipment

    AC Voltage, 50kHz: 700V, ±375ppm DC Current, 3A, ±500ppm AC Current, 1kHz, 3A, ±457ppm Keithley 3930A or 3940 Frequency Synthesizer: 1V RMS, 10V RMS, 1kHz, ±5ppm, steady state and burst modulation General Radio 1433-T Precision Decade Resistance Box: 10Ω to 400Ω, ±0.02%...

  • Page 21: Verification Limits

    The following is an example of how reading limits have been calculated. Assume you are testing the 10V DC range using a 10V input value. Using the Model 2700 one-year accuracy specification for 10V DC of ± (30ppm of reading + 5ppm of range), the calculated limits are: Reading limits = 10V ±...

  • Page 22: Performing The Verification Test Procedures

    Performance Verification Performing the verification test procedures Verification test summary Verification tests can be performed either through the Model 2700 front panel terminals or through plug-in modules. This section contains the following procedures: • Model 2700 verification: Use this procedure to test Model 2700 accuracy through the front panel terminals.

  • Page 23: Test Considerations

    Do not use autoranging for any verification tests because autorange hysteresis may cause the Model 2700 to be on an incorrect range. For each test signal, you must manu- ally set the correct range for the Model 2700 using the range keys.

  • Page 24: Model 2700 Verification

    Note: Use shielded, low-thermal cables for 100mV and 1V ranges. Select the DC volts function by pressing the DCV key, and set the Model 2700 to the 100mV range. Set the calibrator output to 0.00000mV DC, and allow the reading to settle.

  • Page 25: Verifying Ac Voltage

    V•Hz input, because instrument damage may occur. Follow these steps to verify AC voltage accuracy: Connect the Model 2700 HI and LO INPUT jacks to the AC voltage calibrator as shown Figure 1-2. Be sure the INPUTS switch is in the FRONT position.

  • Page 26: Table 1-3 Acv Reading Limits

    Performance Verification Select the AC volts function by pressing the ACV key. Set the Model 2700 for the 100mV range; make sure that REL is disabled. Source 1kHz and 50kHz AC voltages for each of the ranges summarized in Table 1-3, and make sure that the respective Model 2700 readings fall within stated limits.

  • Page 27: Verifying Dc Current

    Verifying DC current Check DC current accuracy by applying accurate DC currents from the DC current calibra- tor to the AMPS input of the Model 2700 and verifying that the displayed readings fall within specified limits. Follow these steps to verify DC current accuracy:...

  • Page 28: Verifying Ac Current

    Check AC current accuracy by applying accurate AC voltage current at specific frequencies from the AC current calibrator to the Model 2700 input, and verifying that the displayed read- ings fall within specified limits. Follow these steps to verify AC current:...

  • Page 29: Verifying Resistance

    Select the Model 2700 4-wire resistance function by pressing the Ω4 key, then choose the SLOW integration rate with the RATE key. Set the Model 2700 for the 100Ω range, and make sure the FILTER is on. Enable OCOMP (offset-compensated ohms) for 100Ω range verification. (Press SHIFT then OCOMP.)

  • Page 30: Figure 1-6 Connections For Model 2700 Resistance Verification (100Mω Range)

    __________ to __________ MΩ 100MΩ 100MΩ 99.7970 to 100.2030MΩ __________ to __________ MΩ * Enable O COMP (offset-compensated ohms) when testing 100Ω range. ** Calculate limits based on actual calibration resistance values and Model 2700 one-year resistance accuracy specifications. See Verification limits.

  • Page 31: Verifying Temperature

    Figure 1-1.) Be sure the INPUTS switch is in the FRONT position. Configure the Model 2700 for °C units, type J temperature sensor, and 0°C simulated reference junction as follows: Press SHIFT then SENSOR, and note the unit displays the temperature units: UNITS: C.
  • Page 32 Be sure the INPUTS switch is in the FRONT position. Configure the Model 2700 temperature function for ˚C units and RTD temperature sen- sor (α=0.00385) as follows: Press SHIFT then SENSOR, and note the unit displays the temperature units: UNITS: C.

  • Page 33: Verifying Frequency

    Set the function generator to output a 1kHz, 1V RMS sine wave. Select the Model 2700 frequency function by pressing the FREQ key. Verify that the Model 2700 frequency reading is between 999.9Hz and 1.0001kHz. Figure 1-7 Connections for Model 2700 frequency verification...

  • Page 34: Model 7700 Verification

    Although the following tests are based on the Model 7700 20-Channel Multiplexer, the same general procedures can be used for other plug-in modules that have similar capabilities. Refer to the Model 2700 User’s Manual for specific information on ter- minals and connections for other plug-in modules.

  • Page 35: Table 1-9 Plug-In Module Dcv Reading Limits

    Performance Verification 1-19 Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS switch is set to the REAR position.

  • Page 36: Figure 1-9 Connections For Model 7700 Ac Volts Verification

    1-20 Performance Verification Verifying AC voltage Check AC voltage accuracy by applying accurate AC voltages at specific frequencies from the AC voltage calibrator to the Model 7700 inputs and verifying that the displayed readings fall within specified ranges. CAUTION Do not exceed 300V RMS between plug-in module INPUT H and L termi- nals or between adjacent channels, or 8 ×...

  • Page 37: Table 1-10 Plug-In Module Acv Reading Limits

    Performance Verification 1-21 Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS switch is set to the REAR position.

  • Page 38: Figure 1-10 Connections For Model 7700 Dc Current Verification

    1-22 Performance Verification Verifying DC current Check DC current accuracy by applying accurate DC currents from the DC current calibra- tor to the input terminals of the Model 7700 and verifying that the displayed readings fall within specified limits. Follow these steps to verify DC current accuracy: Connect the Model 7700 CH21 H and L terminals to the calibrator as shown in Figure 1-10.

  • Page 39: Table 1-11 Plug-In Module Dci Limits

    Performance Verification 1-23 Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS switch is set to the REAR position.

  • Page 40: Verifying Ac Current

    CH11 CH12 CH13 CH14 CH15 CH16 CH21 Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS switch is set to the REAR position.

  • Page 41: Verifying Resistance

    Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS switch is set to the REAR position.

  • Page 42: Figure 1-13 Connections For Model 7700 Resistance Verification (100Mω Range)

    Figure 1-13. Disable external sense on the calibrator. Set the Model 2700 for the 100MΩ range. Source a nominal 100MΩ resistance value, and verify that the reading is within calcu- lated limits for the 100MΩ range. Press the OPEN key to open Channel 1.

  • Page 43: Verifying Temperature

    Figure 1-14. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS switch is set to the REAR position.

  • Page 44: Figure 1-14 Connections For Model 7700 Thermocouple Temperature Verification

    1-28 Performance Verification Source each of the voltages summarized in Table 1-14 and verify that the temperature readings are within limits. Be sure to select the appropriate thermocouple type for each group of readings. (See step 3 above.) Open Channel 1 after the test is complete. Table 1-14 Model 7700 thermocouple temperature verification reading limits Thermocouple type...
  • Page 45 Figure 1-12 similar connecting scheme.) Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS switch is set to the REAR position.

  • Page 46: Verifying Frequency

    Figure 1-15.) Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow the unit to warm up for one hour before proceeding. Be sure the front panel INPUTS switch is set to the REAR position.

  • Page 47: Figure 1-16 Connections For Model 7700 Ratio And Average Verification

    Performance Verification 1-31 Select the Model 2700 RATIO function (press SHIFT then RATIO). Set the calibrator output to 1.00000V DC, and allow the reading to settle. Verify that the ratio reading is between 0.9999926 and 1.000074. Press OPEN to open Channel 1.
  • Page 48 1-32 Performance Verification...

  • Page 49: Calibration

    Calibration...

  • Page 50: Introduction

    A relative humidity of less than 80% unless otherwise noted Warm-up period Allow the Model 2700 Multimeter/Data Acquisition system to warm up for at least two hours before performing calibration. If the instrument has been subjected to temperature extremes (those outside the ranges stated above) allow extra time for the instrument’s internal temperature to stabilize.

  • Page 51: Calibration Considerations

    • Always let the source signal settle before calibrating each point. • If an error occurs during calibration, the Model 2700 will generate an appropriate error message. See Appendix B for more information. WARNING Observe the following safety precautions when performing these tests: •...

  • Page 52: Calibration Code

    Confirm the code by pressing ENTER. The Model 2700 allows you to define a new calibration code. Use the up and down range keys to toggle between yes and no. Choose N if you do not want to change the code.

  • Page 53: Comprehensive Calibration

    100V:±90ppm 700V:±85ppm Miscellaneous equipment: Keithley 8610 low-thermal shorting plug Double banana plug to double banana plug shielded cable BNC to double banana plug shielded cable *1kHz specifications. 10mV and 700V points require 1kHz only. All calibrator specifications are 90-day, 23°C ±5°C specifications...

  • Page 54: Aborting Calibration

    • Setting calibration dates Preparing the Model 2700 for calibration Turn on the Model 2700, and allow it to warm up for at least two hours before perform- ing a calibration procedure. Start the calibration process as follows: Access the calibration menu by pressing SHIFT then TEST, then display TEST: CALIB using the up or down range key.

  • Page 55: Figure 2-1 Low-Thermal Short Connections

    AC voltage and AC current calibration Front panel short and open calibration At the Model 2700 prompt for a front panel short, do the following: Connect the Model 8610 low-thermal short to the instrument front panel INPUT and SENSE terminals as shown in Figure 2-1.

  • Page 56: Figure 2-2 Connections For Dc Volts And Ohms Calibration

    DC volts calibration After the front panel short and open procedure, the unit will prompt you for the first DC voltage: +10V. Do the following: Connect the calibrator to the Model 2700 as shown in Figure 2-2. Wait three minutes to allow for thermal equilibrium before proceeding.

  • Page 57: Table 2-3 Dc Volts Calibration Summary

    If your calibrator cannot output the values recommended in Table 2-3, use the left and right arrow keys, and the up and down range keys to set the Model 2700 display value to match the calibrator output voltage. Table 2-3...

  • Page 58: Figure 2-3 Connections For Dc And Ac Amps Calibration

    After the 1MΩ resistance point has been calibrated, the unit will prompt you to apply 10mA. Follow these steps for DC current calibration: Connect the calibrator to the AMPS and INPUT LO terminals of the Model 2700 as shown in Figure 2-3.

  • Page 59: Figure 2-4 Connections For Ac Volts Calibration

    Calibration 2-11 AC voltage calibration Follow these steps for AC voltage calibration: Connect the calibrator to the Model 2700 INPUT HI and LO terminals as shown in Figure 2-4. Figure 2-4 Connections for AC volts calibration AC Voltage Calibrator Input HI...

  • Page 60: Table 2-7 Ac Current Calibration Summary

    After the 700VAC at 1kHz point has been calibrated, the unit will prompt you for 100mA at 1kHz. Follow these steps for AC current calibration: Connect the calibrator to the AMPS and INPUT LO terminals of the Model 2700 as shown in Figure 2-3.

  • Page 61: Remote Calibration

    RS-232 port using a straight-through 9-pin to 9-pin cable (use a 9-25-pin adapter if necessary). Turn on the Model 2700, and allow it to warm up for at least two hours before perform- ing calibration. Make sure the primary address of the Model 2700 is the same as the address specified in the program that you will be using to send commands.
  • Page 62 Keep drafts away from low-thermal connections to avoid thermal drift, which could affect calibration accuracy. Send the following command: :CAL:PROT:DC:STEP1 After the Model 2700 completes this step, remove the low-thermal short, and then send this command: :CAL:PROT:DC:STEP2 NOTE Be sure to minimize movement near front Input terminals. Excessive movements can cause capacitive coupling errors, which could affect calibration accuracy.

  • Page 63: Table 2-8 Dc Voltage Calibration Programming Steps

    Send the indicated programming command. (Change the voltage parameter if you are using a different calibration voltage.) • Wait until the Model 2700 completes each step before continuing. NOTE Ensure the calibrator has settled to the final value. You can do so by verifying that the “Settled”...

  • Page 64: Table 2-10 Dc Current Calibration Programming Steps

    Calibration DC current calibration After the 1MΩ resistance point has been calibrated, follow these steps for DC current calibration: Connect the calibrator to the AMPS and INPUT LO terminals of the Model 2700 as shown in Figure 2-3. Perform the calibration steps listed in Table 2-10.

  • Page 65: Table 2-11 Ac Voltage Calibration Programming Steps

    700VAC at 1kHz 700.000V, 1kHz :CAL:PROT:AC:STEP10 AC current calibration Follow these steps for AC current calibration: Connect the calibrator to the AMPS and INPUT LO terminals of the Model 2700 as shown in Figure 2-3. Perform the calibration steps summarized in Table 2-12.

  • Page 66: Manufacturing Calibration

    Table 2-13 Recommended equipment for manufacturing calibration Stanford Research Systems DS345 Function Generator: 1V RMS, 3Hz, ±5ppm 1V RMS, 1kHz, ±5ppm Keithley Model 2001 or 2002 Digital Multimeter: 1V, 3Hz AC, ±0.13% Keithley 7797 Calibration/Extender Board Keithley 7798-250B Calibration/Extender/Test Board...

  • Page 67: Extender Board Preparation

    Calibration 2-19 Extender board preparation Before performing manufacturing calibration, short the output HI, LO, SHI, and SLO terminals of the 7798-250B Calibration/Extender/Test Board together using clean, solid copper wires. These connections will form a low-thermal short necessary for the manufacturing calibration procedure.

  • Page 68: Front Panel Manufacturing Calibration

    Perform the entire front panel comprehensive calibration procedure discussed earlier in this section. (See “Comprehensive calibration” earlier in this section.) Connect the function generator to the Model 2700 front panel INPUT jacks as shown in Figure 2-5. Select the front input jacks with the INPUTS switch.

  • Page 69: Remote Manufacturing Calibration

    :CAL:PROT:DC:STEP0 Perform the entire remote comprehensive calibration procedure discussed earlier in this section. (See “Comprehensive calibration” earlier in this section.) Connect the function generator to the Model 2700 INPUT jacks as shown in Figure 2-5. Select the front input jacks with the INPUTS switch.

  • Page 70: Model 7700 Calibration

    The Model 7700 being calibrated should be connected to the 7797 Calibration/Extender Board, and the extender board should then be installed in scanner Slot #1. Note that the module being calibrated will be external to the Model 2700 to avoid card heating during calibration. Model 7700 calibration...
  • Page 71 Accurately measure and record the cold temperature of the Model 7700 card surface at the center of the card. Press in and hold the Model 2700 OPEN key while turning on the power. Enable calibration by sending the :CODE command. For example, the default com-...
  • Page 72 2-24 Calibration...

  • Page 73: Routine Maintenance

    Routine Maintenance...

  • Page 74: Introduction

    The information in this section deals with routine type maintenance and includes procedures for setting the line voltage, replacing the Model 2700 line and front terminal AMPS fuses, and replacing the amps fuses for the Models 7700 and 7702 plug-in modules. Replacement of the Model 2700 non-volatile RAM battery is also covered.

  • Page 75: Figure 3-1 Power Module

    Routine Maintenance Figure 3-1 Model 2700 Power module WARNING: WARNING: NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY. NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY. DIGITAL I/O TRIG. LINK RS232 IEEE-488 MADE IN U.S.A. Line Voltage Selector...

  • Page 76: Replacing The Front Terminal Amps Fuse

    Routine Maintenance Replacing the front terminal AMPS fuse The front terminal AMPS fuse protects the Model 2700 current input from an over-current condition. Follow the steps below to replace the AMPS fuse. WARNING Make sure the instrument is disconnected from the power line and other equipment before replacing the AMPS fuse.

  • Page 77: Replacing Plug-In Module Amps Fuses

    Routine Maintenance Replacing plug-in module amps fuses NOTE The following procedures apply only to the Model 7700 and 7702 plug-in modules. WARNING The information in this section is intended only for qualified service per- sonnel. Do not perform these procedures unless you are qualified to do so. Make sure that all plug-in module connections are de-energized and dis- connected before replacing module amps fuses.

  • Page 78: Replacing Model 7702 Amps Fuses

    De-solder the blown CH21 or CH22 fuse as required, taking care not to damage the cir- cuit board or spread solder flux around the board. Install a new 3A, 250V fast-blow fuse, Keithley part number FU-107-1. CAUTION Do not use a fuse with a higher current rating than specified or module damage may occur.

  • Page 79: Figure 3-4 Model 7702 Amps Fuses

    Routine Maintenance Figure 3-4 Model 7702 amps fuses Model 7702 TE122 TE121 CH41 Fuse CH42 Fuse...

  • Page 80: Replacing Non-Volatile Ram Battery

    Routine Maintenance Replacing non-volatile RAM battery The Model 2700 has a three year battery for non-volatile RAM. Use the procedure below to replace the battery, if required. Refer to the disassembly procedures in Section 5 and the parts list and component layout drawings at the end of Section 6 for more information.

  • Page 81: Troubleshooting

    Troubleshooting...

  • Page 82: Introduction

    Troubleshooting Introduction This section of the manual will assist you in troubleshooting and repairing the Model 2700. Included are self-tests, test procedures, troubleshooting tables, and circuit descriptions. It is left to the discretion of the repair technician to select the appropriate tests and documentation needed to troubleshoot the instrument.

  • Page 83: Front Panel Tests

    Troubleshooting Front panel tests There are two front panel tests: one to test the functionality of the front panel keys and one to test the display. In the event of a test failure, refer to “Display board checks” for details on troubleshooting the display board.

  • Page 84: Principles Of Operation

    Troubleshooting Principles of operation The following information is provided to support the troubleshooting tests and procedures covered in this section of the manual. Refer to the following block diagrams: Figure 4-1 — Power supply block diagram Figure 4-2— Digital circuitry block diagram Figure 4-3 —...

  • Page 85: Table 4-1 Power Supply Components

    Troubleshooting AC power is applied to the AC power module receptacle. Power is routed through the line fuse and line voltage selection switch of the power module to the power transformer. The power transformer has a total of four secondary windings for the various supplies. AC voltage for the display filaments is taken from a power transformer secondary at F1 and F2, and then routed to the display board.

  • Page 86: Display Board

    Troubleshooting Display board Display board components are shown in the digital circuitry block diagram in Figure 4-2. Figure 4-2 Digital circuitry block diagram Battery Y103 BT100 Back Control/ Realtime Clock U171 NVRAM U136 U156, U157 U151, U152 Keypad Line Sync XADTX ADTX Control...

  • Page 87: Digital Circuitry

    Troubleshooting Display DS401 is the display module, which can display up to 12 alpha-numeric characters and includes the various annunciators. The display uses a common multiplexing scheme with each character refreshed in sequence. U402 and U403 are the drivers for the display characters and annunciators. Note that data for the drivers are serially transmitted from the microcontroller (MOSI and PC1).

  • Page 88: Analog Circuitry

    Troubleshooting RS-232 interface Serial data transmission and reception is performed by the TXDB and RXDB lines of the MPU. U159 provides the necessary voltage level conversion for the RS-232 interface port. IEEE-488 interface U158, U160, and U161 make up the IEEE-488 interface. U158, a 9914A GPIA, takes care of routine bus overhead such as handshaking, while U160 and U161 provide the necessary buffering and drive capabilities.

  • Page 89: Analog Circuitry Block Diagram

    Troubleshooting Figure 4-3 Analog circuitry block diagram Front Terminals S101 AMPS Scanner Outputs Current Shunts K103, R158, R205, R338 AC Switching & Gain K102, U102, U103, U105, Front Terminals U112, U118, U111, U110 S101 ACV, K101 FREQ DCV & Ohms MUX &...
  • Page 90 4-10 Troubleshooting AMPS input The ACA or DCA input signal is applied to the Current Shunt circuit, which is made up of K103, R158, R205, and R338. For the 20mA DC range, 5.1Ω (R205/[R338 + R158]) is shunted across the input. Relay K103 is energized (set state) to select the shunts. For all other DCA ranges, and all ACA ranges, 0.1Ω...

  • Page 91: Troubleshooting

    Troubleshooting 4-11 Troubleshooting Troubleshooting information for the various circuits is summarized below. See “Principles of operation” for circuit theory. Display board checks If the front panel DISP test indicates that there is a problem on the display board, use Table 4-2.

  • Page 92: Digital Circuitry Checks

    4-12 Troubleshooting Digital circuitry checks Digital circuit problems can be checked using Table 4-4. Table 4-4 Digital circuitry checks Step Item/component Required condition Remarks Power-on test RAM OK, ROM OK. Verify that RAM and ROM are functional. U152, pin 16 Digital common.

  • Page 93: Analog Signal Switching States

    Troubleshooting 4-13 Analog signal switching states Table 4-5 through Table 4-11 provide switching states of the various relays, FETs, and ana- log switches for the basic measurement functions and ranges. These tables can be used to assist in tracing an analog signal from the input to the A/D multiplexer. Table 4-5 DCV signal switching Range...

  • Page 94: Table 4-7 Ω2 Signal Switching

    4-14 Troubleshooting Table 4-7 Ω2 signal switching Range Q101 Q102 Q114 Q136 Q109 K101* K102* Q113 Q105 Q104 Q108 100Ω RESET 1kΩ RESET 10kΩ RESET 100kΩ RESET 1MΩ RESET 10MΩ RESET 100MΩ RESET * K101 set states: Pin 8 switched to Pin 7 Pin 3 switched to Pin 4 K102 reset states: Pin 8 switched to Pin 9...

  • Page 95: Table 4-10 Dca Signal Switching

    Troubleshooting 4-15 Table 4-10 DCA signal switching Range K103 20mA 100mA Reset Reset Reset K103 set states: Pin 8 to 7 Pin 3 to 4 K103 reset states: Pin 8 to 9 Pin 3 to 2 Table 4-11 ACA signal switching U105 U105 U111...

  • Page 96: Table 4-12 Dcv Signal Multiplexing And Gain

    4-16 Troubleshooting Table 4-12 through Table 4-16 can be used to trace the analog signal through the A/D multi- plexer (U163) to the final amplifier stage. These tables show the MUX lines (S3, S4, S6, S7) that are selected for measurement during the SIGNAL phase of the multiplexing cycle. Also included are switching states of analog switches (U129) that set up the gain for the final ampli- fier stage (U166).

  • Page 97: Table 4-15 Ω2 Signal Multiplexing And Gain

    Troubleshooting 4-17 Table 4-15 Ω2 signal multiplexing and gain Signal U129 U129 U129 Gain Range (U163) pin 1 pin 8 pin 9 (U166) ×100 100Ω ×10 1kΩ ×10 10kΩ ×10 100kΩ ×1 1MΩ ×1 10MΩ ×1 100MΩ Table 4-16 Ω4 signal multiplexing and gain Signal U129 U129...

  • Page 98: No Comm Link Error

    4-18 Troubleshooting No comm link error A “No Comm Link” error indicates that the front panel processor has ceased communication with the main processor, which is located on the motherboard. This error indicates that there may be a problem with the cable connection from the front panel display or one of the main processor ROMs may require reseating in its socket.

  • Page 99: Disassembly

    Disassembly...

  • Page 100: Introduction

    Disassembly Introduction This section explains how to handle, clean, and disassemble the Model 2700 Multimeter/ Data Acquisition System. Disassembly drawings are located at the end of this section. Handling and cleaning To avoid contaminating PC board traces with body oil or other foreign matter, avoid touch- ing the PC board traces while you are repairing the instrument.

  • Page 101: Static Sensitive Devices

    Use the following assembly drawings to assist you as you disassemble and reassemble the Model 2700. Also, refer to these drawings for information about the Keithley part numbers of most mechanical parts in the unit. The drawings are located at the end of this section of the manual.

  • Page 102: Disassembly Procedures

    Disassembly Disassembly procedures Case cover removal Follow the steps below to remove the case cover to gain access to internal parts. WARNING Before removing the case cover, disconnect the line cord and any test leads from the instrument. Remove Handle — The handle serves as an adjustable tilt-bail. Adjust its position by gently pulling it away from the sides of the instrument case and swinging it up or down.

  • Page 103: Card Cage Removal

    Disassembly Disconnect the front input terminals. You must disconnect these input terminal connections: • INPUT HI and LO • SENSE HI and LO • AMPS Remove all the connections except the front AMPS connection by pulling the wires off the pin connectors. To remove the front panel AMPS input wire (white), first remove the AMPS fuse holder, then use needle-nose pliers to grasp the AMPS wire near the fuse housing.

  • Page 104: Front Panel Disassembly

    Disassembly Front panel disassembly Use the following procedures to remove the display board and/or the pushbutton switch pad: NOTE You must first remove the case cover, the front/rear input switch, and the front input terminal wires as described earlier in this section. Unplug the display board ribbon cable from connector J1014.

  • Page 105: Instrument Reassembly

    Yellow SENSE LO Gray AMPS White Power module wire connections Use the information in Table 5-2 and DETAIL B of drawing 2700-050 to connect power module wires. Table 5-2 Power module wire colors Location Wire color Right side Gray Right top...
  • Page 106 Disassembly...

  • Page 107: Replaceable Parts

    Replaceable Parts...

  • Page 108: Parts Lists

    Model 2700 User’s Manual. Parts lists Both electrical and mechanical parts for the Model 2700 are listed in several tables on the following pages. For additional information on mechanical parts, see the assembly drawings provided at the end of Section 5.

  • Page 109: Table 6-1 Model 2700 Motherboard Parts List

    Replaceable Parts Table 6-1 Model 2700 motherboard parts list Circuit Designation Description Keithley Part No. BT100 L1 BATTERY, 3.6V, 950MAH BA-51 C102 CAP, 0.01UF, 10%, 1000V, CERAMIC C-64-.01 C104 CAP, 100UF, 20%, 63V, ALUM ELEC C-403-100 C105 CAP, 0.22UF, 20%, 400V, FILM C-513-.22...
  • Page 110 Replaceable Parts Table 6-1 (Continued) Model 2700 motherboard parts list Circuit Designation Description Keithley Part No. CR106 DIODE, BRIDGE, PE05 RF-48 CR110,CR118 DIODE, DUAL HSM-2822T31 RF-95 CR111,112,115-117,126 DIODE, DUAL SWITCHING, BAV99L RF-82 CR114,CR119 DIODE, SWITCHING, MMBD914 RF-83 CR120,CR122,CR125 DIODE, DUAL COMMON ANODE BAW56LT2...
  • Page 111 Replaceable Parts Table 6-1 (Continued) Model 2700 motherboard parts list Circuit Designation Description Keithley Part No. R123 RES, 73.2K, 1%, 100MW, THICK FILM R-418-73.2K R126,R128,R185,R275 RES, 475, 1%, 125mW, METAL FILM R-391-475 R129 RES, 215, 1%, 100MW, THICK FILM R-418-215...
  • Page 112 Replaceable Parts Table 6-1 (Continued) Model 2700 motherboard parts list Circuit Designation Description Keithley Part No. R241 RES, 34K, 1%, 100MW, THICK FILM R-418-34K R243 RES, 10, 10%, 100MW, THICK FILM R-418-10 R246 RES, 82.5, 1%, 100MW, THICK FILM R-418-82.5 R249 RES, 4.02K, 1%, 100MW, THICK FILM...
  • Page 113 Replaceable Parts Table 6-1 (Continued) Model 2700 motherboard parts list Circuit Designation Description Keithley Part No. U106,U109,U121,U130,U134 IC, 8 STAGE SHIFT/STORE, MC14094BD IC-772 U107,U108 IC, PHOTO, DARLINGTON TRANS, PS2506L-1 IC-911 U110 IC, TRMS TO DC CONVERTER 637JR IC-796 U112 IC, J-FET OP-AMP LF357M...

  • Page 114: Table 6-2 Model 2700 Display Board Parts List

    Y102 OSCILLATOR HIGH SPEED CMOS, 12MHZ CR-37 Y103 CRYSTAL, FSM327 CR-41 *Order current firmware revision, for example: A02. Table 6-2 Model 2700 display board parts list Circuit Designation Description Keithley Part No. C401,C402,C411 CAP, 0.1UF, 20%, 50V, CERAMIC C-418-.1 C403,C404,C405,C407,C409,C410,C412 CAP, 0.1UF, 10%, 25V, CERAMIC...

  • Page 115: Table 6-3 Model 2700 Connector Board Parts List

    Replaceable Parts Table 6-3 Model 2700 connector board parts list Circuit Designation Description Keithley Part No. J1009 CONN, MALE, 3-PIN CS-612-1 J1011 CONN, FEMALE, 8-PIN CS-612-8 J1013 CONN, RT ANGLE HEADER CS-1066-1 J1015,J1016 CONN 2 ROWS OF 16 PINS CS-736-4...

  • Page 116: Table 6-4 Model 2700 Miscellaneous Parts List

    6-10 Replaceable Parts Table 6-4 Model 2700 miscellaneous parts list Description Keithley part no. BANANA JACK, PUSH-IN BLACK BJ-14-0 BANANA JACK, PUSH-IN RED BJ-14-2 BEZEL, REAR 428-303D CABLE ASSEMBLY CA-219-1A CABLE CLAMP CC-37 CAPTIVE PANEL SCREW FA-232-1C CARD CAGE 2700-318A...

  • Page 117: Table 6-5 Model 7700 Parts List

    Replaceable Parts 6-11 Table 6-5 Model 7700 parts list Circuit Designation Description Keithley Part No. C1,C9,C10,C11,C14,C15,C22,C4 CAP, 0.1UF, 20%, 50V, CERAMIC C-418-.1 CAP, 220U, 20%, 10V, TANTALUM C-558-220 C17,C18,C19,C21,C25,C26,C23,C24,C15 CAP, 47P, 5%, 100V, CERAMIC C-465-47P C2,C6,C7,C8,C12,C13,C20,C27,C28,C31 CAP, 0.1UF, 20%, 50V, CERAMIC C-418-.1...

  • Page 118: Table 6-6 Model 7702 Parts List

    6-12 Replaceable Parts Table 6-6 Model 7702 parts list Circuit Designation Description Keithley Part No. C1,C3,C9,C10,C11,C12,C13,C14 CAP, 0.1UF, 20%, 50V, CERAMIC C-418-.1 CAP, 220U, 20%, 10V, TANTALUM C-558-220 C17,C18,C19,C20,C21,C22,C23,C24,C2,C6 CAP, 47P, 5%, 100V, CERAMIC C-465-47P CAP, 47P, 5%, 100V, CERAMIC C-465-47P CAP, 0.1UF, 20%, 50V, CERAMIC...

  • Page 119: Table 6-7 Model 7703 Parts List

    Replaceable Parts 6-13 Table 6-7 Model 7703 parts list Circuit Designation Description Keithley Part No. C1,C9,C20,C2,C23,C24,C25,C26,C27 CAP, 47P, 5%, 100V, CERAMIC C-465-47P CAP, 4.7U, 10%, 35V, TANTALUM C-476-4.7 C3,C4-C8, C10-C14,C19,C21 CAP, 0.1UF, 20%, 50V, CERAMIC C-418-.1 CR1,CR2 ULTRAFAST POWER RECTIFIER...

  • Page 120: Table 6-8 Model 7705 Parts List

    6-14 Replaceable Parts Table 6-8 Model 7705 parts list Circuit Designation Description Keithley Part No. C100 CAP, 4.7U, 10%, 35V, TANTALUM C-476-4.7 C102,106,107,108,109,110,111,121,101 CAP, 0.1UF, 5%, 100V, CERAMIC C-465-.1 C103 CAP, 220U, 20%, 10V, TANTALUM C-558-220 C104,C105,C112-C120 CAP, 47P, 5%, CERAMIC...
  • Page 121 Specifications...
  • Page 122 Specifications 2700 Multimeter/Data Acquisition System DC CHARACTERISTICS CONDITIONS: MED (1 PLC) or 10 PLC or MED (1 PLC) with Digital Filter of 10 ACCURACY: ±(ppm of reading + ppm of range) INPUT (ppm = parts per million) TEST CURRENT RESISTANCE (e.g.,...
  • Page 123 Specifications DC SPEED vs. NOISE REJECTION RMS Noise Rate Filter Readings/s Digits 10V Range NMRR CMRR 0.1 (0.08) < 1.2 µV 110 dB 140 dB 15 (12) < 4 µV 90 dB 140 dB 500 (400) < 22 µV — 80 dB 0.01 2000 (1800)

  • Page 124: Dc Volts

    Specifications DC MEASUREMENT CHARACTERISTICS DC Volts A-D LINEARITY: 2.0 ppm of reading + 1.0 ppm of range. INPUT IMPEDANCE: 100mV–10V Ranges: Selectable >10GΩ// with <400pF or 10MΩ ±1%. 100V, 1000V Ranges: 10MΩ ±1%. INPUT BIAS CURRENT: <75pA at 23°C. COMMON MODE CURRENT: <500nApp at 50Hz or 60 Hz. AUTOZERO ERROR: Add ±(2ppm of range error + 5µV) for <...

  • Page 125: Ac Current

    Specifications AC SPECIFICATIONS Accuracy: ±(% of reading + % of range), 23°C ± 5°C Calibration 3 Hz– 10 Hz– 20 kHz– 50 kHz– 100 kHz– Function Range Resolution Cycle 10 Hz 20 kHz 50 kHz 100 kHz 300 kHz Voltage 100.0000 mV 0.1 µV 90 Days...
  • Page 126 Specifications AC OPERATING CHARACTERISTICS 60Hz (50Hz) Operation Function Digits Readings/s Rate Bandwidth ACV, ACI 2s/Reading SLOW 3 Hz–300 kHz 1.4 (1.1) 30 Hz–300 kHz 4.8 (4) 30 Hz–300 kHz 35 (28) FAST 300 Hz–300 kHz Frequency, 1 (1) SLOW 3 Hz–300 kHz Period 9 (9) 30 Hz–300 kHz...

  • Page 127: General Specifications

    MATH FUNCTIONS: Rel, Min/Max/Average/Std Dev/ Peak-to-Peak (of stored reading), Limit Test, %, and mX + b with user defined units dis- played. REMOTE INTERFACE: Keithley XLinx Up & Running starter software GPIB (IEEE-488.2) and RS-232C. SCPI (Standard Commands for Programmable Instruments)
  • Page 128 For more information, refer to the CONTACT POTENTIAL: <±500nV typical per contact, 1µV max. ROUTe:MULTiple command section AMPS in the Model 2700 User’s Manual. Card <±500nV typical per contact pair, 1µV max. Channels 24 and 25 can be individually OFFSET CURRENT: <100pA.
  • Page 129 For more information, refer to the CONTACT POTENTIAL: <±500nV typical per contact, 1µV max. ROUTe:MULTiple command section <±500nV typical per contact pair, 1µV max. in the Model 2700 User’s Manual. Channels 44 and 45 can be individually OFFSET CURRENT: <100pA. controlled using ROUTe:MULTiple if the module is not to be connected to the CONNECTOR TYPE: Screw terminal, #20 AWG wire size.
  • Page 130 CONNECTOR TYPE: 50 pin D-sub × 2. For more information, refer to the ROUTE:MULT command section in the Model 2700 User’s Manual. RELAY DRIVE CURRENT: 20mA per channel. Ω, <200pF. ISOLATION BETWEEN ANY TWO TERMINALS: >10 Ω, <400pF.
  • Page 131 Specifications A-11 7705 40-Channel Control Module GENERAL RELAY SWITCH CONFIGURATION: 40 independent channels of 1- Channel 1 pole switching. Isolated from internal DMM. CONTACT CONFIGURATION: 1 pole Form A. RELAY TYPE: Latching electromechanical. (Channels 2–39) CONNECTOR TYPE: Two 50-pin female D-sub connectors. Channel 40 INPUTS MAXIMUM SIGNAL LEVEL: 300VDC or rms, 2A switched, 60W (DC,...

  • Page 132: Specifications

    A-12 Specifications Accuracy calculations The information below discusses how to calculate accuracy for both DC and AC characteristics. Calculating DC characteristics accuracy DC characteristics accuracy is calculated as follows: Accuracy = ±(ppm of reading + ppm of range) (ppm = parts per million, and 10ppm = 0.001%) As an example of how to calculate the actual reading limits, assume that you are measuring 5V on the 10V range.

  • Page 133: Calculating Dbm Characteristics Accuracy

    Specifications A-13 Calculating dBm characteristics accuracy As an example of how to calculate the actual reading limits for a 13dBm measurement with a reference impedance of 50Ω, assume an applied signal 0.998815V. The relationship between voltage and dBm is as follows: ⁄...

  • Page 134: Additional Derating Factors

    A-14 Specifications Thus, the actual reading accuracy is 10mV ±36mV or 10.036mV to 9.964mV. Applying the voltage reading accuracy into the dB equation yields: 10.036mV ------------------------ - – 59.96879dB 9.964mV --------------------- - – 60.03133dB Thus, the actual reading accuracy is -60dB + 0.031213dB to -60dB - 0.031326dB. dBm and dB for other voltage inputs can be calculated in exactly the same manner using pertinent specifications, ranges, and other reference voltages.

  • Page 135: Optimizing Measurement Speed

    Specifications A-15 Optimizing measurement speed The configurations listed below assume that the multimeter has had factory setups restored. DC voltage, DC current, and resistance: • Select 3-1/2 digits, 0.01 PLC, filter OFF, fixed range. AC voltage and AC current: • Select 3-1/2 digits, 0.01 PLC, filter OFF, fixed range.
  • Page 136 A-16 Specifications...

  • Page 137: Calibration Reference

    Calibration Reference...

  • Page 138: Introduction

    This appendix contains detailed information about the various Model 2700 remote calibra- tion commands. Section 2 of this manual covers detailed calibration procedures. For informa- tion about additional commands to control other instrument functions, refer to the Model 2700 User’s Manual.
  • Page 139 Calibration Reference Table B-1 (Continued) Remote calibration command summary Command Description :CALibration :PROTected :STEP10 <NRf> 10mA DC step. :STEP11 <NRf> 100mA DC step. :STEP12 <NRf> 1A DC step. AC cal steps. :STEP1 10mV AC at 1kHz step. :STEP2 100mV AC at 1kHz step. :STEP3 100mV AC at 50kHz step.

  • Page 140: Miscellaneous Calibration Commands

    Example Send default code of KI002700. :CAL:PROT:CODE 'KI002700' :COUNt? (:CALibration:PROTected:COUNt?) Purpose To determine how many times the Model 2700 has been calibrated. Format :cal:prot:coun? Response <n> Calibration count. Description The :COUNt? command allows you to determine how many times the Model 2700 has been calibrated.

  • Page 141: Init

    Format :cal:prot:init Parameter None Description The :INIT command enables Model 2700 calibration when performing these procedures over the bus. This command must be sent to the unit after sending the :CODE command, but before sending any other calibration command. NOTE The :INIT command should be sent only once before performing either DC, AC, or factory calibration.

  • Page 142: Lock?

    :cal:prot:lock? Response Comprehensive calibration locked. Comprehensive calibration unlocked. Description The :LOCK? query requests status from the Model 2700 on calibration locked/unlocked state. Calibration must be enabled sending the :CODE command before calibration can be performed. Example Request cal lock state.

  • Page 143: Date

    Calibration Reference :DATE (:CALibration:PROTected:DATE) Purpose To send the calibration date to the instrument. Format :cal:prot:date <year>, <month>, <day> Parameter <year> = 1999 to 2098 <month> = 1 to 12 <day> = 1 to 31 Query format :cal:prot:date? Response <year>, <month>, <day> Description The :DATE command allows you to store the calibration date in instrument memory for future reference.

  • Page 144: Dc Calibration Commands

    Calibration Reference DC calibration commands The :DC commands perform calibration of the DCV, DCI, and ohms functions. Table B-2 summarizes these calibration commands along with parameter limits. Table B-2 DC calibration commands Command Description Parameter limits :CALibration :PROTected :STEP1 Front terminal short circuit. :STEP2 Open circuit.

  • Page 145: Step2

    Calibration Reference :STEP2 (:CALibration:PROTected:DC:STEP2) Purpose To perform front terminal open-circuit calibration. Format :cal:prot:dc:step2 Parameter None Description :STEP2 performs the open-circuit calibration step in the comprehensive calibration procedure. Disconnect all cables and accessories from the input jacks before sending this command. Example Perform open circuit calibration.

  • Page 146: Step5

    B-10 Calibration Reference :STEP5 (:CALibration:PROTected:DC:STEP5) Purpose To program the 100V DC comprehensive calibration step. Format :cal:prot:dc:step5 <Cal_voltage> Parameter <Cal_voltage> = 90 to 110 [V] Description :STEP5 programs the 100V DC comprehensive calibration step. The allowable range of the calibration voltage parameter is from 90 to 110, but 100 is recommended for best results.

  • Page 147: Step8

    Calibration Reference B-11 :STEP8 (:CALibration:PROTected:DC:STEP8) Purpose To program the 100kΩ 4-wire comprehensive calibration step. Format :cal:prot:dc:step8 <Cal_resistance> Parameter <Cal_resistance> = 90E3 to 110E3 [Ω] Description :STEP8 programs the 100kΩ 4-wire resistance comprehensive calibration step. The allowable range of the calibration resistance parameter is from 90E3 to 110E3, but 100E3 is recommended for best results.

  • Page 148: Step11

    B-12 Calibration Reference :STEP11 (CALibration:PROTected:DC:STEP11) Purpose To program the 100mA comprehensive calibration step. Format :cal:prot:dc:step11 <Cal_current> Parameter <Cal_current> = 90E-3 to 110E-3 [A] Description :STEP11 programs the 100mA comprehensive calibration step. The allow- able range of the calibration current parameter is from 90E-3 to 110E-3. Use the 100E-3 value whenever possible for best results.

  • Page 149: Ac Calibration Commands

    Calibration Reference B-13 AC calibration commands The :AC commands perform comprehensive (user) calibration of the ACV and ACI func- tions. Table B-3 summarizes these calibration commands. Table B-3 AC calibration commands Command Description :CALibration :PROTected :STEP1 10mV AC at 1kHz calibration step. :STEP2 100mV AC at 1kHz calibration step.

  • Page 150: Ac:step

    B-14 Calibration Reference :AC:STEP<n> (CALibration:PROTected:AC:STEP<n>) Purpose To program individual AC calibration steps. Format :cal:prot:ac:step<n> Parameter 10mV AC at 1kHz calibration step. 100mV AC at 1kHZ calibration step. 100mV AC at 50kHz calibration step. 1V AC at 1kHz calibration step. 1V AC at 50kHz calibration step. 10V AC at 1kHz calibration step.

  • Page 151: Manufacturing Calibration Commands

    Calibration Reference B-15 Manufacturing calibration commands Three calibration steps are only performed at the factory or when the unit has been repaired: 1V AC at 3Hz :CALibration:PROTected:AC:STEP14 1V AC at 1kHz :CALibration:PROTected:AC:STEP15 Rear scanner terminal short circuit :CALibration:PROTected:DC:STEP0 :AC:STEP<14|15> (CALibration:PROTected:AC:STEP<14|15>) Purpose To program individual AC manufacturing calibration steps.

  • Page 152: Model 7700 Calibration Commands

    B-16 Calibration Reference Model 7700 calibration commands Table B-4 summarizes calibration commands for the Model 7700 plug-in module. Note that CARD1 commands calibrate the card in Slot 1, while CARD2 commands request calibration count and date information from a card in Slot 2. NOTE A Model 7700 must be installed in Slot 1 through a Model 7797 calibration/extender card to be calibrated.

  • Page 153: Code

    Up to a 8-character string including letters and numbers. Description The :CODE command enables the Model 2700 calibration procedures when performing these procedures over the bus. This command must be sent to the unit before sending any other Model 7700 calibration command.

  • Page 154: Date

    Model 7700 in Slot 1 and Slot 2 respectively. NOTE The card calibration date is automatically set to the Model 2700 real time clock date when the card is calibrated. Example Request card 1 cal date.

  • Page 155: Lock

    Response Calibration locked. Calibration unlocked. Description The :LOCK? query requests status from the Model 2700 on Model 7700 calibration locked/unlocked state. Calibration must be enabled sending the :CODE command before calibration can be performed. Example Request card 1 cal lock state.

  • Page 156: Save

    B-20 Calibration Reference :SAVE (:CALibration:PROTected:CARD1:SAVE) Purpose To save calibration constants in card EEROM after the calibration procedure. Format :cal:prot:card1:save Parameter None Description The :SAVE command stores calculated calibration constants derived dur- ing Model 7700 calibration in card EEROM. (EEROM is non-volatile mem- ory.) Calibration constants will be retained indefinitely once saved.

  • Page 157: Remote Error Reporting

    Methods to detect and determine the nature of calibration errors are discussed in the follow- ing paragraphs. Error summary Table B-5 summarizes Model 2700 calibration errors. Table B-5 Calibration error summary Error number and description +400, "10 vdc zero error"...
  • Page 158 B-22 Calibration Reference Table B-5 (Continued) Calibration error summary Error number and description +451, "1 vac dac error" +452, "10 vac dac error" +453, "100 vac dac error" +454, "100m vac zero error" +455, "100m vac full scale error" +456, "1 vac zero error" +457, "1 vac full scale error"...

  • Page 159: Error Queue

    B-23 Error queue As with other Model 2700 errors, any calibration error will be reported in the bus error queue. You can read this queue by using the :SYST:ERR? query. The Model 2700 will respond with the appropriate error message, as summarized in Table B-5.

  • Page 160: Using The *Opc Command

    An IEEE-488 bus SRQ (service request) can be used to detect operation complete instead of repeatedly polling the Model 2700. To use this method, send both *ESE 1 and *SRE 32 to the instrument, then include the *OPC command at the end of each calibration command line, as covered above.

  • Page 161: Calibration Program

    Calibration Program...

  • Page 162: Introduction

    Calibration Program Introduction This appendix includes a calibration program written in BASIC to help you calibrate the Model 2700. Refer to Section 2 for more details on calibration procedures, equipment, and connections. Computer hardware requirements The following computer hardware is required to run the calibration program: •...

  • Page 163: General Program Instructions

    Turn on the computer, the Model 2700, and the calibrator. Allow the Model 2700 and the calibrator to warm up for at least one hour before performing calibration. Make sure the Model 2700 is set for a primary address of 16. (Use the front panel GPIB key to check or change the address.) Make sure the calibrator primary address is at its factory default setting of 4.
  • Page 164 PRINT #1, "OUTPUT 4;"; Msg$ PRINT #1, "OUTPUT 4;OPER" END SELECT IF I > 2 THEN GOSUB Settle PRINT #1, "OUTPUT 16;"; C$; Cmd$; ";*OPC" ' Send cal command to 2700. GOSUB CalEnd ' Wait until cal step ends. GOSUB ErrCheck ' Check for cal error.
  • Page 165 Calibration Program KeyCheck: ' Check for key press routine. WHILE INKEY$ <> "": WEND ' Flush keyboard buffer. PRINT : PRINT "Press any key to continue (ESC to abort program)." DO: I$ = INKEY$: LOOP WHILE I$ = "" IF I$ = CHR$(27) THEN GOTO EndProg ' Abort if ESC is pressed.
  • Page 166 Calibration Program DATA "OUT 10 MV,1 KHZ","AC:STEP1" DATA "OUT 100 MV,1 KHZ","AC:STEP2" DATA "OUT 100 MV,50 KHZ","AC:STEP3" DATA "OUT 1 V,1 KHZ","AC:STEP4" DATA "OUT 1 V,50 KHZ","AC:STEP5" DATA "OUT 10 V,1 KHZ","AC:STEP6" DATA "OUT 10 V,50 KHZ","AC:STEP7" DATA "OUT 100 V,1 KHZ","AC:STEP8" DATA "OUT 100 V,50 KHZ","AC:STEP9"...
  • Page 167 :STEP10 B-11 front panel 2-6 :STEP11 B-12 front panel short and open 2-7 :STEP12 B-12 Model 7700 2-22 :STEP2 B-9 preparing the Model 2700 2-6 :STEP3 B-9 recommended equipment 2-5 :STEP4 B-9 Remote Model 7700 2-23 :STEP5 B-10 resistance 2-9...
  • Page 168 Disassembly procedures 5-4 Input terminal wire 5-7 DISP test 4-3 manufacturing calibration 2-20 Display 4-7 Model 2700 AC current verification 1-12 Display board 4-6 Model 2700 AC volts verification 1-9 Display board checks 4-11 Model 2700 DC current verification 1-11...
  • Page 169 Plug-in module DCI, Model 7700 1-23 Power module removal 5-6 plug-in module resistance verification, Power module wire colors 5-7 Model 7700 1-27 Power supply 4-4 resistance verification, Model 2700 1-14 block diagram 4-4 line fuse Power supply checks 4-11 replacing 3-2 Power supply components 4-5...
  • Page 170 B-2 Trigger circuits 4-8 DC current 2-16 Troubleshooting 4-1 DC volts 2-14 Locking out calibration 2-18 preparing the Model 2700 2-13 verification Programming calibration dates 2-17 Model 2700 1-8 resistance 2-15 Model 7700 1-18 Saving calibration constants 2-18...
  • Page 171 Service Form Model No. _______________ Serial No. __________________ Date _________________ Name and Telephone No. ____________________________________________________ Company _______________________________________________________________________ List all control settings, describe problem and check boxes that apply to problem. _________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ ❑ Intermittent ❑ Analog output follows display ❑...
  • Page 174 Keithley Instruments, Inc. 28775 Aurora Road Cleveland, Ohio 44139 Printed in the U.S.A.

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