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Keithley 7706 User Manual

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Model 7706
Multiplexer Card
User's Guide
PA-719 Rev. C / 2-00
The Model 7706 can be used with Keithley
Models 2700, 2701, and 2750. All references
to the Model 2700 also apply to the Models
2701 and 2750.
A G R E A T E R M E A S U R E O F C O N F I D E N C E

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  • Page 1 Model 7706 Multiplexer Card User’s Guide PA-719 Rev. C / 2-00 The Model 7706 can be used with Keithley Models 2700, 2701, and 2750. All references to the Model 2700 also apply to the Models 2701 and 2750. A G R E A T E R M E A S U R E O F C O N F I D E N C E...
  • Page 2 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. Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable batteries, diskettes, and documentation.

  • Page 3: Safety Precautions

    Keithley products are designed for use with electrical signals that The instrument and accessories must be used in accordance with its are rated Installation Category I and Installation Category II, as de- specifications and operating instructions or the safety of the equip-...
  • Page 4 Keithley Instru- symbol on an instrument indicates that the user should re- ments. Standard fuses, with applicable national safety approvals, fer to the operating instructions located in the manual.

  • Page 5: Table Of Contents

    Connection, operation, calibration, and parts information Introduction This packing sheet contains information specific to the Model 7706 module. If you have any questions after reviewing this in- formation, please contact your local Keithley representative or call one of our Applications Engineers at 1-800-348-3735 (U.S.

  • Page 6: Card Configuration-Schematic

    Figure 1 shows a simplified schematic diagram of the Model 7706 module. As shown, the Model 7706 has channels that are grouped into two banks of ten channels (twenty channels total). Backplane isolation is provided for each bank. Each bank also includes separate cold junction reference points.
  • Page 7 Connection Figure 1 Simplified schematic for Model 7706 NOTES Channels 26–28 in this schematic refer to the designations used for control and not actual available channels. Input Channels 26, 27, and 28 can be individually controlled using ROUTe:MULTiple if the...

  • Page 8: Card Configuration-Connections

    The information in this section is intended for qualified service personnel. Do not attempt to perform this procedure unless qualified to do so. Figure 2 shows how to access the screw terminals on the Model 7706. Channel designations for the screw terminals are con- tained in Figure...

  • Page 9: Wiring Procedure

    Use the following procedure to wire the Model 7706 module. Make all connections using correct wire size (up to 22 AWG). Also, make sure to add supplementary insulation around the harness for voltages above 42V peak (see...
  • Page 10 6. Close and lock cover. WARNING The Model 7706 module provides connections for both high voltage analog measurements as well as dig- ital earth based circuits. Make sure to install and maintain double insulation between the analog and digital circuit wiring using supplementary insulation as required (see...

  • Page 11: Typical Connections (Channels 1-20)

    Connection Typical connections (channels 1–20) The following examples show typical wiring connections for the following types of measurements: • Thermocouple connections, see Figure 5 • Ω 2-Wire and thermistor connections, see Figure 6 • Ω 4-Wire and RTD connections, see Figure 7 •...
  • Page 12 Model 7706 module Figure 7 Ω 4-Wire and RTD connections Ω4-Wire << Channel 1 << (Channels 2–9) << Channel 10 << Channel 11 (Channels 12–19) Channel 20 Figure 8 Voltage connections (DC or AC) DC Voltage AC Voltage Channel 1 (Channels 2–19)

  • Page 13: Digital Outputs (Channels 21-22)

    Connection Digital outputs (channels 21–22) Use the Model 7706 digital outputs to control indicators, fixtures, switches, solenoids, loads, relays, etc. Figure 9 shows a sim- plified schematic of the digital output. Figure 9 Simplified schematic of digital output Channel 21...
  • Page 14 = 138 (this is the NRf value in the command) Therefore, the command to send is: OUTP:DIG:BYTE 138,(@121) Channel 21 of the Model 7706 in slot 1 NRf value of 138 (specifies which terminals are 1 / 0) 8 bit Digital Output...
  • Page 15 = 137 (this is the NRf value in the command) Therefore, the command to send is: OUTP:DIG:BYTE 137,(@122) Channel 22 of the Model 7706 in slot 1 NRf value of 137 (specifies which terminals are 1 / 0) 8 bit Digital Output...
  • Page 16 The digital output allows the use of an external power supply up to 42V. Refer to Figure Inductive loads Model 7706 operation is specified for resistive loads. Reactive (inductive) loads require voltage clamping. Before using induc- tive loads, take adequate circuit protection measures (refer to the appropriate appendices of the Model 2700 User’s Manual).
  • Page 17 Therefore, the command to send is: OUTP:DIG:WORD 49288,(@121) Channel 21 of the Model 7706 in slot 1 (this command can only be sent to Channel 21) NRf value of 49288 (specifies which terminals are 1 / 0) 16 bit...
  • Page 18 Model 7706 module Figure 13 Typical digital output with external power supply Model 7706 Module User supplied circuitry Digital Output Terminal 42V (Maximum) Output Digital ground (non-isolated, referenced to chassis) Figure 14 Typical digital output (no external power supply) Model 7706 Module...

  • Page 19: Analog Outputs (Channels 23-24)

    The Model 7706 contains two DAC (Digital to Analog Converters). Use these analog outputs for tasks such as applying a voltage bias to DUTs or analog control. The two analog outputs of the Model 7706 are capable of providing voltages in the range of ±12V.
  • Page 20 Model 7706 module Sample 2: Set analog output 2 (channel 24) to -5.5V To set analog output 2 using the front panel: under the SHIFT->CARD menu, key in the decimal value (for this example, -5.5) for the menu item “AOUT2: +XX.XX”, and press enter. To set Channel 24 (analog output 2) over the bus, send the following command: OUTP:VOLT -5.5,(@124)
  • Page 21 × Percent Error ---------------------------------- - Load Lead Using the above equation, to keep loading error within 0.1%, the resistance of the Model 7706 system must be at least 1/999 the value of load resistance. Figure 17 Loading effects Lead Source...

  • Page 22: Totalizer

    Model 7706 module Totalizer Use the Totalizer to count more than 4 billion on/off events (contact closures, revolutions, power cycles, etc.). The Totalizer can be accessed from the front panel or over the bus. Figure 18 shows a simplified schematic of the Totalizer connected to a function generator.
  • Page 23 Connection Threshold detection The Totalizer can count events at a rate of up to 100kHz. The count can be initiated manually or by configuring a scan. When counting, the Totalizer can: • Reset to zero every time it is read. •...
  • Page 24 Model 7706 module Gating provides specific control over when the Totalizer readings are taken. A gate always is interpreted if no gating signal is present. To control counting through the G+ screw terminal, send a TTL high signal to enable counting and a TTL low signal to disable counting.
  • Page 25 RATIO,CH-AVG, CONT, OCOMP, PERIOD Blocked. Middle Row Unshifted TRIG Triggers the unit to read the current Totalizer count. Moves between Totalizer channels (if more than one Model 7706 installed). STORE, RECALL, FILTER, REL Blocked. Shifted LIMITS Sets the High Limit count for the Totalizer.

  • Page 26: Totalizer Channel Monitor Scan Example

    Totalizer channel monitor scan example For this example, Channel 25 of the Model 7706 is used to monitor the Totalizer with the Model 7706 inserted into slot 1 of the Model 2700. This is an example of a four channel scan with Channels 101–103 measuring DC voltage while, as previously men- tioned, Channel 125 monitors the Totalizer.
  • Page 27 Connection Figure 22 Monitor scan example Monitor Mode: Close Monitor Channel (125) 100,000 Scan Counts Measure TOTALIZER Scan Mode: Return to Close First Monitor Mode Channel Measurements Open Last Chan Close Next Chan Measure...

  • Page 28: Specifications

    Full Model 7706 specifications are included at the end of this guide. Connection log Make a copy of Table 2 and affix it to the cover of the Model 7706. Use this to record connection information and channel de- scriptions as needed.
  • Page 29 Connection Table 2 Connection log Model 7706 Channel Color Description INPUT SENSE CH10 CH11 CH12 CH13 CH14 CH15 CH16 CH17 CH18 CH19 CH20 CH21 CH22 CH23 CH24 CH25...

  • Page 30: Front Panel Operation

    To open the card specific menu, press SHIFT->CARD (CARD is over the RIGHT arrow key). This menu contains all card- specific functions from the front panel. For example, the analog outputs of a 7706 card would be configured from here. A sample of accessing the card specific functions is contained in...

  • Page 31: Bus Commands

    Bus commands Bus commands When issuing commands over the bus, keep the following channel usage in mind: Table 3 Channel description Channels Description 1-20 Voltage, resistance, temperature, frequency, period, etc., measurements 21-22 Eight-bit digital outputs 23-24 Sixteen-bit analog outputs Totalizer 2/4 pole selection relay.

  • Page 32: Output Subsystem

    Commands to perform output operations are listed in Table 4. Details on these commands follow the table. NOTE The output subsystem is specific to the Model 7706 module. It is only available if a Model 7706 is installed. Table 4 Output subsystem commands Command...

  • Page 33: Sense[1] Subsystem

    :WORD? <clist> — Query the present bit pattern (0 < × < 65535) for the digital output channels (returned in decimal format). This command must be sent to Channel 21. SENSe[1] Subsystem Commands to perform Model 7706 specific operations are listed in Table Table 5...

  • Page 34: Unsupported Scpi Commands

    NOTE After correctly wiring the Model 7706, installing it in the Model 2700, and turning the power on (step 5 in the following procedure), the unit is required to warm up for two hours before proceeding.
  • Page 35 Verification 14. Close channel 2: a. Press the CLOSE key. b. Key in 102. 15. Set analog output 2 to +10V: a. Open the SHIFT-CARD menu (press SHIFT-CARD). b. Key in analog output for AOUT2:+10.000V. 16. Verify analog output reading is within stated limits. 17.

  • Page 36: Totalizer

    NOTE Correctly wire and install the Model 7706 in the Model 2700 before turning on the Model 2700. Use the following steps to verify the Model 7706 Totalizer function. 1. Connect the function generator to the Model 7706 Totalizer IN+ and IN- terminals (see Figure 25).
  • Page 37 Verification Figure 25 Verification—Totalizer connections Function Generator Coax Cable Function Output Gate + Gate - Threshold jumper (J2) IN - closed (1-2 TTL) IN +...

  • Page 38: Calibration

    1. Connect the Model 7706 to the 7798-250B Calibration Extender Board. 2. With the power off, install the Model 7706/7798 combination in Slot 1, and select the rear inputs with the INPUTS switch. 3. Press in and hold the Model 2700 OPEN key while turning on the power.

  • Page 39: Remote Model 7706 Temperature Calibration

    8. Using the up or down range key, select CARD at the CAL:RUN prompt, then press ENTER. 9. Using the up or down range key, select DAC at the next CARD prompt, then press ENTER to complete Model 7706 DAC...

  • Page 40: Remote Model 7706 Analog Output (Dac) Calibration

    • Connect CH24 H and L terminals to CH2 H and L terminals (H to H; L to L). 2. With the power off, install the Model 7706 in Slot 1, and select the rear inputs with the INPUTS switch.
  • Page 41 Calibration commands Table 8 Model 7706 calibration commands Command Description :CALibration Calibration root command. :PROTected All commands in this subsystem are protected by the calibration lock (except queries and :CODE). :CODE '<up to 8 char. string>' Send calibration code. (Default KI002700) :CARD1 Path to card in slot 1.
  • Page 42 The :CODE command should be sent only once before performing calibration. Do not send :CODE before each calibration step. The code parameter must be enclosed in single quotes. Purpose To program the calibration code or password so that you can perform the Model 7706 calibration procedures. Format :CAL:PROT:CODE '<CHAR_STRING>' Parameter Up to a 8-character string including letters and numbers.
  • Page 43 To lock out Model 7706 calibration. Format :CAL:PROT:CARD1:LOCK Parameter None Description The :LOCK command allows you to lock out Model 7706 calibration after completing the procedure. Thus, :LOCK performs the opposite of enabling calibration with the :CODE command. Example Lock out card 1 calibration. :CAL:PROT:CARD1:LOCK...
  • Page 44 Response 0 Calibration locked. 1 Calibration unlocked. Description The :LOCK? query requests status from the Model 2700 on Model 7706 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 45 <temp> parameter during calibration. NOTE Before calibrating the temperature for the Model 7706, make sure that power has been removed from the card for at least two hours to allow card circuitry to cool down. After turning on the power during the calibration procedure, complete the procedure as quickly as possible to minimize card heating that could affect calibra- tion accuracy.

  • Page 46: Remote Error Reporting

    <temp> parameter during calibration. NOTE Before calibrating the temperature on the Model 7706, make sure that power has been removed from the card for at least two hours to allow card circuitry to cool down. After turning on the power during the calibration procedure, complete the procedure as quickly as possible to minimize card heating that could affect calibra- tion accuracy.
  • Page 47 +453, “100 vac dac error” +610, “Questionable calibration” +454, “100m vac zero error” *Model 7706 card specific. 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.

  • Page 48: Detecting Calibration Step Completion

    Model 7706 module Generating an SRQ on error To program the instrument to generate an IEEE-488 bus SRQ when an error occurs, send the following command: *SRE 4. This command will enable SRQ when the EAV bit is set. You can then read the status byte and error queue as outlined above to check for errors, and to determine the exact nature of the error.

  • Page 49: Replaceable Parts

    • Carefully pack the instrument in the original packing carton. • Write ATTENTION REPAIR DEPARTMENT and the RMA number on the shipping label. Component layout A component layout for the Model 7706 circuit board is provided on the pages following the Model 7706 parts list (Table 10).
  • Page 50 Model 7706 module Table 10 (Continued) Model 7706 parts list Circuit Designation Description Keithley Part No. CR29,CR30,CR40,CR41 DUAL HIGH SPEED DIODE RF-147 CR31,32,34,36,38,1,33,35,37,39 DIODE, DUAL SWITCHING, BAV99L RF-82 CR51-CR54 DIODE, DUAL SWITCHING, BAV99L RF-82 DIODE, DUAL COMMON ANODE CR7-CR22 RF-98...
  • Page 51 Replaceable parts Table 10 (Continued) Model 7706 parts list Circuit Designation Description Keithley Part No. U24,U34,U11,U26,U29,U7,U8,U9 IC, OCTAL D FLIP FLOP IC-1353 IC, -5V VOLTAGE REGULATOR IC-1171 IC, 8 STAGE SHIFT/STORE, MC14094BD IC-772 U30,U31 IC, OCTAL BUFFER IC-1252 IC, 2.5V, CASCADABLE SERIAL EEPROM...
  • Page 52 Model 7706 module Figure 26 Component layout (Side-04)
  • Page 53 Replaceable parts Figure 27 Component layout (Side-01)

  • Page 54: Specifications

    7706 All-in-One I/O Module GENERAL NOTES Channels 26–28 in this schematic 20 CHANNELS: 20 channels of 2-pole relay input. refer to the designations used for control and not actual available channels. All channels configurable to 4-pole. Input Channels 26, 27, and 28 can be individually controlled using ROUTe:MULTiple if the RELAY TYPE: Latching electromechanical.
  • Page 55 Specifications are subject to change without notice. All Keithley trademarks and trade names are the property of Keithley Instruments, Inc. All other trademarks and trade names are the property of their respective companies. Keithley Instruments, Inc. 28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: 440-248-6168 1-888-KEITHLEY (534-8453) •...

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