Calibration; Recommended Test Equipment; Extender Board Connections; Model 7708 Calibration - Keithley 7708 User Manual

Calibration

The following procedures calibrate the temperature sensors on the Model 7708 plug-in modules.
WARNING The information in this section is intended only for qualified service personnel. Do not
attempt these procedures unless you are qualified to do so.

Recommended test equipment

In order to calibrate the Model 7708, you will need equipment summarized in
Table 8
Recommended equipment for Model 7708 calibration
Digital Thermometer:
18 to 23°C, ±0.1°C
Keithley 7797 Calibration/Extender Board

Extender board connections

The Model 7708 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 27xx to avoid card
heating during calibration.

Model 7708 calibration

NOTE Before calibrating the Model 7708, 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 cali-
bration procedure, complete the procedure as quickly as possible to minimize card heating that
could affect calibration accuracy. Allow the Model 27xx to warm up for at least two hours.
Front panel Model 7708 calibration
1. Connect the Model 7708 to the Model 7797 Calibration/Extender Board (see "Extender board connections" above).
2. With the power off, install the Model 7708/7797 combination in Slot 1 and select the rear inputs with the INPUTS switch.
Allow three minutes for thermal equilibrium.
3. Accurately measure and record the cold temperature of the Model 7708 card surface at the center of the card with a digital
thermometer.
4. Press in and hold the Model 27xx OPEN key while turning on the power.
5. Press SHIFT then TEST, then display TEST:CALIB with the up or down range key. Press ENTER, select RUN, then enter
the appropriate calibration code (default: 0027xx).
6. With NEW CODE? displayed, use the up or down range key to display N, then press ENTER.
7. Using the up or down range key, select CARD at the CAL:RUN prompt, then press ENTER.
8. Set the display value to the cold calibration temperature (°C) you measured in Step 3, then press ENTER to complete
Model 7708 calibration.
Table 8.
23