Keithley 6514, Instruction Manual

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Performance Verification 18-9
Restoring factory defaults
Before performing each verification procedure, restore the instrument to its factory front
panel defaults as follows:
1. Press SHIFT then SETUP. The instrument will display the following prompt:
RESTORE: FACT
2. Using either RANGE key, select FACT, then restore the factory default conditions by
pressing ENTER.
NOTE
You can use either RANGE key to select among FACT, GPIB, and USR setups. Be sure
to use FACT defaults for the verification procedures.
Input bias current and offset voltage calibration
Before performing the performance verification procedures, perform input bias current and
offset voltage calibration as outlined below. Note that these offsets will be lost if power is cycled
unless you save them first.
Offset voltage calibration
1. From the calibration menu, use the down RANGE key to display the following:
CAL: VOFFSET
2. Press ENTER. The instrument will prompt for a short:
INPUT SHORT
3. Connect the triax short (triax cable with red and alligator black clips connected together)
to the rear panel INPUT jack.
4. Press ENTER to complete offset voltage calibration. The unit will display the following
message:
CALIBRATING
Input bias current calibration
1. Turn on the power, and allow a one-hour warm-up period before calibrating input bias
current or offset voltage.
2. Restore factory defaults as outlined above.
3. Press SHIFT then CAL, and note that the unit displays the following:
CAL: RUN
4. Use the down RANGE key to display the following:
CAL: IOFFSET
5. Press ENTER. The instrument will prompt for an open input:
INPUT CAP