9-11
IM 704420-01E
Troubleshooting and Maintenance
9
Returning to the start condition in the maintenance mode.
14.
Press the < key once. The characters [tEST] appear on the display and the
TA120E enters the start condition in the maintenance mode.
Rebooting the system.
15.
Turn OFF the power switch.
16.
After approximately 3 seconds, turn ON the power switch. Check that
[TA120E
→
704420
→
tESt
→
PASS] is shown on the display. The TA120E is now
ready to make measurements.
Explanation
The calibration function can be used to change the factory default calibration value of the
TA120E. However, once you make the change, you cannot set the calibration value
back to factory default. Perform calibration when the allowable range is exceeded in the
performance test described in section 9.6 or when parts of the TA120E are replaced. If a
problem is detected during the calibration operation, please contact your nearest
YOKOGAWA dealer as listed on the back cover of this manual for repairs.
Signal cable
When performing calibration, remove all cables that are connected to the TA120E
(input and output cables) excluding the power cable and GP-IB cable.
If the TA120E is in the remote mode at this point, calibration cannot be performed.
Switch from remote mode to local mode.
Warm Up
Warm up the TA120E for at least 30 minutes with the power turned ON before
performing calibration.
Calibrated items
The following items can be calibrated:
• DC voltage level.
• Time-voltage converter.
• Programmable delay circuit.
• The Signal multiplexer, the fractional pulse generator, and their peripheral circuits.
Changing the factory default calibration value
• When calibration completes normally, a new calibration value is obtained. To apply
the new calibration value, you must change the factory default calibration value. If
you change the factory default calibration value, you cannot set it back. Please
confirm that it is okay to change the factory default calibration value beforehand.
Note that initialization (see section 7.4) will not set the calibration value back to
factory default.
• If the factory default calibration value is not changed, the new calibration value is
not applied.
• The factory default calibration value can be changed only when all calibrations
complete normally.
• If you are not going to change the factory default calibration value, return to the
start condition in the maintenance mode or turn OFF the power switch.
9.5 Performing Calibration (Changing the Factory Default Calibration Value)