User manual

1 Calibration Procedures
Calibration Process
8 U1271A/U1272A Service Guide
Calibration Process
1 Prior to performing the verification tests, see the “Test
considerations” on page 8.
2 Perform the verification tests to characterize the
multimeter; see “Performance Verification Tests” on
page 10.
3 Unsecure the multimeter for calibration; see “Calibration
Security” on page 18.
4 Prior to performing the adjustments, see the “Adjustment
considerations” on page 23.
5 Perform the adjustment procedure; see “Adjustment
procedure” on page 27.
6 Secure the multimeter against unauthorized calibration;
see “Exiting the adjustment mode” on page 29. Ensure
that the multimeter has quit the adjustment mode and is
turned off.
7 Record the new security code and calibration count in the
multimeter's maintenance records.
Test considerations
For optimum performance, all procedures should comply
with the following recommendations:
• The performance verification test or adjustment should be
performed under laboratory condition which ambient
temperature can be controlled.
• Ensure that the calibration ambient temperature is stable
and is between 18 °C and 28 °C. Ideally the calibration
should be performed at 23 °C ± 1 °C.
• Ensure that the ambient relative humidity is less than
80%.
• The instrument should be put under the laboratory
environment for at least 1 hour.
• Allow a warm- up period of 3 minutes.