Performance Tests and Calibration
5
Keysight U1241B and U1242B User’s and Service Guide
65
Test Considerations
Error may be induced by AC signals that present on the input leads. Long test
leads can also act as an antenna causing pick-up of AC signals.
For optimum performance, all procedures should comply with the following
recommendations:
– Ensure that the calibration ambient temperature is stable and between 18 °C
and 28 °C. Ideally the calibration should be performed at 23 °C ± 2 °C.
– Ensure that the ambient relative humidity (RH) is less than 80%.
– Ensure that the low battery indicator does not appear during the performance
verification test. If it does, replace the batteries to avoid any inaccurate
reading.
– During temperature performance verification test, ensure that the multimeter
has been switched ON and placed in the test environment for at least one hour
with J/K-type thermo-couple connected between the multimeter and
calibration source.
– Allow one minute warm-up period with a Shorting Plug connected to the V
and COM input terminals.
– Use shielded twisted pair PTFE-insulated cables to reduce settling and noise
errors. Keep the input cables as short as possible.
– Connect the input cable shields to earth ground. Except where noted in the
procedures, connect the calibrator
LO
source to earth ground at the calibrator.
It is important that the
LO
to earth ground connection be made at only one
place in the circuit to avoid ground loops.
During DC voltage, DC current, and resistance gain verification measurements,
ensure that the calibrator's “
0
” output is correct. It is recommended to set the
offset for each range of the measuring function being verified.
