Technical data

114 Agilent U1251B/U1252B User’s and Service Guide
6 Performance Tests and Calibration
Test Considerations
Long test leads can also act as antennas which may pick up
AC signals.
For optimum performance, all procedures should comply
with the following recommendations:
• 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%.
• Allow a warm- up period of five minutes with a Shorting
Plug connected to the V and COM input terminals.
• Use shielded twisted pair Teflon- 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.
Please ensure that the calibration standards and test
procedures used do not introduce additional errors. Ideally,
the standards used to verify and adjust the instrument
should be of an order of magnitude more accurate than each
instrument range full- scale error specification.
For the DC voltage, DC current, and resistance gain
verification measurements, ensure that the calibrator's "0"
output is correct. You will need to set the offset for each
range of the measuring function being verified.