Technical data

Performance Tests and Calibration 1
Test Considerations
34450A Service Guide 5
Test Considerations
Errors may be induced by AC signals present on the input leads during
a self test. 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:
• Assure that the calibration ambient temperature is stable and between
18 °C and 28 °C. Ideally the calibration should be performed at
23 °C ±1 °C.
• Assure ambient relative humidity is less than 80 %.
• Allow a two hours warm- up period for performance verification tests
and four hours warm- up period for calibration with a shorting plug
connected to the HI and LO 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.
Because the instrument is capable of making very accurate
measurements, you must take special care to 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
an order of magnitude more accurate than each instrument range full-
scale error specification.
For DC voltage, DC current, and resistance gain verification
measurements, you should ensure the calibrator's "0" output is correct.
You will need to set the offset for each range of the measuring function
being verified.