Keysight U3606B, Service Manual

Page: 25 / 123

Calibration Procedures 1
Keysight U3606B Service Guide 25
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 the pick-up of AC signals.
For optimum performance, all procedures should comply with the following
recommendations:
– The performance verification test or adjustment should be performed under
laboratory conditions where the ambient temperature can be controlled.
– The instrument should be put under the laboratory environment for at least
1 hour.
– Ensure that the calibration ambient temperature (T
cal
) is stable and is between
18 °C and 28 °C. Ideally the calibration should be performed at 23 °C ± 2 °C.
– Ensure that the ambient relative humidity is less than 80%.
– Allow a 60-minute
[1]
warm-up period with a shorting plug connected to the
V (red) and LO (black) input terminals.
– Use a shielded twisted pair of 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 highly 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 of full scale
error specification.
– For the DC voltage, DC current, and resistance gain verification
measurements, you should take careful measures to ensure that the calibrator
“0” output is correct. You will need to set the offset for each range of the
measuring function being verified.
[1] A 120-minute warm-up period is required for instrument adjustments (calibration).