6
Performance Tests and Calibration
88
Keysight U1211A, U1212A, and U1213A User’s and Service Guide
Test Considerations
Long test leads can also act as antennas that pick up AC signal noises.
For optimum performance, all procedures should comply with the following
recommendations:
– Ensure that the ambient temperature is stable between 18 °C and 28 °C.
Ideally, calibration should be performed at 23 °C ± 2 °C.
– Ensure that the ambient relative humidity is less than 80%.
– Place the clamp meter with the non-compensational transfer adapter with
miniature thermal probe connected to the input terminal in the operating
environment for at least 1 hour.
– Allow a 5-minute warm-up period during which a shorting plug is used to
connect 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. Connect the calibrator LO source to
earth at the calibrator, except where otherwise indicated in the procedures. It
is important that the LO-to-earth 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 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 that the calibrator’s “0” output is correct. You will need to set the
offset for each range of the measurement function being verified.
Input connections
For low-thermal offset measurements, test connections to the instrument are best
accomplished by shorting the two terminals using dual banana plug with copper
wire short. Shielded twisted-pair PTFE interconnect cables of minimum length are
recommended between the calibrator and the clamp meter. Cable shields should
be grounded to earth. This configuration is recommended for optimal noise and
settling time performance during calibration.