Fluke PM6681R, PM6685R manual Calibration Subsystem, PM6680B, PM6685

Using the Subsystems

Calibration Subsystem

The interpolators used to increase the res- olution of the measurement result in the counter must be calibrated to maintain the highest possible accuracy of the counter.

The calibration method of the PM6681 differs from the method used in PM6680B and PM6685.

￿PM6680B, PM6685

The intepolators are automatically cali- brated before each measurement. This procedure takes only a fraction of a sec- ond, but to increase speed, you can turn off the auto calibration.

￿PM6681

In PM6681, the interpolators are factory calibrated. Calibration must be performed only after repair and can be performed at your local Service centers.

If the calibration is lost for any reason, the counter will show ZCAL. LOSTZ .

By pressing PRESET you can bypass this message and use the counter anyway, however you must press the front panel key. No bus command takes you past this error message.

This is so that you cannot bypass the message by mistake, and run a test sys- tem without a calibrated instrument.

6-4 Calibration Subsystem