Fluke PM6685 Outdoor Timer User Manual


 
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.
n
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.
n
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
Using the Subsystems