4.7. Timer (C.A 6525)
The timer function is available for insulation testing (MΩ
positions).
When you press the TIMER key, the
symbol appears in front
of the digital threshold display which indicates 0:00 (timer). If
there was a programmed threshold displayed, it disappears.
An initial short press on the yellow key starts both the timer and
insulation measurement. You do not have to keep the key pressed
down.
A second press stops the timer and the measurement. The last
value of the timer remains displayed and the instrument switches
back to voltage measurement.
To perform another timed measurement, simply press the yellow
key again. The timer is then reset to zero and restarts along
with the measurement.
To quit the timer mode, simply press the TIMER key again or
switch the instrument off and then on again. The
symbol is
no longer displayed.
After 30 seconds, 1minute and 10 minutes, the instrument's
buzzer sounds. this is to allow those users who require it to
calculate the dielectric absorption rate
(= measurement after 1 min / measurement after 30 s) and the
polarization index
(= measurement after 10 min / measurement after 1 min).
Reminder : for acceptable insulation, they must be greater than
1.25 and 2, respectively.
When measuring, if a threshold is exceeded, the buzzer sounds
and display of the timer is interrupted to display the
corresponding alarm message (see § 4.5.3).
If you forget to stop the insulation test, the instrument
automatically switches back to voltage measurement after 15
minutes and the TIMER remains blocked at 15:00.
5. USE
In order to successively display the calibration date, the software
version and the serial number of the apparatus, press the yellow
key when turning the switch to start the apparatus up.
To start up the machine, set the rotary switch to the type of
measurement to be performed and then connect the instrument
to the installation to be tested. The unit is displayed and the
calibre is selected automatically for the best reading.
The instrument can be shut down manually by setting the switch
to OFF. Otherwise, the instrument will be shut down
automatically after 5 minutes without any sign of the presence
of a user (see § 4.2).
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