Operation Manual

16 GMC-I Messtechnik GmbH
Note!

Testing the Measurement Cables
Initial testing should be performed by short-circuiting
the measurement cables using their test probes. The
instrument must display nearly 0 Ω. A broken
measurement cable can be detected in this way.
Attention!
!
Do not touch the conductive ends of the test probes
when the instrument has been activated for the
measurement of insulation resistance.
You may otherwise be exposed to a current of
1.5 mA (limited in the measuring instrument), and
although this is not life endangering, the resulting
electrical shock is quite discernible.
If, on the other hand, measurement is being performed on
a capacitive device under test, for example a cable, it may
be charged to approximately ±600 V, depending upon the
selected nominal voltage.
Touching the device under test after measurement has
been performed may be life endangering in this case!
11.2 Insulation Resistance Measurement
Ð Press and hold the FUNC key until the display settles in, in
order to measure insulation resistance.
Attention!
!
The selected and displayed test voltage blinks during
measurement.
Attention: Contact hazard!
Current voltage at the device under test appears at the
interference or residual voltage display during measurement.
This value is slightly less than nominal voltage.
Insulation resistance measurement is ended by releasing the
FUNC key.
Auto-ranging is active during insulation resistance
measurement. Manual measuring range selection is not
possible.
Note!

The instrument’s storage batteries are rapidly
depleted during insulation resistance measurement.
Only hold the multifunction key depressed as long as
is actually necessary. The continuous measurement
described below should only be performed if
absolutely necessary.
Use NiMH storage batteries only.
Continuous Measurement
Ð Activation: Briefly press the multifunction key and the
MAN|AUTO key simultaneously. This is acknowledged with
an acoustic signal.
Ð Deactivation: Briefly press the multifunction key.
11.3 Ending the Measurement and Discharging
After measurement has been completed, any remaining
residual voltage is displayed which may result from cable
capacitance. These charges are quickly dispersed by means
of two internal resistors with a value of 2 MΩ. However,
contact to the device under test must be maintained. The
falling voltage value can be observed at the interference or
residual voltage display.
Do not disconnect the device under test until the voltage value has
dropped to below 25 V!
mΩ
S+S–
MΩ
R
ISO
U
Measured
(50 to 500V)
Ω: 10 k
Ω … 3GΩ
Measuring Range:
!