User manual

GMC-I Messtechnik GmbH 39
Measurements: V/Hz, , , Temp (°C/°F), , M
@UISO
, A/Hz
5.7 Insulation Resistance Measurement – M
@UISO
5.7.1 Preparing for Measurement
Note
Testing the Measurement Cables
The test probes at the ends of the measurement cables
should be short circuited before performing insulation
resistance measurements with the selector switch in the 
or the position, in order to make sure that a value close
to 0  is displayed at the instrument. Incorrect connection or
a broken measurement cable can be detected in this way.
Note
Insulation resistance may only be measured at voltage-free
devices. The measurement cables may not come into con-
tact with one another during high-resistance insulation
measurements.
➭ Set the rotary switch to “
M 
@UISO
”.
➭ Connect the measurement cables to the two accessible jacks.
➭ Interference voltage measurement (V AC+DC TRMS) is
conducted in this switch position.
The FUNC | ENTER key for U
ISO ON / OFF may only be pressed in
order to start the insulation resistance measurement if the
device under test is voltage-free.
Note
The M
@UISO
switch position may only be used for insula-
tion resistance measurement and interturn short-circuit
detection (METRAHIT COIL). However, if interference voltage is
inadvertently applied with the switch in this position, it
appears at the display. If an interference voltage of  50 V is
present, insulation resistance measurement is disabled. The
LCD continues to display the interference voltage value. If a
voltage of greater than 1000 V is present, an acoustic signal
is generated as well.
COM mA A
V
Tem p
 MISO
00 . 00

Short circuit the measurement cables.
R
x
0V !
!

M
@UISO
V
Interference Voltage Detection
000.0
V
DC
AC
TRMS
1M
ISO 500 V