Operation Manual

GMC-I Messtechnik GmbH 41
Measurements: V/Hz – R
SL
– Ω – – Temp – – m – M Ω
ISO
– A/Hz
Ð Starting the insulation resistance measurement:
Briefly press the U
ISO ON / OFF key.
Insulation resistance is displayed for the currently selected
conductor pair.
Ð Reversing polarity of the cable under test:
– Normal polarity reversal:
Press and hold the POL / U
ISO key.
– Rapid polarity reversal:
Press the POL / UISO key at short intervals. bAL.C appears at
the display (ballistic capacitance) for relative cable length
determination. After key activation has ceased for a period
of approximately 2 seconds, the instrument is switched
back to standard insulation resistance measurement.
Ð Switch the rotary selector switch to the MΩ
ISO
_a-b, MΩ
ISO
_a-
E and MΩ
ISO
_b-E positions, one after the other, in order to
execute the desired tests.
Auto-ranging is active during insulation resistance measurement.
If the measured value is less than 10% of the measuring range
after manual measuring range selection (see chapter 4.1.2), u r
(under-range) appears at the display. You should then select the
next smaller measuring range with the help of the
 key.
Automatic Recognition of Interference Voltage During
Insulation Resistance Measurement
If, during insulation measurement, the instrument detects an
interference voltage of greater than 15 V AC or 25 V DC (assuming: U
in-
terference
≠ U
ISO
, Riq < 100 kΩ), „Error“ is briefly displayed at the
LCD. The instrument is then automatically switched to voltage
measurement, and the currently measured voltage value is dis-
played.
000.00
M Ω
MΩ
a-b
a-E
b-E
MΩ
iso
at 100 V
iso
a-b
FUNC
ENTER
UISO ON / OFF
ZERO
ESC
POL / UISO
FUNC
ENTER
UISO ON / OFF
a-E
FUNC
ENTER
UISO ON / OFF
ZERO
ESC
POL / UISO
FUNC
ENTER
UISO ON / OFF
b-E
FUNC
ENTER
UISO ON / OFF
ZERO
ESC
POL / UISO
FUNC
ENTER
UISO ON / OFF
UISO
000.0
UISO
V
FUNC
ENTER
+–
+–
a
a
b
b
E
E
+
–
0V !
Reverse polarity
Discharge
Switch test
voltage on
DC
AC
TRMS
100 V
iso