Operation Manual

GMC-I Messtechnik GmbH 45
Measurements R
SL
– MΩ
ISO
@10 V/100 V – CAP Switch positions (a-b) (a-E) (b-E)
6.2 Detection of Interference Voltages
Ð Set the rotary switch to the a-b, a-E and b-E positions, one
after the other, in order to display any interference voltage for
all three conductor pairs.
Note
Insulation resistance may only be measured at voltage-free
devices.
6.3 Insulation Resistance Measurement:
in Telecommunications Networks – MΩISO Function
Three jacks (a, b and E) are provided for measurements in
symmetrical copper cable networks with two conductors and a
shield. The rotary selector switch can be set to determine whether
insulation testing will be performed between a and b, a and E or
b and E.
Interruption of a single core or contact with an open-circuit core
(capacitive asymmetry) can be recognized by switching rapidly
with the POL / U
ISO key.
In the event of a good cable, the bar graph must be identical in the
a-E and b-E selector switch positions (open-circuit cable only!).
Long cable: long bar graph display
Short cable: short bar graph display
The overall length of the bar graph represents a range of
capacitance from 50 nF to 100 nF.
Note
Insulation resistance measurement with 10 V test voltage
The measuring range of the digital display is limited to
30 MΩ.
Exceeding values are shown as „OL“.
In contrast, the bargraph serves as a trend indicator and dis-
plays values up to 100 MΩ, however, without any specified
accuracy.
a-b
a-E
b-E
MΩ
ISO
@10V/100V
U ISO
Interference Voltage Detection
000.0
U ISO
V
DC
AC
TRMS
ISO
100V
V: 6,0 V … 110,0 V
Measuring Range: