IRDH275BM-7_D00123_07_M_XXEN / 08/2020 23
ISOMETER® IRDH275BM-7
4.4.5 Current output for external measuring instruments
Factory setting: 0…20 mA
The current output of the IRDH275BM-7 can be set to „0…20 mA“ or „4…20 mA“ via the menu point
„M+/M-:“. The maximum load is 500 Ω.
Function 0…20 mA:
R
F
= insulation fault,
I = current in mA
R
F
= 20 mA x 2800 kΩ - 2800 kΩ
I
Funktion 4…20 mA:
R
F
= insulation fault,
I = current in mA
R
F
= 16 mA x 2800 kΩ - 2800 kΩ
I - 4 mA
The associated characteristic curves are illustrated on page 36.
4.5
Menu ISO ADVANCED: Setting of the extended functions
4.5.1 Coupling devices AGH: 675S-7…
The ISOMETER® is connected to the AGH675S-7 by connecting the terminal AK to terminal 5. The nomi-
nal operating range is extended to AC 0…7.2 kV (AGH475S-7) or AC 0…15.5 kV (two AGH475S-7MV).
When terminal 2 will be connected to the midpoint of the DC intermediate circuit, a voltage of 14.4 kV
is permitted.
4.5.2 Adaptation to the system leakage capacitance C
e
max
This menu allows to adapt the ISOMETER® to the maximum system leakage capacitance (2 or 5 μF).
Please note that the basic measuring time will take no longer than five minutes when virtually no con-
verter-related disturbances are present.
Factory setting = 2 μF.
4.5.3 Measuring principle (Measure: AMP)
The AMP measuring principle is factory set.
4.5.4 Setting the repetition time for automatic self tests (Autotest: 24h)
The time for the repetition of automatic self tests can either be set to 1 hour or to 24 hours or can be
deactivated.
Factory setting = 24 h
4.5.5 Setting the real-time clock (Clock)
The setting of the real-time clock is the time base for the memory and for the automatic self test. In
case of failure of the supply voltage, the real-time clock keeps running for approximately 30 days. When
the device will be switched on after this period, a flashing „C“ appears on the display and the clock has
to be set again.
