Important information
14
isoHV425_D00082_03_M_XXEN/05.2020
3.2.2
Undervoltage/overvoltage monitoring
In the response value menu "AL" (see
Page 29), the two parameters ("U <" and
"U >") for monitoring the system voltage
U
n
can be activated or deactivated. The maxi-
mum undervoltage value is limited by the overvoltage value.
The r.m.s. value of the system voltage
U
n
is monitored. If the system voltage
U
n
reaches,
falls below or exceeds the limit values ("U <" or "U >"), an alarm will be signalled. If the
maximum permissible system voltage
U
n
set for the ISOMETER® is exceeded, an alarm
message will be triggered even if the overvoltage limit value has been deactivated. The
alarm will be deleted when the limit values plus hysteresis (see
) are no longer
violated.
3.2.3
Self test/error codes
The isoHV425xx contains test routines for checking that the device is functioning cor-
rectly during operation. Some test routines are performed cyclically or continuously in
the background during the normal measuring function. Other test routines are trig-
gered by the user. The following options are available to the user:
cyclically via a timer (menu item "t" / "test")
via the internal test button
via the external test button
via the communication interface (COM)
In case of a device error, all 3 LEDs on the device flash, the display shows the message
"E.xx" according to the following error code table and depending on the signalling as-
signment, the relays switch.