Monitoring The Insulation Resistance; Undervoltage/Overvoltage Monitoring; Stop Mode; Self Test Functions (Device Errors) - Bender ISOMETER isoCHA425 Manual

2.3.7

Monitoring the insulation resistance

The insulation resistance R
chapter 4.4). The value 'R1' can only be set higher than the value 'R2'. If the insulation resistance R
falls below the activated values 'R1' or 'R2', an alarm message is triggered. If R
plus the hysteresis value, the alarm will be cleared.
2.3.8

Undervoltage/overvoltage monitoring

To monitor the nominal system voltage U
value menu 'AL' (chapter 4.4). The maximum undervoltage value is limited by the overvoltage value.
The RMS value of the nominal system voltage U
falls below, or exceeds the limit values 'U ˂' and 'U ˃', an alarm will be signalled. If the maximum permissible
nominal system voltage U
overvoltage limit value has been deactivated. The alarm will be deleted when the limit values plus hysteresis
(chapter 4.4.2) are no longer violated.
2.3.9

Stop mode

For applications where the ISOMETER® is not needed and the measuring pulse interferes with other measuring
functions, it can be set to stop mode via the Modbus protocol or by pressing and holding the external test/
reset button ('T/R'). The measuring pulse generator is turned off and the measuring function is deactivated.
The message 'StP' appears on the display. It sends the identifiers 'warning' and 'external test' via the
communication interface.
The L+ and L- connections disconnect from the monitored mains. The electronic circuit breakers are in the
device.

2.3.10 Self test functions (device errors)

During the normal measuring function the ISOMETER® checks its correct function in the background.
Other tests interrupt the the measuring function of the device. The user can trigger these as follows:
• cyclically via a timer (menu item 't' / 'test') or
• via the internal or external test button or
• via the communication interface (COM)
In case of a device error, all LEDs flash, the display shows the message 'E.xx' according to the error code table
and, depending on the message assignment, the relays switch.
Cyclic background test
The cyclic background test checks the functionality of the C. It is not visible to the user and does not influence
the measuring function. In case of malfunction, the respective device error messages 'E.09' to 'E.16' appear.
Continuous PE connection monitoring
The connection of terminal 'E' to the PE protective conductor is monitored continuously and in parallel with
the measuring function of the device via the input 'KE', which is also connected to the PE protective conductor.
When the connection is interrupted, the device error message 'E.01' appears.
is monitored by means of the parameters 'R1' (prewarning) and 'R2' (alarm) (see
F
, the two parameters 'U ˂' and 'U ˃' can be enabled in the response-
n
n
set for the ISOMETER® is exceeded, an alarm message will be triggered even if the
n
is monitored. If the nominal system voltage U
isoCHA425_D00352_03_M_XXEN/08.2023
ISOMETER® isoCHA425
F
exceeds the values 'R1' or 'R2'
F
reaches,
n
reaches or
11