Functional Tests Of Contactors In The Charging Station And The Vehicle; Monitoring The Insulation Resistance; Undervoltage/Overvoltage Monitoring; Stop Mode - Bender ISOMETER isoCHA425HV Manual

Function
2.3.6

Functional tests of contactors in the charging station and the vehicle

If the ISOMETER® is disconnected on one pole from the monitored voltage source during a functional test of
the charging station or vehicle contactors, a false alarm may occur depending on the location of an existing
insulation fault. For insulation faults above 600 k the false alarm can be prevented by a resistor of 200 k
connected directly between the terminals L1/+ and L2/–.
2.3.7

Monitoring the insulation resistance

The insulation resistance R
chapter 4.4.1). The value "R1" can only be set higher than the value "R2". If the insulation resistance R
or falls below the activated values "R1" or "R2", an alarm message is triggered. If R
"R2" plus the hysteresis value, the alarm will be cleared.
2.3.8

Undervoltage/overvoltage monitoring

To monitor the system voltage U
menu "AL" (see chapter 4.4). The maximum undervoltage value is limited by the overvoltage value.
The RMS value of the system voltage U
the limit values "U˂" and "U˃", an alarm will be signalled. If the maximum permissible system voltage U
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 chapter 4.4.2) are no longer
violated.
2.3.9

Stop mode

If the measuring pulse interferes with other measuring functions, the ISOMETER® can be set to stop mode,
either via the Modbus protocol or by holding the external test/reset button ("T/R").
In stop mode, the measuring pulse generator stops clocking and the measuring function is deactivated. The
message "StP" appears on the display. The communication interface returns the identifiers "warning" and
"external test".
For applications where the ISOMETER® is temporarily not needed and if it is coupled with the AGH421-1, the
isometer can be disconnected from the monitored system by activating stop mode via the Modbus protocol.
There is no disconnection if stop mode is activated via the external test/reset button.

2.3.10 Self test functions (device errors)

During the normal measuring function the cyclic test of the µC as well as the continuous PE connection
monitoring run in the background.
User-controlled test functions interrupt the measuring function of the device. They are triggered 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 table in the
section "Error codes", page 14 and, depending on the message assignment, the relays switch.
12 isoCHA425HV_D00404_04_M_XXEN/10.2023
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-value
n
is monitored. If the system voltage U
n
exceeds the values "R1" or
F
reaches, falls below, or exceeds
n
reaches
F
set for
n