VAMP Ltd
Overcurrent and earth-fault relay
Technical Description
VAMP 130
VM130.EN003
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2.7.
Self-supervision
The functions of the micro controller and the associated
circuitry as well as the program execution are supervised by
means of a separate watchdog circuit. Besides supervising the
relay the watchdog circuit attempts to restart the micro
controller in a fault situation. If the restarting fails the
watchdog issues a self-supervision alarm because of a permanent
relay fault.
When the watchdog circuit detects a permanent fault it always
blocks any control of the other output relays, except for the self-
supervision output relay.
Also the internal supply voltage is supervised. Should the auxil-
iary supply of the relay disappear, an IF alarm is automatically
given. The IF relay contact is normally closed type of contact.
This means that the IF relay contact is closed, when there is an
internal fault or there is no auxiliary power supply. If the relay
is fully operational with the auxiliary power supply, the IF
contact is on the open position.
