9
Operation
indicators
A measuring relay module is provided with two
separate operating stages, each of which with its
own yellow/red operation indicator on the lower
part of the front plate of the relay module.
The operation indicator starts glowing yellow
when the operating stage starts and red when a
delayed tripping operates. The functions of the
start and operation indicators are described in
detail in the different protection relay module
manuals.
Fault codes
In addition to the protective functions the relay
module is provided with a self-supervision sys-
tem which continuously supervises the function
of the microprocessor, its program execution
and the electronics.
When the self-supervision system has detected a
permanent fault in the relay module, the red
IRF indicator on the panel starts glowing soon
after the fault was discovered. At the same time
the module puts forward a signal to the self-
supervision contact of the relay assembly.
In most fault situations a fault code, indicating
the nature of the fault, appears on the display of
the module. The fault code, which consists of a
red digit (1) and a three digit green code number,
cannot be removed from the display by reset-
ting. When a fault occurs, the fault code should
be recorded and stated when service is ordered.
