3.14.4 Device Response
The response of the P631 is dependent on the type of monitoring signal. The
following responses are possible:
●
Signaling Only
If there is no malfunction associated with the monitoring signal, then only a
signal is issued, and there are no further consequences. This situation
exists, for example, when internal data acquisition memories overflow.
●
Selective Blocking
If a fault is diagnosed solely in an area that does not affect the protective
functions, then only the affected area is blocked. This would apply, for
example, to the detection of a fault on the communication module or in the
area of the PC interface.
●
Warm Restart
If the self-monitoring function detects a fault that might be eliminated by a
system restart – such as a fault in the hardware –, then a procedure called
a warm restart is automatically initiated. During this procedure, as with any
start-up, the computer system is reset to a defined state. A warm restart is
characterized by the fact that no stored data and, in particular, no setting
parameters are affected by the procedure. A warm restart can also be
triggered manually by control action. During a warm restart sequence the
protective functions and the communication through serial interfaces will
be blocked. If the same fault is detected after a warm restart has been
triggered by the self-monitoring system, then the protective functions
remain blocked but communication through the serial interfaces will usually
be possible again.
●
Cold Restart
If a corrupted parameter subset is diagnosed during the checksum test,
which is part of the self-monitoring procedure, then a cold restart is carried
out. This is necessary because the P631 cannot identify which parameter in
the subset is corrupted. A cold restart causes all internal memories to be
reset to a defined state. This means that all the protection device settings
are also erased after a cold restart. In order to establish a safe initial state,
the default values have been selected so that the protective functions are
blocked. Both the monitoring signal that triggered the cold restart and the
value indicating parameter loss are entered in the monitoring signal
memory.
P631
3 Operation
3-92 P631/EN M/R-11-C // P631-310-650
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