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1MRS750881-MUM
5.7.
5.7.1.
5.7.2.
5.7.3.
Remote Monitoring and Control Unit
Technical Reference Manual
Self-supervision (IRF)
The REC 523 device is provided with an extensive self-supervision system. The
self-supervision system handles run-time fault situations and informs the user of
faults through the LON/SPA and remote communication protocol.
Fault indication
The self-supervision signalling output operates on the closed circuit principle.
Under normal operating conditions, the self-supervision output relay, that is, the IRF
output relay, is energized and the contact gap X7.1/3-5 is closed. After a fault has
been detected, the device delivers a fault signal to the IRF relay, which operates, that
is, the relay drops off and the NO contact X7.1/4-5 closes.
The fault is indicated by the IRF LED on the LED panel and the PSC card of the
REC 523 device. Additionally, an event E57 is generated over the serial
communication.
If the internal fault disappears, event E56 is generated over the serial
communication.
Normal condition
IRF
Fig. 5.7.1.-1
Self-supervision output (IRF)
Fault operation
When entering IRF state, the relay takes the following actions to ensure that a false
trip can not be caused by the fault:
• All relay outputs are forced to zero (released), and subsequent changes blocked.
• All virtual outputs (COMM_OUT1...64) are written to zero, and subsequent
changes blocked.
• Event transmission is blocked, except for IRF events E56/E57 and start-up event
E50.
Fault recovery
This feature is supported in the REC 523 revision F or later.
The relay tries to recover from a fault either by restarting the module (I/O module)
that reported the fault, or by restarting the whole relay. During a restart, the IRF state
remains active until the internal self-supervision program has determined that the
relay is operating normally. If the fault is still present after three restarts, the relay is
in permanent IRF state.
Fault condition
3
4
IRF
5
REC 523
3
4
5
IRFoutput
43
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