IDEC FL1E SmartRelay - Manual (Page 294)

Applications
280 IDEC SmartRelay Manual 
You can also generate a message at output Q4:
Q3 Q4
Error Messege
The relay contacts of output Q4 are always closed when the
system is in operation. Relay Q4 does not drop off unless
there is a power failure or a fault in the system. This contact
can be used for remote monitoring, for example.