Areva MiCOM P921, Technical Manual

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Technical Guide P92x/EN CT/E11
Modbus Protocol
MiCOM P921-P922-P923 Page 11/118
1.5.1 Request to retrieve the oldest non-acknowledge event
Slave number Function code Word address Word number CRC
xx 03h 36h 00 00 09h xx........xx
This event request may be answered an error message with the error code :
EVT_EN_COURS_ECRIT (5) : An event is being written into the saved RAM.
NOTA : On event retrieval, two possibilities exist regarding the event
record acknowledgement :
Automatic event record acknowledgement on event retrieval.
Non automatic event record acknowledgement on event
retrieval.
a) Automatic event record acknowledgement on event retrieval :
The bit12 of the remote order frame (format F9 - mapping address 0400h) shall be
set to 0. On event retrieval, this event record is acknowledged.
b) Non automatic event record acknowledgement on event retrieval :
The bit12 of the remote order frame (format F9 - mapping address 0400h) shall be
set to 1. On event retrieval, this event record is not acknowledged.
To acknowledge this event, an other remote order shall be sent to the relay. The bit
13 of this frame (format F9 – mapping address 0400h) shall be set to 1.
1.5.2 Request to retrieve a dedicated event
Slave number Function code Word address Word number CRC
xx 03h Refer to mapping 00 09h xx........xx
This event request may be answered an error message with the error code :
EVT_EN_COURS_ECRIT (5) : An event is being written into the saved RAM.
NOTA : This event retrieval does not acknowledge this event.
1.6 Modbus request definition used to retrieve the fault records
Two ways can be followed to retrieve a fault record :
1. Send a request to retrieve the oldest non-acknowledge fault record.
2. Send a request to retrieve a dedicated fault record.