Areva MiCOM P225, Technical Manual

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Communication P225/EN CT/B11
MiCOM P225 Page 1/52
CONTENT
1. MODBUS PROTOCOL 3
1.1 MODBUS communication characteristics 3
1.1.1 MODBUS network characteristics 3
1.1.2 Parameters of the MODBUS connection 4
1.1.3 Synchronisation of exchange messages 4
1.1.4 Message validity check 4
1.1.5 Address of the MiCOM relays 4
1.2 MODBUS functions of the MiCOM relays 5
1.3 Presentation of the MODBUS protocol 5
1.3.1 Frame size received by the MiCOM P225 relay 5
1.3.2 Format of frames sent by the MiCOM P225 relay 6
1.3.3 Messages validity check 6
1.4 Modbus request definition used to retrieve the disturbance records 7
1.4.1 Request to know the number of available disturbance records in the Saved RAM. 7
1.4.2 Service request 7
1.4.3 Request to retrieve the data of a disturbance record channel 7
1.4.4 Request to retrieve an index frame 8
1.5 Modbus request definition used to retrieve the event records 8
1.5.1 Request to retrieve the oldest non-acknowledge event 8
1.5.2 Request to retrieve a dedicated event 8
1.6 Modbus request definition used to retrieve the fault records 9
1.6.1 Request to retrieve the oldest non-acknowledge fault record 9
1.6.2 Request to retrieve a dedicated fault record 9
1.7 Modbus request definition used to retrieve both start-up current & voltage form record10
1.7.1 Request to know the number of current values stored into the saved memory 10
1.7.2 Request to retrieve the start-up current form record data 10
1.7.3 Request to know the number of voltage values stored into the saved memory 10
1.7.4 Request to retrieve the start-up voltage form record data 10
1.8 MiCOM P225 database organisation 11