GE 745 TRANSFORMER MANAGEMENT RELAY, Instruction Manual

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GE Power Management 745 Transformer Management Relay 8-13
8 COMMUNICATIONS 8.2 MODBUS PROTOCOL
8
1. First, preload the addresses listed in the first column of the table to in User Map Addresses #1 to #6
(addresses 0180 to 0185 hex).
2. Now that the User Map Addresses have been setup, the required memory map locations can be accessed
via the User Map Values #1 to #6 (addresses 0100 to 0105 hex). Both actual values and setpoints may be
read.
Master Query Message: Example (hex):
SLAVE ADDRESS 11 query message for slave 11
FUNCTION CODE 10 store multiple setpoint values
DATA STARTING ADDRESS: high order byte 01 data starting at address 0180
DATA STARTING ADDRESS: low order byte 80
NUMBER OF SETPOINTS: high order byte 00 6 setpoint values = 12 bytes total
NUMBER OF SETPOINTS: low order byte 06
BYTE COUNT 0C 12 bytes of data
DATA #1: high order byte 02 0200
→
Relay Status
DATA #1: low order byte 00
DATA #2: high order byte 02 0210
→
W3 Phase Time O/C Flag
DATA #2: low order byte 10
DATA #3: high order byte 03 0300
→
W1 Phase A 4th Harmonic Content
DATA #3: low order byte 00
DATA #4: high order byte 03 0301
→
W1 Phase B 4th Harmonic Content
DATA #4: low order byte 01
DATA #5: high order byte 03 0302
→
W1 Phase C 4th Harmonic Content
DATA #5: low order byte 02
DATA #6: high order byte 20 2002
→
Percent Differential Pickup
DATA #6: low order byte 02
CRC: low order byte 2F
CRC: high order byte 8A
Field: Example (hex):
SLAVE ADDRESS 11 response message from slave 11
FUNCTION CODE 10 store multiple setpoint values
DATA STARTING ADDRESS: high order byte 11 data starting at address 0180
DATA STARTING ADDRESS: low order byte 80
NUMBER OF SETPOINTS: high order byte 00 6 setpoint values = 12 bytes total
NUMBER OF SETPOINTS: low order byte 06
CRC: low order byte 42
CRC: high order byte 8F
Master Query Message: Example (hex):
SLAVE ADDRESS 11 query message for slave 11
FUNCTION CODE 03 read register values
DATA STARTING ADDRESS: high order byte 01 data starting at address 0100
DATA STARTING ADDRESS: low order byte 00
NUMBER OF REGISTERS: high order byte 00 6 setpoint values = 12 bytes total
NUMBER OF REGISTERS: low order byte 06
CRC: low order byte C6
CRC: high order byte A4