GE 745 TRANSFORMER MANAGEMENT RELAY, Instruction Manual

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GE Power Management 745 Transformer Management Relay 8-9
8 COMMUNICATIONS 8.2 MODBUS PROTOCOL
8
8.2.12 FUNCTION CODE 10H: STORE MULTIPLE SETPOINTS
Modbus Implementation: Preset Multiple Registers
GE Power Management Implementation: Store Multiple Setpoints
This function code allows the master to modify the contents of a one or more consecutive setpoint registers in
the addressed slave device. Setpoint registers are 16 bit (two byte) values transmitted high order byte first.
The maximum number of register values (setpoints) that can be stored in a single message is 60.
MESSAGE FORMAT AND EXAMPLE:
Request slave device 11 to write the value 00C8 at setpoint address 1100, and the value 0001 at setpoint
address 1101.
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 11 data starting at address 1100
DATA STARTING ADDRESS: low order byte 00
NUMBER OF SETPOINTS: high order byte 00 2 setpoint values = 4 bytes total
NUMBER OF SETPOINTS: low order byte 02
BYTE COUNT 04 4 bytes of data
DATA #1: high order byte 00 data for address 1100 = 00C8
DATA #1: low order byte C8
DATA #2: high order byte 00 data for address 1101 = 0001
DATA #2: low order byte 01
CRC: low order byte 27
CRC: high order byte 01
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 1100
DATA STARTING ADDRESS: low order byte 00
NUMBER OF SETPOINTS: high order byte 00 2 setpoint values = 4 bytes total
NUMBER OF SETPOINTS: low order byte 02
CRC: low order byte 46
CRC: high order byte 64