GE Multilin
745 Transformer Management Relay
7-7
7 COMMUNICATIONS
7.3 MODBUS FUNCTIONS
7
d) FUNCTION CODE 06H: STORE SINGLE SETPOINT
Modbus Implementation:
Preset Single Register
GE Multilin Implementation:
Store Single Setpoint
This function code allows the master to modify the contents of a single setpoint register in the addressed slave device. The
response of the slave device to this function code is an echo of the entire master query message.
MESSAGE FORMAT AND EXAMPLE:
Request slave device 11 to write the value 00C8 at setpoint address 1100.
e) FUNCTION CODE 10H: STORE MULTIPLE SETPOINTS
Modbus Implementation:
Preset Multiple Registers
GE Multilin 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
06
store single setpoint value
DATA STARTING ADDRESS: high order byte, low order byte
11 00
data starting at address 1100
DATA: high order byte, low order byte
00 C8
data for address 1100 = 00C8
CRC: low order byte, high order byte
8F F0
CRC computed by master
SLAVE RESPONSE:
EXAMPLE (HEX):
SLAVE ADDRESS
11
response message from slave 11
FUNCTION CODE
06
store single setpoint value
DATA STARTING ADDRESS: high order byte, low order byte
11 00
data starting at address 1100
DATA: high order byte, low order byte
00 C8
data for address 1100 = 00C8
CRC: low order byte, high order byte
8F F0
CRC computed by slave
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, low order byte
11 00
data starting at address 1100
NUMBER OF SETPOINTS: high order byte, low order byte
00 02
2 setpoint values = 4 bytes total
BYTE COUNT
04
4 bytes of data
DATA #1: high order byte, low order byte
00 C8
data for address 1100 = 00C8
DATA #2: high order byte, low order byte
00 01
data for address 1101 = 0001
CRC: low order byte, high order byte
27 01
CRC computed by master
SLAVE RESPONSE:
EXAMPLE (HEX):
SLAVE ADDRESS
11
response message from slave 11
FUNCTION CODE
10
store multiple setpoint values
DATA STARTING ADDRESS: high order byte, low order byte
11 00
data starting at address 1100
NUMBER OF SETPOINTS: high order byte, low order byte
00 02
2 setpoint values = 4 bytes total
CRC: low order byte, high order byte
46 64
CRC computed by slave
