10-4 869 MOTOR PROTECTION SYSTEM – COMMUNICATIONS GUIDE
MODBUS PROTOCOL CHAPTER 10: MODBUS PROTOCOL
Function Code 05H
Modbus Implementation: Force Single Coil
869 Implementation: Execute Operation
The function code allows the master to request an 869 to perform specific command
operations.
For example, to request slave 17 to execute operation code 1 (reset), we have the following
master/slave packet format:
Table 10-5: Master Packet Format for Function Code 05H
Table 10-6: Slave Packet Format for Function Code 05H
Function Code 06H
Modbus Implementation: Preset Single Register
869 Implementation: Store Single Setpoint
The command allows the master to store a single setpoint into the memory of an
869
relay. The slave response to this function code is to echo the entire master
transmission.
For example, request slave 17 to store the value 2 in setpoint address 04 5C. After the
transmission in this example is complete, setpoints address 04 5C contains the value 0002.
The master/slave packet format is shown next.
Table 10-7: Master Packet Format for Function Code 06H
BYTE COUNT 1 02 1 register = 2 bytes
DATA (see definition above) 2 00 00 value in address 0008
CRC 2 78 F3 CRC error code
MASTER TRANSMISSION BYTES EXAMPLE DESCRIPTION
SLAVE ADDRESS 1 11 message for slave 17
FUNCTION CODE 1 05 execute operation
OPERATION CODE 2 00 01 operation code 1
CODE VALUE 2 FF 00 perform function
CRC 2 DF 6A CRC error code
SLAVE RESPONSE BYTES EXAMPLE DESCRIPTION
SLAVE ADDRESS 1 11 message from slave 17
FUNCTION CODE 1 05 execute operation
OPERATION CODE 2 00 01 operation code 1
CODE VALUE 2 FF 00 perform function
CRC 2 DF 6A CRC error code
MASTER TRANSMISSION BYTES EXAMPLE DESCRIPTION
SLAVE ADDRESS 1 11 message for slave 17
FUNCTION CODE 1 06 store single setpoint
DATA STARTING ADDRESS 2 04 5C setpoint address 04 5C
DATA 2 00 02 data for setpoint address 04 5C
CRC 2 CB B9 CRC error code
SLAVE RESPONSE BYTES EXAMPLE DESCRIPTION
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