Function Code Fc6 (Write Single Register) - WAGO 750 Series Manual

168 • MODBUS Functions
Description of the MODBUS Functions

6.3.6 Function Code FC6 (Write single register)

This function writes the value of one single output register to a slave device in
word format.
Request
The request specifies the reference number (register address) of the first
output word to be written. The value to be written is specified in the "Register
Value" field. The reference number of the request is zero based; therefore, the
first register starts at address 0.
Example: Write a value of 0x1234 to the second output register.
Byte
Byte 0, 1
Byte 2, 3
Byte 4, 5
Byte 6
Byte 7
Byte 8, 9
Byte 10, 11
Response
The reply is an echo of the inquiry.
Byte
.....
Byte 7
Byte 8, 9
Byte 10, 11
Exception
Byte
.....
Byte 7
Byte 8
Field name
Transaction identifier
protocol identifier
length field
Unit identifier
MODBUS function code
reference number
Register Value
Field name
MODBUS function code
Reference number
Register Value
Field name
MODBUS function code
Exception code
Example
0x0000
0x0000
0x0006
0x01 not used
0x06
0x0001
0x1234
Example
0x06
0x0001
0x1234
Example
0x85
0x01 or 0x02
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