Function Code Fc22 (Mask Write Register) - WAGO 750 Series Manual

172 • MODBUS Functions
Description of the MODBUS Functions

6.3.10 Function Code FC22 (Mask Write Register)

This function manipulates individual bits within a register using a combination
of an AND mask, an OR mask, and the register's current content.
Request
Byte
Byte 0, 1
Byte 2, 3
Byte 4, 5
Byte 6
Byte 7
Byte 8-9
Byte 10-11
Byte 12-13
Response
Byte
.....
Byte 7
Byte 8-9
Byte 10-11
Byte 12-13
Exception
Byte
.....
Byte 7
Byte 8
Field name
Transaction identifier
protocol identifier
length field
Unit identifier
MODBUS function code
Reference Number
AND-Mask
OR-Mask
Field name
MODBUS function code
Reference Number
AND-Mask
OR-Mask
Field name
MODBUS function code
Exception code
Example
0x0000
0x0000
0x0002
0x01 not used
0x16
0x0000
0x0000
0xAAAA
Example
0x10
0x0000
0x0000
0xAAAA
Example
0x85
0x01 or 0x02
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