Siemens SIMATIC TI500 - Code 06 - Write a Single Register; Write a Single Register Example - Request; Write a Single Register Example - Response

Modbus Commands
C-14
TIWAY I Gateway User Manual
Modbus Function Descriptions (continued)
Code 06 allows the contents of a holding register to be changed. Addressing
is sequential up to the maximum memory size for a particular PLC. This
function is limited to integer values contained in V -memory . The Gateway
will also direct any broadcast address (00) to all attached secondaries.
[This command is comparable to a TIW A Y I request using Primitive 30 and
TT -type 01 (V ariable memory)].
Example:
I000000
Request: 07 06 0064 0220 XXXX
Checksum (XXXX)
Data value (0220)
Register address (0064)
Function code (06)
Slave address (07)
Figur e C-15 Write a Single Register Example — Request
This request to secondary 7 is asking for the value of holding register 0064
(100 decimal) to be changed to 0220 (544 decimal).
I000000
Response: 07 06 0064 0220 XXXX
Checksum (XXXX)
Data value (0220)
Register address (0064)
Function code (06)
Slave address (07)
Figur e C-16 Write a Single Register Example — Response
The response to Function Code 06 is to return the request as received. In
the case of a broadcast request, there is no response.
Code 06 — W rite a
Single Register