I am trying to communicate by Modbus TCP being Codesys the master to a Micro 820 from Rockwell automation but i get the error " Slave does not support this register offset ". Any help to solve this issue ?
What does your Modbus Mapping look like in CCW?
What does your Modbus channel configuration look like in CODESYS?
In CCW the mapping should be ok because using a Modbus tool i can read register and coil values as you can see in the attachments .
The Modbus Tool that communicates fine with CCW does not communicate with Codesys as a Master . Any tip ?
When i use the same tool being Codesys the slave the communication is fine. Help ?
As I see in CODESYS you use Modbus function 03 but in Modbus tool you use function 01 (because variable type: coils). I think you should try function 01 in CODESYS too.
Thanks, but i have already tried all type of Modbus Function with Codesys and even i tried to use a PLC from Siemens insetad of Micro820 but no success so far.
Codesys as a slave seems to work fine but not as a master. 😟
I am using a Pi 3+.
Why don't you try to read/write into your localhost pi using the CODESYS master first? That way you can test it without external tools and get a better feeling for it.
It´s working well with CCW now. Thank you for your wise advice.
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