Hello,

I have CPU 1215+CM1241+CB1241 configuration with TIA V11 SP5. I tried to communicate with some energy measurement devices but could not do it from both devices. I communicated correctly with SW on PC and some RS232 to RS485 convertor.

Problem: I tried that CM is master then CB is master (both situation only with one of them), in both situation TX led is blinking but there is no response. Then I connected sniffer to modbus I noticed that in some situation 2 byte are transmitted in some 3, not 8 as defined in protocol. Could see that one of them is address, because it changed in same waywhen I change address in SW.
I changed address, baud rate, parity and nothing helped (I attached project, which is slightly change project which I found here on forum).
Does anybody know what could be a problem?

TNX and regards

Damir

Thank you for you mail.

Problem for me was different. Althought I set some communication parameter in MB_COMM_LOAD it was different in HW properties (parity was "even" on SW element and "none" in HW prop).

When I changed HW prop, everything worked OK.

Regards

Damir