tia portal v14 modbus

[RY_Guthrie]

I am trying to commission a compressor that is using a s7-1200 to communicate rs485/modbus to a the compressor interface. My rs485 module is a cm-1241. I have no tx or rx lighs on the module, the program seems to be not connecting to the "slave" at the compressor. I have the mode set to 4 which I believe is rs485 on mb master fb, I have the baud, parity, stop bits set correctly I believe in my mb_comm_load i also think the port is correct. (see pics of both)I am wanting to use a modbus slave on my laptop to try and determine which end the problem is on. Can anyone first off see any obvious issues with the modbus setup form the pics? And what is a good modbus slave simulator to use? Thanks

 

[Lare]

Modbus com load pin MB_DB should point to DBx.MB_DB parameter, now it only points to whole DB32-area.


I think that it should be %DB32.dbx24.0. (MB_MASTER_DB_1.MB_DB symbolically with your symbols.)

 

[RY_Guthrie]

thank you very much, Im new to Siemens and to very honest it has been a struggle! Thank you again. I will try this out tomorrow.