Hello everyone!

I am having a hard time trying to make CB 1241 work normally. I have PLC - S7-1200 1214C DC/DC/DC and CB1241 (RS485). I have implemented a typical programm to load data from slave with MB_COMM_LOAD and MB_MASTER STEP7 native blocks. When I start the programm, I see that MB_COMM_LOAD is initialized and MB_MASTER always shows BUSY status. Also I started Modbus slave on PC with SimplyModbusSlave 8.0.6 and connected everything together as it is shown in manual. I can see requests in SimplyModbusSlave, bu they have wrong frame structure - 00 00 00 00 FB 00 87 00 00. If I change Slave address on MB_MASTER block from 6 to 2, I have this request frame on Slave - 00 00 00 00 FB EE 00. So definitely something is happening but I can't understand why don't I have normal frame structure?

Any advice or help will be appreciated! 

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Split from Modbus_master freezing in Busy.

Kaulquappe, thanks a lot! I still don't understand why but it works now. I had controller connected to RS485toUSB converter by A->A and B->B. But when I changed A->B and B->A it worked. I am confused because when I connect Circutor CVM-NRG96 to converter I used A->A and B->B scheme and it worked...