Hi Guys,

I'm using CM PtP RS422/485 HF (6ES7 541-1AB00-0AB0) and I want to communicate with Schneider Altivar 61 VFD. I just want to read 8 words: status word, current, actual speed, etc. I have done port initialization with Modbus_Comm_Load  block (MODE: 4 "Half-duplex") and define my device as master with Modbus Master block. The code has been written according to Siemens template:

https://support.industry.siemens.com/cs/document/47756141/how-do-you-establish-a-modbus-rtu-communication-with-step-7-(tia-portal)-for-the-simatic-s7-1200?dti=0&lc=en-WW

I'm getting error 80C8. I have tried everything, from inserting line termination on both sides, swapping A and B signals, checking baud rate, parity... Only Tx LED is active and also LED for modbus activity is present on the VFD, but I can't read anything. I have attached part of the code.

I would be thankful if someone have idea how to solve this problem!