Modbus RTU over TCP Support for Arduino Opta

[wicopretorius]

Was able to modify the current library to generate the correct RTU request with CRC16 and send over TCP connection, but I am not able to receive any data. I am using a Arduino Opta connected to a Waveshare ethernet to RS485 converter (as a TCP Server) and the RS485 is connected to a RS485 to USB cable running Modbus Slave on my PC. Can someone please help with completing the ArduinoModbus library modification. I have attached my version of the library and an example Arduino IDE code.

ArduinoModbus.zip
ModbusRTUoverTCP_Ver1_0_0.zip

[zsoltyfm]

Hello!
I have exactly such an OPTA PLC and I would also be interested in such a working solution, since it often happens in the industry that modbus communication takes place via an ethernet->RS232->RS485 gateway and the data frames must be formatted to comply with the modbus standard, therefore i think the native library should also support this option to transmit and receive RTU frames using TCP and UDP protocols. I've been programming at an amateur level for quite some time, but unfortunately I don't have deep enough c++ programming knowledge to see how the library works and modify it, but I'm sure it won't need a complete overhaul. So I could only encourage the creator of the library to help solve this.