This is Modbus RTU Communication Module on serial bus. Tested on ModbusMaster-Master Library on Arduino: https://github.com/4-20ma/ModbusMaster
The module supports all 10 functions of the library.
The module uses on PySerial 3.0 : https://pythonhosted.org/pyserial/index.html
Functions available : ModbusBegin(Baudrate,comPort,changeFlag,byteSize,stopBits,parityBits) ModbusRead(slaveId) ModbusReadNewData()