SerialPort port = new SerialPort("COM3");
// configure serial port
port.BaudRate = 115200;
port.DataBits = 8;
port.Parity = Parity.None;
port.StopBits = StopBits.One;
port.ReadTimeout = 30;
port.Open();
// create modbus master
IModbusSerialMaster master = ModbusSerialMaster.CreateRtu(port);
master.WriteSingleRegister(17,5,10);
master.WriteMultipleRegisters(17,5,new ushort[] {100});