Example: Protocol configuration in request/response mode

With the WriteBytes method, the command is sent through the serial port, and with the subsequent ReadBytes method, it waits for a response from the controller. If the controller does not respond within the time indicated by the Timeout property, an exception is generated and the read/write fails.

You can download a sample project from ../../../downloads/SerialPortDemoRequestResponseMode.zip.

public class RuntimeNetlogic1 : BaseNetLogic
{
    private SerialPort serialPort;
    private PeriodicTask periodicTask;
    public override void Start()
    {
        serialPort = (SerialPort)Owner;
        periodicTask = new PeriodicTask(Read, 300, Owner);
        periodicTask.Start();
    }
    private void Read()
    {
        try
        {
            ReadImpl();
        }
        catch (Exception ex)
        {
            Log.Error("Failed to read from Modbus: " + ex);
        }
    }
    private void ReadImpl()
    {
        serialPort.WriteBytes(Serialize());
        var result = serialPort.ReadBytes(3);
        if ((result[1] & 0x80) == 0)
        {
            result = serialPort.ReadBytes((uint)(result[2] + 2));
            Log.Info(Deserialize(result));
        }
        else
        {
            Log.Error("Failed to read from Modbus");
        }
    }
    private byte[] Serialize()
    {
        var buffer = new byte[]
        {
            0x01, // UnitId
            0x03, // Function code
            0x00, // Starting address
            0x00,
            0x00, // Quantity Of Registers
            0x01,
            0x84, // CRC
            0x0a
        };
        return buffer;
    }
    private ushort Deserialize(byte[] buffer)
    {
        var first = (ushort)buffer[1];
        var second = (ushort)(buffer[0] << 8);
        return (ushort)(first | second);
    }
}