16_Custom_Serial_communication_(RS485).md

Example 16 - Custom serial communication (on RS485)

Prerequisites:

• Required Xserver.IoT firmware: 10.2.3
• IoT Server connects to one serial device on RS485
• Configure IoT Server with IoT Explorer

1) Set serial port configuration

2) Enable the use of the serial port for the Onboard Task

3) Require a restart after modification

Example:

The following example shows how to send custom message (or protocol) on RS485 interface

Code:

....
using Driver.Device;
using Driver.Device.Interface;
using System.Threading.Tasks;
using SystemDB.Model;
using System.Diagnostics;

    ....

    #region Helpers
    ....
    //Serial port hardware Id
    private const string SerialPortDeviceId = @"\\?\ACPI#BCM2836#0#{86e0d1e0-8089-11d0-9ce4-08003e301f73}";
    ResultSerialPortSettings SerialSettings = new ResultSerialPortSettings();
    Extension DeviceExt = new Extension();
    //Information about serial communication
    bool ReceivedAnswer;
    bool NotReceived;
    #endregion

    ....
    
    public async void Run(IBackgroundTaskInstance taskInstance)
    {
      
        ....

        //Serial Port Initialize
        SerialSettings = await SerialPort.GetSettings();
        var res = await SerialPortInitialize();
        DeviceExt.SlaveRequestEvent += DeviceExt_ClientRequestEvent;

        .....
    }

    /// <summary>
    /// IoT Onboard Task
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private async void OnboardTask(object sender, EventArgs e)
    {
        try
        {
            NotReceived = false;
            ReceivedAnswer = false;

            Stopwatch stopWatch = new Stopwatch();

            byte[] message = {1,3,0,0,0,2,196,11};  //Your Message
            var res = await DeviceExt.SendComMessage(message, SerialPortDeviceId);  //Send serial message

            if (res.Success == true)
            {
                stopWatch.Reset();
                stopWatch.Start();

                while (stopWatch.Elapsed.TotalMilliseconds < SerialSettings.SerialTimeOut && ReceivedAnswer == false)
                {
                    await Task.Delay(5);
                }
                stopWatch.Stop();

                if (ReceivedAnswer)
                {
                    
                }
                else
                {
                    NotReceived = true;
                   
                }
            }
            else
            {
                NotReceived = true;
            }
        }
        catch (Exception ex)
        {
            EventLogging.AddLogMessage(MessageType.ExceptionError, this.GetType().Name + " - " + ServiceDisplayName + " - " + "OnboardTask exception error! Error: " + ex.Message);
        }
        OnboardTaskHandler.Run();  //Task continues to run
    }

    ....
    
    //Initialize RS485 Serial Port
    private async Task<bool> SerialPortInitialize(bool reinitialize = false)
    {
        bool result = false;

        try
        {
            CommonFunctions.ComPortSettings findcom = null;

            if (reinitialize == true)
            {
                //Dispose objects
                try
                {
                    DeviceExt.Dispose();
                }
                catch (Exception)
                {
                    //Object disposed
                }
                DeviceExt = null;

                await Task.Delay(5000);
                //Recrate objects
                DeviceExt = new Extension();

                int t = 0;
                while (t < 10 && findcom == null)
                {
                    try
                    {
                        findcom = DeviceExt.GetComPortSettings(SerialPortDeviceId);
                    }
                    catch (Exception)
                    {
                        //Error
                    }

                    if (findcom == null)
                    {
                        await Task.Delay(15000);
                    }
                    t = +1;
                }
            }
            else
            {
                findcom = DeviceExt.GetComPortSettings(SerialPortDeviceId);
            }

            if (findcom != null)
            {
                var portopen = findcom.PortOpen;
                if (portopen == true)
                {
                    var res = DeviceExt.CloseComPort(SerialPortDeviceId);
                    if (res.Success == false)
                    {
                        EventLogging.AddLogMessage(MessageType.Error, this.GetType().Name + " - " + ServiceDisplayName + " - " + "It is not able to close serial port! " + res.ErrorMessage);
                    }
                    else
                    {
                        portopen = false;
                    }
                }
                if (portopen == false)
                {
                    if (SerialSettings.SerialBaudRate == SerialBaudRate.BR_9600)
                    {
                        findcom.BaudRate = Driver.Device.Interface.CommonFunctions.SerialBaudRate.BR_9600;
                    }
                    else if (SerialSettings.SerialBaudRate == SerialBaudRate.BR_19200)
                    {
                        findcom.BaudRate = Driver.Device.Interface.CommonFunctions.SerialBaudRate.BR_19200;
                    }
                    else
                    {
                        findcom.BaudRate = Driver.Device.Interface.CommonFunctions.SerialBaudRate.BR_38400;
                    }

                    if (SerialSettings.SerialParity == SerialParity.Even)
                    {
                        findcom.Parity = Driver.Device.Interface.CommonFunctions.SerialParity.Even;
                    }
                    else if (SerialSettings.SerialParity == SerialParity.Odd)
                    {
                        findcom.Parity = Driver.Device.Interface.CommonFunctions.SerialParity.Odd;
                    }
                    else
                    {
                        findcom.Parity = Driver.Device.Interface.CommonFunctions.SerialParity.None;
                    }

                    findcom.ReadTimeout = 20;
                    findcom.WriteTimeout = 20;

                    var res = await DeviceExt.OpenComPort(SerialPortDeviceId);
                    if (res.Success == false)
                    {
                        EventLogging.AddLogMessage(MessageType.Error, this.GetType().Name + " - " + ServiceDisplayName + " - " + "Serial port configuration error! " + res.ErrorMessage);
                    }
                    else
                    {
                        result = true;
                        EventLogging.AddLogMessage(MessageType.Info, this.GetType().Name + " - " + ServiceDisplayName + " - " + "Serial port configuration success.");
                    }
                }
            }
            else
            {
                EventLogging.AddLogMessage(MessageType.Error, this.GetType().Name + " - " + ServiceDisplayName + " - " + "Can't find serial port!");
            }
        }
        catch (Exception ex)
        {
            EventLogging.AddLogMessage(MessageType.ExceptionError, this.GetType().Name + " - " + ServiceDisplayName + " - " + "Serial port configuration exception error! " + ex.Message);
        }

        return result;
    }

    //Serial answer
    private void DeviceExt_ClientRequestEvent(object sender, CommonFunctions.SlaveRequestEventArgs e)   
    {
        if (NotReceived == false)
        {
            ReceivedAnswer = true;
            var result = "ClientRequestEvent: " + e.Success.ToString() + " " + e.DeviceId.ToString();

            string received = "";

            for (int i = 0; i < e.ReadBytes.Length - 1; i++)
            {
                received += " " + e.ReadBytes[i].ToString();
            }

            var Answer = received;
        }
    }