3_InternetConnectionChecking.md

Checking Internet connection with IoT server - Set a PLC bit

The IoT server sets a bit in the PLC to "1" if the Internet connection is working, and to "0" if the Internet connection is interrupted.

Prerequisites:

• Configure IoT Server with IoT Explorer (Create Sources. More details: Field device (Power Meter, PLC) communication settings)
• Create OnboardTasks user group with Control privilege and create onboardtask user (password: onboardtask)
• Create InternetChecking OnboardTask and install to IoT Server
• Install Write Register from Azure app from App Store to IoT Server with IoT Explorer
• Add a property to Device Twin (Syntax: Source>source name|quantity name)
• Send desired properties to Device Twin and update desired properties on the IoT Device from Device Twin

Code:

    #region Helpers
    //....
    Realtime RObj = new Realtime();
    #endregion

    ...
    
     /// <summary>
     /// Start OnboardTask Service initialize
     /// </summary>
     private async void Initialize()
     {
         _logger.LogInformation(ServiceDisplayName + " - " + "Start initializing...");
         await EventLogging.AddLogMessage(MessageType.Info, this.GetType().Name + " - " + ServiceDisplayName + " - " + "Start initializing...");
    
         try
         {
             //Initialize Http REST server
             await RestServer.HttpRESTServerStart();
             RestServer.ClientEvent += HttpRestServer_ClientRequestEvent;
    
             await EventLogging.AddLogMessage(MessageType.Info, this.GetType().Name + " - " + ServiceDisplayName + " - " + "Checking services...");
             _logger.LogInformation("Checking services...");
             bool exit = false;
             while (exit == false)
             {
                 var com = await Services.ComIsInitialized();
                 var data = await Services.DataIsInitialized();
                 var core = await Services.CoreIsInitialized();
                 if (com.Initialized == true && data.Initialized == true && core.Initialized == true)
                 {
                     exit = true;
                     await EventLogging.AddLogMessage(MessageType.Info, this.GetType().Name + " - " + ServiceDisplayName + " - " + "Services are running.");
                     _logger.LogInformation("Services are running.");
                 }
                 await Task.Delay(5000);
             }
    
             #region Login to Xserver.IoT Service
             var res = await Authentication.Login("onboardtask", "onboardtask");
             if (res.Success == false)
             {
                 await EventLogging.AddLogMessage(MessageType.Error, this.GetType().Name + " - " + ServiceDisplayName + " - " + res.ErrorMessage);
             }
             #endregion
    
             #region Gets List of Sources and Quantities
             var result = await RObj.GetSourcesQuantities();
             if (result.Success == false)
             {
                 await EventLogging.AddLogMessage(MessageType.Error, this.GetType().Name + " - " + ServiceDisplayName + " - " + result.ErrorMessage);
             }
             #endregion
         }
         catch (Exception ex)
         {
             await EventLogging.AddLogMessage(MessageType.ExceptionError, this.GetType().Name + " - " + ServiceDisplayName + " - " + "Initialization exception error! Error: " + ex.Message);
         }
    
         InitFinished = true;
         await EventLogging.AddLogMessage(MessageType.Info, this.GetType().Name + " - " + ServiceDisplayName + " - " + "Finished initialization.");
         _logger.LogInformation(ServiceDisplayName + " - " + "Finished initialization.");
     }
    
    ...

    Stopwatch InternetChecking = new Stopwatch();
    /// <summary>
    /// Periodic Task
    /// </summary>
    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        while (!stoppingToken.IsCancellationRequested)
        {
            try
            {
                if (InitFinished)
                {
                    #region Checking Internet connection
                    if (InternetChecking.IsRunning == false)
                    {
                        InternetChecking.Reset();
                        InternetChecking.Start();
                    }
                    else
                    {
                        if (InternetChecking.Elapsed.TotalSeconds>60)
                        {
                            InternetChecking.Stop();
                            var pingres =await TCPIP.Ping("www.google.com");
                            if (pingres.Success == true)
                            {
                                var writeresult = await RObj.WriteValue("Siemens PLC", "Internet Status", 1);
                                _logger.LogInformation("Debug, Internet OK.");
                            }
                            else
                            {
                                var writeresult = await RObj.WriteValue("Siemens PLC", "Internet Status", 0);
                                _logger.LogInformation("Debug, Internet error!");
                            }
                        }
                    }
                    #endregion
                }
            }
            catch (Exception ex)
            {
                await EventLogging.AddLogMessage(MessageType.ExceptionError, this.GetType().Name + " - " + ServiceDisplayName + " - " + "OnboardTask exception error! Error: " + ex.Message);
            }
    
            await Task.Delay(TaskHandlerPeriod, stoppingToken);
        }
    }

    ...