// Hooking up events and receiving OPC item changes. // // Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . // OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp . // Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own // a commercial license in order to use Online Forums, and we reply to every post. using System; using System.Threading; using OpcLabs.EasyOpc.DataAccess; using OpcLabs.EasyOpc.DataAccess.OperationModel; namespace DocExamples.DataAccess._EasyDAClient { partial class SubscribeItem { public static void Main1() { // Instantiate the client object. using (var client = new EasyDAClient()) { var eventHandler = new EasyDAItemChangedEventHandler(client_ItemChanged); client.ItemChanged += eventHandler; Console.WriteLine("Subscribing item..."); client.SubscribeItem("", "OPCLabs.KitServer.2", "Demo.Ramp", 200); Console.WriteLine("Process item change notifications for 30 seconds..."); Thread.Sleep(30 * 1000); Console.WriteLine("Unsubscribing all items..."); client.UnsubscribeAllItems(); client.ItemChanged -= eventHandler; } Console.WriteLine("Finished."); } static void client_ItemChanged(object sender, EasyDAItemChangedEventArgs e) { if (e.Succeeded) Console.WriteLine(e.Vtq); else Console.WriteLine($"*** Failure: {e.ErrorMessageBrief}"); } } }
# Hooking up events and receiving OPC item changes. # # Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . # OPC client and subscriber examples in PowerShell on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-PowerShell . # Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own # a commercial license in order to use Online Forums, and we reply to every post. #requires -Version 5.1 using namespace OpcLabs.EasyOpc.DataAccess # The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows . Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassicCore.dll" Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassic.dll" Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassicComponents.dll" # Instantiate the client object. $client = New-Object EasyDAClient # Item changed event handler Register-ObjectEvent -InputObject $client -EventName ItemChanged -Action { if ($EventArgs.Succeeded) { Write-Host $EventArgs.Vtq } else { Write-Host "*** Failure: $($EventArgs.ErrorMessageBrief)" } } Write-Host "Subscribing item..." [IEasyDAClientExtension]::SubscribeItem($client, "", "OPCLabs.KitServer.2", "Demo.Ramp", 200) Write-Host "Processing item changes for 30 seconds..." $stopwatch = [System.Diagnostics.Stopwatch]::StartNew() while ($stopwatch.Elapsed.TotalSeconds -lt 30) { Start-Sleep -Seconds 1 } Write-Host "Unsubscribing items..." $client.UnsubscribeAllItems() Write-Host "Finished."
' Hooking up events and receiving OPC item changes. ' ' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . ' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET . ' Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own ' a commercial license in order to use Online Forums, and we reply to every post. Imports System.Threading Imports OpcLabs.EasyOpc.DataAccess Imports OpcLabs.EasyOpc.DataAccess.OperationModel Namespace DataAccess._EasyDAClient Partial Friend Class SubscribeItem Shared Sub Main1() Using client = New EasyDAClient() Dim eventHandler = New EasyDAItemChangedEventHandler(AddressOf client_ItemChanged) AddHandler client.ItemChanged, eventHandler Console.WriteLine("Subscribing item...") client.SubscribeItem("", "OPCLabs.KitServer.2", "Demo.Ramp", 200) Thread.Sleep(30 * 1000) client.UnsubscribeAllItems() RemoveHandler client.ItemChanged, eventHandler End Using End Sub Private Shared Sub client_ItemChanged(sender As Object, e As EasyDAItemChangedEventArgs) If e.Succeeded Then Console.WriteLine(e.Vtq) Else Console.WriteLine("*** Failure: {0}", e.ErrorMessageBrief) End If End Sub End Class End Namespace
// This example shows how to subscribe to changes of a single item and display the value of the item with each change. // // Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . // OPC client and subscriber examples in Object Pascal (Delphi) on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-OP . // Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own // a commercial license in order to use Online Forums, and we reply to every post. type TSubscribeItem_ClientEventHandlers = class // Item changed event handler procedure OnItemChanged( ASender: TObject; sender: OleVariant; const eventArgs: _EasyDAItemChangedEventArgs); end; procedure TSubscribeItem_ClientEventHandlers.OnItemChanged( ASender: TObject; sender: OleVariant; const eventArgs: _EasyDAItemChangedEventArgs); begin if eventArgs.Succeeded then WriteLn(eventArgs.Vtq.ToString) else WriteLn(Format('*** Failure: %s', [eventArgs.ErrorMessageBrief])); end; class procedure SubscribeItem.Main; var Client: TEasyDAClient; ClientEventHandlers: TSubscribeItem_ClientEventHandlers; begin // Instantiate the client object and hook events Client := TEasyDAClient.Create(nil); ClientEventHandlers := TSubscribeItem_ClientEventHandlers.Create; Client.OnItemChanged := ClientEventHandlers.OnItemChanged; Client.SubscribeItem('', 'OPCLabs.KitServer.2', 'Simulation.Random', 1000); WriteLn('Processing item changed events for 1 minute...'); PumpSleep(60*1000); WriteLn('Unsubscribing...'); Client.UnsubscribeAllItems; WriteLn('Waiting for 5 seconds...'); PumpSleep(5*1000); WriteLn('Finished.'); FreeAndNil(Client); FreeAndNil(ClientEventHandlers); end;
// This example shows how to subscribe to changes of a single item and display the value of the item with each change. // // Some related documentation: http://php.net/manual/en/function.com-event-sink.php . Pay attention to the comment that says // "Be careful how you use this feature; if you are doing something similar to the example below, then it doesn't really make // sense to run it in a web server context.". What they are trying to say is that processing a web request should be // a short-lived code, which does not fit well with the idea of being subscribed to events and received them over longer time. // It is possible to write such code, but it is only useful when processing the request is allowed to take relatively long. Or, // when you are using PHP from command-line, or otherwise - not to serve a web page directly. // // Subscribing to QuickOPC-COM events in the context of PHP Web application, while not imposing the limitations to the request // processing time, has to be "worked around", e.g. using the "event pull" mechanism. // // Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . // OPC client and subscriber examples in PHP on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-PHP . // Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own // a commercial license in order to use Online Forums, and we reply to every post. class DEasyDAClientEvents { function ItemChanged($varSender, $varE) { if ($varE->Succeeded) { print $varE->Vtq->ToString(); print "\n"; } else { printf("*** Failure: %s\n", $varE->ErrorMessageBrief); } } } $Client = new COM("OpcLabs.EasyOpc.DataAccess.EasyDAClient"); $Events = new DEasyDAClientEvents(); com_event_sink($Client, $Events, "DEasyDAClientEvents"); $Client->SubscribeItem("", "OPCLabs.KitServer.2", "Simulation.Random", 1000); print "Processing item changed events for 1 minute...\n"; $startTime = time(); do { com_message_pump(1000); } while (time() < $startTime + 60);
REM This example shows how to subscribe to changes of a single item and display the value of the item with each change. REM REM Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . REM OPC client and subscriber examples in Visual Basic on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VB . REM Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own REM a commercial license in order to use Online Forums, and we reply to every post. ' The client object, with events 'Public WithEvents Client1 As EasyDAClient Private Sub SubscribeItem_Main_Command_Click() OutputText = "" ' Instantiate the client object and hook events Set Client1 = New EasyDAClient OutputText = OutputText & "Subscribing..." & vbCrLf Call Client1.SubscribeItem("", "OPCLabs.KitServer.2", "Simulation.Random", 1000) OutputText = OutputText & "Processing item changed events for 1 minute..." & vbCrLf Pause 60000 OutputText = OutputText & "Unsubscribing..." & vbCrLf Client1.UnsubscribeAllItems OutputText = OutputText & "Waiting for 5 seconds..." & vbCrLf Pause 5000 OutputText = OutputText & "Finished." & vbCrLf Set Client1 = Nothing End Sub Public Sub Client1_ItemChanged(ByVal sender As Variant, ByVal eventArgs As EasyDAItemChangedEventArgs) If eventArgs.Succeeded Then OutputText = OutputText & eventArgs.vtq & vbCrLf Else OutputText = OutputText & "*** Failure: " & eventArgs.ErrorMessageBrief & vbCrLf End If End Sub
Rem This example shows how to subscribe to changes of a single item and display the value of the item with each change. Rem Rem Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . Rem OPC client and subscriber examples in VBScript on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBScript . Rem Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own Rem a commercial license in order to use Online Forums, and we reply to every post. Option Explicit Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient") WScript.ConnectObject Client, "Client_" Client.SubscribeItem "", "OPCLabs.KitServer.2", "Simulation.Random", 1000 WScript.Echo "Processing item changed events for 1 minute..." WScript.Sleep 60*1000 Sub Client_ItemChanged(Sender, e) If Not (e.Succeeded) Then WScript.Echo "*** Failure: " & e.ErrorMessageBrief Exit Sub End If WScript.Echo e.Vtq.ToString End Sub
# Hooking up events and receiving OPC item changes. # # Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . # OPC client and subscriber examples in Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python . # Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own # a commercial license in order to use Online Forums, and we reply to every post. # The QuickOPC package is needed. Install it using "pip install opclabs_quickopc". import opclabs_quickopc import time # Import .NET namespaces. from OpcLabs.EasyOpc.DataAccess import * # Item changed event handler. def itemChanged(sender, e): if e.Succeeded: print(e.Vtq) else: print('*** Failure: ', e.ErrorMessageBrief, sep='') # Instantiate the client object. client = EasyDAClient() client.ItemChanged += itemChanged print('Subscribing item changes...') IEasyDAClientExtension.SubscribeItem(client, '', 'OPCLabs.KitServer.2', 'Demo.Ramp', 200) print('Processing item change notifications for 30 seconds...') time.sleep(30) print('Unsubscribing all items...') client.UnsubscribeAllItems() client.ItemChanged -= itemChanged print('Finished.')
// This example subscribes to changes of 2 items separately, and displays rich information available with each item changed // event notification. // // Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . // OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp . // Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own // a commercial license in order to use Online Forums, and we reply to every post. using System; using System.Diagnostics; using System.Threading; using OpcLabs.EasyOpc.DataAccess; using OpcLabs.EasyOpc.DataAccess.OperationModel; namespace DocExamples.DataAccess._EasyDAItemChangedEventArgs { class General { public static void Main1() { // Instantiate the client object. using (var client = new EasyDAClient()) { var eventHandler = new EasyDAItemChangedEventHandler(client_ItemChanged); client.ItemChanged += eventHandler; Console.WriteLine("Subscribing items..."); client.SubscribeItem("", "OPCLabs.KitServer.2", "Simulation.Random", 5 * 1000); client.SubscribeItem("", "OPCLabs.KitServer.2", "Trends.Ramp (1 min)", 5 * 1000); Console.WriteLine("Processing item changed events for 1 minute..."); Thread.Sleep(60 * 1000); } } static void client_ItemChanged(object sender, EasyDAItemChangedEventArgs e) { Console.WriteLine(); Console.WriteLine($"e.Arguments.State: {e.Arguments.State}"); Console.WriteLine($"e.Arguments.ServerDescriptor.MachineName: {e.Arguments.ServerDescriptor.MachineName}"); Console.WriteLine($"e.Arguments.ServerDescriptor.ServerClass: {e.Arguments.ServerDescriptor.ServerClass}"); Console.WriteLine($"e.Arguments.ItemDescriptor.ItemId: {e.Arguments.ItemDescriptor.ItemId}"); Console.WriteLine($"e.Arguments.ItemDescriptor.AccessPath: {e.Arguments.ItemDescriptor.AccessPath}"); Console.WriteLine($"e.Arguments.ItemDescriptor.RequestedDataType: {e.Arguments.ItemDescriptor.RequestedDataType}"); Console.WriteLine($"e.Arguments.GroupParameters.Locale: {e.Arguments.GroupParameters.Locale}"); Console.WriteLine($"e.Arguments.GroupParameters.RequestedUpdateRate: {e.Arguments.GroupParameters.RequestedUpdateRate}"); Console.WriteLine($"e.Arguments.GroupParameters.PercentDeadband: {e.Arguments.GroupParameters.PercentDeadband}"); if (e.Succeeded) { Debug.Assert(!(e.Vtq is null)); Console.WriteLine($"e.Vtq.Value: {e.Vtq.Value}"); Console.WriteLine($"e.Vtq.Timestamp: {e.Vtq.Timestamp}"); Console.WriteLine($"e.Vtq.TimestampLocal: {e.Vtq.TimestampLocal}"); Console.WriteLine($"e.Vtq.Quality: {e.Vtq.Quality}"); } else { Debug.Assert(!(e.Exception is null)); Console.WriteLine($"e.Exception.Message: {e.Exception.Message}"); Console.WriteLine($"e.Exception.Source: {e.Exception.Source}"); } } // Example output: // //Processing item changed events for 1 minute... // //e.Arguments.State: //e.Arguments.ServerDescriptor.MachineName: //e.Arguments.ServerDescriptor.ServerClass: OPCLabs.KitServer.2 //e.Arguments.ItemDescriptor.ItemId: Simulation.Random //e.Arguments.ItemDescriptor.AccessPath: //e.Arguments.ItemDescriptor.RequestedDataType: Empty //e.Arguments.GroupParameters.Locale: 0 //e.Arguments.GroupParameters.RequestedUpdateRate: 5000 //e.Arguments.GroupParameters.PercentDeadband: 0 //e.Vtq.Value: 0.00125125888851588 //e.Vtq.Timestamp: 4/10/2020 4:35:25 PM //e.Vtq.TimestampLocal: 4/10/2020 6:35:25 PM //e.Vtq.Quality: GoodNonspecific (192) // //e.Arguments.State: //e.Arguments.ServerDescriptor.MachineName: //e.Arguments.ServerDescriptor.ServerClass: OPCLabs.KitServer.2 //e.Arguments.ItemDescriptor.ItemId: Trends.Ramp(1 min) //e.Arguments.ItemDescriptor.AccessPath: //e.Arguments.ItemDescriptor.RequestedDataType: Empty //e.Arguments.GroupParameters.Locale: 0 //e.Arguments.GroupParameters.RequestedUpdateRate: 5000 //e.Arguments.GroupParameters.PercentDeadband: 0 //e.Vtq.Value: 0.431881904602051 //e.Vtq.Timestamp: 4/10/2020 4:35:25 PM //e.Vtq.TimestampLocal: 4/10/2020 6:35:25 PM //e.Vtq.Quality: GoodNonspecific (192) // //... } }
Rem This example subscribes to changes of 2 items separately, and displays rich information available with each item changed Rem event notification. Rem Rem Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html . Rem OPC client and subscriber examples in VBScript on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBScript . Rem Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own Rem a commercial license in order to use Online Forums, and we reply to every post. Option Explicit Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient") WScript.ConnectObject Client, "Client_" Client.SubscribeItem "", "OPCLabs.KitServer.2", "Simulation.Random", 5*1000 Client.SubscribeItem "", "OPCLabs.KitServer.2", "Trends.Ramp (1 min)", 5*1000 WScript.Echo "Processing item changed events for 1 minute..." WScript.Sleep 60*1000 Sub Client_ItemChanged(Sender, e) On Error Resume Next WScript.Echo WScript.Echo "e.Arguments.State: " & e.Arguments.State WScript.Echo "e.Arguments.ServerDescriptor.MachineName: " & e.Arguments.ServerDescriptor.MachineName WScript.Echo "e.Arguments.ServerDescriptor.ServerClass: " & e.Arguments.ServerDescriptor.ServerClass WScript.Echo "e.Arguments.ItemDescriptor.ItemId: " & e.Arguments.ItemDescriptor.ItemId WScript.Echo "e.Arguments.ItemDescriptor.AccessPath: " & e.Arguments.ItemDescriptor.AccessPath WScript.Echo "e.Arguments.ItemDescriptor.RequestedDataType: " & e.Arguments.ItemDescriptor.RequestedDataType WScript.Echo "e.Arguments.GroupParameters.Locale: " & e.Arguments.GroupParameters.Locale WScript.Echo "e.Arguments.GroupParameters.RequestedUpdateRate: " & e.Arguments.GroupParameters.RequestedUpdateRate WScript.Echo "e.Arguments.GroupParameters.PercentDeadband: " & e.Arguments.GroupParameters.PercentDeadband WScript.Echo "e.Exception.Message: " & e.Exception.Message WScript.Echo "e.Exception.Source: " & e.Exception.Source WScript.Echo "e.Exception.ErrorCode: " & e.Exception.ErrorCode WScript.Echo "e.Vtq.Value: " & e.Vtq.Value WScript.Echo "e.Vtq.Timestamp: " & e.Vtq.Timestamp WScript.Echo "e.Vtq.TimestampLocal: " & e.Vtq.TimestampLocal WScript.Echo "e.Vtq.Quality: " & e.Vtq.Quality End Sub
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