Examples - OPC Alarms&Events

.NET

// This example shows how to subscribe to events and obtain the notification events by pulling them.
//
// 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 OpcLabs.EasyOpc.AlarmsAndEvents;
using OpcLabs.EasyOpc.AlarmsAndEvents.OperationModel;

namespace DocExamples.AlarmsAndEvents._EasyAEClient
{
    class PullNotification
    {
        public static void Main1()
        {
            // Instantiate the client object.
            // In order to use event pull, you must set a non-zero queue capacity upfront.
            using (var client = new EasyAEClient { PullNotificationQueueCapacity = 1000 })
            {
                Console.WriteLine("Subscribing events...");
                int handle = client.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000);

                Console.WriteLine("Processing event notifications for 1 minute...");
                int endTick = Environment.TickCount + 60 * 1000;
                do
                {
                    EasyAENotificationEventArgs eventArgs = client.PullNotification(2 * 1000);
                    if (!(eventArgs is null))
                        // Handle the notification event
                        Console.WriteLine(eventArgs);
                } while (Environment.TickCount < endTick);

                Console.WriteLine("Unsubscribing events...");
                client.UnsubscribeEvents(handle);

                Console.WriteLine("Finished.");
            }
        }
    }
}

# This example shows how to subscribe to events and obtain the notification events by pulling them.
#
# 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.AlarmsAndEvents

# 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 EasyAEClient
# In order to use event pull, you must set a non-zero queue capacity upfront.
$client.PullNotificationQueueCapacity = 1000

Write-Host "Subscribing events..."
$handle = [OpcLabs.EasyOpc.AlarmsAndEvents.IEasyAEClientExtension]::SubscribeEvents($client, 
    "", "OPCLabs.KitEventServer.2", 1000)

Write-Host "Processing event notifications for 1 minute..."
$stopwatch =  [System.Diagnostics.Stopwatch]::StartNew() 
while ($stopwatch.Elapsed.TotalSeconds -lt 60) {    
    $eventArgs = $client.PullNotification(2*1000)
    if ($eventArgs -ne $null) {
        # Handle the notification event
        Write-Host $eventArgs
    }
}

Write-Host "Unsubscribing events..."
$client.UnsubscribeEvents($handle)

Write-Host "Finished."

' This example shows how to subscribe to events and obtain the notification events by pulling them.
'
' 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 OpcLabs.EasyOpc.AlarmsAndEvents
Imports OpcLabs.EasyOpc.AlarmsAndEvents.OperationModel

Namespace AlarmsAndEvents._EasyAEClient
    Partial Friend Class PullNotification
        Public Shared Sub Main1()
            Using client = New EasyAEClient()
                ' In order to use event pull, you must set a non-zero queue capacity upfront.
                client.PullNotificationQueueCapacity = 1000

                Console.WriteLine("Subscribing events...")
                Dim handle As Integer = client.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000)

                Console.WriteLine("Processing event notifications for 1 minute...")
                Dim endTick As Integer = Environment.TickCount + 60 * 1000
                Do
                    Dim eventArgs As EasyAENotificationEventArgs = client.PullNotification(2 * 1000)
                    If Not eventArgs Is Nothing Then
                        ' Handle the notification event
                        Console.WriteLine(eventArgs)
                    End If
                Loop While Environment.TickCount < endTick

                Console.WriteLine("Unsubscribing events...")
                client.UnsubscribeEvents(handle)
            End Using

            Console.WriteLine("Finished.")
        End Sub
    End Class
End Namespace

COM

// This example shows how to subscribe to events and obtain the notification events by pulling them.
//
// 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.

class procedure PullNotification.Main;
var
  Client: OpcLabs_EasyOpcClassic_TLB._EasyAEClient;
  EndTick: Cardinal;
  EventArgs: _EasyAENotificationEventArgs;
  Handle: Integer;
  ServerDescriptor: _ServerDescriptor;
  State: OleVariant;
  SubscriptionParameters: _AESubscriptionParameters;
begin
  ServerDescriptor := CoServerDescriptor.Create;
  ServerDescriptor.ServerClass := 'OPCLabs.KitEventServer.2';

  // Instantiate the client object
  Client := CoEasyAEClient.Create;
  // In order to use event pull, you must set a non-zero queue capacity upfront.
  Client.PullNotificationQueueCapacity := 1000;

  WriteLn('Subscribing events...');
  SubscriptionParameters := CoAESubscriptionParameters.Create;
  SubscriptionParameters.NotificationRate := 1000;
  Handle := Client.SubscribeEvents(ServerDescriptor, SubscriptionParameters, true, State);

  WriteLn('Processing event notifications for 1 minute...');
  EndTick := Ticks + 60*1000;
  while Ticks < EndTick do
  begin
    EventArgs := Client.PullNotification(2*1000);
    if EventArgs <> nil then
      // Handle the notification event
      WriteLn(EventArgs.ToString);
  end;

  WriteLn('Unsubscribing events...');
  Client.UnsubscribeEvents(Handle);

  WriteLn('Finished.');
end;

// This example shows how to subscribe to events and obtain the notification events by pulling them.
//
// 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.

$ServerDescriptor = new COM("OpcLabs.EasyOpc.ServerDescriptor");
$ServerDescriptor->ServerClass = "OPCLabs.KitEventServer.2";

$Client = new COM("OpcLabs.EasyOpc.AlarmsAndEvents.EasyAEClient");
// In order to use event pull, you must set a non-zero queue capacity upfront.
$Client->PullNotificationQueueCapacity = 1000;

print "Subscribing events...\n";
$SubscriptionParameters = new COM("OpcLabs.EasyOpc.AlarmsAndEvents.AESubscriptionParameters");
$SubscriptionParameters->NotificationRate = 1000;
$handle = $Client->SubscribeEvents($ServerDescriptor, $SubscriptionParameters, TRUE, NULL);

print "Processing event notifications for 1 minute...\n";
$endTime = time() + 60;
do {
    $EventArgs = $Client->PullNotification(2*1000);
    if (!is_null($EventArgs)) {
        // Handle the notification event
        print $EventArgs->ToString();
        print "\n";
    }
} while (time() < $endTime);

print "Unsubscribing events...\n";
$Client->UnsubscribeEvents($handle);

print "Finished.\n";

# This example shows how to subscribe to events and obtain the notification events by pulling them.
#
# The Python for Windows (pywin32) extensions package is needed. Install it using "pip install pypiwin32".
# CAUTION: We now recommend using Python.NET package instead. Full set of examples with Python.NET is available!
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
import time
import win32com.client

serverDescriptor = win32com.client.Dispatch('OpcLabs.EasyOpc.ServerDescriptor')
serverDescriptor.UrlString = 'opcae://localhost/OPCLabs.KitEventServer.2'
#serverDescriptor.ServerClass = 'OPCLabs.KitEventServer.2'

# Instantiate the client object
client = win32com.client.Dispatch('OpcLabs.EasyOpc.AlarmsAndEvents.EasyAEClient') 
# In order to use event pull, you must set a non-zero queue capacity upfront.
client.PullNotificationQueueCapacity = 1000

print('Subscribing events...')
subscriptionParameters = win32com.client.Dispatch('OpcLabs.EasyOpc.AlarmsAndEvents.AESubscriptionParameters')
subscriptionParameters.NotificationRate = 1000
handle = client.SubscribeEvents(serverDescriptor, subscriptionParameters, True, None)

print('Processing event notifications for 1 minute...')
endTime = time.time() + 60
while time.time() < endTime:
    eventArgs = client.PullNotification(2*1000)
    if eventArgs is not None:
        # Handle the notification event
        print(eventArgs)

print('Unsubscribing events...')
client.UnsubscribeAllEvents()

print('Finished.')

REM This example shows how to subscribe to events and obtain the notification events by pulling them.
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.

Private Sub PullNotification_Main_Command_Click()
    OutputText = ""
    
    Dim eventArgs As EasyAENotificationEventArgs
    
    Dim serverDescriptor As New serverDescriptor
    serverDescriptor.ServerClass = "OPCLabs.KitEventServer.2"
        
    ' Instantiate the client object
    Dim client As New EasyAEClient
    
    ' In order to use event pull, you must set a non-zero queue capacity upfront.
    client.PullNotificationQueueCapacity = 1000
    
    OutputText = OutputText & "Subscribing events..." & vbCrLf
    Dim subscriptionParameters As New AESubscriptionParameters
    subscriptionParameters.notificationRate = 1000
    Dim handle
    Dim state
    handle = client.SubscribeEvents(serverDescriptor, subscriptionParameters, True, state)

    OutputText = OutputText & "Processing event notifications for 1 minute..." & vbCrLf
    Dim endTick As Long
    endTick = GetTickCount + 60000
    While GetTickCount < endTick
        Set eventArgs = client.PullNotification(2 * 1000)
        If Not eventArgs Is Nothing Then
            ' Handle the notification event
            OutputText = OutputText & eventArgs & vbCrLf
        End If
    Wend
    
    OutputText = OutputText & "Unsubscribing events..." & vbCrLf
    client.UnsubscribeEvents handle

    OutputText = OutputText & "Finished." & vbCrLf

End Sub

Rem This example shows how to subscribe to events and obtain the notification events by pulling them.
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 ServerDescriptor: Set ServerDescriptor = CreateObject("OpcLabs.EasyOpc.ServerDescriptor")
ServerDescriptor.ServerClass = "OPCLabs.KitEventServer.2"

Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.EasyAEClient")
' In order to use event pull, you must set a non-zero queue capacity upfront.
Client.PullNotificationQueueCapacity = 1000

WScript.Echo "Subscribing events..."
Dim SubscriptionParameters: Set SubscriptionParameters = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.AESubscriptionParameters")
SubscriptionParameters.NotificationRate = 1000
Dim handle: handle = Client.SubscribeEvents(ServerDescriptor, SubscriptionParameters, True, Nothing)

WScript.Echo "Processing event notifications for 1 minute..."
Dim endTime: endTime = Now() + 60*(1/24/60/60)
Do
    Dim EventArgs: Set EventArgs = Client.PullNotification(2*1000)
    If Not (EventArgs Is Nothing) Then
        ' Handle the notification event
        WScript.Echo EventArgs
    End If    
Loop While Now() < endTime

WScript.Echo "Unsubscribing events..."
Client.UnsubscribeEvents handle

WScript.Echo "Finished."

Python

Python (.NET)

# This example shows how to subscribe to events and obtain the notification events by pulling them.
#
# 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 import *
from OpcLabs.EasyOpc.AlarmsAndEvents import *


# Instantiate the client object
client = EasyAEClient()
# In order to use event pull, you must set a non-zero queue capacity upfront.
client.PullNotificationQueueCapacity = 1000

print('Subscribing events...')
handle = IEasyAEClientExtension.SubscribeEvents(client, '', 'OPCLabs.KitEventServer.2', 1000)

print('Processing event notifications for 1 minute...')
endTime = time.time() + 60
while time.time() < endTime:
    eventArgs = IEasyAEClientExtension.PullNotification(client, 2*1000)
    if eventArgs is not None:
        # Handle the notification event
        print(eventArgs)

print('Unsubscribing events...')
client.UnsubscribeAllEvents()

print('Finished.')

Concepts

Event Pull Mechanism

Subscribing to OPC A&E Events

Examples - Client OPC UA Alarms&Conditions

Examples - OPC UA Alarms&Conditions - Event pull