Examples - OPC Alarms&Events

.NET

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

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.

#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.

# 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.')

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

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.

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.

$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!
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.

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.

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."

Conceptual

Event Pull Mechanism

Subscribing to OPC A&E Events

Examples - OPC UA Alarms&Conditions

Examples - OPC UA Alarms&Conditions - Event pull