OPC Studio User's Guide and Reference
Examples - OPC Alarms&Events - Refresh an event subscription

.NET

// This example shows how to for a refresh for all active conditions and inactive, unacknowledged conditions.
//
// 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.AlarmsAndEvents;
using OpcLabs.EasyOpc.AlarmsAndEvents.OperationModel;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.OperationModel;

namespace DocExamples.AlarmsAndEvents._EasyAEClient
{
    class RefreshEventSubscription
    {
        // Instantiate the OPC-A&E client object.
        static readonly EasyAEClient AEClient = new EasyAEClient();

        // Instantiate the OPC-DA client object.
        static readonly EasyDAClient DAClient = new EasyDAClient();

        public static void Main1()
        {
            var eventHandler = new EasyAENotificationEventHandler(AEClient_Notification);
            AEClient.Notification += eventHandler;

            Console.WriteLine("Processing event notifications...");
            var subscriptionFilter = new AESubscriptionFilter
            {
                Sources = new AENodeDescriptor[] { "Simulation.ConditionState1", "Simulation.ConditionState2", "Simulation.ConditionState3" }
            };
            int handle = AEClient.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000, null, subscriptionFilter);

            // The component will perform auto-refresh at this point, give it time to happen
            Console.WriteLine("Waiting for 10 seconds...");
            Thread.Sleep(10 * 1000);

            // Set some events to active state, which will cause them to appear in refresh
            Console.WriteLine("Activating conditions and waiting for 10 seconds...");
            try
            {
                DAClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState1.Activate", true);
                DAClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState2.Activate", true);
            }
            catch (OpcException opcException)
            {
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
                return;
            }
            Thread.Sleep(10 * 1000);

            Console.WriteLine("Refreshing subscription and waiting for 10 seconds...");
            AEClient.RefreshEventSubscription(handle);
            Thread.Sleep(10 * 1000);

            AEClient.UnsubscribeEvents(handle);
            AEClient.Notification -= eventHandler;
        }

        // Notification event handler
        static void AEClient_Notification(object sender, EasyAENotificationEventArgs e)
        {
            Console.WriteLine();
            if (!e.Succeeded)
            {
                Console.WriteLine("*** Failure: {0}", e.ErrorMessageBrief);
                return;
            }

            Console.WriteLine("Refresh: {0}", e.Refresh);
            Console.WriteLine("RefreshComplete: {0}", e.RefreshComplete);
            AEEventData eventData = e.EventData;
            if (!(eventData is null))
            {
                Console.WriteLine("Event.QualifiedSourceName: {0}", eventData.QualifiedSourceName);
                Console.WriteLine("Event.Message: {0}", eventData.Message);
                Console.WriteLine("Event.Active: {0}", eventData.Active);
                Console.WriteLine("Event.Acknowledged: {0}", eventData.Acknowledged);
            }
        }
    }
}
' This example shows how to for a refresh for all active conditions and inactive, unacknowledged conditions.
'
' 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.AlarmsAndEvents
Imports OpcLabs.EasyOpc.AlarmsAndEvents.OperationModel
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.OperationModel

Namespace AlarmsAndEvents._EasyAEClient

    Friend Class RefreshEventSubscription
        _
        Private Shared ReadOnly AEClient As New EasyAEClient()
        _
        Private Shared ReadOnly DAClient As New EasyDAClient()

        Public Shared Sub Main1()
            Dim eventHandler = New EasyAENotificationEventHandler(AddressOf AEClient_Notification)
            AddHandler AEClient.Notification, eventHandler

            Console.WriteLine("Processing event notifications...")
            Dim subscriptionFilter As New AESubscriptionFilter
            subscriptionFilter.Sources = New AENodeDescriptor() {"Simulation.ConditionState1", "Simulation.ConditionState2", "Simulation.ConditionState3"}
            Dim handle As Integer = AEClient.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000, Nothing, subscriptionFilter)

            ' The component will perform auto-refresh at this point, give it time to happen
            Console.WriteLine("Waiting for 10 seconds...")
            Thread.Sleep(10 * 1000)

            ' Set some events to active state, which will cause them to appear in refresh
            Console.WriteLine("Activating conditions and waiting for 10 seconds...")
            Try
                DAClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState1.Activate", True)
                DAClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState2.Activate", True)
            Catch opcException As OpcException
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
                Exit Sub
            End Try
            Thread.Sleep(10 * 1000)

            Console.WriteLine("Refreshing subscription and waiting for 10 seconds...")
            AEClient.RefreshEventSubscription(handle)
            Thread.Sleep(10 * 1000)

            AEClient.UnsubscribeEvents(handle)
            RemoveHandler AEClient.Notification, eventHandler
        End Sub

        ' Notification event handler
        Private Shared Sub AEClient_Notification(ByVal sender As Object, ByVal e As EasyAENotificationEventArgs)
            Console.WriteLine()
            If Not e.Succeeded Then
                Console.WriteLine("*** Failure: {0}", e.ErrorMessageBrief)
                Exit Sub
            End If

            Console.WriteLine("Refresh: {0}", e.Refresh)
            Console.WriteLine("RefreshComplete: {0}", e.RefreshComplete)
            If e.EventData IsNot Nothing Then
                Dim eventData As AEEventData = e.EventData
                Console.WriteLine("Event.QualifiedSourceName: {0}", eventData.QualifiedSourceName)
                Console.WriteLine("Event.Message: {0}", eventData.Message)
                Console.WriteLine("Event.Active: {0}", eventData.Active)
                Console.WriteLine("Event.Acknowledged: {0}", eventData.Acknowledged)
            End If
        End Sub
    End Class
End Namespace

COM

Rem This example shows how to for a refresh for all active conditions and inactive, unacknowledged conditions.
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 DAClient: Set DAClient = CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient")
Dim AEClient: Set AEClient = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.EasyAEClient")
WScript.ConnectObject AEClient, "AEClient_"

WScript.Echo "Processing event notifications..."
Dim ServerDescriptor: Set ServerDescriptor = CreateObject("OpcLabs.EasyOpc.ServerDescriptor")
ServerDescriptor.ServerClass = "OPCLabs.KitEventServer.2"
Dim SourceDescriptor1: Set SourceDescriptor1 = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.AENodeDescriptor")
SourceDescriptor1.QualifiedName = "Simulation.ConditionState1"
Dim SourceDescriptor2: Set SourceDescriptor2 = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.AENodeDescriptor")
SourceDescriptor2.QualifiedName = "Simulation.ConditionState1"
Dim SourceDescriptor3: Set SourceDescriptor3 = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.AENodeDescriptor")
SourceDescriptor3.QualifiedName = "Simulation.ConditionState1"
Dim SubscriptionParameters: Set SubscriptionParameters = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.AESubscriptionParameters")
SubscriptionParameters.Filter.Sources = Array(SourceDescriptor1, SourceDescriptor2, SourceDescriptor3)
SubscriptionParameters.NotificationRate = 1000
Dim handle: handle = AEClient.SubscribeEvents(ServerDescriptor, SubscriptionParameters, True, Nothing)

Rem The component will perform auto-refresh at this point, give it time to happen
WScript.Echo "Waiting for 10 seconds..."
WScript.Sleep 10*1000

Rem Set some events to active state, which will cause them to appear in refresh
On Error Resume Next
WScript.Echo "Activating conditions and waiting for 10 seconds..."
DAClient.WriteItemValue "", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState1.Activate", True
DAClient.WriteItemValue "", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState2.Activate", True
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0
WScript.Sleep 10*1000

WScript.Echo "Refreshing subscription and waiting for 10 seconds..."
AEClient.RefreshEventSubscription handle
WScript.Sleep 10*1000

AEClient.UnsubscribeEvents handle



Rem Notification event handler
Sub AEClient_Notification(Sender, e)
    If Not (e.Succeeded) Then
        WScript.Echo "*** Failure: " & e.ErrorMessageBrief
        Exit Sub
    End If

    WScript.Echo 
    WScript.Echo "Refresh: " & e.Refresh
    WScript.Echo "RefreshComplete: " & e.RefreshComplete

    If Not (e.EventData Is Nothing) Then
        With e.EventData
            WScript.Echo "EventData.QualifiedSourceName: " & .QualifiedSourceName
            WScript.Echo "EventData.Message: " & .Message
            WScript.Echo "EventData.Active: " & .Active
            WScript.Echo "EventData.Acknowledged: " & .Acknowledged
        End With
    End If
End Sub

Python

# This example shows how to for a refresh for all active conditions and inactive, unacknowledged conditions.
#
# 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 *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.OperationModel import *


# Notification event handler
def notification(sender, e):
    if not e.Succeeded:
        print('*** Failure: ', e.ErrorMessageBrief, sep='')
        return
    print('Refresh: ', e.Refresh, sep='')
    print('RefreshComplete: ', e.RefreshComplete, sep='')
    eventData = e.EventData
    if eventData is not None:
        print('Event.QualifiedSourceName: ', eventData.QualifiedSourceName, sep='')
        print('Event.Message: ', eventData.Message, sep='')
        print('Event.Active: ', eventData.Active, sep='')
        print('Event.Acknowledged: ', eventData.Acknowledged, sep='')


# Instantiate the OPC-A&E client object.
aeClient = EasyAEClient()

# Instantiate the OPC-DA client object.
daClient = EasyDAClient()

#
aeClient.Notification += notification

print('Processing event notifications...')
subscriptionFilter = AESubscriptionFilter()
subscriptionFilter.Sources = [
    AENodeDescriptor('Simulation.ConditionState1'),
    AENodeDescriptor('Simulation.ConditionState2'),
    AENodeDescriptor('Simulation.ConditionState3'),
]
handle = IEasyAEClientExtension.SubscribeEvents(aeClient, '', 'OPCLabs.KitEventServer.2', 1000, None, subscriptionFilter)

# The component will perform auto-refresh at this point, give it time to happen.
print('Waiting for 10 seconds...')
time.sleep(10)

# Set some events to active state, which will cause them to appear in refresh.
print('Activating conditions and waiting for 10 seconds...')
try:
    IEasyDAClientExtension.WriteItemValue(daClient, '', 'OPCLabs.KitServer.2',
                                          'SimulateEvents.ConditionState1.Activate', True)
    IEasyDAClientExtension.WriteItemValue(daClient, '', 'OPCLabs.KitServer.2',
                                          'SimulateEvents.ConditionState2.Activate', True)
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message)
    exit()
time.sleep(10)

print('Refreshing event subscription and waiting for 10 seconds...')
aeClient.RefreshEventSubscription(handle)
time.sleep(10)

aeClient.UnsubscribeEvents(handle)
aeClient.Notification -= notification

print('Finished.')

 

See Also

Concepts