Examples - OPC Alarms&Events - Retrieve attribute values

.NET

C#
VB.NET

// This example shows how to subscribe to events with specified event attributes, and obtain the attribute values in event 
// notifications.
//
// 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.Collections.Generic;
using System.Threading;
using OpcLabs.EasyOpc.AlarmsAndEvents;
using OpcLabs.EasyOpc.AlarmsAndEvents.OperationModel;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.OperationModel;

namespace DocExamples.AlarmsAndEvents._EasyAENotificationEventArgs
{
    class AttributeValues
    {
        public static void Main1()
        {
            // Instantiate the OPC-A&E client object.
            var aeClient = new EasyAEClient();

            // Instantiate the OPC-DA client object.
            var daClient = new EasyDAClient();

            var eventHandler = new EasyAENotificationEventHandler(aeClient_Notification);
            aeClient.Notification += eventHandler;

            // Inactivate the event condition (we will later activate it and receive the notification)
            daClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState1.Inactivate", true);

            var subscriptionFilter = new AESubscriptionFilter
            {
                Sources = new AENodeDescriptor[] { "Simulation.ConditionState1" }
            };

            // Prepare a dictionary holding requested event attributes for each event category
            // The event category IDs and event attribute IDs are hard-coded here, but can be obtained from the OPC 
            // server by querying as well.
            var returnedAttributesByCategory = new AEAttributeSetDictionary
            {
                [0x00ECFF02] = new long[] {0x00EB0003, 0x00EB0008}
            };

            Console.WriteLine("Subscribing to events...");
            int handle = aeClient.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000, null, subscriptionFilter,
                returnedAttributesByCategory);

            // Give the refresh operation time to complete
            Thread.Sleep(5 * 1000);

            // Trigger an event carrying specified attributes (activate the condition)
            try
            {
                daClient.WriteItemValue("", "OPCLabs.KitServer.2",
                    "SimulateEvents.ConditionState1.AttributeValues.15400963", 123456);
                daClient.WriteItemValue("", "OPCLabs.KitServer.2",
                    "SimulateEvents.ConditionState1.AttributeValues.15400968", "Some string value");
                daClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState1.Activate", true);
            }
            catch (OpcException opcException)
            {
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
                return;
            }

            Console.WriteLine("Processing event notifications for 10 seconds...");
            Thread.Sleep(10 * 1000);

            aeClient.UnsubscribeEvents(handle);
        }

        // Notification event handler
        static void aeClient_Notification(object sender, EasyAENotificationEventArgs e)
        {
            if (!e.Succeeded)
            {
                Console.WriteLine("*** Failure: {0}", e.ErrorMessageBrief);
                return;
            }
            if (!e.Refresh && (!(e.EventData is null)))
            {
                // Display all received event attribute IDs and their corresponding values
                Console.WriteLine("Event attribute count: {0}", e.EventData.AttributeValues.Count);
                foreach (KeyValuePair<long, object> pair in e.EventData.AttributeValues)
                    Console.WriteLine("    {0}: {1}", pair.Key, pair.Value);
            }
        }
    }
}

' This example shows how to subscribe to events with specified event attributes, and obtain the attribute values in event 
' notifications.
'
' 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._EasyAENotificationEventArgs
    Friend Class AttributeValues
        Public Shared Sub Main1()
            Dim aeClient = New EasyAEClient()
            Dim daClient = New EasyDAClient()

            Dim eventHandler = New EasyAENotificationEventHandler(AddressOf aeClient_Notification)
            AddHandler aeClient.Notification, eventHandler

            ' Inactivate the event condition (we will later activate it and receive the notification)
            daClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState1.Inactivate", True)

            Dim subscriptionFilter As New AESubscriptionFilter
            subscriptionFilter.Sources = New AENodeDescriptor() {"Simulation.ConditionState1"}

            ' Prepare a dictionary holding requested event attributes for each event category
            ' The event category IDs and event attribute IDs are hard-coded here, but can be obtained from the OPC 
            ' server by querying as well.
            Dim returnedAttributesByCategory = New AEAttributeSetDictionary()
            returnedAttributesByCategory(&HECFF02) = New Long() {&HEB0003, &HEB0008}

            Console.WriteLine("Subscribing to events...")
            Dim handle As Integer = aeClient.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000, Nothing, subscriptionFilter, returnedAttributesByCategory)

            ' Give the refresh operation time to complete
            Thread.Sleep(5 * 1000)

            ' Trigger an event carrying specified attributes (activate the condition)
            Try
                daClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState1.AttributeValues.15400963", 123456)
                daClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState1.AttributeValues.15400968", "Some string value")
                daClient.WriteItemValue("", "OPCLabs.KitServer.2", "SimulateEvents.ConditionState1.Activate", True)
            Catch opcException As OpcException
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
                Exit Sub
            End Try

            Console.WriteLine("Processing event notifications for 10 seconds...")
            Thread.Sleep(10 * 1000)

            aeClient.UnsubscribeEvents(handle)
        End Sub

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

            If (Not e.Refresh) AndAlso (e.EventData IsNot Nothing) Then
                ' Display all received event attribute IDs and their corresponding values
                Console.WriteLine("Event attribute count: {0}", e.EventData.AttributeValues.Count)
                For Each pair As KeyValuePair(Of Long, Object) In e.EventData.AttributeValues
                    Console.WriteLine("    {0}: {1}", pair.Key, pair.Value)
                Next pair
            End If
        End Sub
    End Class
End Namespace

.NET

VBScript

Rem This example subscribe to events, and displays rich information available with each 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 ServerDescriptor: Set ServerDescriptor = CreateObject("OpcLabs.EasyOpc.ServerDescriptor")
ServerDescriptor.ServerClass = "OPCLabs.KitEventServer.2"

Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.EasyAEClient")
WScript.ConnectObject Client, "Client_"

WScript.Echo "Subscribing..."
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..."
WScript.Sleep 60*1000

Client.UnsubscribeEvents handle



Rem Notification event handler
Sub Client_Notification(Sender, e)
    On Error Resume Next
    WScript.Echo
    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.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.SubscriptionParameters.Active: " & e.Arguments.SubscriptionParameters.Active
    WScript.Echo "e.Arguments.SubscriptionParameters.NotificationRate: " & e.Arguments.SubscriptionParameters.NotificationRate
    Rem IMPROVE: Display Arguments.SubscriptionParameters.Filter details
    WScript.Echo "e.Arguments.SubscriptionParameters.Filter: " & e.Arguments.SubscriptionParameters.Filter  
    Rem IMPROVE: Display Arguments.SubscriptionParameters.ReturnedAttributesByCategory details
    WScript.Echo "e.Arguments.SubscriptionParameters.ReturnedAttributesByCategory: " & e.Arguments.SubscriptionParameters.ReturnedAttributesByCategory
    WScript.Echo "e.Refresh: " & e.Refresh
    WScript.Echo "e.RefreshComplete: " & e.RefreshComplete
    WScript.Echo "e.EnabledChanged: " & e.EnabledChanged 
    WScript.Echo "e.ActiveChanged: " & e.ActiveChanged 
    WScript.Echo "e.AcknowledgedChanged: " & e.AcknowledgedChanged 
    WScript.Echo "e.QualityChanged: " & e.QualityChanged  
    WScript.Echo "e.SeverityChanged: " & e.SeverityChanged 
    WScript.Echo "e.SubconditionChanged: " & e.SubconditionChanged 
    WScript.Echo "e.MessageChanged: " & e.MessageChanged
    WScript.Echo "e.AttributeChanged: " & e.AttributeChanged 
    WScript.Echo "e.EventData.QualifiedSourceName: " & e.EventData.QualifiedSourceName 
    WScript.Echo "e.EventData.Time: " & e.EventData.Time
    WScript.Echo "e.EventData.TimeLocal: " & e.EventData.TimeLocal
    WScript.Echo "e.EventData.Message: " & e.EventData.Message
    WScript.Echo "e.EventData.EventType: " & e.EventData.EventType 
    WScript.Echo "e.EventData.CategoryId: " & e.EventData.CategoryId 
    WScript.Echo "e.EventData.Severity: " & e.EventData.Severity 
    Rem IMPROVE: Display EventData.AttributeValues details
    WScript.Echo "e.EventData.AttributeValues: " & e.EventData.AttributeValues 
    WScript.Echo "e.EventData.ConditionName: " & e.EventData.ConditionName 
    WScript.Echo "e.EventData.SubconditionName: " & e.EventData.SubconditionName 
    WScript.Echo "e.EventData.Enabled: " & e.EventData.Enabled 
    WScript.Echo "e.EventData.Active: " & e.EventData.Active 
    WScript.Echo "e.EventData.Acknowledged: " & e.EventData.Acknowledged 
    WScript.Echo "e.EventData.Quality: " & e.EventData.Quality 
    WScript.Echo "e.EventData.AcknowledgeRequired: " & e.EventData.AcknowledgeRequired 
    WScript.Echo "e.EventData.ActiveTime: " & e.EventData.ActiveTime
    WScript.Echo "e.EventData.ActiveTimeLocal: " & e.EventData.ActiveTimeLocal
    WScript.Echo "e.EventData.Cookie: " & e.EventData.Cookie 
    WScript.Echo "e.EventData.ActorId: " & e.EventData.ActorId 
End Sub

Python

Python (.NET)

# This example shows how to subscribe to events with specified event attributes, and obtain the attribute values in
# event notifications.
#
# 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
    if (not e.Refresh) and (e.EventData is not None):
        # Display all received event attribute IDs and their corresponding values.
        print('Event attribute count: ', e.EventData.AttributeValues.Count, sep='')
        for pair in e.EventData.AttributeValues:
            print('    ', pair.Key, ': ', pair.Value, sep='')


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

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

#
aeClient.Notification += notification

# Inactivate the event condition (we will later activate it and receive the notification).
try:
    IEasyDAClientExtension.WriteItemValue(daClient, '', 'OPCLabs.KitServer.2',
                                          'SimulateEvents.ConditionState1.Inactivate', True)
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message)
    exit()

subscriptionFilter = AESubscriptionFilter()
subscriptionFilter.Sources = [AENodeDescriptor('Simulation.ConditionState1')]

# Prepare a dictionary holding requested event attributes for each event category.
# The event category IDs and event attribute IDs are hard-coded here, but can be obtained from the OPC
# server by querying as well.
returnedAttributesByCategory = AEAttributeSetDictionary()
returnedAttributesByCategory.Add(0x00ECFF02, [0x00EB0003, 0x00EB0008])

print('Subscribing to events...')
handle = IEasyAEClientExtension.SubscribeEvents(aeClient, '', 'OPCLabs.KitEventServer.2', 1000, None,
                                                subscriptionFilter, returnedAttributesByCategory)

# Give the refresh operation time to complete.
time.sleep(5)

# Trigger an event carrying specified attributes (activate the condition).
try:
    IEasyDAClientExtension.WriteItemValue(daClient, '', 'OPCLabs.KitServer.2',
                                          'SimulateEvents.ConditionState1.AttributeValues.15400963', 123456)
    IEasyDAClientExtension.WriteItemValue(daClient, '', 'OPCLabs.KitServer.2',
                                          'SimulateEvents.ConditionState1.AttributeValues.15400968', 'Some string value')
    IEasyDAClientExtension.WriteItemValue(daClient, '', 'OPCLabs.KitServer.2',
                                          'SimulateEvents.ConditionState1.Activate', True)
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message)
    exit()

print('Processing event notifications for 10 seconds...')
time.sleep(10)

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

print('Finished.')

Concepts

OPC A&E Notification Event

Subscribing to OPC A&E Events

Querying for OPC A&E Event Attributes

Examples - Client OPC UA Alarms&Conditions

Examples - OPC UA Alarms&Conditions - Retrieve fields from event data