OPC Studio User's Guide and Reference
Or(UAFilterOperand,UAFilterOperand) Method
Example 



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.Filtering Namespace > UAFilterElements Class > Or Method : Or(UAFilterOperand,UAFilterOperand) Method

The value of this parameter cannot be null (Nothing in Visual Basic).

The value of this parameter cannot be null (Nothing in Visual Basic).

TRUE if operand[0] or operand[1] are TRUE.

Remarks:

The following restrictions apply to the operands:
[0]: Any operand that resolves to a Boolean.
[1]: Any operand that resolves to a Boolean.
If any operand cannot be resolved to a Boolean it is considered a NULL.

Syntax
'Declaration
 
<NotNullAttribute()>
Public Overloads Shared Function Or( _
   ByVal operand0 As UAFilterOperand, _
   ByVal operand1 As UAFilterOperand _
) As UAContentFilterElement
'Usage
 
Dim operand0 As UAFilterOperand
Dim operand1 As UAFilterOperand
Dim value As UAContentFilterElement
 
value = UAFilterElements.Or(operand0, operand1)

Parameters

operand0

The value of this parameter cannot be null (Nothing in Visual Basic).

operand1

The value of this parameter cannot be null (Nothing in Visual Basic).

Return Value

This method never returns null (Nothing in Visual Basic).

Example
// This example shows how to specify criteria for 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 OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.AddressSpace;
using OpcLabs.EasyOpc.UA.AddressSpace.Standard;
using OpcLabs.EasyOpc.UA.AlarmsAndConditions;
using OpcLabs.EasyOpc.UA.Filtering;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples.AlarmsAndConditions
{
    class WhereClause
    {
        public static void Main1()
        {
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer";

            // Instantiate the client object and hook events.
            var client = new EasyUAClient();
            client.EventNotification += client_EventNotification;

            Console.WriteLine("Subscribing...");
            client.SubscribeEvent(
                endpointDescriptor,
                UAObjectIds.Server,
                1000,
                new UAEventFilterBuilder(
                    // Either the severity is >= 500, or the event comes from a specified source node
                    UAFilterElements.Or(
                        UAFilterElements.GreaterThanOrEqual(UABaseEventObject.Operands.Severity, 500),
                        UAFilterElements.Equals(
                            UABaseEventObject.Operands.SourceNode, 
                            new UANodeId("nsu=http://opcfoundation.org/Quickstarts/AlarmCondition ;ns=2;s=1:Metals/SouthMotor"))),
                    UABaseEventObject.AllFields));

            Console.WriteLine("Processing event notifications for 30 seconds...");
            System.Threading.Thread.Sleep(30 * 1000);

            Console.WriteLine("Unsubscribing...");
            client.UnsubscribeAllMonitoredItems();

            Console.WriteLine("Waiting for 5 seconds...");
            System.Threading.Thread.Sleep(5 * 1000);

            Console.WriteLine("Finished.");
        }

        static void client_EventNotification(object sender, EasyUAEventNotificationEventArgs e)
        {
            // Display the event.
            Console.WriteLine(e);
        }


        // Example output:
        //
        //Subscribing...
        //13000008
        //Processing event notifications for 30 seconds...
        //[] Success
        //[] Success; Refresh; RefreshInitiated
        //[] Success; Refresh; [SouthMotor] 100! {DialogConditionType} "The dialog was activated" @9/9/2021 2:22:18 PM (10 fields)
        //[] Success; Refresh; [SouthMotor] 700! {ExclusiveDeviationAlarmType} "The alarm severity has increased." @9/22/2021 7:17:59 AM (10 fields)
        //[] Success; Refresh; [SouthMotor] 900! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/22/2021 7:17:57 AM (10 fields)
        //[] Success; Refresh; [SouthMotor] 100! {TripAlarmType} "The alarm is active." @9/22/2021 7:17:59 AM (10 fields)
        //[] Success; Refresh; [SouthMotor] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:39:51 PM (10 fields)
        //[] Success; Refresh; [SouthMotor] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:38:57 PM (10 fields)
        //[] Success; Refresh; RefreshComplete
        //[] Success; [SouthMotor] 100! {NonExclusiveLevelAlarmType} "The alarm was deactivated by the system." @9/22/2021 7:18:05 AM (10 fields)
        //[] Success; [SouthMotor] 300! {TripAlarmType} "The alarm severity has increased." @9/22/2021 7:18:08 AM (10 fields)
        //[] Success; [SouthMotor] 900! {ExclusiveDeviationAlarmType} "The alarm severity has increased." @9/22/2021 7:18:10 AM (10 fields)
        //[] Success; [SouthMotor] 100! {NonExclusiveLevelAlarmType} "The alarm is active." @9/22/2021 7:18:13 AM (10 fields)
        //[] Success; [SouthMotor] 500! {TripAlarmType} "The alarm severity has increased." @9/22/2021 7:18:17 AM (10 fields)
        //[] Success; [SouthMotor] 100! {ExclusiveDeviationAlarmType} "The alarm was deactivated by the system." @9/22/2021 7:18:21 AM (10 fields)
        //[] Success; [SouthMotor] 300! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/22/2021 7:18:21 AM (10 fields)
        //[] Success; [SouthMotor] 700! {TripAlarmType} "The alarm severity has increased." @9/22/2021 7:18:26 AM (10 fields)
        //[] Success; [SouthMotor] 500! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/22/2021 7:18:29 AM (10 fields)
        //[] Success; [SouthMotor] 100! {ExclusiveDeviationAlarmType} "The alarm is active." @9/22/2021 7:18:32 AM (10 fields)
        //Unsubscribing...
        //Waiting for 5 seconds...
        //Finished.
    }
}
# This example shows how to specify criteria for 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 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.UA
using namespace OpcLabs.EasyOpc.UA.AddressSpace
using namespace OpcLabs.EasyOpc.UA.AddressSpace.Standard

# The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows .
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcUA.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcUAComponents.dll"

# Define which server we will work with.
[UAEndpointDescriptor]$endpointDescriptor = "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer"

# Instantiate the client object.
$client = New-Object EasyUAClient

# Event notification handler
Register-ObjectEvent -InputObject $client -EventName EventNotification -Action { 
    # Display the event.
    Write-Host $EventArgs
}

Write-Host "Subscribing..."
[IEasyUAClientExtension]::SubscribeEvent($client, 
    $endpointDescriptor, 
    [UAObjectIds]::Server, 
    1000,
    [UAEventFilter](New-Object UAEventFilterBuilder(
        [UAFilterElements]::Equals(
            [UABaseEventObject+Operands]::SourceNode, 
            (New-Object UANodeId("nsu=http://opcfoundation.org/Quickstarts/AlarmCondition ;ns=2;s=1:Metals/SouthMotor"))),
        [UABaseEventObject]::AllFields))
    )

Write-Host "Processing event notifications for 30 seconds..."
$stopwatch =  [System.Diagnostics.Stopwatch]::StartNew() 
while ($stopwatch.Elapsed.TotalSeconds -lt 30) {    
    Start-Sleep -Seconds 1
}

Write-Host "Unsubscribing..."
$client.UnsubscribeAllMonitoredItems()

Write-Host "Waiting for 5 seconds..."
Start-Sleep -Seconds 5

Write-Host "Finished."


# Example output:
#
#Subscribing...
#13000008
#Processing event notifications for 30 seconds...
#[] Success
#[] Success; Refresh; RefreshInitiated
#[] Success; Refresh; [SouthMotor] 100! {DialogConditionType} "The dialog was activated" @9/9/2021 2:22:18 PM (10 fields)
#[] Success; Refresh; [SouthMotor] 700! {ExclusiveDeviationAlarmType} "The alarm severity has increased." @9/22/2021 7:17:59 AM (10 fields)
#[] Success; Refresh; [SouthMotor] 900! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/22/2021 7:17:57 AM (10 fields)
#[] Success; Refresh; [SouthMotor] 100! {TripAlarmType} "The alarm is active." @9/22/2021 7:17:59 AM (10 fields)
#[] Success; Refresh; [SouthMotor] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:39:51 PM (10 fields)
#[] Success; Refresh; [SouthMotor] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:38:57 PM (10 fields)
#[] Success; Refresh; RefreshComplete
#[] Success; [SouthMotor] 100! {NonExclusiveLevelAlarmType} "The alarm was deactivated by the system." @9/22/2021 7:18:05 AM (10 fields)
#[] Success; [SouthMotor] 300! {TripAlarmType} "The alarm severity has increased." @9/22/2021 7:18:08 AM (10 fields)
#[] Success; [SouthMotor] 900! {ExclusiveDeviationAlarmType} "The alarm severity has increased." @9/22/2021 7:18:10 AM (10 fields)
#[] Success; [SouthMotor] 100! {NonExclusiveLevelAlarmType} "The alarm is active." @9/22/2021 7:18:13 AM (10 fields)
#[] Success; [SouthMotor] 500! {TripAlarmType} "The alarm severity has increased." @9/22/2021 7:18:17 AM (10 fields)
#[] Success; [SouthMotor] 100! {ExclusiveDeviationAlarmType} "The alarm was deactivated by the system." @9/22/2021 7:18:21 AM (10 fields)
#[] Success; [SouthMotor] 300! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/22/2021 7:18:21 AM (10 fields)
#[] Success; [SouthMotor] 700! {TripAlarmType} "The alarm severity has increased." @9/22/2021 7:18:26 AM (10 fields)
#[] Success; [SouthMotor] 500! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/22/2021 7:18:29 AM (10 fields)
#[] Success; [SouthMotor] 100! {ExclusiveDeviationAlarmType} "The alarm is active." @9/22/2021 7:18:32 AM (10 fields)
#Unsubscribing...
#Waiting for 5 seconds...
#Finished.
' This example shows how to specify criteria for 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 OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.AddressSpace
Imports OpcLabs.EasyOpc.UA.AddressSpace.Standard
Imports OpcLabs.EasyOpc.UA.AlarmsAndConditions
Imports OpcLabs.EasyOpc.UA.Filtering
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace AlarmsAndConditions
    Friend Class WhereClause
        Public Shared Sub Main1()
            ' Instantiate the client object and hook events
            Dim client = New EasyUAClient()
            AddHandler client.EventNotification, AddressOf client_EventNotification

            Console.WriteLine("Subscribing...")
            ' Either the severity is >= 500, or the event comes from a specified source node
            client.SubscribeEvent( _
                "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer", _
                UAObjectIds.Server, _
                1000, _
                New UAEventFilterBuilder( _
                    UAFilterElements.Or( _
                        UAFilterElements.GreaterThanOrEqual(UABaseEventObject.Operands.Severity, 500),
                        UAFilterElements.Equals( _
                            UABaseEventObject.Operands.SourceNode,
                            New UANodeId("nsu=http://opcfoundation.org/Quickstarts/AlarmCondition ;ns=2;s=1:Metals/SouthMotor"))),
                    UABaseEventObject.AllFields))

            Console.WriteLine("Processing event notifications for 30 seconds...")
            Threading.Thread.Sleep(30 * 1000)

            Console.WriteLine("Unsubscribing...")
            client.UnsubscribeAllMonitoredItems()

            Console.WriteLine("Waiting for 5 seconds...")
            Threading.Thread.Sleep(5 * 1000)
        End Sub

        Private Shared Sub client_EventNotification(ByVal sender As Object, ByVal e As EasyUAEventNotificationEventArgs)
            ' Display the event
            Console.WriteLine(e)
        End Sub
    End Class
End Namespace
# This example shows how to specify criteria for 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.UA import *
from OpcLabs.EasyOpc.UA.AddressSpace import *
from OpcLabs.EasyOpc.UA.AddressSpace.Standard import *
from OpcLabs.EasyOpc.UA.AlarmsAndConditions import *
from OpcLabs.EasyOpc.UA.Filtering import *
from OpcLabs.EasyOpc.UA.OperationModel import *


def eventNotification(sender, eventArgs):
    # Display the event.
    print(eventArgs)


# Define which server we will work with.
endpointDescriptor = UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer')

# Instantiate the client object and hook events.
client = EasyUAClient()
client.EventNotification += eventNotification

print('Subscribing...')

eventFilterBuilder = UAEventFilterBuilder(
    # Either the severity is >= 500, or the event comes from a specified source node.
    UAFilterElements.Or(
        UAFilterElements.GreaterThanOrEqual(UABaseEventObject.Operands.Severity, 500),
        UAFilterElements.Equals(
            UABaseEventObject.Operands.SourceNode,
            UANodeId('nsu=http://opcfoundation.org/Quickstarts/AlarmCondition ;ns=2;s=1:Metals/SouthMotor'))),
    UABaseEventObject.AllFields)

IEasyUAClientExtension.SubscribeEvent(
    client,
    endpointDescriptor,
    UANodeDescriptor(UAObjectIds.Server),
    1000,
    UAEventFilterBuilder.ToUAEventFilter(eventFilterBuilder))

print('Processing event notifications for 30 seconds...')
time.sleep(30)

print('Unsubscribing...')
client.UnsubscribeAllMonitoredItems()

print('Waiting for 5 seconds...')
time.sleep(5)

print('Finished.')
Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also