Examples - OPC Unified Architecture - Isolated client objects

.NET

C#
VB.NET

// This example shows how to create and use two isolated client objects, resulting in two separate connections to the target
// OPC UA server.
//
// 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.Diagnostics;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples._EasyUAClient
{
    class Isolated
    {
        public static void Main1()
        {
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"

            // Instantiate the client objects and make them isolated
            var client1 = new EasyUAClient { Isolated = true };
            var client2 = new EasyUAClient { Isolated = true };

            // The callback is a local method the displays the value
            void DataChangeCallback(object sender, EasyUADataChangeNotificationEventArgs eventArgs)
            {
                Debug.Assert(!(eventArgs is null));

                string displayPrefix = $"[{eventArgs.Arguments.State}]";
                if (eventArgs.Succeeded)
                {
                    Debug.Assert(!(eventArgs.AttributeData is null));
                    Console.WriteLine($"{displayPrefix} {eventArgs.AttributeData}");
                }
                else
                    Console.WriteLine($"{displayPrefix} *** Failure: {eventArgs.ErrorMessageBrief}");
            }

            Console.WriteLine("Subscribing...");
            client1.SubscribeDataChange(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853", 1000, 
                DataChangeCallback, state: 1);
            client2.SubscribeDataChange(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853", 1000,
                DataChangeCallback, state: 2);

            Console.WriteLine("Processing data change events for 10 seconds...");
            System.Threading.Thread.Sleep(10 * 1000);

            Console.WriteLine("Unsubscribing...");
            client1.UnsubscribeAllMonitoredItems();
            client2.UnsubscribeAllMonitoredItems();

            Console.WriteLine("Waiting for 2 seconds...");
            System.Threading.Thread.Sleep(2 * 1000);
        }
    }
}

' This example shows how to create and use two isolated client objects, resulting in two separate connections to the target
' OPC UA server.
'
' 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.Windows.Forms.AxHost
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Partial Class Isolated
        Public Shared Sub Main1()

            ' Define which server we will work with.
            Dim endpointDescriptor As UAEndpointDescriptor =
                    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
            ' or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            ' or "https://opcua.demo-this.com:51212/UA/SampleServer/"

            ' Instantiate the client objects and make them isolated
            Dim client1 = New EasyUAClient() With {.Isolated = True}
            Dim client2 = New EasyUAClient() With {.Isolated = True}

            ' The callback is a local method the displays the value
            Dim dataChangeCallback = Sub(ByVal sender As Object, ByVal eventArgs As EasyUADataChangeNotificationEventArgs)
                                         Debug.Assert(eventArgs IsNot Nothing)

                                         Dim displayPrefix As String = $"[{eventArgs.Arguments.State}]"
                                         If eventArgs.Succeeded Then
                                             Debug.Assert(eventArgs.AttributeData IsNot Nothing)
                                             Console.WriteLine($"{displayPrefix} {eventArgs.AttributeData}")
                                         Else
                                             Console.WriteLine($"{displayPrefix} *** Failure: {eventArgs.ErrorMessageBrief}")
                                         End If
                                     End Sub

            Console.WriteLine("Subscribing...")
            client1.SubscribeDataChange(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853", 1000,
                dataChangeCallback, state:=1)
            client2.SubscribeDataChange(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853", 1000,
                dataChangeCallback, state:=2)

            Console.WriteLine("Processing data change events for 10 seconds...")
            Threading.Thread.Sleep(10 * 1000)

            Console.WriteLine("Unsubscribing...")
            client1.UnsubscribeAllMonitoredItems()
            client2.UnsubscribeAllMonitoredItems()

            Console.WriteLine("Waiting for 2 seconds...")
            Threading.Thread.Sleep(2 * 1000)
        End Sub
    End Class
End Namespace

Python

Python (.NET)

# This example shows how to create and use two isolated client objects, resulting in two separate connections to the
# target OPC UA server.
#
# 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.OperationModel import *


# The callback is a regular method the displays the value.
def dataChangeCallback(sender, eventArgs):
    displayPrefix = '[{}]'.format(eventArgs.Arguments.State)
    if eventArgs.Succeeded:
        assert eventArgs.AttributeData is not None
        print(displayPrefix + ' Value: ' + '{}'.format(eventArgs.AttributeData.Value) + '\n', end='')
    else:
        print(displayPrefix + ' *** Failure: ' + eventArgs.ErrorMessageBrief + '\n', end='')


endpointDescriptor = UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:51210/UA/SampleServer')
# or 'http://opcua.demo-this.com:51211/UA/SampleServer' (currently not supported)
# or 'https://opcua.demo-this.com:51212/UA/SampleServer/'

# Instantiate the client objects and make them isolated.
client1 = EasyUAClient()
client1.Isolated = True
client2 = EasyUAClient()
client2.Isolated = True

print('Subscribing...')
IEasyUAClientExtension.SubscribeDataChange(client1,
    endpointDescriptor,
    UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10853'),
    1000,
    EasyUADataChangeNotificationEventHandler(dataChangeCallback),
    1)  # state
IEasyUAClientExtension.SubscribeDataChange(client2,
    endpointDescriptor,
    UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10853'),
    1000,
    EasyUADataChangeNotificationEventHandler(dataChangeCallback),
    2)  # state

print('Processing data change events for 10 seconds...')
time.sleep(10)

print('Unsubscribing...')
client1.UnsubscribeAllMonitoredItems()
client2.UnsubscribeAllMonitoredItems()

print('Waiting for 2 seconds...')
time.sleep(2)

print('Finished.')

Fundamentals

Isolated Clients and Subscribers