Examples - OPC UA Layered Extensions

.NET

C#
VB.NET

// This example shows how to wait on an item until a value with "good" status severity becomes available.
//
// 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.Extensions;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples._EasyUAClientExtension
{
    class WaitForValue
    {
        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 object
            var client = new EasyUAClient();

            Console.WriteLine("Waiting until an item value with \"good\" status severity becomes available...");
            object value;
            try
            {
                value = client.WaitForValue(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221",
                    monitoringParameters: 100,  // this is the sampling rate
                    millisecondsTimeout: 60*1000);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            // Display the obtained value.
            Console.WriteLine("value: {0}", value);
        }
    }
}

' This example shows how to wait on an item until a value with "good" status severity becomes available.
'
' 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 Opc.Ua
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.Extensions
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClientExtension
    Friend Class WaitForValue
        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 object
            Dim client = New EasyUAClient()

            Console.WriteLine("Waiting until an item value with ""good"" status severity becomes available...")
            Dim value As Object
            Try
                value = client.WaitForValue(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221",
                    monitoringParameters:=100,  ' this is the sampling rate
                    millisecondsTimeout:=60 * 1000)
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try

            ' Display the obtained value.
            Console.WriteLine("value: {0}", value)
        End Sub
    End Class
End Namespace

Python

Python (.NET)

# This example shows how to wait on an item until a value with "good" status severity becomes available.
#
# 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 .NET namespaces.
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.Extensions import *
from OpcLabs.EasyOpc.UA.OperationModel import *


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 object.
client = EasyUAClient()

print('Waiting until an item value with "good" status severity becomes available...')
try:
    value = IEasyUAClientExtension2.WaitForValue(client,
                                                 endpointDescriptor,
                                                 UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10221'),
                                                 UAMonitoringParameters(100),   # this is the sampling rate
                                                 60*1000)   # millisecondsTimeout
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

# Display the obtained value.
print('value: ', value, sep='')

print()
print('Finished.')

Examples - Client OPC Unified Architecture

Examples - OPC Unified Architecture - Read a single value

Examples - OPC Unified Architecture - Read a single attribute of a single node

Examples - OPC Unified Architecture - Subscribe to a single node for data changes

Concepts

Waiting for OPC UA Data