Examples - OPC Unified Architecture

.NET

C#
VB.NET

// This example shows how to read value of server's NamespaceArray, and display the namespace URIs in it.
//
// 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.Standard;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples._EasyUAClient
{
    partial class ReadValue
    {
        public static void NamespaceArray()
        {
            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();

            // Perform the operation: Obtain value of a node
            object value;
            try
            {
                value = client.ReadValue(endpointDescriptor, UAVariableIds.Server_NamespaceArray);  // i=2255
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            if (!(value is string[] arrayValue))
            {
                Console.WriteLine("*** Not a string array");
                return;
            }

            // Display results
            for (int i = 0; i < arrayValue.Length; i++)
                Console.WriteLine($"{i}: {arrayValue[i]}");
        }


        // Example output:
        //
        //0: http://opcfoundation.org/UA/
        //1: urn:DEMO-5:UA Sample Server
        //2: http://test.org/UA/Data/
        //3: http://test.org/UA/Data//Instance
        //4: http://opcfoundation.org/UA/Boiler/
        //5: http://opcfoundation.org/UA/Boiler//Instance
        //6: http://opcfoundation.org/UA/Diagnostics
        //7: http://samples.org/UA/memorybuffer
        //8: http://samples.org/UA/memorybuffer/Instance
    }
}

' This example shows how to read value of server's NamespaceArray, and display the namespace URIs in it.
'
' 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.Standard
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Partial Friend Class ReadValue
        Public Shared Sub NamespaceArray()

            ' 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/"

            ' Perform the operation: Obtain value of a node
            Dim client = New EasyUAClient()

            ' Obtain value of a node
            Dim value As Object
            Try
                value = client.ReadValue(endpointDescriptor, UAVariableIds.Server_NamespaceArray) ' i = 2255
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try

            If TypeOf value IsNot String() Then
                Console.WriteLine("*** Not a string array")
                Exit Sub
            End If

            Dim arrayValue() As String = CType(value, String())

            ' Display results
            For i = 0 To arrayValue.Length - 1
                Console.WriteLine($"{i}: {arrayValue(i)}")
            Next i
        End Sub

        ' Example output
        '
        '0: http://opcfoundation.org/UA/
        '1: urn:DEMO-5:UA Sample Server
        '2: http://test.org/UA/Data/
        '3: http://test.org/UA/Data'Instance
        '4: http://opcfoundation.org/UA/Boiler/
        '5: http://opcfoundation.org/UA/Boiler'Instance
        '6: http://opcfoundation.org/UA/Diagnostics
        '7: http://samples.org/UA/memorybuffer
        '8: http://samples.org/UA/memorybuffer/Instance
    End Class
End Namespace

COM

VBScript

Rem This example shows how to read value of server's NamespaceArray, and display the namespace URIs in it.
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

Const endpointDescriptorUrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"

' Instantiate the client object
Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.UA.EasyUAClient")

' Perform the operation
On Error Resume Next
Dim value: value = Client.ReadValue(endpointDescriptorUrlString, "i=2255")
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

' Work around the fact that elements of object arrays returned cannot be retrieved in VBScript directly.
Dim ElasticVector: Set ElasticVector = CreateObject("OpcLabs.BaseLib.Collections.ElasticVector")
ElasticVector.Assign(value)

' Display results
Dim i: For i = ElasticVector.LowerBound To ElasticVector.UpperBound
    WScript.Echo i & ": " & ElasticVector(i)
Next

' Example output:
'
'0: http://opcfoundation.org/UA/
'1: urn:DEMO-5:UA Sample Server
'2: http://test.org/UA/Data/
'3: http://test.org/UA/Data//Instance
'4: http://opcfoundation.org/UA/Boiler/
'5: http://opcfoundation.org/UA/Boiler//Instance
'6: http://opcfoundation.org/UA/Diagnostics
'7: http://samples.org/UA/memorybuffer
'8: http://samples.org/UA/memorybuffer/Instance

Python

Python (.NET)

# This example shows how to read value of server's NamespaceArray, and display the namespace URIs in it.
#
# 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 System import *
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.AddressSpace.Standard 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()

# Perform the operation: Obtain value of a node.
try:
    value = IEasyUAClientExtension.ReadValue(client,
                                             endpointDescriptor,
                                             UANodeDescriptor(UAVariableIds.Server_NamespaceArray)) # i=2255
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

if not isinstance(value, Array):
    print('*** Not an array')
    exit()
arrayValue = value

# Display results.
for i, element in enumerate(arrayValue):
    print(i, ': ', element, sep='')

print()
print('Finished.')