OPC Studio User's Guide and Reference
Write(IEasyUAClient,UAEndpointDescriptor,UANodeDescriptor,UAAttributeData) Method
Example 



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA Namespace > IEasyUAClientExtension Class > Write Method : Write(IEasyUAClient,UAEndpointDescriptor,UANodeDescriptor,UAAttributeData) Method
The client object that will perform the operation.
Endpoint descriptor. Identifies the OPC-UA server.
Node descriptor. Identifies the node in OPC server's address space.
Value of an attribute, together with status code and timestamps, to be written.
Writes into an attribute in an OPC server. Value, status code and timestamps are written. Writes data into a Value attribute of a node, using an endpoint descriptor and a node Id.
Syntax

Parameters

client
The client object that will perform the operation.
endpointDescriptor
Endpoint descriptor. Identifies the OPC-UA server.
nodeDescriptor
Node descriptor. Identifies the node in OPC server's address space.
attributeData
Value of an attribute, together with status code and timestamps, to be written.
Exceptions
ExceptionDescription

A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

The OPC UA operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause.

This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

Remarks

You can obtain nodeDescriptor e.g. by calling one of the browsing methods on EasyUAClientCore object.

Example

.NET

COM

// This example shows how to write data (a value, timestamps and status code) into a single attribute of a node.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples._EasyUAClient
{
    class Write
    {
        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("Modifying data of a node's attribute...");
            try
            {
                client.Write(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221",
                    new UAAttributeData(12345, UASeverity.GoodOrSuccess, DateTime.UtcNow));

                // The target server may not support this, and in such case a failure will occur.
            }
            catch (UAException uaException)
            {
                Console.WriteLine($"*** Failure: {uaException.GetBaseException().Message}");
                return;
            }

            Console.WriteLine("Finished.");
        }
    }
}
# This example shows how to write data (a value, timestamps and status code) into a single attribute of a node.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

#requires -Version 5.1
using namespace OpcLabs.EasyOpc.UA
using namespace OpcLabs.EasyOpc.UA.OperationModel

# 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"

[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.
$client = New-Object EasyUAClient

Write-Host "Modifying data of a node's attribute..."
try {
    $client.Write($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 
        (New-Object UAAttributeData(12345, [UASeverity]::GoodOrSuccess, [DateTime]::UtcNow)))

    # The target server may not support this, and in such case a failure will occur.
}
catch [UAException] {
    Write-Host "*** Failure: $($PSItem.Exception.GetBaseException().Message)"
    return
}

Write-Host "Finished."
# This example shows how to write data (a value, timestamps and status code) into a single attribute of a node.
#
# 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 .
# 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.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("Modifying data of a node's attribute...")
try:
    IEasyUAClientExtension.Write(client,
        endpointDescriptor,
        UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10221'),
        UAAttributeData(12345, UAStatusCode(UASeverity.GoodOrSuccess), DateTime.UtcNow))
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

print('Finished.')
' This example shows how to write data (a value, timestamps and status code) into a single attribute of a node.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Friend Class Write
        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()

            Try
                ' Modify data of a node's attribute
                client.Write(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221",
                                   New UAAttributeData(12345, UASeverity.GoodOrSuccess, Date.UtcNow)) ' or "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"

                ' The target server may not support this, and in such case a failure will occur.
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message)
            End Try
        End Sub
    End Class
End Namespace
REM This example shows how to write data (a value, timestamps and status code)
REM into a single attribute of a node.
REM
REM Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Public Sub Write_Main_Command_Click()
    OutputText = ""

    Const GoodOrSuccess = 0

    ' Instantiate the client object
    Dim Client As New EasyUAClient

    ' Modify data of a node's attribute
    Dim StatusCode As New UAStatusCode
    StatusCode.Severity = GoodOrSuccess
    Dim AttributeData As New UAAttributeData
    AttributeData.SetValue 12345
    Set AttributeData.StatusCode = StatusCode
    AttributeData.SourceTimestamp = Now()
    
    ' Perform the operation
    On Error Resume Next
    Call Client.Write("opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", "nsu=http://test.org/UA/Data/ ;i=10221", AttributeData)
    If Err.Number <> 0 Then
        OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
        Exit Sub
    End If
    On Error GoTo 0
End Sub
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