QuickOPC User's Guide and Reference
Writing Attributes of OPC UA Nodes
Development Models > Imperative Programming Model > Imperative Programming Model for OPC Data (Classic and UA) > Modifying Information (OPC Data) > Writing Attributes of OPC UA Nodes
In This Topic

A single node and attribute

If you want to write a data value into an attribute of a specific node in OPC UA, call the WriteValue method, passing it the data value you want to write, arguments for endpoint descriptor, node ID, and an optional data type.

One-time write:

.NET

// This example shows how to write a value into a single node.

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

namespace UADocExamples._EasyUAClient
{
    partial class WriteValue
    {
        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 value of a node...");
            try
            {
                client.WriteValue(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 12345);
            }
            catch (UAException uaException)
            {
                Console.WriteLine($"*** Failure: {uaException.GetBaseException().Message}");
                return;
            }

            Console.WriteLine("Finished.");
        }
    }
}

# This example shows how to write a value into a single node.

#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 value of a node..."
try {
    $client.WriteValue($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 12345)
}
catch [UAException] {
    Write-Host "*** Failure: $($PSItem.Exception.GetBaseException().Message)"
    return
}

Write-Host "Finished."

# This example shows how to write a value into a single node.

# 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.OperationModel import *


# Instantiate the client object.
client = EasyUAClient()

# Perform the operation.
try:
    IEasyUAClientExtension.WriteValue(client,
        UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:51210/UA/SampleServer'),
        UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10221'),
        12345)
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

print('Finished.')

' This example shows how to write a value into a single node.

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

Namespace _EasyUAClient
    Partial Friend Class WriteValue
        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()

            ' Modify value of a node
            Try
                client.WriteValue(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 12345)
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try
        End Sub
    End Class
End Namespace

COM

// This example shows how to write a value into a single node.

#include "stdafx.h"    // Includes "QuickOpc.h", and other commonly used files
#include "WriteValue.h"

namespace _EasyUAClient
{
    void WriteValue::Main()
    {
        // Initialize the COM library
        CoInitializeEx(NULL, COINIT_MULTITHREADED);
        {
            // Instantiate the client object
            _EasyUAClientPtr ClientPtr(__uuidof(EasyUAClient));

            // Perform the operation
            ClientPtr->WriteValue(
                //L"http://opcua.demo-this.com:51211/UA/SampleServer", 
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer",
                L"nsu=http://test.org/UA/Data/ ;i=10221",
                12345);
        }
         // Release all interface pointers BEFORE calling CoUninitialize()
        CoUninitialize();
    }
}

// This example shows how to write a value into a single node.

class procedure WriteValue.Main;
var
  Client: EasyUAClient;
begin
  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  // Perform the operation
  Client.WriteValue(
    //'http://opcua.demo-this.com:51211/UA/SampleServer',
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer',
    'nsu=http://test.org/UA/Data/ ;i=10221',
    12345);
end;

// This example shows how to write a value into a single node.

class procedure WriteValue.Main;
var
  Client: OpcLabs_EasyOpcUA_TLB._EasyUAClient;
begin
  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  // Perform the operation
  try
    Client.WriteValue(
      //'http://opcua.demo-this.com:51211/UA/SampleServer',
      //'https://opcua.demo-this.com:51212/UA/SampleServer/',
      'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer',
      'nsu=http://test.org/UA/Data/ ;i=10221',
      12345);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

end;

// This example shows how to write a value into a single node.

// Instantiate the client object
$Client = new COM("OpcLabs.EasyOpc.UA.EasyUAClient");

// Perform the operation
try
{
    $Client->WriteValue(
        //"http://opcua.demo-this.com:51211/UA/SampleServer", 
        "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", 
        "nsu=http://test.org/UA/Data/ ;i=10221", 
        12345);
}
catch (com_exception $e)
{
    printf("*** Failure: %s\n", $e->getMessage());
}

// This example shows how to write a value into a single node.

mle_outputtext.Text = ""

// Instantiate the client object
OLEObject client
client = CREATE OLEObject
client.ConnectToNewObject("OpcLabs.EasyOpc.UA.EasyUAClient")

// Modify value of a node
TRY
    client.WriteValue("http://opcua.demo-this.com:51211/UA/SampleServer", "nsu=http://test.org/UA/Data/ ;i=10221", 12345)
CATCH (OLERuntimeError oleRuntimeError)
    mle_outputtext.Text = mle_outputtext.Text + "*** Failure: " + oleRuntimeError.Description + "~r~n"
    RETURN
END TRY

mle_outputtext.Text = mle_outputtext.Text + "~r~n" 
mle_outputtext.Text = mle_outputtext.Text + "Finished." + "~r~n" 

# This example shows how to write a value into a single node.

# The Python for Windows (pywin32) extensions package is needed. Install it using "pip install pypiwin32".
# CAUTION: We now recommend using Python.NET package instead. Full set of examples with Python.NET is available!
import win32com.client
from pywintypes import com_error

# Instantiate the client object
client = win32com.client.Dispatch('OpcLabs.EasyOpc.UA.EasyUAClient') 

# Perform the operation
try:
    client.WriteValue(
        'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer',
        'nsu=http://test.org/UA/Data/ ;i=10221',
        12345)
except com_error as e:
    print('*** Failure: ' + e.args[2][1] + ': ' + e.args[2][2])
    exit()

Rem This example shows how to write a value into a single node.

Public Sub WriteValue_Main_Command_Click()
    OutputText = ""

    ' Instantiate the client object
    Dim Client As New EasyUAClient

    ' Perform the operation
    On Error Resume Next
    Call Client.WriteValue("opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", "nsu=http://test.org/UA/Data/ ;i=10221", 12345)
    If Err.Number <> 0 Then
        OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
        Exit Sub
    End If
    On Error GoTo 0

End Sub

Rem This example shows how to write a value into a single node.

Option Explicit

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

' Perform the operation
On Error Resume Next
Client.WriteValue "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", "nsu=http://test.org/UA/Data/ ;i=10221", 12345
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

Incrementing write:

.NET

// This example shows how to write an ever-incrementing value to an OPC UA variable.

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

namespace UADocExamples._EasyUAClient
{
    partial class WriteValue
    {
        public static void Incrementing()
        {
            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/"
            UANodeId nodeId = "nsu=http://test.org/UA/Data/ ;i=10221";
            // Example settings with Softing dataFEED OPC Suite: 
            //UAEndpointDescriptor endpointDescriptor =
            //    "opc.tcp://localhost:4980/Softing_dataFEED_OPC_Suite_Configuration1";
            //UANodeId nodeId = "nsu=Local%20Items ;s=Local Items.EAK_Test1.EAK_Testwert1_I4";

            // Instantiate the client object
            var client = new EasyUAClient();

            //
            int i = 0;

            do
            {
                Console.WriteLine($"@{DateTime.Now}: Writing {i}");
                try
                {
                    client.WriteValue(endpointDescriptor, nodeId, i);
                }
                catch (UAException uaException)
                {
                    Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                    return;
                }
                i = unchecked((i + 1) & 0x7FFFFFFF);
                Thread.Sleep(2 * 1000);
            } while (!Console.KeyAvailable);
        }
    }
}

COM

Rem This example shows how to write an ever-incrementing value to an OPC UA variable.

Option Explicit

Const endpointDescriptorUrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
Const nodeIdExpandedText = "nsu=http://test.org/UA/Data/ ;i=10221"
' Example settings with Softing dataFEED OPC Suite: 
'Const endpointDescriptorUrlString = "opc.tcp://localhost:4980/Softing_dataFEED_OPC_Suite_Configuration1"
'Const nodeIdExpandedText = "nsu=Local%20Items ;s=Local Items.EAK_Test1.EAK_Testwert1_I4"

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

' 
Dim i: i = 0

Do While True
    WScript.Echo "@" & Time & ": Writing " & i
    On Error Resume Next
    Client.WriteValue endpointDescriptorUrlString, nodeIdExpandedText, i
    If Err.Number <> 0 Then
        WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
        WScript.Quit
    End If
    On Error Goto 0
    i = (i + 1) And &H7FFFFFFF
    WScript.Sleep 2*1000
Loop

When you specify individual arguments to the simplest overload of the WriteValue method, the method will write to the Value attribute of the node, and if the value type is an array, it will modify the whole contents of that array. If you want to write into a different attribute, or write only to a subset of an array, use one of the more complex overloads of the WriteValue method, such as with an argument of UAWriteValueArguments type, and fill this argument will all necessary information.

Multiple nodes or attributes

For writing data values into multiple OPC attributes (in the same or different nodes) in an efficient manner, call the WriteMultipleValues method. You pass in an array of UAWriteValueArgument objects, each specifying the location of OPC node, attribute, and the value to be written.

Example 1:

// This example shows how to write values into 3 nodes at once.

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

namespace UADocExamples._EasyUAClient
{
    partial class WriteMultipleValues
    {
        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();

            // Modify value of a node
            client.WriteMultipleValues(new[]
                {
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 2.34567890),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10227", "ABC")
                });
            // Production code would check the success of the operation. See separate example for that.
        }
    }
}

# This example shows how to write values into 3 nodes at once.

# 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.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 values of nodes...')
writeResultArray = IEasyUAClientExtension.WriteMultipleValues(client, [
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10221'), 23456),
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10226'), 2.34567890),
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10227'), 'ABC'),
    ])

# Production code would check the success of the operation. See separate example for that.

print()
print('Finished.')

' This example shows how to write values into 3 nodes at once.

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

Namespace _EasyUAClient
    Partial Friend Class WriteMultipleValues
        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()

            ' Modify value of a node
            client.WriteMultipleValues(New UAWriteValueArguments() _
                { _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456), _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 2.3456789), _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10227", "ABC") _
                } _
             )
            ' Production code would check the success of the operation. See separate example for that.
        End Sub
    End Class
End Namespace

Example 2:

The example above can be extended by properly testing for success of each operation, like this:

.NET

// This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
// message in case of failure.

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

namespace UADocExamples._EasyUAClient
{
    partial class WriteMultipleValues
    {
        public static void TestSuccess()
        {
            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 values of nodes...");
            OperationResult[] operationResultArray = client.WriteMultipleValues(new[]
                {
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 
                        "This string cannot be converted to Double"),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;s=UnknownNode", "ABC")
                });

            for (int i = 0; i < operationResultArray.Length; i++)
                if (operationResultArray[i].Succeeded)
                    Console.WriteLine($"Result {i}: success");
                else
                    Console.WriteLine($"Result {i}: {operationResultArray[i].Exception.GetBaseException().Message}");


            // Example output:
            //
            //Modifying values of nodes...
            //Result 0: success
            //Result 1: Input string was not in a correct format.
            //+ Attempting to change an object of type "System.String" to type "System.Double".
            //+ The specified original value (string) was "This string cannot be converted to Double".
            //+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;i=10226".
            //+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.
            //Result 2: The status of the OPC-UA attribute data is not Good. The actual status is 'BadNodeIdUnknown'.
            //+ During writing or method calls, readings may occur when value type is not specified.
            //+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;s=UnknownNode".
            //+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.
        }
    }
}

# This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
# message in case of failure.

#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 values of nodes..."
$operationResultArray = $client.WriteMultipleValues([UAWriteValueArguments[]]@(
        (New-Object UAWriteValueArguments($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456)),
        (New-Object UAWriteValueArguments($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 
            "This string cannot be converted to Double")),
        (New-Object UAWriteValueArguments($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;s=UnknownNode", "ABC"))
    ))

for ($i = 0; $i -lt $operationResultArray.Length; $i++) {
    if ($operationResultArray[$i].Succeeded) {
        Write-Host "Result $($i): success"
    }
    else {
        Write-Host "Result $($i): $($operationResultArray[$i].Exception.GetBaseException().Message)"
    }
}


# Example output:
#
#Modifying values of nodes...
#Result 0: success
#Result 1: Input string was not in a correct format.
#+ Attempting to change an object of type "System.String" to type "System.Double".
#+ The specified original value (string) was "This string cannot be converted to Double".
#+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;i=10226".
#+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.
#Result 2: The status of the OPC-UA attribute data is not Good. The actual status is 'BadNodeIdUnknown'.
#+ During writing or method calls, readings may occur when value type is not specified.
#+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;s=UnknownNode".
#+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.


# This example shows how to write values into 3 nodes at once, test for success of each write and display the exception
# message in case of failure.

# 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.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 values of nodes...')
writeResultArray = IEasyUAClientExtension.WriteMultipleValues(client, [
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10221'), 23456),
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10226'),
                          'This string cannot be converted to Double'),
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;s=UnknownNode'), 'ABC'),
    ])

for i, writeResult in enumerate(writeResultArray):
    if writeResult.Succeeded:
        print('writeResultArray[', i, ']: success', sep='')
    else:
        print('writeResultArray[', i, '] *** Failure: ', writeResult.Exception.GetBaseException().Message, sep='')

print()
print('Finished.')

' This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
' message in case of failure.

Imports System
Imports OpcLabs.BaseLib.OperationModel
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Partial Friend Class WriteMultipleValues
        Public Shared Sub TestSuccess()

            ' 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()

            ' Modify value of a node
            Dim operationResultArray() As OperationResult = client.WriteMultipleValues(New UAWriteValueArguments() _
                { _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456), _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", "This string cannot be converted to Double"), _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;s=UnknownNode", "ABC") _
                } _
             )

            For i As Integer = 0 To operationResultArray.Length - 1
                If operationResultArray(i).Succeeded Then
                    Console.WriteLine("Result {0}: success", i)
                Else
                    Console.WriteLine("Result {0}: {1}", i, operationResultArray(i).Exception.GetBaseException().Message)
                End If
            Next i
        End Sub
    End Class
End Namespace

COM

// This example shows how to write values into 3 nodes at once, test for success of each write and display the exception
// message in case of failure.

#include "stdafx.h"    // Includes "QuickOpc.h", and other commonly used files
#include <atlsafe.h>
#include "WriteMultipleValues.h"

namespace _EasyUAClient
{
    void WriteMultipleValues::TestSuccess()
    {
        // Initialize the COM library
        CoInitializeEx(NULL, COINIT_MULTITHREADED);
        {
            // Instantiate the client object
            _EasyUAClientPtr ClientPtr(__uuidof(EasyUAClient));

            _UAWriteValueArgumentsPtr WriteValueArguments1Ptr(_uuidof(UAWriteValueArguments));
            WriteValueArguments1Ptr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            WriteValueArguments1Ptr->NodeDescriptor->NodeId->ExpandedText = L"nsu=http://test.org/UA/Data/ ;i=10221";
            WriteValueArguments1Ptr->Value = 23456;

            _UAWriteValueArgumentsPtr WriteValueArguments2Ptr(_uuidof(UAWriteValueArguments));
            WriteValueArguments2Ptr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            WriteValueArguments2Ptr->NodeDescriptor->NodeId->ExpandedText = L"nsu=http://test.org/UA/Data/ ;i=10226";
            WriteValueArguments2Ptr->Value = L"This string cannot be converted to Double";

            _UAWriteValueArgumentsPtr WriteValueArguments3Ptr(_uuidof(UAWriteValueArguments));
            WriteValueArguments3Ptr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            WriteValueArguments3Ptr->NodeDescriptor->NodeId->ExpandedText = L"nsu=http://test.org/UA/Data/ ;s=UnknownNode";
            WriteValueArguments3Ptr->Value = L"ABC";

            CComSafeArray<VARIANT> arguments(3);
            arguments.SetAt(0, _variant_t((IDispatch*)WriteValueArguments1Ptr));
            arguments.SetAt(1, _variant_t((IDispatch*)WriteValueArguments2Ptr));
            arguments.SetAt(2, _variant_t((IDispatch*)WriteValueArguments3Ptr));
            CComVariant vArguments(arguments);

            // Obtain values. By default, the Value attributes of the nodes will be Write.
            CComSafeArray<VARIANT> results;
            results.Attach(ClientPtr->WriteMultipleValues(&vArguments));
            
            // Display results
            for (int i = results.GetLowerBound(); i <= results.GetUpperBound(); i++)
            {
                _UAWriteResultPtr ResultPtr = results[i];

                if (ResultPtr->Succeeded)
                    _tprintf(_T("Result %d success\n"), i);
                else
                    _tprintf(_T("Result d: s\n"), i, (LPCTSTR)CW2CT(ResultPtr->Exception->GetBaseException()->Message));
            }
        }
         // Release all interface pointers BEFORE calling CoUninitialize()
        CoUninitialize();
    }
}

// This example shows how to write values into 3 nodes at once, test for
// success of each write and display the exception message in case of failure.

class procedure WriteMultipleValues.TestSuccess;
var
  Arguments: OleVariant;
  Client: EasyUAClient;
  I: Cardinal;
  WriteResult: _UAWriteResult;
  WriteValueArguments1, WriteValueArguments2, WriteValueArguments3: _UAWriteValueArguments;
  Results: OleVariant;
begin
  WriteValueArguments1 := CoUAWriteValueArguments.Create;
  WriteValueArguments1.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  WriteValueArguments1.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10221';
  WriteValueArguments1.Value := 23456;

  WriteValueArguments2 := CoUAWriteValueArguments.Create;
  WriteValueArguments2.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  WriteValueArguments2.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10226';
  WriteValueArguments2.Value := 'This string cannot be converted to Double';

  WriteValueArguments3 := CoUAWriteValueArguments.Create;
  WriteValueArguments3.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  WriteValueArguments3.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;s=UnknownNode';
  WriteValueArguments3.Value := 'ABC';

  Arguments := VarArrayCreate([0, 2], varVariant);
  Arguments[0] := WriteValueArguments1;
  Arguments[1] := WriteValueArguments2;
  Arguments[2] := WriteValueArguments3;

  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  // Modify values of nodes
  TVarData(Results).VType := varArray or varVariant;
  TVarData(Results).VArray := PVarArray(Client.WriteMultipleValues(
    PSafeArray(TVarData(Arguments).VArray)));

  // Display results
  for I := VarArrayLowBound(Results, 1) to VarArrayHighBound(Results, 1) do
  begin
    WriteResult := IInterface(Results[I]) as _UAWriteResult;
    if WriteResult.Succeeded then
      WriteLn('Result ', I, ' success')
    else
      WriteLn('Result ', I, ': ', WriteResult.Exception.GetBaseException.Message);
  end;
end;

// This example shows how to write values into 3 nodes at once, test for
// success of each write and display the exception message in case of failure.

class procedure WriteMultipleValues.TestSuccess;
var
  Arguments: OleVariant;
  Client: OpcLabs_EasyOpcUA_TLB._EasyUAClient;
  I: Cardinal;
  WriteResult: _UAWriteResult;
  WriteValueArguments1, WriteValueArguments2, WriteValueArguments3: _UAWriteValueArguments;
  Results: OleVariant;
begin
  WriteValueArguments1 := CoUAWriteValueArguments.Create;
  WriteValueArguments1.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    //'https://opcua.demo-this.com:51212/UA/SampleServer/';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  WriteValueArguments1.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10221';
  WriteValueArguments1.Value := 23456;

  WriteValueArguments2 := CoUAWriteValueArguments.Create;
  WriteValueArguments2.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    //'https://opcua.demo-this.com:51212/UA/SampleServer/';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  WriteValueArguments2.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10226';
  WriteValueArguments2.Value := 'This string cannot be converted to Double';

  WriteValueArguments3 := CoUAWriteValueArguments.Create;
  WriteValueArguments3.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    //'https://opcua.demo-this.com:51212/UA/SampleServer/';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  WriteValueArguments3.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;s=UnknownNode';
  WriteValueArguments3.Value := 'ABC';

  Arguments := VarArrayCreate([0, 2], varVariant);
  Arguments[0] := WriteValueArguments1;
  Arguments[1] := WriteValueArguments2;
  Arguments[2] := WriteValueArguments3;

  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  // Modify values of nodes
  TVarData(Results).VType := varArray or varVariant;
  TVarData(Results).VArray := PVarArray(Client.WriteMultipleValues(Arguments));

  // Display results
  for I := VarArrayLowBound(Results, 1) to VarArrayHighBound(Results, 1) do
  begin
    WriteResult := IInterface(Results[I]) as _UAWriteResult;
    if WriteResult.Succeeded then
      WriteLn('Result ', I, ' success')
    else
      WriteLn('Result ', I, ': ', WriteResult.Exception.GetBaseException.Message);
  end;

  VarClear(Results);
  VarClear(Arguments);
end;

// This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
// message in case of failure.

// Instantiate the client object
$Client = new COM("OpcLabs.EasyOpc.UA.EasyUAClient");

$WriteValueArguments1 = new COM("OpcLabs.EasyOpc.UA.OperationModel.UAWriteValueArguments");
$WriteValueArguments1->EndpointDescriptor->UrlString = 
    //"http://opcua.demo-this.com:51211/UA/SampleServer";
    //"https://opcua.demo-this.com:51212/UA/SampleServer/";
    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
$WriteValueArguments1->NodeDescriptor->NodeId->ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10221";
$WriteValueArguments1->Value = 23456;

$WriteValueArguments2 = new COM("OpcLabs.EasyOpc.UA.OperationModel.UAWriteValueArguments");
$WriteValueArguments2->EndpointDescriptor->UrlString = 
    //"http://opcua.demo-this.com:51211/UA/SampleServer";
    //"https://opcua.demo-this.com:51212/UA/SampleServer/";
    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
$WriteValueArguments2->NodeDescriptor->NodeId->ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10226";
$WriteValueArguments2->Value = "This string cannot be converted to Double";

$WriteValueArguments3 = new COM("OpcLabs.EasyOpc.UA.OperationModel.UAWriteValueArguments");
$WriteValueArguments3->EndpointDescriptor->UrlString = 
    //"http://opcua.demo-this.com:51211/UA/SampleServer";
    //"https://opcua.demo-this.com:51212/UA/SampleServer/";
    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
$WriteValueArguments3->NodeDescriptor->NodeId->ExpandedText = "nsu=http://test.org/UA/Data/ ;s=UnknownNode";
$WriteValueArguments3->Value = "ABC";

$arguments[0] = $WriteValueArguments1;
$arguments[1] = $WriteValueArguments2;
$arguments[2] = $WriteValueArguments3;

// Modify values of nodes
$results = $Client->WriteMultipleValues($arguments);

// Display results
for ($i = 0; $i < count($results); $i++)
{
    $WriteResult = $results[$i];
    // The UA Test Server does not support this, and therefore a failure will occur.
    if ($WriteResult->Succeeded)
        printf("Result %d success\n", $i);
    else
        printf("Result d: s \n", $i, $WriteResult->Exception->GetBaseException()->Message);
}

// This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
// message in case of failure.

mle_outputtext.Text = ""

// Instantiate the client object
OLEObject client
client = CREATE OLEObject
client.ConnectToNewObject("OpcLabs.EasyOpc.UA.EasyUAClient")

// Prepare arguments. 

OLEObject writeValueArguments1
writeValueArguments1 = CREATE OLEObject
writeValueArguments1.ConnectToNewObject("OpcLabs.EasyOpc.UA.OperationModel.UAwriteValueArguments")
writeValueArguments1.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
writeValueArguments1.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10221"
writeValueArguments1.Value = 23456

OLEObject writeValueArguments2
writeValueArguments2 = CREATE OLEObject
writeValueArguments2.ConnectToNewObject("OpcLabs.EasyOpc.UA.OperationModel.UAwriteValueArguments")
writeValueArguments2.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
writeValueArguments2.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10226"
writeValueArguments2.Value = "This string cannot be converted to Double"

OLEObject writeValueArguments3
writeValueArguments3 = CREATE OLEObject
writeValueArguments3.ConnectToNewObject("OpcLabs.EasyOpc.UA.OperationModel.UAwriteValueArguments")
writeValueArguments3.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
writeValueArguments3.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;s=UnknownNode"
writeValueArguments3.Value = "ABC"

OLEObject writeValueArgumentsList
writeValueArgumentsList = CREATE OLEObject
writeValueArgumentsList.ConnectToNewObject("OpcLabs.BaseLib.Collections.ElasticVector")
writeValueArgumentsList.Add(writeValueArguments1)
writeValueArgumentsList.Add(writeValueArguments2)
writeValueArgumentsList.Add(writeValueArguments3)

// Modify value of nodes

OLEObject operationResultList
operationResultList = client.WriteValueList(writeValueArgumentsList)

// Display results
Int i
FOR i = 0 TO operationResultList.Count - 1
    OLEObject operationResult
    operationResult = operationResultList.Item[i]
    IF operationResult.Succeeded THEN
        mle_outputtext.Text = mle_outputtext.Text + "Result " + String(i) + ": success" + "~r~n"
    ELSE
        mle_outputtext.Text = mle_outputtext.Text + "Result " + String(i) + ": " + operationResult.Exception.GetBaseException().Message + "~r~n"
    END IF    
NEXT

mle_outputtext.Text = mle_outputtext.Text + "~r~n" 
mle_outputtext.Text = mle_outputtext.Text + "Finished." + "~r~n" 

Rem This example shows how to write values into 3 nodes at once, test for success of each write and display the exception
Rem message in case of failure.

Public Sub WriteMultipleValues_TestSuccess_Command_Click()
    OutputText = ""

    ' Instantiate the client object
    Dim Client As New EasyUAClient

    Dim WriteValueArguments1 As New UAWriteValueArguments
    WriteValueArguments1.endpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
    WriteValueArguments1.nodeDescriptor.NodeId.expandedText = "nsu=http://test.org/UA/Data/ ;i=10221"
    WriteValueArguments1.SetValue 23456

    Dim WriteValueArguments2 As New UAWriteValueArguments
    WriteValueArguments2.endpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
    WriteValueArguments2.nodeDescriptor.NodeId.expandedText = "nsu=http://test.org/UA/Data/ ;i=10226"
    WriteValueArguments2.SetValue "This string cannot be converted to Double"

    Dim WriteValueArguments3 As New UAWriteValueArguments
    WriteValueArguments3.endpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
    WriteValueArguments3.nodeDescriptor.NodeId.expandedText = "nsu=http://test.org/UA/Data/ ;s=UnknownNode"
    WriteValueArguments3.SetValue "ABC"

    Dim arguments(2) As Variant
    Set arguments(0) = WriteValueArguments1
    Set arguments(1) = WriteValueArguments2
    Set arguments(2) = WriteValueArguments3

    ' Modify values of nodes
    Dim results As Variant
    results = Client.WriteMultipleValues(arguments)

    ' Display results
    Dim i: For i = LBound(results) To UBound(results)
        Dim Result As UAWriteResult: Set Result = results(i)
        If Result.Succeeded Then
            OutputText = OutputText & "Result " & i & " success" & vbCrLf
        Else
            OutputText = OutputText & "Result " & i & ": " & Result.Exception.GetBaseException().Message & vbCrLf
        End If
    Next
End Sub

Rem This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
Rem message in case of failure.

Option Explicit

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

Dim WriteValueArguments1: Set WriteValueArguments1 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.UAWriteValueArguments")
WriteValueArguments1.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
WriteValueArguments1.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10221"
WriteValueArguments1.Value = 23456

Dim WriteValueArguments2: Set WriteValueArguments2 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.UAWriteValueArguments")
WriteValueArguments2.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
WriteValueArguments2.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10226"
WriteValueArguments2.Value = "This string cannot be converted to Double"

Dim WriteValueArguments3: Set WriteValueArguments3 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.UAWriteValueArguments")
WriteValueArguments3.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
WriteValueArguments3.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;s=UnknownNode"
WriteValueArguments3.Value = "ABC"

Dim arguments(2)
Set arguments(0) = WriteValueArguments1
Set arguments(1) = WriteValueArguments2
Set arguments(2) = WriteValueArguments3

' Modify values of nodes
Dim results: results = Client.WriteMultipleValues(arguments)

' Display results
Dim i: For i = LBound(results) To UBound(results)
    Dim WriteResult: Set WriteResult = results(i)
    If WriteResult.Succeeded Then
        WScript.Echo "Result " & i & " success"
    Else
        WScript.Echo "Result " & i & ": " & WriteResult.Exception.GetBaseException().Message
    End If
Next

 

Write results

The WriteMultiple and WriteMultipleValues methods return an array of UAWriteResult objects. Besides the inherited members of OperationResult, such as the Exception, the UAWriteResult contains additional information that describes the outcome of the Write operation in case of success:

Advanced

If you access some node or nodes repeatedly, it might be possible to improve the performance of it by (pre-)registering the node or nodes with the server. The performance improvement will only occur if the target OPC UA server supports the necessary node registration services. For more information, see OPC UA Node Registration Service.

See Also
Writing value, timestamps and status code (OPC UA)
Data Type in OPC UA Write
OPC UA Complex Data writing
Writing to OPC Classic Items
Modifying Information (OPC Data)
Imperative Programming Model for OPC Data (Classic and UA)
Imperative Programming Model
Writing less common OPC UA data types
OPC UA Node Registration Service

 

 

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