OPC Studio User's Guide and Reference
Examples - OPC Unified Architecture - Read multiple values

.NET

// This example shows how to read the Value attributes of 3 different nodes at once. Using the same method, it is also possible 
// to read multiple attributes of the same node.
//
// 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.BaseLib.OperationModel;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;

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

            // Obtain values. By default, the Value attributes of the nodes will be read.
            ValueResult[] valueResultArray = client.ReadMultipleValues(new[]
                {
                    new UAReadArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10845"),
                    new UAReadArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853"),
                    new UAReadArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10855")
                });

            // Display results.
            foreach (ValueResult valueResult in valueResultArray)
            {
                if (valueResult.Succeeded)
                    Console.WriteLine($"Value: {valueResult.Value}");
                else
                    Console.WriteLine($"*** Failure: {valueResult.ErrorMessageBrief}");
            }


            // Example output:
            //
            //Value: 8
            //Value: -8.06803E+21
            //Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^            
        }
    }
}

# This example shows how to read the Value attributes of 3 different nodes at once. Using the same method, it is also possible 
# to read multiple attributes of the same node.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in PowerShell on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-PowerShell .
# 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.

#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

# Obtain values. By default, the Value attributes of the nodes will be read.
$valueResultArray = $client.ReadMultipleValues([UAReadArguments[]]@(
        (New-Object UAReadArguments($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10845")), 
        (New-Object UAReadArguments($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853")), 
        (New-Object UAReadArguments($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10855"))
    ))

foreach ($valueResult in $valueResultArray) {
    if ($valueResult.Succeeded) {
        Write-Host "Value: $($valueResult.Value)"
    }
    else {
        Write-Host "*** Failure: $($valueResult.ErrorMessageBrief)"
    }
}


# Example output:
#
#Value: 8
#Value: -8.06803E+21
#Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^            


' This example shows how to read the Value attributes of 3 different nodes at once. Using the same method, it is also possible 
' to read multiple attributes of the same node.
'
' 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
Imports OpcLabs.BaseLib.OperationModel
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Partial Friend Class ReadMultipleValues
        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()

            ' Obtain values. By default, the Value attributes of the nodes will be read.
            Dim valueResultArray() As ValueResult = client.ReadMultipleValues(New UAReadArguments() _
               {
                   New UAReadArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10845"),
                   New UAReadArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853"),
                   New UAReadArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10855")
               }
            )

            ' Display results
            For Each valueResult As ValueResult In valueResultArray
                If valueResult.Succeeded Then
                    Console.WriteLine("Value: {0}", valueResult.Value)
                Else
                    Console.WriteLine("*** Failure: {0}", valueResult.ErrorMessageBrief)
                End If
            Next valueResult

            ' Example output:
            '
            'Value: 8
            'Value: -8.06803E+21
            'Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^            
        End Sub
    End Class
End Namespace

COM

// This example shows how to read the Value attributes of 3 different nodes at once. Using the same method, it is also possible 
// to read multiple attributes of the same node.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// 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.

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

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

            _UAReadArgumentsPtr ReadArguments1Ptr(_uuidof(UAReadArguments));
            ReadArguments1Ptr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            ReadArguments1Ptr->NodeDescriptor->NodeId->ExpandedText = L"nsu=http://test.org/UA/Data/ ;i=10845";

            _UAReadArgumentsPtr ReadArguments2Ptr(_uuidof(UAReadArguments));
            ReadArguments2Ptr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            ReadArguments2Ptr->NodeDescriptor->NodeId->ExpandedText = L"nsu=http://test.org/UA/Data/ ;i=10853";

            _UAReadArgumentsPtr ReadArguments3Ptr(_uuidof(UAReadArguments));
            ReadArguments3Ptr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            ReadArguments3Ptr->NodeDescriptor->NodeId->ExpandedText = L"nsu=http://test.org/UA/Data/ ;i=10855";

            CComSafeArray<VARIANT> arguments(3);
            arguments.SetAt(0, _variant_t((IDispatch*)ReadArguments1Ptr));
            arguments.SetAt(1, _variant_t((IDispatch*)ReadArguments2Ptr));
            arguments.SetAt(2, _variant_t((IDispatch*)ReadArguments3Ptr));
            CComVariant vArguments(arguments);

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

                _variant_t vString;
                vString.ChangeType(VT_BSTR, &ValueResultPtr->Value);
                _tprintf(_T("Value: %s\n"), (LPCTSTR)CW2CT((_bstr_t)vString));
            }

            // Example output:
            //
            //Value: 8
            //Value: -8.06803E+21
            //Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^            
        }
         // Release all interface pointers BEFORE calling CoUninitialize()
        CoUninitialize();
    }
}

// This example shows how to read the Value attributes of 3 different nodes at
// once. Using the same method, it is also possible to read multiple attributes
// of the same node.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// 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.

class procedure ReadMultipleValues.Main;
var
  Client: EasyUAClient;
  ReadArguments1, ReadArguments2, ReadArguments3: _UAReadArguments;
  Arguments, Results: OleVariant;
  I: Cardinal;
  Result: _ValueResult;
begin
  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  ReadArguments1 := CoUAReadArguments.Create;
  ReadArguments1.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  ReadArguments1.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10845';

  ReadArguments2 := CoUAReadArguments.Create;
  ReadArguments2.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  ReadArguments2.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10853';

  ReadArguments3 := CoUAReadArguments.Create;
  ReadArguments3.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  ReadArguments3.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10855';

  Arguments := VarArrayCreate([0, 2], varVariant);
  Arguments[0] := ReadArguments1;
  Arguments[1] := ReadArguments2;
  Arguments[2] := ReadArguments3;

  // Obtain values. By default, the Value attributes of the nodes will be read.
  TVarData(Results).VType := varArray or varVariant;
  TVarData(Results).VArray := PVarArray(Client.ReadMultipleValues(
    PSafeArray(TVarData(Arguments).VArray)));

  // Display results
  for I := VarArrayLowBound(Results, 1) to VarArrayHighBound(Results, 1) do
  begin
      Result := IInterface(Results[I]) as _ValueResult;
      WriteLn('Value: ', Result.Value);
  end;

  // Example output:
  //
  //Value: 8
  //Value: -8.06803E+21
  //Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^
end;

// This example shows how to read the Value attributes of 3 different nodes at
// once. Using the same method, it is also possible to read multiple attributes
// of the same node.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in Object Pascal (Delphi) on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-OP .
// 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.

class procedure ReadMultipleValues.Main;
var
  Client: OpcLabs_EasyOpcUA_TLB._EasyUAClient;
  ReadArguments1, ReadArguments2, ReadArguments3: _UAReadArguments;
  Arguments, Results: OleVariant;
  I: Cardinal;
  Result: _ValueResult;
begin
  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  ReadArguments1 := CoUAReadArguments.Create;
  ReadArguments1.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';
  ReadArguments1.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10845';

  ReadArguments2 := CoUAReadArguments.Create;
  ReadArguments2.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';
  ReadArguments2.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10853';

  ReadArguments3 := CoUAReadArguments.Create;
  ReadArguments3.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';
  ReadArguments3.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10855';

  Arguments := VarArrayCreate([0, 2], varVariant);
  Arguments[0] := ReadArguments1;
  Arguments[1] := ReadArguments2;
  Arguments[2] := ReadArguments3;

  // Obtain values. By default, the Value attributes of the nodes will be read.
  TVarData(Results).VType := varArray or varVariant;
  TVarData(Results).VArray := PVarArray(Client.ReadMultipleValues(Arguments));

  // Display results
  for I := VarArrayLowBound(Results, 1) to VarArrayHighBound(Results, 1) do
  begin
      Result := IInterface(Results[I]) as _ValueResult;
      if Result.Succeeded then
        WriteLn('Value: ', Result.Value)
      else
        WriteLn('results(', I, ') *** Failure: ', Result.ErrorMessageBrief);
  end;

  VarClear(Results);
  VarClear(Arguments);

  // Example output:
  //
  //Value: 8
  //Value: -8.06803E+21
  //Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^
end;

// This example shows how to read the Value attributes of 3 different nodes at once. Using the same method, it is also possible 
// to read multiple attributes of the same node.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in PHP on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-PHP .
// 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.

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

$ReadArguments1 = new COM("OpcLabs.EasyOpc.UA.OperationModel.UAReadArguments");
$ReadArguments1->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";
$ReadArguments1->NodeDescriptor->NodeId->ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10845";

$ReadArguments2 = new COM("OpcLabs.EasyOpc.UA.OperationModel.UAReadArguments");
$ReadArguments2->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";
$ReadArguments2->NodeDescriptor->NodeId->ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10853";

$ReadArguments3 = new COM("OpcLabs.EasyOpc.UA.OperationModel.UAReadArguments");
$ReadArguments3->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";
$ReadArguments3->NodeDescriptor->NodeId->ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10855";

$arguments[0] = $ReadArguments1;
$arguments[1] = $ReadArguments2;
$arguments[2] = $ReadArguments3;

// Obtain values. By default, the Value attributes of the nodes will be read.
$results = $Client->ReadMultipleValues($arguments);

// Display results
for ($i = 0; $i < count($results); $i++)
{
    $ValueResult = $results[$i];
    if ($ValueResult->Succeeded)
        printf("Value: %s\n", $ValueResult->Value);
    else
        printf("*** Failure: %s\n", $ValueResult->ErrorMessageBrief);
}

// Example output:
//
//Value: 8
//Value: -8.06803E+21
//Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^            


// This example shows how to read the Value attributes of 3 different nodes at once. Using the same method, it is also possible 
// to read multiple attributes of the same node.

mle_outputtext.Text = ""

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

// Prepare arguments. By default, the Value attributes of the nodes will be read.

OLEObject readArguments1
readArguments1 = CREATE OLEObject
readArguments1.ConnectToNewObject("OpcLabs.EasyOpc.UA.OperationModel.UAReadArguments")
readArguments1.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
readArguments1.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10845"

OLEObject readArguments2
readArguments2 = CREATE OLEObject
readArguments2.ConnectToNewObject("OpcLabs.EasyOpc.UA.OperationModel.UAReadArguments")
readArguments2.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
readArguments2.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10853"

OLEObject readArguments3
readArguments3 = CREATE OLEObject
readArguments3.ConnectToNewObject("OpcLabs.EasyOpc.UA.OperationModel.UAReadArguments")
readArguments3.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
readArguments3.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10855"

OLEObject readArgumentsList
readArgumentsList = CREATE OLEObject
readArgumentsList.ConnectToNewObject("OpcLabs.BaseLib.Collections.ElasticVector")
readArgumentsList.Add(readArguments1)
readArgumentsList.Add(readArguments2)
readArgumentsList.Add(readArguments3)

// Obtain values. 
OLEObject valueResultList
valueResultList = client.ReadValueList(readArgumentsList)

// Display results
Int i
FOR i = 0 TO valueResultList.Count - 1
    OLEObject valueResult
    valueResult = valueResultList.Item[i]
    IF valueResult.Succeeded THEN
        mle_outputtext.Text = mle_outputtext.Text + "Value: " + String(valueResult.Value) + "~r~n"
    ELSE
        mle_outputtext.Text = mle_outputtext.Text + "*** Failure: " + valueResult.ErrorMessageBrief + "~r~n"
    END IF    
NEXT

// Example output:
//
//Value: 8
//Value: -8.06803E+21
//Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^            


REM This example shows how to read the Value attributes of 3 different nodes at once. Using the same method, it is also possible
REM to read multiple attributes of the same node.
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 Visual Basic on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VB .
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.

Public Sub ReadMultipleValues_Main_Command_Click()
    OutputText = ""

    ' Instantiate the client object
    Dim Client As New EasyUAClient

    Dim readArguments1 As New UAReadArguments
    readArguments1.endpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
    readArguments1.nodeDescriptor.NodeId.expandedText = "nsu=http://test.org/UA/Data/ ;i=10845"

    Dim ReadArguments2 As New UAReadArguments
    ReadArguments2.endpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
    ReadArguments2.nodeDescriptor.NodeId.expandedText = "nsu=http://test.org/UA/Data/ ;i=10853"

    Dim ReadArguments3 As New UAReadArguments
    ReadArguments3.endpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
    ReadArguments3.nodeDescriptor.NodeId.expandedText = "nsu=http://test.org/UA/Data/ ;i=10855"

    Dim arguments(2) As Variant
    Set arguments(0) = readArguments1
    Set arguments(1) = ReadArguments2
    Set arguments(2) = ReadArguments3

    ' Obtain values. By default, the Value attributes of the nodes will be read.
    Dim results() As Variant
    results = Client.ReadMultipleValues(arguments)

    ' Display results
    Dim i: For i = LBound(results) To UBound(results)
        Dim Result As valueResult: Set Result = results(i)
        If Result.Succeeded Then
            OutputText = OutputText & "Value: " & Result.value & vbCrLf
        Else
            OutputText = OutputText & "*** Failure: " & Result.ErrorMessageBrief & vbCrLf
        End If
    Next

    ' Example output:
    '
    'Value: 8
    'Value: -8.06803E+21
    'Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^
End Sub

Rem This example shows how to read the Value attributes of 3 different nodes at once. Using the same method, it is also possible 
Rem to read multiple attributes of the same node.
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

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

Dim ReadArguments1: Set ReadArguments1 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.UAReadArguments")
ReadArguments1.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
ReadArguments1.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10845"

Dim ReadArguments2: Set ReadArguments2 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.UAReadArguments")
ReadArguments2.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
ReadArguments2.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10853"

Dim ReadArguments3: Set ReadArguments3 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.UAReadArguments")
ReadArguments3.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
ReadArguments3.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10855"

Dim arguments(2)
Set arguments(0) = ReadArguments1
Set arguments(1) = ReadArguments2
Set arguments(2) = ReadArguments3

' Obtain values. By default, the Value attributes of the nodes will be read.
Dim results: results = Client.ReadMultipleValues(arguments)

' Display results
Dim i: For i = LBound(results) To UBound(results)
    Dim ValueResult: Set ValueResult = results(i)
    If ValueResult.Succeeded Then
        WScript.Echo "Value: " & ValueResult.Value
    Else
        WScript.Echo "*** Failure: " & ValueResult.ErrorMessageBrief
    End If
Next

' Example output:
'
'Value: 8
'Value: -8.06803E+21
'Value: Strawberry Pig Banana Snake Mango Purple Grape Monkey Purple? Blueberry Lemon^

Python

# This example shows how to read the Value attributes of 3 different nodes at once. Using the same method, it is also possible
# to read multiple attributes of the same 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 .
# 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 *


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()

# Obtain values. By default, the Value attributes of the nodes will be read.
valueResultArray = IEasyUAClientExtension.ReadMultipleValues(client, [
    UAReadArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10845')),
    UAReadArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10853')),
    UAReadArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10855')),
    ])

# Display results.
for valueResult in valueResultArray:
    if valueResult.Succeeded:
        print('Value: ', valueResult.Value, sep='')
    else:
        print('*** Failure: ', valueResult.ErrorMessageBrief, sep='')

print()
print('Finished.')

 

See Also
Examples - OPC Unified Architecture - Read multiple nodes or attributes
Examples - OPC Unified Architecture - Read a single value
Examples - OPC Unified Architecture - Write multiple values
Examples - OPC Unified Architecture - Subscribe to multiple nodes for data changes
Examples - OPC Unified Architecture - Read nodes specified by browse paths
Examples - OPC Unified Architecture - Read values from two servers
Examples - OPC Unified Architecture - Read multiple values from device

Concepts

Reading just the value (OPC UA)

Examples - Client OPC Data Access

Examples - OPC Data Access - Read multiple item values

Examples - Client OPC UA Services

Examples - OPC UA Services - Register and unregister multiple nodes, with connection locking

 

 

Copyright © 2004-2024 CODE Consulting and Development, s.r.o., Plzen. All rights reserved.

Documentation Home, Send Documentation Feedback. Technical Support