In This Topic

Some newer OPC servers allow a combination of value, timestamp, and quality (VTQ) be written into their items.

If you need to do this, call WriteItem or WriteMultipleItems method.

A single item

.NET

// This example shows how to write a value, timestamp and quality into a single item.

using System;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.OperationModel;

namespace DocExamples.DataAccess._EasyDAClient
{
    class WriteItem
    {
        public static void Main1()
        {
            // Instantiate the client object.
            var client = new EasyDAClient();

            try
            {
                client.WriteItem("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 
                    12345, DateTime.SpecifyKind(new DateTime(1980, 1, 1), DateTimeKind.Utc), 192);
            }
            catch (OpcException opcException)
            {
                Console.WriteLine($"*** Failure: {opcException.GetBaseException().Message}");
                return;
            }
            Console.WriteLine("Success");
        }
    }
}

# This example shows how to write a value, timestamp and quality into a single item.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from System import *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.OperationModel import *


# Instantiate the client object.
client = EasyDAClient()

# Perform the operation
try:
    IEasyDAClientExtension.WriteItem(client, '', 'OPCLabs.KitServer.2', 'Simulation.Register_I4',
                                     12345, DateTime.SpecifyKind(DateTime(1980, 1, 1), DateTimeKind.Utc),
                                     DAQuality(192))
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message)
    exit()

print('Finished.')

# This example shows how to write a value, timestamp and quality into a single item.

#requires -Version 5.1
using namespace System
using namespace OpcLabs.EasyOpc.DataAccess
using namespace OpcLabs.EasyOpc.OperationModel

# The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows .
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassicCore.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassic.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassicComponents.dll"

# Instantiate the client object.
$client = New-Object EasyDAClient

try {
    [IEasyDAClientExtension]::WriteItem($client, "", "OPCLabs.KitServer.2", "Simulation.Register_I4",
        12345, [DateTime]::SpecifyKind((New-Object DateTime(1980, 1, 1)), [DateTimeKind]::Utc), 192)
}
catch [OpcException] {
    Write-Host "*** Failure: $($PSItem.Exception.GetBaseException().Message)"
    return
}

Write-Host "Success"

COM

// This example shows how to write a value, timestamp and quality into a single item.

class procedure WriteItem.Main;
var
  Client: OpcLabs_EasyOpcClassic_TLB._EasyDAClient;
begin
  // Instantiate the client object
  Client := CoEasyDAClient.Create;

  try
    Client.WriteItem('', 'OPCLabs.KitServer.2', 'Simulation.Register_I4', 12345, EncodeDate(1980, 1, 1), DAQualities_GoodNonSpecific);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

end;

Rem This example shows how to write a value, timestamp and quality into a single item.

Private Sub WriteItem_Main_Command_Click()
    OutputText = ""
    
    ' Instantiate the client object
    Dim client As New EasyDAClient

    On Error Resume Next
    Call client.WriteItem("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 12345, DateSerial(1980, 1, 1), DAQualities_GoodNonspecific)
    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, timestamp and quality into a single item.

Option Explicit

Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient")
On Error Resume Next
Client.WriteItem "", "OPCLabs.KitServer.2", "Simulation.Register_I4", 12345, DateSerial(1980, 1, 1), 192
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

Multiple items

.NET

// This example shows how to write values, timestamps and qualities into 3 items at once.

using System;
using System.Diagnostics;
using OpcLabs.BaseLib.OperationModel;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.OperationModel;

namespace DocExamples.DataAccess._EasyDAClient
{
    class WriteMultipleItems
    {
        public static void Main1()
        {
            // Instantiate the client object.
            var client = new EasyDAClient();

            Console.WriteLine("Writing multiple items...");
            OperationResult[] resultArray = client.WriteMultipleItems(
                new[] { 
                    new DAItemVtqArguments("OPCLabs.KitServer.2", "Simulation.Register_I4", 
                        new DAVtq(23456, DateTime.UtcNow, DAQualities.GoodNonspecific)),
                    new DAItemVtqArguments("OPCLabs.KitServer.2", "Simulation.Register_R8", 
                        new DAVtq(2.34567890, DateTime.UtcNow, DAQualities.GoodNonspecific)),
                    new DAItemVtqArguments("OPCLabs.KitServer.2", "Simulation.Register_BSTR", 
                        new DAVtq("ABC", DateTime.UtcNow, DAQualities.GoodNonspecific))
                });
            
            for (int i = 0; i < resultArray.Length; i++)
            {
                Debug.Assert(resultArray[i] != null);
                if (resultArray[i].Succeeded)
                    Console.WriteLine("Result {0}: success", i);
                else
                {
                    Debug.Assert(!(resultArray[i].Exception is null));
                    Console.WriteLine("Result {0} *** Failure: {1}", i, resultArray[i].ErrorMessageBrief);
                }
            }
        }
    }
}

# This example shows how to write values, timestamps and qualities into 3 items at once.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from System import *
from OpcLabs.EasyOpc import *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.DataAccess.OperationModel import *
from OpcLabs.EasyOpc.OperationModel import *


# Instantiate the client object.
client = EasyDAClient()

print('Writing multiple items...')
operationResultArray = client.WriteMultipleItems([
    DAItemVtqArguments(ServerDescriptor('OPCLabs.KitServer.2'), DAItemDescriptor('Simulation.Register_I4'),
                       DAVtq(23456, DateTime.UtcNow, DAQuality(DAQualities.GoodNonspecific))),
    DAItemVtqArguments(ServerDescriptor('OPCLabs.KitServer.2'), DAItemDescriptor('Simulation.Register_R8'),
                       DAVtq(2.34567890, DateTime.UtcNow, DAQuality(DAQualities.GoodNonspecific))),
    DAItemVtqArguments(ServerDescriptor('OPCLabs.KitServer.2'), DAItemDescriptor('Simulation.Register_BSTR'),
                       DAVtq('ABC', DateTime.UtcNow, DAQuality(DAQualities.GoodNonspecific))),
    ])

for i, operationResult in enumerate(operationResultArray):
    assert operationResult is not None
    if operationResult.Succeeded:
        print('operationResultArray[', i, ']: success', sep='')
    else:
        assert operationResult.Exception is not None
        print('operationResultArray[', i, '] *** Failure: ', operationResult.ErrorMessageBrief, sep='')

print('Finished.')

# This example shows how to write values, timestamps and qualities into 3 items at once.

#requires -Version 5.1
using namespace System
using namespace OpcLabs.EasyOpc.DataAccess
using namespace OpcLabs.EasyOpc.DataAccess.OperationModel

# The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows .
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassicCore.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassic.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassicComponents.dll"

# Instantiate the client object.
$client = New-Object EasyDAClient

Write-Host "Writing multiple items..."
$resultArray = $client.WriteMultipleItems(@(
    (New-Object DAItemVtqArguments("OPCLabs.KitServer.2", "Simulation.Register_I4", 
        (New-Object DAVtq(23456, [DateTime]::UtcNow, [DAQualities]::GoodNonspecific)))),
    (New-Object DAItemVtqArguments("OPCLabs.KitServer.2", "Simulation.Register_R8", 
        (New-Object DAVtq(2.345667890, [DateTime]::UtcNow, [DAQualities]::GoodNonspecific)))),
    (New-Object DAItemVtqArguments("OPCLabs.KitServer.2", "Simulation.Register_BSTR",
        (New-Object DAVtq("ABC", [DateTime]::UtcNow, [DAQualities]::GoodNonspecific))))
    ))

for ($i = 0; $i -lt $resultArray.Length; $i++) {
    $result = $resultArray[$i]
    if ($result.Succeeded) {
        Write-Host "Result $($i): success"
    }
    else {
        Write-Host "Result $($i) *** Failure: $($result.ErrorMessageBrief)"
    }
}

COM

// This example shows how to write values, timestamps and qualities into 3 items at once.

class procedure WriteMultipleItems.Main;
var
  Arguments: OleVariant;
  Client: OpcLabs_EasyOpcClassic_TLB._EasyDAClient;
  I: Cardinal;
  ItemVtqArguments1: _DAItemVtqArguments;
  ItemVtqArguments2: _DAItemVtqArguments;
  ItemVtqArguments3: _DAItemVtqArguments;
  Results: OleVariant;
  OperationResult: _OperationResult;

begin
  ItemVtqArguments1 := CoDAItemVtqArguments.Create;
  ItemVtqArguments1.ServerDescriptor.ServerClass := 'OPCLabs.KitServer.2';
  ItemVtqArguments1.ItemDescriptor.ItemID := 'Simulation.Register_I4';
  ItemVtqArguments1.Vtq.Value := 23456;
  ItemVtqArguments1.Vtq.TimestampLocal := Now();
  ItemVtqArguments1.Vtq.Quality.NumericalValue := DAQualities_GoodNonSpecific;

  ItemVtqArguments2 := CoDAItemVtqArguments.Create;
  ItemVtqArguments2.ServerDescriptor.ServerClass := 'OPCLabs.KitServer.2';
  ItemVtqArguments2.ItemDescriptor.ItemID := 'Simulation.Register_R8';
  ItemVtqArguments2.Vtq.Value := 2.34567890;
  ItemVtqArguments2.Vtq.TimestampLocal := Now();
  ItemVtqArguments2.Vtq.Quality.NumericalValue := DAQualities_GoodNonSpecific;

  ItemVtqArguments3 := CoDAItemVtqArguments.Create;
  ItemVtqArguments3.ServerDescriptor.ServerClass := 'OPCLabs.KitServer.2';
  ItemVtqArguments3.ItemDescriptor.ItemID := 'Simulation.Register_BSTR';
  ItemVtqArguments3.Vtq.Value := 'ABC';
  ItemVtqArguments3.Vtq.TimestampLocal := Now();
  ItemVtqArguments3.Vtq.Quality.NumericalValue := DAQualities_GoodNonSpecific;

  Arguments := VarArrayCreate([0, 2], varVariant);
  Arguments[0] := ItemVtqArguments1;
  Arguments[1] := ItemVtqArguments2;
  Arguments[2] := ItemVtqArguments3;

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

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

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

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

Rem This example shows how to write values, timestamps and qualities into 3 items at once.

Private Sub WriteMultipleItems_Main_Command_Click()
    OutputText = ""
    
    Dim itemVtqArguments1 As New DAItemVtqArguments
    itemVtqArguments1.serverDescriptor.ServerClass = "OPCLabs.KitServer.2"
    itemVtqArguments1.ItemDescriptor.itemId = "Simulation.Register_I4"
    itemVtqArguments1.vtq.SetValue 23456
    itemVtqArguments1.vtq.TimestampLocal = Now()
    itemVtqArguments1.vtq.Quality.NumericalValue = DAQualities_GoodNonspecific
    
    Dim itemVtqArguments2 As New DAItemVtqArguments
    itemVtqArguments2.serverDescriptor.ServerClass = "OPCLabs.KitServer.2"
    itemVtqArguments2.ItemDescriptor.itemId = "Simulation.Register_R8"
    itemVtqArguments2.vtq.SetValue 2.3456789
    itemVtqArguments2.vtq.TimestampLocal = Now()
    itemVtqArguments2.vtq.Quality.NumericalValue = DAQualities_GoodNonspecific
    
    Dim itemVtqArguments3 As New DAItemVtqArguments
    itemVtqArguments3.serverDescriptor.ServerClass = "OPCLabs.KitServer.2"
    itemVtqArguments3.ItemDescriptor.itemId = "Simulation.Register_BSTR"
    itemVtqArguments3.vtq.SetValue "ABC"
    itemVtqArguments3.vtq.TimestampLocal = Now()
    itemVtqArguments3.vtq.Quality.NumericalValue = DAQualities_GoodNonspecific
    
    Dim arguments(2) As Variant
    Set arguments(0) = itemVtqArguments1
    Set arguments(1) = itemVtqArguments2
    Set arguments(2) = itemVtqArguments3

    ' Instantiate the client object
    Dim client As New EasyDAClient

    ' Modify values of nodes
    Dim results() As Variant
    results = client.WriteMultipleItems(arguments)

    ' Display results
    Dim i: For i = LBound(results) To UBound(results)
        Dim operationResult As operationResult: Set operationResult = results(i)
        If operationResult.Succeeded Then
            OutputText = OutputText & "result " & i & " success" & vbCrLf
        Else
            OutputText = OutputText & "result " & i & " *** Failure: " & operationResult.ErrorMessageBrief & vbCrLf
        End If
    Next
End Sub

Rem This example shows how to write values, timestamps and qualities into 3 items at once.

Option Explicit

Dim ItemVtqArguments1: Set ItemVtqArguments1 = CreateObject("OpcLabs.EasyOpc.DataAccess.OperationModel.DAItemVtqArguments")
ItemVtqArguments1.ServerDescriptor.ServerClass = "OPCLabs.KitServer.2"
ItemVtqArguments1.ItemDescriptor.ItemID = "Simulation.Register_I4"
ItemVtqArguments1.Vtq.Value = 23456
ItemVtqArguments1.Vtq.TimestampLocal = Now()
ItemVtqArguments1.Vtq.Quality.NumericalValue = 192

Dim ItemVtqArguments2: Set ItemVtqArguments2 = CreateObject("OpcLabs.EasyOpc.DataAccess.OperationModel.DAItemVtqArguments")
ItemVtqArguments2.ServerDescriptor.ServerClass = "OPCLabs.KitServer.2"
ItemVtqArguments2.ItemDescriptor.ItemID = "Simulation.Register_R8"
ItemVtqArguments2.Vtq.Value = 2.34567890
ItemVtqArguments2.Vtq.TimestampLocal = Now()
ItemVtqArguments2.Vtq.Quality.NumericalValue = 192

Dim ItemVtqArguments3: Set ItemVtqArguments3 = CreateObject("OpcLabs.EasyOpc.DataAccess.OperationModel.DAItemVtqArguments")
ItemVtqArguments3.ServerDescriptor.ServerClass = "OPCLabs.KitServer.2"
ItemVtqArguments3.ItemDescriptor.ItemID = "Simulation.Register_BSTR"
ItemVtqArguments3.Vtq.Value = "ABC"
ItemVtqArguments3.Vtq.TimestampLocal = Now()
ItemVtqArguments3.Vtq.Quality.NumericalValue = 192

Dim arguments(2)
Set arguments(0) = ItemVtqArguments1
Set arguments(1) = ItemVtqArguments2
Set arguments(2) = ItemVtqArguments3

Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient")
Dim results: results = Client.WriteMultipleItems(arguments)

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

More...

You can also specify the requested data type when writing the value, timestamp and quality. See Data Type in OPC Classic Write.