TopicWrite Property (EasyDAClientHoldPeriods)

After an item write call, connection to an OPC item will be maintained at least for the time period specified here.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<DataMemberAttribute()>
<DefaultValueAttribute(30000)>
Public Property TopicWrite As Integer

'Usage
 
Dim instance As EasyDAClientHoldPeriods
Dim value As Integer
 
instance.TopicWrite = value
 
value = instance.TopicWrite

[DataMember()]
[DefaultValue(30000)]
public int TopicWrite {get; set;}

[DataMember()]
[DefaultValue(30000)]
public:
property int TopicWrite {
   int get();
   void set (    int value);
}

Remarks

This property is used by following client implementations:

Native client: yes
NET API client: no

Example

.NET

CSharp
Python
VB.NET

// This example shows how the OPC server can quickly be disconnected after writing a value into one of its OPC items.

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

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

            client.InstanceParameters.HoldPeriods.TopicWrite = 100; // in milliseconds

            try
            {
                client.WriteItemValue("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 12345);
            }
            catch (OpcException opcException)
            {
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
            }
        }
    }
}

# This example shows how the OPC server can quickly be disconnected after writing a value into one of its OPC items.

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

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


# Instantiate the client object.
client = EasyDAClient()

client.InstanceParameters.HoldPeriods.TopicWrite = 100  # in milliseconds

# Perform the operation
try:
    IEasyDAClientExtension.WriteItemValue(client, '', 'OPCLabs.KitServer.2', 'Simulation.Register_I4', 12345)
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message)
    exit()

print('Finished.')

' This example shows how the OPC server can quickly be disconnected after writing a value into one of its OPC items.

Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.OperationModel

Namespace DataAccess._EasyDAClientHoldPeriods
    Friend Class TopicWrite
        Public Shared Sub Main1()
            Dim client = New EasyDAClient()

            client.InstanceParameters.HoldPeriods.TopicWrite = 100 ' in milliseconds

            Try
                client.WriteItemValue("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 12345)
            Catch opcException As OpcException
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
            End Try
        End Sub
    End Class
End Namespace

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

Reference

EasyDAClientHoldPeriods Class
EasyDAClientHoldPeriods Members

Send Documentation Feedback. Resources: Knowledge Base. Technical support: Online Forums, FAQ.