Examples - OPC Data Access - Subscribe to multiple items with percent deadband

.NET

C#
VB.NET

// This example shows how subscribe to changes of multiple items with percent deadband.
//
// 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 System.Threading;
using OpcLabs.BaseLib.ComInterop;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.OperationModel;

namespace DocExamples.DataAccess._EasyDAClient
{
    partial class SubscribeMultipleItems
    {
        public static void PercentDeadband()
        {
            // Instantiate the client object.
            using (var client = new EasyDAClient())
            {
                client.ItemChanged += client_PercentDeadband_ItemChanged;

                Console.WriteLine("Subscribing with different percent deadbands...");
                client.SubscribeMultipleItems(
                    new[] {
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Ramp 0:100 (10 s)", 
                                VarTypes.Empty, requestedUpdateRate:100, percentDeadband:10.0f, null), 
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Ramp 0:100 (1 min)",
                                VarTypes.Empty, requestedUpdateRate:100, percentDeadband:5.0f, null),
                        });

                Console.WriteLine("Processing item changed events for 1 minute...");
                Thread.Sleep(60 * 1000);
            }
        }

        // Item changed event handler
        static void client_PercentDeadband_ItemChanged(object sender, EasyDAItemChangedEventArgs e)
        {
            if (e.Succeeded)
                Console.WriteLine("{0}: {1}", e.Arguments.ItemDescriptor.ItemId, e.Vtq);
            else
                Console.WriteLine("{0} *** Failure: {1}", e.Arguments.ItemDescriptor.ItemId, e.ErrorMessageBrief);
        }
    }
}

' This example shows how subscribe to changes of multiple items with percent deadband.
'
' 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.Threading
Imports OpcLabs.BaseLib.ComInterop
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.OperationModel

Namespace DataAccess._EasyDAClient
    Partial Friend Class SubscribeMultipleItems
        Public Shared Sub PercentDeadband()
            ' Instantiate the client object.
            Using client = New EasyDAClient()
                AddHandler client.ItemChanged, AddressOf client_PercentDeadband_ItemChanged

                Console.WriteLine("Subscribing with different percent deadbands...")
                client.SubscribeMultipleItems(New DAItemGroupArguments() {
                    New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Ramp 0:100 (10 s)",
                        VarTypes.Empty, requestedUpdateRate:=100, percentDeadband:=10.0F, Nothing),
                    New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Ramp 0:100 (1 min)",
                        VarTypes.Empty, requestedUpdateRate:=100, percentDeadband:=5.0F, Nothing)
                    })

                Console.WriteLine("Processing item changed events for 1 minute...")
                Thread.Sleep(60 * 1000)
            End Using
        End Sub

        ' Item changed event handler
        Private Shared Sub client_PercentDeadband_ItemChanged(ByVal sender As Object, ByVal e As EasyDAItemChangedEventArgs)
            If e.Succeeded Then
                Console.WriteLine("{0}: {1}", e.Arguments.ItemDescriptor.ItemId, e.Vtq)
            Else
                Console.WriteLine("{0} *** Failure: {1}", e.Arguments.ItemDescriptor.ItemId, e.ErrorMessageBrief)
            End If
        End Sub
    End Class
End Namespace

Python

Python (.NET)

# This example shows how subscribe to changes of multiple items with percent deadband.
#
# 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.BaseLib.ComInterop import *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.DataAccess.OperationModel import *


# Item changed event handler.
def itemChanged(sender, e):
    if e.Succeeded:
        print(e.Arguments.ItemDescriptor.ItemId, ': ', e.Vtq, sep='')
    else:
        print(e.Arguments.ItemDescriptor.ItemId, ' *** Failure: ', e.ErrorMessageBrief, sep='')


# Instantiate the client object.
client = EasyDAClient()

client.ItemChanged += itemChanged

print('Subscribing item changes with different percent deadbands...')
IEasyDAClientExtension.SubscribeMultipleItems(client, [
    DAItemGroupArguments('', 'OPCLabs.KitServer.2', 'Simulation.Ramp 0:100 (10 s)',
                         VarType(VarTypes.Empty), 100, 10.0, None),
    DAItemGroupArguments('', 'OPCLabs.KitServer.2', 'Simulation.Ramp 0:100 (1 min)',
                         VarType(VarTypes.Empty), 100, 5.0, None),
    ])

print('Processing item change notifications for 1 minute...')
time.sleep(60)

print('Unsubscribing all items...')
client.UnsubscribeAllItems()

client.ItemChanged -= itemChanged

print('Finished.')

.NET

Python

Concepts

Examples - Client OPC Unified Architecture

Examples - Client OPC XML-DA