ChangeMonitoredItemSubscription Method (

Changes parameters of a subscription. Specify the handle, and a new sampling interval.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
Sub ChangeMonitoredItemSubscription( _
   ByVal handle As Integer, _
   ByVal samplingInterval As Integer _
)

'Usage
 
Dim instance As _EasyUAClient
Dim handle As Integer
Dim samplingInterval As Integer
 
instance.ChangeMonitoredItemSubscription(handle, samplingInterval)

void ChangeMonitoredItemSubscription( 
   int handle,
   int samplingInterval
)

void ChangeMonitoredItemSubscription( 
   int handle,
   int samplingInterval
)

Parameters

handle: Monitored item subscription handle as returned by the subscription method.
samplingInterval: The sampling interval (in milliseconds) indicates the fastest rate at which the Server should sample its underlying source for data changes.

Example

// This example shows how to change the sampling rate of an existing monitored
// item subscription.
//
// Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

type
  TClientEventHandlers110 = class
    procedure OnDataChangeNotification(
      ASender: TObject;
      sender: OleVariant;
      const eventArgs: _EasyUADataChangeNotificationEventArgs);
  end;

procedure TClientEventHandlers110.OnDataChangeNotification(
  ASender: TObject;
  sender: OleVariant;
  const eventArgs: _EasyUADataChangeNotificationEventArgs);
begin
  // Display the data
  if eventArgs.Succeeded then
      WriteLn(eventArgs.AttributeData.ToString)
  else
      WriteLn('*** Failure: ',
      eventArgs.ErrorMessageBrief);
end;

class procedure ChangeMonitoredItemSubscription.Main;
var
  Client: TEasyUAClient;
  ClientEventHandlers: TClientEventHandlers110;
  Handle: Cardinal;
begin
  // Instantiate the client object and hook events
  Client := TEasyUAClient.Create(nil);
  ClientEventHandlers := TClientEventHandlers110.Create;
  Client.OnDataChangeNotification := ClientEventHandlers.OnDataChangeNotification;

  WriteLn('Subscribing...');
  Handle := Client.SubscribeDataChange(
    //'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=10853',
    1000);

  WriteLn('Processing monitored item changed events for 10 seconds...');
  PumpSleep(10*1000);

  Client.ChangeMonitoredItemSubscription(Handle, 100);

  WriteLn('Processing monitored item changed events for 10 seconds...');
  PumpSleep(10*1000);

  WriteLn('Unsubscribing...');
  Client.UnsubscribeAllMonitoredItems;

  WriteLn('Waiting for 5 seconds...');
  PumpSleep(5*1000);

  WriteLn('Finished.');
  FreeAndNil(Client);
  FreeAndNil(ClientEventHandlers);
end;

REM This example shows how to change the sampling rate of an existing monitored
REM item subscription.
REM
REM Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

' The client object, with events
'Public WithEvents Client5 As EasyUAClient

Public Sub ChangeMonitoredItemSubscription_Main_Command_Click()
    OutputText = ""
    
    Set Client5 = New EasyUAClient

    OutputText = OutputText & "Subscribing..." & vbCrLf
    Dim Handle As Long
    Handle = Client5.SubscribeDataChange("opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", "nsu=http://test.org/UA/Data/ ;i=10853", 1000)

    OutputText = OutputText & "Processing monitored item changed events for 10 seconds..." & vbCrLf
    Pause 10000

    Call Client5.ChangeMonitoredItemSubscription(Handle, 100)

    OutputText = OutputText & "Processing monitored item changed events for 10 seconds..." & vbCrLf
    Pause 10000

    OutputText = OutputText & "Unsubscribing..." & vbCrLf
    Client5.UnsubscribeAllMonitoredItems

    OutputText = OutputText & "Waiting for 5 seconds..." & vbCrLf
    Pause 5000

    OutputText = OutputText & "Finished." & vbCrLf
    Set Client5 = Nothing
End Sub

Public Sub Client5_DataChangeNotification(ByVal sender As Variant, ByVal eventArgs As EasyUADataChangeNotificationEventArgs)
    ' Display the data
    If eventArgs.Exception Is Nothing Then
        OutputText = OutputText & eventArgs.AttributeData & vbCrLf
    Else
        OutputText = OutputText & eventArgs.ErrorMessageBrief & vbCrLf
    End If
End Sub

Rem This example shows how to change the sampling rate of an existing monitored item subscription.
Rem
Rem Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Option Explicit

' Instantiate the client object and hook events
Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.UA.EasyUAClient")
WScript.ConnectObject Client, "Client_"

WScript.Echo "Subscribing..."
Dim handle: handle = Client.SubscribeDataChange( _
    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", _
    "nsu=http://test.org/UA/Data/ ;i=10853", _
    1000)

WScript.Echo "Processing monitored item changed events for 10 seconds..."
WScript.Sleep 10 * 1000

WScript.Echo "Changing subscription..."
Client.ChangeMonitoredItemSubscription handle, 100

WScript.Echo "Processing monitored item changed events for 10 seconds..."
WScript.Sleep 10 * 1000

WScript.Echo "Unsubscribing..."
Client.UnsubscribeAllMonitoredItems

WScript.Echo "Waiting for 5 seconds..."
WScript.Sleep 5 * 1000



Sub Client_DataChangeNotification(Sender, e)
    Dim display: If e.Exception Is Nothing Then display = e.AttributeData Else display = e.ErrorMessageBrief
    WScript.Echo display
End Sub

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

_EasyUAClient Interface
_EasyUAClient Members

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