OPC Studio User's Guide and Reference
SessionTimeout Property (_UASmartClientSessionParameters)
Example 



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OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.Engine.ComTypes Namespace > _UASmartClientSessionParameters Interface : SessionTimeout Property
A session timeout (in milliseconds).
Syntax
'Declaration
 
Property SessionTimeout As Integer
 
'Usage
 
Dim instance As _UASmartClientSessionParameters
Dim value As Integer
 
instance.SessionTimeout = value
 
value = instance.SessionTimeout

Property Value

Valid values of this property are in the range from 1 to 2147483647 (Int32.MaxValue).

Unit of measurement is ms.

The default value of this property is 60000.

Exceptions
ExceptionDescription

The value of an argument is outside the allowable range of values as defined by the invoked method.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

Remarks

This parameter is not interpreted by the component; it is simply passed down to the OPC UA Stack for processing.

The value of this parameter is only used if no debugger is attached to the process. Otherwise, the value from SessionTimeoutDebug parameter is used.

Note that the actual session timeout that will be used is negotiated between the OPC UA client and OPC UA server. The value of this parameter is only a "request" from the client side, and can be revised by the server - the server has the final word.

CreateSession Service Parameters, RequestedSessionTimeout: "Duration. Requested maximum number of milliseconds that a Session should remain open without activity. If the Client fails to issue a Service request within this interval, then the Server shall automatically terminate the Client Session."

In order to obtain or modify this parameter, in the default state (when OpcLabs.EasyOpc.UA.EasyUAClientCore.Isolated equals to false), access OpcLabs.EasyOpc.UA.Engine.UAClientAdaptableParameters.SessionParameters property of static OpcLabs.EasyOpc.UA.EasyUAClientCore.AdaptableParameters. If you have set OpcLabs.EasyOpc.UA.EasyUAClientCore.Isolated to true, you need to access OpcLabs.EasyOpc.UA.Engine.UAClientAdaptableParameters.SessionParameters property of OpcLabs.EasyOpc.UA.EasyUAClientCore.IsolatedParameters.

The getter method of this property is pure, i.e. it does not have observable side effects.

This member or type is for use from COM. It is not meant to be used from .NET or Python. Refer to the corresponding .NET member or type instead, if you are developing in .NET or Python.

Example
// This example shows how to set fairly short OPC UA timeouts (failures can thus occur).
//
// 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.EasyOpc.UA;

namespace UADocExamples._UAClientSessionParameters
{
    class Timeouts
    {
        public static void Isolated()
        {
            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 and set timeouts
            var client = new EasyUAClient
            {
                Isolated = true,
                IsolatedParameters =
                {
                    SessionParameters =
                    {
                        EndpointSelectionTimeout = 1500,
                        SessionConnectTimeout = 3000,
                        SessionTimeout = 3000,
                        SessionTimeoutDebug = 3000
                    }
                }
            };

            Console.WriteLine("Subscribing...");
            // The callback is a lambda expression the displays the value
            client.SubscribeDataChange(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853", 1000,
                (sender, eventArgs) =>
                {
                    if (eventArgs.Succeeded)
                        Console.WriteLine("Value: {0}", eventArgs.AttributeData.Value);
                    else
                        Console.WriteLine("*** Failure: {0}", eventArgs.ErrorMessageBrief);
                });

            Console.WriteLine("Processing data change events for 10 seconds...");
            System.Threading.Thread.Sleep(10 * 1000);

            Console.WriteLine("Unsubscribing...");
            client.UnsubscribeAllMonitoredItems();

            Console.WriteLine("Waiting for 2 seconds...");
            System.Threading.Thread.Sleep(2 * 1000);
        }
    }
}
// Shows an OPC UA data change observable with specified timeouts.
//
// 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 OpcLabs.EasyOpc.UA.Reactive;
using System;
using System.Threading;
using OpcLabs.EasyOpc.UA;

namespace ReactiveDocExamples
{
    namespace _UADataChangeNotificationObservable
    {
        partial class Subscribe
        {
            public static void Timeouts()
            {
                // Define which server we will work with.
                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/"

                Console.WriteLine("Creating observable...");
                UADataChangeNotificationObservable<float> observable =
                    UADataChangeNotificationObservable.Create<float>(
                        endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853", 1000);
                // Set fairly short timeouts (failure can thus occur).
                observable.ClientSelector.Isolated = true;
                observable.ClientSelector.IsolatedParameters.SessionParameters.EndpointSelectionTimeout = 1500;
                observable.ClientSelector.IsolatedParameters.SessionParameters.SessionConnectTimeout = 3000;
                observable.ClientSelector.IsolatedParameters.SessionParameters.SessionTimeout = 3000;
                observable.ClientSelector.IsolatedParameters.SessionParameters.SessionTimeoutDebug = 3000;

                Console.WriteLine("Subscribing...");
                using (observable.Subscribe(e => Console.WriteLine(
                    (e.Exception is null) ? e.AttributeData.ToString() : e.Exception.GetBaseException().ToString())))
                {
                    Console.WriteLine("Waiting for 10 seconds...");
                    Thread.Sleep(10*1000);

                    Console.WriteLine("Unsubscribing...");
                }

                Console.WriteLine("Waiting for 2 seconds...");
                Thread.Sleep(2 * 1000);
            }
        }
    }
}
Requirements

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

See Also