AnyTypeExtensionsPollValuesT(IAdsConnection, String, Int32, TimeSpan) Method

C#

public static IObservable<T> PollValues<T>(
    this IAdsConnection connection,
    string instancePath,
    int[]? args,
    TimeSpan period
)

Parameters

Type Parameters

Return Value

IObservableT
IObservable<System.Object>.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IAdsConnection. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Example

Polling ANY_TYPE values.

Observe changing ADS Symbols by polling (Read Polling) (ANY_TYPE)

// To Test the Observer run a project on the local PLC System (Port 851)
using (AdsClient client = new AdsClient())
{
    // Connect to target
    client.Connect(new AmsAddress(AmsNetId.Local, 851));

    // Create Symbol information
    var symbolLoader = SymbolLoaderFactory.Create(client, SymbolLoaderSettings.Default);
    IValueSymbol cycleCount = (IValueSymbol)symbolLoader.Symbols["TwinCAT_SystemInfoVarList._TaskInfo.CycleCount"];

    // Reactive Notification Handler
    var valueObserver = Observer.Create<object>(val =>
    {
    Console.WriteLine(string.Format("Instance: {0}, Value: {1}", cycleCount.InstancePath, val.ToString()));
    }
    );

    // Take 20 Values in an Interval of 500ms
    IDisposable subscription = cycleCount.PollValues(TimeSpan.FromMilliseconds(500)).Take(20).Subscribe(valueObserver);

    Console.ReadKey(); // Wait for Key press
    subscription.Dispose(); // Dispose the Subscription
}

Reference

AnyTypeExtensions Class PollValues Overload TwinCAT.Ads.Reactive Namespace

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