AdsClientExtensions.PollDeviceStateAsync Method (IAdsConnection, TimeSpan, CancellationToken)
Gets an observable sequence of ResultReadDeviceStates via Polling.
Namespace: TwinCAT.Ads.Reactive
Assembly: TwinCAT.Ads.Reactive (in
TwinCAT.Ads.Reactive.dll) Version: 6.0.328+39e3229
Syntax
C#
public static IObservable<ResultReadDeviceState> PollDeviceStateAsync(
this IAdsConnection connection,
TimeSpan interval,
CancellationToken cancel
)
Parameters
|
connection |
Type: TwinCAT.Ads.IAdsConnection |
|
interval |
Type: System.TimeSpan |
|
cancel |
Type: System.Threading.CancellationToken |
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).
Examples
The following sample shows how observe AdsState via polling with the reactive AdsClientExtensions
Observe changing ADS States with reactive extensions.
// To Test the observer, Start/Stop the local PLC
using (AdsClient client = new AdsClient())
{
// Connect to target
client.Connect(new AmsAddress(AmsNetId.Local, 851));
// Create Symbol information
var symbolLoader = SymbolLoaderFactory.Create(client, SymbolLoaderSettings.DefaultDynamic);
// Reactive Change Handler
var valueObserver = Observer.Create<IList<AdsState>>(not =>
{
AdsState oldValue = not[0];
AdsState newValue = not[1];
Console.WriteLine(string.Format("Changed ADSState from '{0}' --> '{1}!", oldValue, newValue));
}
);
// Create a subscription for the AdsState change and buffering 2 Values (for oldValue --> newValue output).
IDisposable subscription = client.PollAdsState(TimeSpan.FromMilliseconds(200)).Buffer(2, 1).Subscribe(valueObserver);
Console.ReadKey(); // Wait for Key press
subscription.Dispose(); // Dispose the Subscription
}