ValueSymbolExtensions.PollValues Method (IValueSymbol, IObservable.Unit., Boolean)

Polls symbol values on trigger signals.

Namespace:  TwinCAT.Ads.Reactive
Assembly:  TwinCAT.Ads.Reactive (in TwinCAT.Ads.Reactive.dll) Version: 6.0.328+39e3229

Syntax

C#

public static IObservable<Object?> PollValues(
    this IValueSymbol symbol,
    IObservable<Unit> trigger,
    bool ignoreErrors
)

Parameters

symbol

Type: TwinCAT.TypeSystem.IValueSymbol
The symbol.

trigger

Type: System.IObservable.Unit.
The Polling trigger

ignoreErrors

Type: System.Boolean
if set to true ADS errors are ignored and a NULL value is returned.

Return Value

Type: IObservable.Object.
IObservable<System.Object>.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IValueSymbol. 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).

Remarks

If ignoreErrors is not set and ReadRequest errors occur, the observable will be closed with error./> If errors are ignored, the observable will return NULL values on erroneous requests.

Reference

ValueSymbolExtensions Class

PollValues Overload

TwinCAT.Ads.Reactive Namespace

ValueSymbolExtensions.PollValues2(IValueSymbol, IObservable.Unit.)

ValueSymbolExtensions.PollValues(IValueSymbol, IObservable.Unit.)

ValueSymbolExtensions.PollValues(IValueSymbol, TimeSpan, Boolean)