AdsSymbolicServer.HasValueChanged Method
Determines whether the value of the Symbol has changed.
Namespace: TwinCAT.Ads.Server
Assembly: TwinCAT.Ads.SymbolicServer (in
TwinCAT.Ads.SymbolicServer.dll) Version: 6.0.328+39e3229
Syntax
C#
protected virtual bool HasValueChanged(
ISymbol symbol
)
Return Value
Type: Boolean
true if the value has changed; otherwise,
false.
Remarks
This Method is used internally to find out, if a symbol was changed since the last notification trigger. Collecting Notifications and send them in cycles enforces that the information about changed values is cached somehow. In the case of the AdsSymbolicServer Symbols with outstanding notifications will have a flag in the internal notification tables.