Items can be accessed by their name without first creating a group. The items are added to the object internal data cache and to the associated OPC group. The object internal data cache is updated in the data changed callback handler and the application cna alwys read current data from the cache. The user can optionally install a user callback handler to get notified on value changes. The user callback handler is called after the internal cache is updated.
The class is designed for the simple handling of individual items. The OpcGroup class is more efficient for handling multiple items, especially large number of items.
Object Model
Syntax
| Visual Basic (Declaration) | |
|---|---|
Public Class RefreshGroup Inherits SyncIOGroup | |
| C# | |
|---|---|
public class RefreshGroup : SyncIOGroup | |
Inheritance Hierarchy
System.Object
OPCDA.NET.SyncIOGroup
OPCDA.NET.RefreshGroup