dOPCDA.TdOPCDAClient.OnDatachange

Events

Delphi

property OnDatachange: TOnOPCDataChangeEvent;

C++

__property TOnOPCDataChangeEvent OnDatachange;

Description

TOnOPCDataChangeEvent is generated when a value or the quality of a value for an item has changed.

Remarks

This event will not be triggered before the group update. Therefore item values will be buffered by the server until the next update, which is defined by UpdateRate. Only values of items that are active and whose groups are active will be sent to the client in this event.

Example

Copy Code

procedure TForm1.OPCServerDatachange(Sender: TObject; ItemList: TdOPCItemList); var i: integer; Item: TdOPCItem; begin for i := 0 to ItemList.Count - 1 do // more than one item possible begin Item := ItemList[i]; Memo1.Lines.Add(format('Item %s Value %s', [Item.ItemId, Item.ValueStr])); end; end;

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