Example

This example shows you how simple it is to connect to an OPC server with the dOPC Client Toolkit. It is based on our dOPC Simulation Server, but it's a trivial matter to change to any other OPC Server. You will find this example program also in our example programs, folder "verySimple".

If you want to add a huge amount of OPC items to a OPC Group (TdOPCGroup) please look at the example program "BulkRead"

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unit Unit1; interface uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, dOPCDA, dOPCComn, dOPCIntf; type TForm1 = class(TForm) Memo1: TMemo; Panel1: TPanel; bStart: TButton; OPCClient: TdOPCDAClient; procedure OPCClientDatachange(Sender: TObject; ItemList: TdOPCItemList); procedure bStartClick(Sender: TObject); private public end; var Form1: TForm1; implementation {$R *.DFM} // connect to the OPC server procedure TForm1.bStartClick(Sender: TObject); var G : TdOPCGroup; begin OPCClient.Servername := 'dOPCSim.Kassl.Simulation'; // select your OPC Server G := OPCClient.OPCGroups.Add('testgroup'); // make your own new group G.OPCItems.AddItem('Random.String'); // add new OPC Item to group OPCClient.Active := true; // let's go end; // the OPC server sends OnDatachange events procedure TForm1.OPCClientDatachange(Sender: TObject; ItemList: TdOPCItemList); var i : integer; begin for i := 0 to Itemlist.Count-1 do // for all changed Items Memo1.Lines.Add(TimetoStr(Itemlist[i].TimeStamp)+': '+ Itemlist[i].ItemName +'->'+ Itemlist[i].ValueStr +' ('+ Itemlist[i].QualityAsString+')' ); // shows the changed OPC Item in the memo end; end.