[NumLock]

так если попробовать?

Код:

unit Unit1;

interface

uses
  S7PROSIMLib_TLB,
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  procedure S7ProSimConnectionError(ASender: TObject; const ControlEngine: WideString;
    Error: Integer);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var
  S7ProSim: TS7ProSim;
begin
  S7ProSim:=TS7ProSim.Create(Self);
  S7ProSim.OnConnectionError:=S7ProSimConnectionError;
  S7ProSim.Connect;
  S7ProSim.SetScanMode(ContinuousScan);
  S7ProSim.SetState('RUN');
end;

procedure TForm1.S7ProSimConnectionError(ASender: TObject;
  const ControlEngine: WideString; Error: Integer);
begin
  // обработчик OnConnectionError
end;

end.