Client.Connected issue

[AngryBinary]

Using snap7 1.4.0 with Delphi XE7.
Playing around with S7-1200 plc and my test program.
I have problem with Client.Connected function.
Let's say I connect to plc and exchange data. At this point everything as expected Client.Connected returns 1.
Then I pull out cable out of plc and expect Client.Connected to return 0, buts it's not. It keeps returning 1.
What I'm missing here?

My code:

~~~~~~~~~~~~~~
Form1.Client.SetConnectionParams(RemoteAddress, LocalTSAP, RemoteTSAP);
while not Terminated do
begin
if Form1.Client.Connected then
begin
Form1.Client.DBRead(100, 0, 4, @real_val);
Form1.Client.DBRead(100, 4, 2, @word_val);
end
else //connect if not connected
begin
LastError :=Form1.Client.Connect;
if LastError = 0 then
//Connected
else
//CliErrorText(LastError);
end;
Sleep(5000);
end;
~~~~~~~~~~~~~~~~~~~

Edit:Sorry, wrong section.

[Davide Nardella]

Connected function is only a "reminder", there is no way in a client-server scheme to know if a cable was unplugged until a request is performed.

So, your thread code should looks like this:

TMyThread.execute;
Var
  CliReturn : integer;
  TCPError  : boolean;

  procedure CheckConnection;
  begin
    if TCPError then
    begin
      Client.Disconnect;
      repeat
        sleep(500);
      until (Client.Connect=0) or terminated;
    end;
  end;

begin

  while not Terminated do
  begin    
     CheckConnection;
     if not Terminated then
     begin
       CliReturn:=Client.DBRead(100, 0, 4, @real_val):
       //
       // other operations  
       //
       TCPError:=(CliReturn and $0000FF)<>0;

     end;
     Sleep(5000);
  end;

end;

[AngryBinary]

Thanks for reply, works like charm:)

[Davide Nardella]

Sorry, the re was a mistake:
TCPError:=(CliReturn AND $0000FFFF)<>0