Author Topic: Reopen (keep open) serial port after plugin RS232 (USB,BT,IrDA) adapter  (Read 2698 times)

Roman Novgorodov

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You can add following method into main form of application for monitor the WM_DEVICECHANGE:

Code: [Select]
procedure WMDeviceChange(var Msg:TMessage); message WM_DEVICECHANGE;

You can see such methods in several Demo projects of nrComm Lib distribution.

After that you can use following handler for reopen serial port after it will appear in the system again:

Code: [Select]
procedure TForm1.WMDeviceChange(var Msg: TMessage);
  if (nrComm1.DeviceIndex > 0) and (not nrComm1.Active)
        nrComm1.Active := True;
        Memo2.Lines.Add('port is reopened');
        on e:Exception do Memo2.Lines.Add(e.Message);

Please note that at least once before this, the nrComm1 should have a correct selected serial port (DeviceIndex value).

Good luck!

Roman Novgorodov


I am trying to monitor the connection(s) of a USB -> Serial adaptor to the
USB ports. I wish to have the first adaptor connected attach to nrComm1,
and the next one to nrComm2.

If one is disconnected, the program needs to be able to reconnect to that
nrComm component when a USB connection is made again, without affecting
the other port assignment.

I am having trouble managain to do this. Do you have any thoughts that
would help?

I am attachign somne sample code I have tried to  use. port 1 & port 2 are
string variables.

« Last Edit: June 30, 2008, 05:34:55 pm by Roman Novgorodov »
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