Basler camera / pypylon: Logical error exception

petrblahos report abuse __ edited

Hi, I've encountered a strange error in my python application. The function

RetrieveResult(5000, pylon.TimeoutHandling_ThrowException) 

raises an exception, which reads:

_genicam.LogicalErrorException: Control channel not open. : LogicalErrorException thrown (file 'GxPort.cpp', line 74)

The exception is raised every 5s, which is also the timeout for the RetrieveResult function, and since the first time the exception is raised, the camera won't return any images. Some images are retrieved though (I am not sure if just one) before the error occurs.

This does not happen in the Pylon application.

Camera model: acA4024-8gc

Any leads? Thanks a million.

-- Petr


BST report abuse

Hi, please open the "pylon C++ Programmer's Guide". On the main page, click the first link "Programmer's Guide" and on that page the third link "Debugging pylon Applications Using GigE Cameras" and read carefully (there's another link to "Advanced Topics" that you'll need to click on).

If this exception does not occur, while debugging your application, but in Release Build, then the reason might be a misconfigured GigE connection. If the camera does not receive anything from the PC on it's "Control Channel" connection, the "Heartbeat Timeout" will be triggered and the connection will be closed. Reasons for "lost packages" could be too high traffic on the connection; maybe you don't have activated "Jumbo Frames" on your network card or your network card simply doesn't perform good enough... These FAQs may give further hints:

petrblahos report abuse
Thanks BST. Strangely enough, the camera seemed to "forget" the setting of the packet size and used some 1500B instead of around 9K (I have the jumbo frames enabled). I played a bit with the profiles (I think it was profiles, I cannot access the camera now), and now the settings survive the restart of computer and/or camera and the problem is gone. Thanks again for the answer.
BST report abuse

Two more comments: - As far as I know, pypylon always uses the release build of the pylon libraries, single stepping in, e.g. VS Code would trigger the heartbeat timeout for sure...

  • You can check with PylonViewer, if there are packet losts on your connection (User Level: Guru !): Stream Parameters / Statistic
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