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LabView 2010 Web Server front panel freezes

Hi all,


I wrote a GUI with LabView 2010. It runs as an executable on a machine with only the run time engine installed. It is configured to run as a web server.

When it is being accessed and controlled remotely thru a client it works fine 99% of the time.

However occasionally (and apparently in a random manner) when the client releases the control of the VI and the server is supposed to assume the control of the VI, the front panel on the server PC freezes and does no longer respond to any activities of the mouse related to the GUI front panel. (But it will react OK to other Windows related commands).

When this is happening the VI is still running and the client can successfully gain control of the VI, but when the client releases the control of the VI, the server keeps being hung up. The only way to recover from this is to abort the GUI application and launch it again.


Ps: - I tried to run the same VI (not as an executable) on the PC where it was developed (where Labview is installed) and the same thing is happening.

      - The GUI never freezes when not accessed remotely by the client.

      - The same thing happens regardless if I connect the two PCs thru a network or directly to each other using a crossover RJ45 cable.


Can anyone please suggest what is going on? Anyone had the same issue with LV 2010?


Thank you!!





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Hi Beppe69,


Are you, by any chance, using event structures in your code?  This behavior is common with Event Structures and while it is not very common with web servers, it is worth a shot!


I hope this helps!


Kim W.

Applications Engineer
National Instruments
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Anyone ever get an answer to this problem?  I have the same situation with the LV2011 Web Server.  There is an event structure in the code, but I don't see how that should make the GUI freeze up once web control is relinquished.  If the app works correctly in the native environment there should be nothing wrong with the event structure.  Could this be a bug with the event structure and Web-based control being used together?

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