Blank display panel problem

[bandrewsk4]

I have an application which collects data from several sources, displays the data on multiple panels, and writes the data to disk. This program also uses the CIVIC Web Server. The program has run correctly for days and even weeks.  Eventually the display panels all go blank.  The panels are still there but contain only white space.  The collection and writing of data to disk, however, continues.  When the program is stopped (from the task bar or task manager) and restarted, it performs normally again.

Has anyone else seen this kind of behavior?  I suspect that it might have something to do with the web server, but I have another very similar program running on a different PC also using the web server.  This program does not have the blank screen problem.  

Thanjs for any light you can shed on this.

Bruce Andrews 

[StevieZ]

Bruce,

Have you checked your CPU usage while the program is running? If your resources are maxing out then the panels may not be able to update or display.

Regards,

Steven Zittrower

Applications Engineer

National Instruments

http://www.ni.com/support

[Wolfgang]

Did you check if the 'OK' phase of your program is something like 49 days? Then it might be related to a timer issue...

Wolfgang

[judyh]

We are seeing the same thing, and without the use of a server, in our release builds that go to testing.  It is intermittant but does not recover to the normal panel when it happens.  It seems to show up more often than you are seeing.  This is on two different machines with different speed CPUs and different size RAM.  I never see this in debug mode while I'm developing and one of the machines is faster and has more RAM than mine, the other is the same speed with less RAM.  It looks like the redraw function has some kind of bug.

Judy

[judyh]

PS.  I am running CVI2010 on Windows XP.

Thanks,

Judy

[nickb]

Hello Judy -

I recently saw this in a CVI program I had written, and in my case, the cause was a memory leak in my program.  If you open task manager when you see this white screen, how much memory is the CVI application using?? 

I would also make sure you've enabled extended debugging on your development machine in debug mode, which should show you any memory leaks you may have.  Just enable extended debugging through the Options»Build Options dialog, and then run your program under the debugger.  You should allow the program to exit normally.  If the Resource Tracking window then displays, it is an indication of resources that need to be cleaned up.  For more information, refer to this document.

NickB

National Instruments

[James_D]

Greetings,

Here's a few questions that should hopefully help clear up exactly what kind of issue you're running into. Did you check to see if your memory or cpu usage is being maxxed out in the task manager? What % of the CPU is the program using when the panel issue arises? Is your program particularly resource intensive? How much data are you trying to display on your front panel?

Please let me know, thanks.

[judyh]

Hi James,

These questions are hard to answer since this never happens when I am developing or testing in debug mode.  I will forward them to my tester and hopefully we can get some answers.  As for the data.  Each panel has about 6-10 controls that get populated when the panel comes up.  The incoming data is being handled by an Async Timer that we've been using forever.  These particular applications don't go any graphing, simply plop the data into an array and then write it to a file if the user chooses to save the data.

Thanks,

Judy