Problem with LabVIEW PDA 8.0: Freezing in while-loop

[HDRM]

Hi,

i encounterd a problem with the VI attached in this post on my PDA device (WinCE).

In order to get an alternative to the LV PDA Graphs, I arranged several VControls2D_2x in a cluster. The VControls get their input from an array of doubles, the last element of the array gets updated once in a while loop (for testing reasons only with a random value). The array is connected to a shift register.

Problem: On a WinXP PC (LabVIEW 8.0), the attached VI executes without problems. But on my WinCE PDA device, the loop execution time (delay) increases permanently and the VI freezes after a few minutes completely. I can't say if this is a hardware problem with my device or if any other things go wrong on executing the VI with LabVIEW PDA. In addition, my PDA device isn't able to execute a "wait until next ms" like it is described in this thread: https://forums.ni.com/t5/LabVIEW/Loop-timing-in-PDAs/m-p/121521

Any help would be appreciated!

Best regards,

Manuel

P.S. Sorry for the double post! I could not find any button to delete the unwanted post. 😞

Message Edited by Manuel Häderle on 01-04-2006 05:32 AM

[chilly_charly]

On a PDA Acer 50, the vi runs without problem during 2 mins, at 300 ms/loop. After about 2 mins, the duration increases randomly to about 400 ms, to settle batck to 300 after a few iterations. After about 10 mins, the loops duration stays steady at 400 ms, then the display suddenly changes, with only some cluster elements being updated, on a random basis.  30s later, the display freezes. A hard reset is required to recover a normal display.

I tried to identify the issue. When a waveform graph is used, instead of the cluster display, there is no problem, showing that the rotate array function is not the cause. When the cluster is replaced by a slider array, the vi hangs after a while, so the problem is not the array to cluster conversion.

It seems that the problem is directly related to the generation of the parts of the indicators which require some drawing. No problem with strings. This is clearly a bug.

[HDRM]

Hi,

thanks for your response. Indeed the problem seems to be caused by the drawing of the VControls.

The VI attached doesn't use any cluster structure, but it provides the same output: This time, the VControls are refreshed in a while-loop with a case structure (ugly programming!).

Unfortunately, this VI freezes, too. I think it runs a little bit longer before it freezes.

Is there any possibility to fix this problem?

Best regards,

Manuel

[HDRM]

Me again...

I made a new VI with only 1 VControl connected to a "randomize numeric value"-element. It is executed repeatingly in a while loop.

After the loop was executed for about 17500 times, LabVIEW PDA began to run slower (x-y = 600 to 1000 ms) and freezed completely.

I thought that the error might occur from the many VControls in my previous VIs, but refreshing just 1 VControl causes the same error

after executing many times.

Any help would be appreciated! We would like to use the VControls for Visualization purposes.
Manuel

[Travis_M.]

Hello,

Thanks for the feedback on this problem! I'll take a look into this and let you know if we can reproduce it here too.  If I can, I'll report this to R&D and hopefully get back to you with some additional information on how to proceed.

-thanks-

[Travis_M.]

Hello!

I was able to reproduce this on the Pocket PC emulator (after about 5 hours of running), and again on a iPaq PDA after 46000 iterations or so.  The emulator ran about 300ms, the PDA at about 150ms.  I am unsure of what the problem is, but I think the best way to proceed is to avoid using that control, or hopefully find a way that it won’t result in the crash.  I have filed this as a bug to R&D for them to take a look at and I will update this thread as they look into the problem.  Have you been able to find something that you find suitable for your needs that does not result in this?

[HDRM]

Hello,

our application is still under development. We can use either the PDA XY-Graph or the (freezing) VControls for our testing purposes, because our measurements usually don't take too much time (and therefore the VI doesn't freeze). But making the freezing VControls reliable would be best. 🙂

Best regards,

Manuel

[THailey3]

This was reported to R&D (# 3TGAKK3A) for further investigation.

[HDRM]

@ Travis H.

We tried LV PDA 8.2 first beta, and the VControls don't freeze anymore.

Best regards,

Manuel

[THailey3]

As Manuel mentioned...

This was reported to R&D (# 3TGAKK3A) and was fixed in LabVIEW 8.2 PDA. Here is a link to the current evaluation software download for LabVIEW.

Thanks!