Waveform chart on hidden VI becomes resource intensive

[malocascio]

Is anyone aware of different memory management for VIs in the "hidden" (vs. the "standard") front panel state? I have a subVI that has a waveform chart on it. It acquires data and plots it in the waveform chart. There's a lot of data there, the chart history is 1024 waveforms and each one is 1/4 second of data at 125kHz. When the VI's front panel is in Standard, it's fine. When I change it to Hidden, it becomes very CPU and memory intensive, enough to bog down the entire application until it crashes. If I remove the chart, it runs fine when hidden.

This is in LV2013 SP1. I've had trouble getting the same result in a stripped-down VI using the waveform generator VIs. If I can, I'll post one.

Thanks,

[mikeporter]

If you are having trouble duplicating the problem in a stripped down example it sounds like the issue may be an interaction between the chart and something else in the code.

What version of LV?

Do you have the same issue when the VI with the chart is built into an executable?

Also, what happens if instead of being hidden, the VI is launched dynamically and the front panel simply isn't opened?

Mike...

[malocascio]

Hi Mike,

The chart's terminal is the only interaction. There are no local variables, no implicit or explicit property nodes, no references of any kind. The terminal just keeps getting fed more data in every iteration of the loop. Unless it's doing something really weird, I don't know that there are any other interactions.

This same problem occurs in both the development environment and a compiled executable.

This is LabVIEW 2013, SP1.

I haven't had time to set up a dynamic launch situation or a test VI that behaves the same way, but even just putting the terminal in a diagram disable structure makes the problem go away.

Thanks for the suggestions. Let me know if you can think of anything else.

[mikerophone]

Do you have any front panel objects that are overlapping?  Although it wouldn't account for the delay all by itself, it would be one thing to check since this situation can cause a significant drop in performance.

[malocascio]

Hi Michael,

Nothing overlaps, but the chart IS on one page of a tab control, if that counts.

Thanks

[mikeporter]

Your graph is on a tab control?!? I will bet you dollars to donuts that is your problem.

Most of the time you shouldn't use tab controls at all, and never use them with charts and graphs.

LV has a long, long history (going back to at least 2004-2005 time period) of tabs causing all sorts of problems -- and especially with charts and graphs.

Mike...