Waveform chart update bug with larger datasets

[parsec43]

I have an issue with waveform charts that I cannot seem to solve. It may have something to do with the way they autoscale, although I have been able to reproduce the problem with autoscaling.

I have attached a video of the issue (apologies for not doing a proper screencap. I don't have elevation so it's an arduous process).

When a larger amplitude dataset is removed from the chart array, when it scrolls off the chart, this intermittent flickering in the chart occurs where the data dances around on the left hand side of the chart and rarely draws across the whole pane.

Has anyone encountered this problem before? Know a workaround/solution?

[Bob_Schor]

Seeing "symptoms" without seeing "causes" (i.e. looking at pictures instead of examining code, meaning the VIs themselves) is like the Elephant and the Blind Men.

Is your Chart set to auto-scale?  I'll wager if you turn off autoscaling on both X and Y, your flickering will cease.  But that's just a guess ...

Bob Schor

[parsec43]

I left the code out because it's difficult to capture well in a single screenshot without context. Here's the chart writing part.

Essentially single value waveforms are created inside this queue consumer. The true case for when the chart array size is less than the plot index is to build array. It is odd because it seems to happen only when removing datasets with larger amplitudes from those which are to be plotted.

Turning off autoscaling in both X and Y does not seem to fix the issue.

[Bob_Schor]

Screenshots of code are (almost) completely useless.  Attach the VI, itself, and let us worry about its bloated size -- at least we'll be able to see it.

Bob "No-PNGs" Schor

[parsec43]

The data comes from shared variables (compact rio) and there are a bunch of typedef references used to populate a tree control (which toggles the chart data sending). Unless I write some kind of data generator it won't be easy to reproduce the bug. Do you still want me to upload it?

[natasftw]

If the problem is related to waveform charts and large data sets, the rest of the application is relatively meaningless.  Throw some random data into the waveform chart and let it build up.  You'll either see the behavior or you won't.  It'll take ~5min to create this test and you'll have something easy to work with to experiment and see what's causing the problem.  It wouldn't be difficult to make the RNG operate in the same range as your data.