Chart Autoscale not Working Reliably? Bug?

[jvon20]

Software:

G Web Development 2022, Full Edition, Build number 9.3.0.49613

(And according to NI Package Manager, there are no updates to G Web)

What I am trying to do:

Plot 12 traces simultaneously on the same chart and update the values each loop cycle. This shows the history of each trace through time on one chart.

The issue:

The autoscale setting on the chart indicator does not reliably work.

The attached G Web project has 4 charts - all identical except for their autoscale settings, which are each one of the four options: Fit Exactly, Fit Loosely, Grow Only, and None.  The default values of the 12-member input array are all 25 except the 2nd and 3rd elements, which are 0. If I run the gviweb project (in either browser or IDE), then none of the charts show any traces greater than 10. If I make either of the 2nd or 3rd input array element values any value slightly ABOVE 0 (below 0 does not seem to make autoscale work), then suddenly the Fit Exactly and Grow Only charts correctly autoscale as I would expect and show the traces valued at 25.

Is anyone else able to reproduce this weird behavior?

Am I doing something wrong or is this a G Web bug?

[DerrickB]

You're creating 12 plots in each graph with only 1 data point in each plot. Since there are no line segments to draw to connect a 2nd (or more) data points then there's no drawing / updating being done.

On top of that you're starting your indexing at 1 instead of 0, array indexing starts at 0 for the first element. When you do want all items starting from the first you don't need to specify any indices at all.

You probably just want to be wiring the array directly into the 4 charts.

[jvon20]

Thank you for looking into this!

Re: no drawing/updating -

It IS drawing/updating. The issue is that the Y-axis of the plots are not auto-scaling properly when the data values for indices 0 and 1 are both equal to 0. Changing either of these values to be other than 0 results in the graphs autoscaling properly. I am pretty sure this behavior is due to a bug in G Web itself.

Re: index start point - 

I changed the array logic to be 0-based instead of 1-based.  The same behavior persists.  See attached.

Re: wiring the array directly to the charts -

This is not what I want because wiring the array directly to the chart results in the values being plotted sequentially through time instead of in parallel. Perhaps wiring directly would work in LabVIEW, but it does not achieve what I want in G Web. 

To be crystal clear, the plots work as intended at startup as long as the input array values in indices 0 and 1 are not 0. 

Thank you

[DerrickB]

You're still only putting 1 point in per plot, is that what you actually want to be doing or do you want all the points in all the graphs?

[jvon20]

All the points are in all the graphs. Please see the attached images for what I see when I run the gviweb:

• When I first run the gviweb file in G Web, the autoscale feature does not work because the input array has 0 values in its first 2 indices. The plots are there but they appear off the chart. I know they are there because the traces jump up to ~25 for the non-zero input array members when I click run.
• Autoscale starts working as expected when I change either of the first two input array members to be greater than 0.

Thank you for looking at this.

[DerrickB]

Sorry, for some reason my eyes completely missed this running in a loop and adding the same values over and over to the charts. I'll work on reproducing and see whats up.

[DerrickB]

I've reproduced and am submitting the bug to the developers.

[DerrickB]

Bug # 2091629 if you care to watch for future release notes to see when it gets fixed. If there's activity on it in the near future I'll post an update here. Thanks for reporting the issue.

[jvon20]

How does one submit a bug report?

[DerrickB]

You can go to ni.com/support and support a ticket that's flagged as a bug but I already created a bug for this issue for you.