Waveform chart LabVIEW 2009

[MayanBlood]

I have this problem with the waveform chart in LabVIEW 2009, The Graph will not be displayes on the chart after a few iterations. This is a bug that appeared in LabVIEW 2009. The same program worked fine with LV 8.6. Does anyone know a workaround for this problem? I am currently using Version 9.0f2

See attached block diagram

[stevem181 · Accepted solution]

That is strange ...

I verified that saving this back to 8.6 does indeed work.

If you replace the Merge signals function with a Bundle function things seem to function properly.

There is also something odd going on with the property node. If you start with a pnode for active plot and then drag it down to add another element, then change that new element to plot color, you get an error on the property node.

"Interesting" stuff.

steve

[RavensFan]

What error do you see with this property node?

You aren't talking about the red error output are you?  That indicates that the property node is set to ignore errors inside the node and is something you must have set within the right click menu.

[stevem181]

You are right of course Ravensfan, I was in a hurry because dinner was ready 🙂 and I was seeing an error on the output when I ran the vi which was possibly caused by something else (like maybe not setting an input - not sure now).

However, I did not right click to select "Ignore errors inside node". Just the act of changing the 2nd element to Plot.Color caused "Ignore errors inside node" to be set.

This is not expected behavior is it?

Steps to recreate:

1) Put a chart on the block diagram

2) Create a property node for active plot

3) Drag down to get another element

4) Select Plot Color - bingo the setting changes

steve

[RavensFan]

No, that is not the expected behavior.  I tried the steps you listed, and for me it does not automatically change that error output.  I have no idea why it would automatically change it for you.

In running the OP's code, I did see an error 1055 happen for an unreferenced object.  That was due to the fact that with VI snippets, things like property nodes that are implicitly linked to an object get recreated in a way where a reference control is created and feeds into the property node.  That raised an invalid object reference because the Waveform chart reference control is no longer actually connected to the waveform chart.  The empty reference causes an error.  So you need to delete reference control, then relink the property node to the waveform chart.

Once I did that, (and fixed the property nodes so they were all in one block instead of 4 space hogging blocks), I was able to the run the VI.  I did notice odd things happening with the chart.

1. Almost immediately, there were redraw issues with plot 0.  It would show 1 data point, then nothing after that.  If I stopped and restarted the VI, the missing data points for plot 0 from the previous run would suddenly appear, but then not show any for the current run of the VI.

2.  After about 100 iterations, plot 1 stopped moving across the control like it should and just seemed to only show the last two data points at the right hand side of the chart.

Overall, there seem to be bugs.  There seem to have been several bugs related to the waveform chart in LV 2009.  Whether this is one of them, related to one of them, or a new, completely undiscovered bug, I don't know.  Here is a cleaned up version saved as an actual VI (instead of a snippet), for others to try and confirm in LV 2009.

[stevem181]

2009 0f2

I get the same (incorrect) functionality with Ravens Fan's Chartbug.vi

To reiterate, a workaround is to use a Bundle function (from the Cluster palette) rather than the Merge Signals function.

I put a probe on the Dynamic Data wire to try and see if the data going into the chart was correct, but there does not seem to be any useful info in the probe display. There is a data tab where nothing changes and a Graph tab that just jumps around without plotting anything. So its hard to say whether the Merge Signals function is generating bad data or the chart is not plotting correctly.

steve

P.S. The odd property node issue I see on my PC is not related to the original problem so I don't want to dilute this thread with that discussion. Of note, it is also exhibited in 8.5 and 8.6 (on my machine). I'll try some other PCs and start a new thread if necessary.

[Davidek]

Hi

I get the same behavior after recreating the VI from scratch. Another workaround is to convert from Dynamic Data to an array before the Waveform Chart.

Did a quick search in the CAR database and I found some cases that are similar to this. I think I'll add this to one of them. Thanks for bringing it to our attention.

Best Regards

David

NISW

[Ben]

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Davidek wrote:

Hi

I get the same behavior after recreating the VI from scratch. Another workaround is to convert from Dynamic Data to an array before the Waveform Chart.

Did a quick search in the CAR database and I found some cases that are similar to this. I think I'll add this to one of them. Thanks for bringing it to our attention.

Best Regards

David

NISW

---

Which CAR # ?

Now that we have attention on these chart issues I'd like to get them fixed before the responsible developers get assigend to another project.

Ben

[Davidek]

Hi Ben

After a closer look at the CARs I found I felt it was better to file a new one. I created CAR #194437 for this.

Best regards

David

[MayanBlood]

Thank you all for the suggestions, both Steve's and David's solutions worked, I did liked Steve's solution better.

Thank you All!!!