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Waveform Chart Digital Display Blinks 0.00

Hello, I am using Labview 2016.  I have 8 signals displaying on a waveform chart with the digital displays also showing.  Occasionally, one or more of the digital displays shows 0.00 even though the waveforms never approach 0.  Any idea what the issue could be?  I cannot put my code up here because it is for work.  Thanks.  

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Message 1 of 21
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Hello NiAchilles,

Are there tab controls and front panel updates deferring in your code?

Some time ago I had troubles with a waveform chart placed inside a tab control that received data when FP updates were deferred. Maybe your issue could be similar?

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Hello Cente90, thanks for the reply.  I do have the waveform chart in a tab but I do not know what you mean by deferring front panel updates.  Please clarify, thanks.  

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Message 3 of 21
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There is a property you can set to "freeze" front panel updating until you write it back to false, in order to improve performances; you can use it through a property node connected to the front panel.

You can find more info here.

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Message 4 of 21
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I would also monitor the actual waveforms until you are convinced that these zeroes are LabVIEW artifacts and not real data.

 

Or are you saying that the digital display doesn't match what the chart is showing?

Bill
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(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.
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Message 5 of 21
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Thanks, I am not using that currently.  The values are only updating at 2Hz so I am not terribly concerned with performance.  

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Message 6 of 21
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Just as an experiment, at least, is it possible for you to have a try with the same chart and the same code but placing the chart outside the tab?

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Hi billko, yeah the digital display does not match the chart.  I even log the data to a file and do not see any 0 values in the data.  

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Message 8 of 21
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If it is just the digital display blinking 0.0 but the chart data does not change, I have seen this since version 7 or before.  One thing to do is use indicators instead of the digital displays.

 

https://forums.ni.com/t5/LabVIEW/Waveform-chart-digital-display-blinks-zero/td-p/554868

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Message 9 of 21
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@_Bryan wrote:

If it is just the digital display blinking 0.0 but the chart data does not change, I have seen this since version 7 or before.  One thing to do is use indicators instead of the digital displays.

 

https://forums.ni.com/t5/LabVIEW/Waveform-chart-digital-display-blinks-zero/td-p/554868


I concur.

 

I often have waveform charts on a tab  page so that may be another commonality.

 

I was never able to come up with a example where NI could duplicate the issues. For the customers that did notice the zeros, I told them it was a bug and to ignore until NI fixes.

 

Spoiler
After all in real-world measurements I have never seen a real "0.000". NEVER!

 

 

Ben

Retired Senior Automation Systems Architect with Data Science Automation LabVIEW Champion Knight of NI and Prepper LinkedIn Profile YouTube Channel
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