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waveform chart

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Using LabVIEW 2009:

 

I put a waveform chart on my front panel and found the context help to be empty. The block diagram context help has a connection diagram but not much more. It suggests the example Charts.vi which a directory search could not find. I also looked in labView help but found little. 

 

Could you recommend a location to get some info on charts? In particular is there a way to have the strip chart show new data at mid-screen instead of the right edge?

 

 

thanks, 

 

jvh 

 

 

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Solution
Accepted by jvh75021

The Charts.vi example can be found in C:\Program Files\National Instruments\LabVIEW 2009\examples\general\graphs\charts.llb library. 

 

Some information about waveform charts could be found in this NI article.

 

But I can't provide a solution for the update in the middle of the chart, sorry. Maybe some more advanced members of the forum will help you.

Message Edited by Giedrius.S on 02-09-2010 01:04 AM
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While evaluating my code please have in mind that I am a LV novice. Therefore sometimes my code might violate some coding rules that I have to learn about myself. But how else could I do that... 🙂

Chart zoom with "Mouse Over" effect
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Much obliged!

 

jvh 

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Hi,

 

Getting a chart to start in the middle is actually a bit more complicated than it sounds.  There would be a couple of ways to do it, but all of them involve a bit of hacking. 

 

1- Resize plot area, add a flat box decoration on the right (done in example below).  The plot area will only go to the middle, so it will look like its updating in the middle.   The only downside is that the XScale only goes to the middle of the plot.  We could work to create some sort of dummy indicator so that looks like it went all the way, but it wouldnt' be the whole thing. 

2- Pad the end of your data with 0, nonsense data and have it plot that. A graph would probably work better for this.

3- Do it with an X control- more complicated than regular controls, but believe it would be possible.  

 

Before we dive too deep into this, I was wondering why you would want to do this?

 

Regards, 

Marti C
Applications Engineer
National Instruments
NI Medical
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JVH,

 

This VI has that dummy indicator and looks much better. 


Marti C
Applications Engineer
National Instruments
NI Medical
Message 5 of 11
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Thanks for the posts Marti.

 

The only reason I wanted to do this is visual appeal. The grids are streaming right to left and to me it seems visually appealing to have the new points start in the middle rather than from the right edge. When new data arrives from the right edge I subconsciously think "What's further to the right, am I seeing the whole thing?". On the other hand I guess it seems foolish to waste half a display.

 

BTW, is there a way to make the chart background white instead of black?

 

Thanks again,

 

jvh 

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Sure. Right-click on your chart, select Create -> Property Node -> Plot Area -> Colors -> BG Color and wire a Color Box Constant from Programming -> Graphics and Sound -> Picture Functions pallete to it.
Message Edited by Giedrius.S on 02-09-2010 09:29 PM
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While evaluating my code please have in mind that I am a LV novice. Therefore sometimes my code might violate some coding rules that I have to learn about myself. But how else could I do that... 🙂

Chart zoom with "Mouse Over" effect
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Highlighted
Or just use the paintbrush tool on the front panel.
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To change the background of the flat box you can also use the paintbrush tool so that it matches your graph. 
Marti C
Applications Engineer
National Instruments
NI Medical
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Dennis Knutson wrote:
Or just use the paintbrush tool on the front panel.
 
Do you mean the one in the tools palette? 

 

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