lab view waveform chart

[dragic010]

Hi,

i need help with some zoom options on wavefrom chart. Need to zoom wavefrom chart which buffer size iz 10000 on half of measurements when i press button to do that. I post VI with button to zoom all measurements and button to zoom measurements in the last 10 seconds. Can anyone help me with this i need one more in form like this two just to zoom half of the measurements. And where is ambient sensor?

Untitled 1 is for LabVIEW 9.0

help 14 is for LabVIEW 14.0

Sorry for bad english.

Thank you!

[Artem.SPb · Accepted solution]

you can use History property and get half of array length.

[Bob_Schor]

What do you really want to do?  Are you really interested in holding (and looking at) 10,000 points?  Might you be instead interested in the last 10, 100, or 1000 seconds of data, all plotted on the same Graph and all "scrolling" as through they were a Chart?

I stumbled upon an interesting Blog post (http://culverson.com/tips-and-tricks/) and implemented it.  It really works remarkably well.  If your plot shows 100 points (10 seconds at 10 Hz) and you are simply changing the Time Base, this scheme only requires 3 * 100 points for storage (if you want to show more points, say, 500, then it's 3*500, still very managable).  Changing from a scrolling Graph showing the last 10 seconds to one showing the last 1000 seconds is basically instantaneous.

Bob Schor  

[dragic010]

Thank you very much for replay,

i will try to do like you explain.

Thank you!

[dragic010]

Thank you very much for reply,

i need all measurement data to be zoomed on half. It's not about points, my max points are 10000, and i need to show constantly half of measurement data in that time when i press button. For exemple, in this moment my measurement data are on 1000 points, i need to show 500, if my measurement data are on 2000 points, i need to show 1000, etc. 

[Bob_Schor]

---

@dragic010 wrote:

Thank you very much for reply,

i need all measurement data to be zoomed on half. It's not about points, my max points are 10000, and i need to show constantly half of measurement data in that time when i press button. For exemple, in this moment my measurement data are on 1000 points, i need to show 500, if my measurement data are on 2000 points, i need to show 1000, etc. 

---

Why?  Is there a "requirement" that all of the points are to be kept in memory?  Actually, if they are, then the problem becomes almost trivial ...

Bob Schor

[dragic010]

Yes they are kept in memory, look in VI i attached on the begining you will understand what i need. Like those buttons zoom measurement data on the last 10 sec,and on all data, simple i need like that to zoom half of measurement data.

Thank you

[Bob_Schor · Accepted solution]

Did you look at Artem's response (I think it has a bug, but he shows you the key step)?  Did you look at your own "last 10 second" method and ask "how can I change this from" ...

Oh, I know what your problem might be.  You know how to specify the maximum/minimum in terms of time, but you need to express this as points (namely, half of them).  Ask yourself (really, you should figure this out without one of us telling you) "How do I convert from "number of points I want to plot" to "the time duration over which I am plotting"?  Hint -- see if there is a Timing function in your VI.

Bob Schor