automatically find a value

[meganme]

I don't think I said that I wanted to use LabVIEW for my teaching actually, however that's besides the point. 

I also think that you've misunderstood me with regards to my 'time' comment. I was merely saying that giving current working commitments (that include undergraduate and postgraduate teaching) I need to be chosey when making new time committments. 

@crossrulzs.... many thanks for the link.

[NIquist]

The question at hand of searching a waveform for particular values sounds like a reasonably good place to start learning to me.  It's true we like to help people that help themselves (just like... well, GOD ) but unless it's obviously homework we can certainly help you through this task as a way to help learn basic LabVIEW.  

Do you actually have a waveform to analyze?  How did you collect the data?  What form is it in now (Spreadsheet, DAQ waveform, cocktail napkin)???

The key here is that waveform data is really just some timing information (start time [t0] and time between points[dt]), plus a big ARRAY of numbers.  You can pull the array out of the waveform and use the array tools like (search 1D array) to anaylize the points.  OR, you can make it even easier and use the waveform VIs.  There is one called... Search Waveform

If you understand all that then you're more than ready to code a VI that will do your analysis for you.  Post your data and take a look at some examples Help > Find Examples...

Of course take the suggestions to go through the LabVIEW tutorials as well.  You can come up to speed pretty fast by reading them, looking at the examples and just practicing and playing around.

[nyc_(is_out_of_here)]

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@meganme wrote:

I don't think I said that I wanted to use LabVIEW for my teaching actually, however that's besides the point. 

---

I misinterpreted your statement - My job revolves around lecturing and undergraduate and postgraduate student project supervision, with research on top of this. I've been using LabVIEW as a more time effcient tool to process research data.

LabVIEW is an acutal programming language much as NI tries to present it as something anyone can use.

How much time you want to devote to learning how to use it is up to you.

Maybe you'd rather learn Matlab. I don't know Matlab, but I have been told it is great for processing of data.

Or learn R the statistical processing language. No personal experience with this either.

[meganme]

Hi NIquist,

Many thanks for your response. I attached a vi and sample set of data in my first (maybe second post-on page one of this thread). Essentially I recorded ground reaction forces from a force platform. I'm interested in studying the vertical component of this and have created the (attached) vi to do so. I've built similar vi's that have allowed me to identify the weight of the subject (by calculating the mean of the period of 'quiet standing), subtract this from the vertical force to obtain 'net' force, divide this by the weight divided by the gravitational constant (mass) to get acceleration, and then integrate this twice to obtain first velocity then displacement of the centre of mass. Phases of interest (like 'quiet standing') have been identified using active cursors. I thought that a reasonably logical next step might be to see if I could make this even more efficient by automatically identifying points on the array to take values from or begin further analysis from.

I will look into your suggestions.

Thanks again,

Jason 

[meganme]

Hi nyc

The university bought LabVIEW a few years ago, so I'd like to make the most of this.

Hard to give defitive amounts of time, but I'm certainly willing to put effort into learning, just can't focus solely on it.

Jason

[GregFreeman]

This response from me in another thread will not help you solve the problem at hand, but may be of some releavance to you. I was once in your shoes.

[meganme]

That's great... thank you.

Jason

[NIquist]

Ah, sorry but I completely missed your code and spreadsheet attachments.  So, you're not really a total beginner here.  Your block diagram is rather large and a bit messy but I've seen a LOT worse.  There is definitely a few places that could use some sub VIs.  Mainly to make it easier to read and understand but also to start you on the right track towards code re-use and self documentation.  I'll take a closer look and see what I can come up with to help out...

[NIquist]

Edit > Clean Up Diagram

The LabVIEW automatic block diagram clean-up function works pretty well on your diagram.  I suggest you use it and continue coding from there.  You'll find yourself working more efficiently when you don't have to deal with wires going backwards and hiding under icons where it makes it difficult to follow the logical flow (one of the strengths of a graphical language).  Just a suggestion.

[meganme]

Ha... I knew it was there but rarely used it... it does make for quite a tidier block diagram, doesn't it?!?!?!

And yes, sub VIs would not only tidy things up now, but I'm guessing make repeat processes in later VIs easier to implement.

Thanks

Jason