automatically find a value

[meganme]

Dear all, 

First post here, so please forgive me if I'm posting in the wrong place, and if so, please point me to where I should be. 

I have a series of very basic questions, but the burning question, at the moment is this: Is there a way to automatically locate a point on a waveform graph?

So, I'm studying a vertical ground reaction force-time curve and want to find the point at which the subject leaves the ground, say when a value below 10 N is recorded, and when they land again, say when a value above 10 N is then recorded. I'm using an active cursor to identify some key points (other questions on these later I'm afraid) and wonder if I could use this as some sort of 'onset' from which the search begins?

Any help will be greatly appreciated.

Jason

[crossrulz]

Care to share what you have tried?  Showing some code is encouraged also since it helps us understand the situation.

Sounds like you should just use a for loop and look for a threshold on the data to find your data point.

[meganme]

Hi crossrulz,

I'm afraid I haven't tried anything yet, as I'm really struggling to understand how this might work. I'm guessing that it's something relatively simple, but because I haven't come across whatever it might be before I probably wouldn't realise I'd found what I was looking for even if I had found it. 

I've attached the VI and a text file of data. If you want to run it you'll need to select channel '3' as the Fz channel, and delete 11 rows. The sample time is 500.

Many thanks,

Jason

[nyc_(is_out_of_here)]

You can't expect to come to this forum everytime you have a LabVIEW program to write.

It is time you learn how to program in LabVIEW.  http://www.ni.com/white-paper/5241/en

Sooner or later you are going to have to put in the time and the effort. Might as well do it now.

[meganme]

Hi nyc,

Many thanks for taking the time to respond. I am trying to learn, but I'm finding it very difficult... to the point where I'm struggling to see where to start on any 'next step'.

Jason

[nyc_(is_out_of_here)]

Sounds like you have never done *any* programming before.

If that is the case, I am not sure where one would go from there except to learn how to program.

[meganme]

So what you are saying is that you need to know how to program (in general or just in LV) to be able to achieve past basic tasks? 

The rep didn't tell us that when he sold it to us.

[P@Anand]

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@meganme wrote:

Hi nyc,

Many thanks for taking the time to respond. I am trying to learn, but I'm finding it very difficult... to the point where I'm struggling to see where to start on any 'next step'.

Jason

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The same case I had before I start with LabVIEW you need a right point to kick start once you have started then learning is very easy. Try to program very simple things ( I started with a program to find the resistance value depending on the color code). Simply going through the Manual won't help you much take a concept and start and use the manual as reference.

Good luck.

[meganme]

Thanks. I suppose what I'm trying to avoid is to embarkn on a task to learn only to find that it has little relevance... time is precious.

[nyc_(is_out_of_here)]

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@meganme wrote:

Thanks. I suppose what I'm trying to avoid is to embarkn on a task to learn only to find that it has little relevance... time is precious.

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I don't understand this statement.

You are using LabVIEW so taking time to learn it is of little relevance? In that case, what is of "relevance"?