Finding the x value where a y value crosses a threshold in a chart

[bernhardspuida]

When creating a plot of a curve derived from measurements, I need to find the x value for the point where the curve goes above a given value on the y axis (e.g. 50) - or at least the closest x value for the next y value above that crossing . Judging from the LabView documentation, the limit test vis do not give the x value I need. How can i accomplish that? Maybe this can be done using MathScript?

[smercurio_fc]

The Threshold 1D Array function will do that, assuming your data is monotonically increasing.

[Ray.R]

There exists an example for what you would like to do.

Under the Help Menu, do a search for Waveforms (with an s - plural).

You should be able to find an example called "Search Waveform Example.vi".

It looks like the image below:

RayR

Message Edited by JoeLabView on 06-15-2008 01:44 PM

[bernhardspuida]

Thanks!

That indeed was just what I needed. I wasted half a day looking for something like this, but obviously in all the wrong places 😞

Cheers,

Bernhard

[Ray.R]

Two good places to look for info and examples are the Example Finder (Help > Search) and this forum..  🙂

Usually, solutions are easier than people think.  Glad to read it helped.

RayR

[DonRoth]

If you look at this example, it looks to me like it is missing a whole load of crossing indices.

Has anyone take a closer look at this?

I also need a VI that is the equivalent of threshold 1-d array, but works for oscillating data.

Any thoughts?

Don

[DonRoth]

Anyone had a chance to take a look at this example to verify that it is not working properly, and whether it will be corrected?

Don