How to calculate slope of XY curve?

[Nicky87]

Hi all,

I want to calculate the slope of a X-Y curve, for example, amplitude v.s. position. I was trying to use the derivative method but failed. Could anyone help me with this problem? The example vi. is attached.

Regards,

Nicky.

[aeastet · Accepted solution]

Like this

[paulmw]

Dang it, too slow...

Try the Linear Fit VI

[tbob]

Although it involves a Rube method as compared to Linear Fit, the attached vi teaches what a slope really is.

[shubhi]

Can you post the same solved example with labview 8.2?

[aeastet]

Here is an 8.0 version.

[shubhi]

Hey

Attached is the Vi.

Could you please help me if I want to find the slope and I want to stop the loop and measurement when the maximum slope has been attained.

Help will be very much appreciated.

[crossrulz]

How are you defining "maximum slope".  Is it a simple threadhold (stop when slope >= a set value) or are you looking for the inflection point (calculating on the fly the maximum slope and stopping when it is reached)?  The threshold is a simple comparison.

[shubhi]

No it is infection point, as in after getting the measurement value , finding the slope and stopping when the slope is highest as in it has maximum deviation from the previous value.

[P@Anand]

You should be having a Max limit value so that you can compare on the fly and stop if the max slope is achieved. Check the attached example and also keep it in a single thread

Good luck