XY-graph intersection and numeric controle

[Cornee]

Sorry for the confusing subject. I don't really how to put it.

I am working on an assignment for school.
In an XY-graph I need a horizontal line from a numeric controle and a curved line.

I need the intersection point and a way to insert the horizontal line.

The photo is how it is supposed to be. I do have the white line already, with to array's.

Thanks

[RavensFan]

Attach your VI.

It is hard to help with your code when you don't attach the code.

[Cornee]

you're right. I'm sorry

[altenbach]

XY graphs can display more than one plot, so the horizontal line could be created using a plot containing two points with equal y and suitable x-values. Check the help or examples to see how to graph more than one plot. Alternatively, you could use a cursor.

Finding the intersection is hard in the most general case, because there could be millions of intersections. Can we make certain assumptions, e.g. that the white data is nondescending? Do you have a mathematical model for the white data? Do they contain noise? Are the x-values spaced equally? Is a linear interpolation between the two closest adjacent points sufficient?

[Cornee]

In the graphs there is no dept.

the exponential line is made from 2 array's and is as good as exponential.

And the horizontal line I want to make from a numberic indicator.

[RavensFan]

What does "dept" (abbreviation for (department") mean in this context? 

Numeric indicators don't control anything.  They show results.  You want a numeric control.  Use the value from the control to create a 2 point horizontal ine.