Can I fit an equation to points entered on a front panel graph?

[Peter C]

I'm trying to create a VI to control a syringe pump using Labview 7.0. I was hoping to be able to input points on a front panel graph (using the curser), have labview fit the points to a curve and control the syringe pump to achieve the desired pH profile. Is it possible to use the curser to input data points from the front panel?

[Jonnie_5]

Yes, one way you can do this is using various property nodes.

Attached is a LV 6.1 Example (fine for LV 7, of course).

It's also a fun way to draw in labview 🙂

[Greg_McKaskle2]

> I'm trying to create a VI to control a syringe pump using Labview 7.0.
> I was hoping to be able to input points on a front panel graph (using
> the curser), have labview fit the points to a curve and control the
> syringe pump to achieve the desired pH profile. Is it possible to use
> the curser to input data points from the front panel?

There used to be an example that shipped with LV, but it seems like it
is now available on the web site at
http://sine.ni.com/apps/we/niepd_web_display.DISPLAY_EPD4?p_guid=B45EACE3E0F156A4E034080020E74861&p_node=DZ52038&p_submitted=N&p_rank=&p_answer=&p_source=External

I didn't look at this one, but typically, they read the cursor position
based on either event or time and enter that into the array passed back
i
nto the graph.

You can style the cursor to hide crosshairs, make a different point
style, etc. You can either have the user draw and collect many points
into the array, or you could have a button to add cursors and let the
user place N cursors along the curve as control points.

It might also be worth searching around for other people's editors as
with a little time, they can be quite specialized and quite nice.

Greg McKaskle

[Jonnie_5]

At least in LV 6.1, there's also a shipped example called Draw Graph.vi (search for 'graph' under Help->Find Examples)... but it seemed kinda non-intuitive and clunky.
~j5