look up table implementation

[leongchuan]

hello
I am implementing a simulation model of a solar sensor that use a look-up table to simulate the results.
the look-up table is supposed to provide the sensor voltage level at different angles to a light source.i have used 2 look-up-tables, each with 500 entries.
however my simulation system is a bit laggy and i wonder if there is any alternative besides a look-up table?
if i want to do in a mathematical way, how can i identify the maths equation to use to provide the sensor level output with a solar angle input?i have made a plot of the input-output graph and i think it is quite impossible to derive a maths equation myself.is there any vi in labview that can do this?

[NeilR]

Hi

It sounds like you need to look at the LabVIEW's Curve Fitting VIs although these are NOT available in the Base Development package.
In the LabVIEW help index go to "Curve Fitting VIs" this will give you links to various VIs and also a link to "LabVIEW Analysis Concepts" which gives you more information (see Chapter 9).

Good luck
Neil

[altenbach]

Two lookup tables with 500 entries are peanuts for labview. This will not be the bottleneck. I would guess that your "lagging" (whatever you mean by that) is caused by something else in your program design. Make sure there is a short wait statement in your main loop, else the user interface might get starved for attention.

Please post some of your code.

In any case, your function is probably quite simple, shouldn't it go nearly with the cosine? You could probably decimate it to 20-50 points and use a spline between them. The simple lookup table is probably faster and easier though.