I have following data in the link.

http://www.8052.com/users/Nagarajan/CURVEFIT.xls

The data is for Magneto Force Restoration Technology based weighing scale. It is having non-linearity as shown in the Graph and is reproducable. I want to corerct the error in software. I can not do a software LUT since the data can vary from 0 to 1200000. I would like to find a function to best fit the curve.

First i accept that i am new to these Curve fitting and polynomials and done lot of search on net and here. But still i am not able to understand this.

I have tried using Matlab command polyfit() and 2nd order. But the curve is not fitting properly.

one thing i noticed is the x axis value, if i change to actual weight instead of counts, then Matlab polyfit() gives me a best curve fit. but i need before the weight calculation to remove the non linearity error.

I even tried the excel function Logest() but without success.

I would like to have some help to proceed in the right direction.


Thanks.

V.Nagarajan.