So, I was doing a bit of calibration using a modified version of the example curve fit VI found on help. So far so good, but when calibrating a load cell, I found it that after inputing the values, I was getting wildly different results on the equation than what I was supposed to be reading and, after digging around a bit more, what remains constant is the fact that the conversion gives me opposite sign result when done with primitive funcions (add, multiply nodes) than when done with a formula express VI, which DOES give me the correct value. Anyone know why this happens? The equation is a standard A + B*X + C*X^2 + D*X^3
Attached you will find a very simple layout with my 3 candidates; open "Wrap" for the main example VI, and input a value from -1 to 1 in the 4th square (index 3, zero indexed) of the array, which is the usual range I'll be working on and for the results the 3 VIs are as follows: one that uses barebones primitives (cumulative multiplication instead of power functions), one that uses more "advanced" primitives like x power y, and one made with formula express VI (didn't know how to input x^y so used x*x*x instead). Why am I getting incorrect results in the primitives? What am I missing?
