Saturation problem with Polynomial in MAX

[wholland]

I seem to be having a problem with my poly in MAX.  My input signal is a from a 0-5v source and when I try to apply my polynomial fit to convert my pre-scaled unit to my scaled unit it maxes out at the half way point.  I created a scale to read in volts on a 0-5 scale (i.e. 1 to 1 scale) and it seems to repond correctly but as soon as I change it back to poly, it maxes out at 1.8volts.  One thing I notice is when I have MAX generate the reverse poly it changes the Min and Max range.  For example, I generate the reverse for a Min=0 and a Max=5 and I get a horrible test result.  When I go back a check the reverse poly, it chaned the Min to -34.7027 and the Max=10.    Is there something I'm missing? 

MAX version:  3.1.1.3003

LabView Version: 7.1

[Justin_M]

Hello wholland,

What are you setting for the Min and Max range?  Make sure that you are setting the range of your signal after the custom polynomial scale is applied.  For example, if you knew that your original signal was between 0-5 V and you applied a scale that multiplied all values by 2, your new range would be 0-10 [custom units].  In this case, you would set the Min to 0 and the Max to 10, even though your highest voltage is 5V.  The Min and Max correspond to the custom units, not the original voltage.

Thanks,

Justin M.

National Instruments