Poly Sensor Linearization

[peter paul fenske]

>>> Subject: Sensor Linearization
>>there to do that and should be simple 2-3 term polynomial since curve
>>is simple. with a math function, you do not need any lookup table and no
>>loss of resolution.
>>
>>	frank parker> > 
>>
Hi Frank:
Well you got me to thinking. I now remember reading a paper on
Ford with their EEC linearizing their MAF sensor. I believe this
used an adaptive table with some type of poly fit. Only ford!
This leads to an interesting algorithm:
Get the CTC sensor info from the AD in a range of 0 255. Shift right
four times to get an intermediate lookup of 16 values. Use this to
access a table with the linearizing poly multipliers. Then mult the
sensor AD value by the multiplier. You then shift the D accum right
four times. What the end result is a linearizing function of 16 steps.
Not perfect but pretty close. I will have to check this code but
I believe it is faster than interpolation with about the same
accuracy.
Tnx Frank
GL: peter