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Thread: Software temp. compensation of pressuire sensors
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face BY : mikeEraseME@spamwhitewing.co.uk



I'm after any info or apnotes anyone may know of that discuss software
techniques for temperature-compensating silicon pressure sensors
accurately.
Basically what I want to do is use low-cost sensors (<US$30 in low
volume), a high-resolution A/D converter, and do all temperature
compensation, linearisation, and offset/span compensation in software.

All the apnotes I've seen from sensor manufacturers only show hardware
solutions to temp compensation, usually limited to about 1% FS
accuracy or less due to hardware constraints.

I want to to temp compensation by measuring the bridge resistance to
get the temperature, and use this to compensate the pressure reading,
ideally to 0.1% of full scale over a temp range of 10-30 deg.C

Is there any chance that sensors will have a fixed (from sensor to
sensor) relationship between the TC of the bridge resistance, and the
TC of offset & span, so we don't have to calibrate over temperature ?
Would be nice but I suspect the answer is no, especially if we want
0.1% accuracy!

Is the offset & span TC, and the TCR of overall bridge resistance
generally linear ? This would allow compenstion and linearisation by
an automatic cal jig that calibrated at only 2 temperatures, but
multiple pressures (for linearisation).

Any comments etc. welcome.  
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