According to Roland Andrag:
>
> I beg to differ here - although the differential (guage) models like
> the MPX5100D support a differential pressure of 100 kPa, the absolute
> pressure sensors (MPX5100A) use an internal reference that sits at
> about 15 kPa.  The absolute range measurable with the MPX5100A is
> thus also 15 - 115 kPa.
>
> I am in the process of building an altimeter using a PIC and the
> MPX5100A sensor, which is very well suited due to the fact that it is
> fully temperature compensated. Is there any reason for using an
> external A/D converter instead of using something like the PIC16C71
> which has a four channel 8-bit A/D built in (besides the '84 EEPROM
> vs '71 EPROM)??
>
> Cheers
>     Roland
>

I also have an altimiter in the pipeline.  I chose to go with an external
12bit A/D converter.  The quantiums of the 8 bit were > 40 feet (if i remember
correctly).  I wanted something with less than 2' quantiums.  Other than that
the issue might be size.  The 84 + small serial A/D is less realestate than
the 71

--
Les Troyer
Sr. Analyst
Siemens Power Corp
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