> Questions...
> - If pressure at port 1 (P1) is equal to that at port 2 (P2), is the  
> output zero?
>   
The datasheet and curves show as much as 0.184 volt offset. After I had 
a board built up, I programmed the 18F1320 PIC to output raw data, then 
used Excel chart curve fitting to generate a formula. For the 3 same 
model sensors I have, the formula gives good zero readings within 0.1 
PSI. I should note,  in 3 years, I have had 2 sensors go bad, and have 
went to MSI sensors at 3 times the cost. The usage is a natural gas well 
with 50 PSI. max, 100 PSI. sensor, next to zero vibration. The zmbient 
pressure port is exposed to a dry location, but some moisture is possible.

> - If P1>P2, I am pretty sure the output is positive ... correct?
> - But what if P2>P1?  With a single supply, I can't see the output  
> going negative, so what is the output?  Stuck at zero?  If so, is  
> there any way to detect the magnitude of the negative pressure  
> differential?
>   
I have to assume the signal level has to e between the "rails" of source 
and ground, so there shouldn't be any negative values. My application 
doesn't go negative so no experience.
> - The start of the datasheet shows the pins 1-6 as Vout, Gnd, Vcc, NC,  
> NC, NC respectively.   But the packaging diagrams show these as Vout,  
> Gnd, Vcc, V1, V2, Vex respectively.  What are those other 3 for?   
> Could V1 and V2 really be independent voltages reflecting pressures at  
> P1 and P2?
>   
I didn't connect the unused pins, just connected the gnd, +5, and signal 
out.
> I don't have any of these here, so I can't test.  Hoping to get a  
> response sooner than having to wait until we can contact Freescale  
> during the week, so any assistance appreciated.
>
> Cheers,
> -Neil.
>
>
>
>   
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist