Hi Dave,

Appreciate the help, still struggling to get PBP to understand my math, :-)

yip, i do,

Code:
;----- NEW LCD Configuration for Testing-------------
DEFINE OSC 20	'20 MHz Osc
DEFINE ADC_BITS 10
yes, the input from the regulator is acutally 3.26v which is just under the sensors "Max", output @ rest should be "Min" = 0.45v Typ = "0.60" and "Max" = 0.75 i assme this is due to the barometric pressure varying.

Range of the sensor is: 0 to 3.92kpa

in excel the maths seems to give me a realistic number based on changing the Vo cell where i would expect the reading from the sensor to be, however the testing has been blowing into the tube so not really very scientific, :-)

Kind Regards
Rob