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3.2.2 Pressure Sensor Temperature
Starting in the May 2011 timeframe, coefficients for converting 16-bit Pressure Sensor Temperature
values to °C have been appended to the EEPROM contents of new IPT transducers. This supplemental
information allows users, if desired, to separately monitor the temperature of the pressure sensor. The
algorithm is a simple 3
rd
order polynomial as described below:
3.2.2.1 Algorithm
Y = g1 + (g2 × t) + (g3 × t
2
) + (g4 × t
3
)
Output:
Y
= pressure sensor temperature in °C
Inputs:
t
= 16-bit temperature channel ADC value, normalized 0
– 1:
Normalized temperature channel ADC value = temperature channel ADC value / 65,535
Coefficients (g1, g2, g3 and g4) for the identified algorithm are stored in the IPT EEPROM.
3.2.2.1.1 Horner’s Method
Horner’s method is a suggested microcontroller-friendly alternative for evaluating the above equation:
Y = g1 + t(g2 + t(g3 + t(g4)))
(3 multiplies, 3 additions)