For less than four temperature gaps the last temperature point should be set to 1023. This means
that the last gap extends out to the end of the temperature range.
4.4) Signal linearization
The signal linearization is only available when the device is in digital mode. This means that the
entire calibration procedure should be done in digital mode. A calibration in analog mode may
not yield a valid calibration in digital mode.
It is the best to first do the baseline calibration then linearize the sensor signal and then then
temperature compensation. The baseline offset calibration must be perform in that way that the
digitized signal has the value 0 or 1 LSB ( be careful with clamping at 0 value).
The total number of linearization gaps plus the temperature gaps cannot be more than five. This
is because the temperature coefficients and the linearization coefficients share the same memory
locations.
1) Set all of the PC values to 1024. This corresponds to a real value of +1.000. Also, set P2 thru
P5 to a value of 1023. (P1 = 0)
2) With no signal (zero pressure) find the correct value of P1 to have the correct voltage on the
output.
3) Raise the signal to the signal point (pressure point) P2. This is an arbitrary value (can be
based on where the output varies from the desired output by a set amount). Adjust the output to
the desired level by adjusting PC1.
4) Set P2 by copying the pressure value by copying the digitized pressure value to the P2
location. This must happen after step 3.
5) Repeat steps 3 and 4 for P3, P4, and P5 setting PC2, PC3, and PC4.
6) Raise the pressure to its maximum and set PC5
If fewer than 5 pressure gaps are used the last P value (highest) should be set to 1023.
MLX90308CCC & MLX90314AB Software Users Manual
Rev 2.0
21
11/28/01