My colleagues and I are evaluating the LPS25HB and came across some behavior we don't understand. There are two issues we are trying to resolve right now:
- Embedded temperature compensation behavior is confusing.
- Accuracy isn't what it should be.
- In one of our datalogs (pressureLog_25Hz.xlsx) we see absolute pressure tracking with temperature. We expected temperature to change, but not absolute pressure. Absolute pressure is changing at a rate of about 3 hPa/C. Shouldn't the embedded temperature compensation deal with this?
- In a test we did in a car (car pressure log.xlsx), we saw temperature drop and then increase, but the pressure is almost constant if you draw a trend line through the data. It seems like embedded temperature compensation is doing something this time.
- We need help determining why is the sensor acting differently.
- The datasheet for the part claims an absolute accuracy of +/-0.2 hPa between 20 and 60 C. So far, the data we have taken from the sensor does not meet the spec. For example,
- I a recent test, our local weather stations reported a sea level pressure of 1016.2 mbar.
- The LPS25HB evaluation kit is told us the absolute pressure was 1026.5 mbar.
- We are about 160 above sea level, which equates to a pressure difference of -6 mbar, so the LPS25HB should have reported about 1010 mbar. It was off by 16.5 mbar!