LPS25HB temperature difference?

[ksw280]

Posted on October 18, 2016 at 09:49

Hi!

The HTS221 sensor and LPS25HB pressure sensor are together in the development board. The temperature difference between the output of the two sensors too high. HTS221 temperature value is close to the actual temperature, LPS25HB outputs 5~10'C lower than that at room temperature environment.

The output temperature of the two devices is a 2's complement form of the same.

I'm not sure about the cause of this difference is.

Please give advice on this matter.

Best regards.

Kwon

#lps25hb

Posted on April 15, 2017 at 22:34

Hello,

I would also like to know, why does LPS25HB measure ca 4 centigrades lower ambient temperature (15-25 centigrades) than other temperature sensors (for example

HTS221 and 

calibrated Sensirion's SHT21 a SHT31).

The formula mentioned in

http://www.st.com/content/ccc/resource/technical/document/technical_note/23/dd/08/f8/ac/cf/47/83/DM00242307.pdf/files/DM00242307.pdf/jcr:content/translations/en.DM00242307.pdf

 uses an offset of 42.5 centigrades. Is it a fixed value, or value that can be set in the device?

I use

http://www.st.com/en/ecosystems/x-nucleo-iks01a1.html

board, so I hope bad PCB design and/or soldering can be ruled out.

Thank you for any advice.

David

[Miroslav BATEK]

Posted on April 18, 2017 at 10:36

The LPS25HB is primarily intended for pressure measurement, so the accuracy of temperature measurement is worse that HTS221 or other calibrated sensors which are intended for temperature measurement. The datasheet says that the temperature accuracy of LPS25HB is +-2°C but is it typical value so there could be parts with worse accuracy, which could be your case.

Posted on April 18, 2017 at 18:24

Thank You for the answer. Given the fact that the sensor characteristics should be linear, I will use a different offset in firmware and hope for more accurate results.