Low pressure calibration for the MPL3115A2

[swhanly]

According to the application note on pressure altimetry using the MPL3115A2 (http://www.nxp.com/files/sensors/doc/app_note/AN4528.pdf?fasp=1&WT_TYPE=Application%20Notes&WT_VENDO... )  "if the measured pressure is out of this range, but within the operational pressure range, the sensor still functions reasonably well, but does not meet all accuracy requirements in the data sheet." 

We use this sensor in our vibration data logger product (Shock & Vibration Data Loggers – Mide Technology ) that US Navy uses for some hypoxia testing on the F/A-18.  They are flying to altitudes well above the 5574m maximum "calibrated range."  Do you have any data on its performance and accuracy in lower pressure environments?  We are hoping there may be some non-linear calibration that we can apply to the output to compensate for any loss of accuracy. 

Any additional information available for higher altitude / lower pressure operation would be greatly appreciated.

Best regards,

Steve

[SanDiegoSeth]

Hi Tomas,

I purchased and am using the Sentient Things Weather Station and Level Adapter as part of the Sentient Things IoT node.  See here:  https://sentientthings.com/products/weather-station-and-level-adapter

I understand that the Sentient Things level Adapter includes the MPL3115A2 to measure altitude and pressure.

Our weather station is now up and running, but I notice that the atmospheric pressure reported by the MPL3115A2 is consistently under-reporting atmospheric pressure by about .75 inches of Hg.  I would like to calibrate the MPL3115A2 so that it properly reports atmospheric pressure.

Our weather station uses Particle Boron to transmit weather data via cellular network.  I programmed the code for the weather station using the Particle web IDE interface.  Is there a way I can calibrate the MPL3115A2 by sending code via the Particle web interface?

Thanks for your help.

Seth

[TomasVaverka]

Hello Steve,

I have asked our device group to comment on this and expect a response later today or tomorrow.

Thank you for your patience.

Best regards,

Tomas

[TomasVaverka]

Hello Steve,

The characterization data are available under NDA only. You will need to contact our local sales office or distributor to sign the required NDA to get the data. I would also recommend to create a standard ticket.

That being said, at lower temperatures and pressures, 20kPa at 0°C, the sensors look to be offset by an additional 300Pa. This test was done on a small sample size and we do not guarantee the performance.

What pressure and temperatures are critical for this application?

Best regards,

Tomas

[swhanly]

Tomas,

These are being used in aircraft that are climbing to 50,000 feet (as low as 11.5 kPa) and below 0C.  It's being used as part of a hypoxia study and the Navy is in need of some more information about the validity of the data they capture at lower-than-expected pressures.

A minor 300Pa variance is not a big deal at all, so that's good news!