NXP5100AP

[karloss]

Hello,

I'm using NXP5100AP sensor for measurement barometric pressure. And have some trouble with precision.

In documentation is maximum error 2.5%. And in transfer function is error defined as ± (Pressure Error x Temp. Mult. x 0.009 x VS).

Means this that 2.5% error is manufacturing calibration error? And error in transfer function is measurement error?

Question is if the 2.5% error is stable and if I can calibrate this error in MCU?

Thank you

[karloss]

Thank you for information. I will to try MCU calibration. I think that Auto-zero is not usable in this case because I measuring atmospheric pressure....

The second option is use some sensor with better precision MPX4115AP looks better but is not easy available in CZ....

Karel

[JozefKozon]

 Hello Karloss,

you can do the Auto-Zero calibration for the MPX5100AP. It has its own internal reference. The quote "(atmospheric pressure is a zero reference for a gauge measurement)" is meant, that the MPX5100GP or GC6U or GC7U has not internal reference, but the atmospheric pressure should be taken as a reference.

Yes for the moment, there is a shortage of pressure sensors due to significant unforecasted Covid19 medical demand for respirators/ventilators.

With Best Regards,

Jozef

[JozefKozon]

Hello Karloss,

your conclusion is correct. The MPX5100GP is factory calibrated and temperature compensated, after this calibration, it is normal to have variation on the output for the pressure sensors, according to the datasheet should be ~+/-2.5%.

You can do the calibration with your MCU. It is even recommended to implement Auto-zero calibration in our pressure sensors, this is a compensation technique based on sampling the offset of the sensor at reference pressure (atmospheric pressure is a zero reference for a gauge measurement) in order to correct the sensor output for long term offset drift or variation.
Please take a look at the Application Note AN1636 on the following link for the instructions for implement this technique.
AN1636: https://www.nxp.com/docs/en/application-note/AN1636.pdf

Please note, that the device is ratiometric, which means, that the output varies with the change in supply voltage. Therefore a stable 5V supply voltage is recommended and use one 1.0uF and one 0.01uF decoupling capacitors placed close to Vs pin of the pressure sensor, and a 470pF capacitor close to the Vout pin as an output filter capacitor.

With Best Regards,

Jozef