MPX5100 Fluctation in readings from temperature changes

[kevinroach]

I am using a MPX5100 to read back pressure or resistive flow from a needle valve. I am using two micros air pumps to feed the air for pressure and it reads great and steady at room temperature, but when it is colder or less humid air it seem to fluctuate. I am using a 1uf capacitor and a couple of resistors for a filter circuit which made it really stable except for the temperature issue.

Anybody have any ideas how I can deal with the temp issue on the sensor?

Thanks,

Kevin

[darioarias]

Hi Kevin,

When you have this type of fluctuations we recommend to implement an auto zero correction. Auto-zero is a compensation technique based on sampling the offset of the sensor at reference pressure in order to correct the sensor output for long- term offset drift or variation.
Implementing Auto-Zero for Integrated pressure sensors

Another useful application note is the AN1646: Noise considerations for integrated pressure sensors, because explains the most common issues that can cause value fluctuations in the pressure sensors.

Also, keep in mind the typical accuracy of the device is ± 2.5% Vfss (2.5kPa with a Vfss of 4.5V)

Regards,
Darío