MXPV7007G drift

[ThomasX]

Hi

I am using the MXPV7007G to measure negative pressure in the range 0 to -1000 Pa.

In normal cases the pressure is varying within this range frequented.  But at times there should be no change in pressure for several days. The sensor however reports an increase in negative pressure over time. A relatively constant change.

Over 3 days for instance the sensor is reporting a change from -500 to -1000 Pa.

There is nothing in the system that I see could cause an increase in negative pressure. 

So I wonder if this could be due to sensor drift.

Any thoughts on this? 

Thanks

[JozefKozon]

Hi Thomas,

please refer to the transfer function in the page 6. in the datasheet attached for the possible drift reasons.

JozefKozon_2-1623054024710.png

The pressure error is guarantied to be maximally 500Pa. So the output can change reflecting a change up to 500Pa without any reason, even if there is no change in the pressure applied. 

JozefKozon_0-1623053755374.png

Then there is Temperature error factor. For the temperature from 0°C to 85°C, the temperature error factor is one, but for the temperature below 0°C up to -40°C the factor increases from 1 to 3. The same for the temperature above 85°C up to 125°C.

JozefKozon_1-1623053974471.png

The device is ratiometric to Vs supply, meaning if there is a change in the Vs supply voltage it will reflect in the output voltage even if there is no change in the applied pressure or in the Temperature error factor.

JozefKozon_3-1623054187851.png

With Best Regards,

Jozef