MPX5100DP true sensibility

[Kaique]

Hi, 

I have a MPX5100DP sensor, and I can´t undestand him sensibility and acuracy. In the manual, the especification is ±2.5 %VFSS . With the VFSS = 4,5, the acuracy would be close to 0,11V or 110mV, right? This value applied to the sensibility, that is 45mV/kPA, I would have +/- 2.44KPA. This is what I can conclude with informations of the manual, but doing some tests, tying to measure a level of  water, I discover that the true sensibility is much more less. I did increases in 1 cmca (0,098kpa), and the sensor detect this variation, and the acuracy that I observed was +/- 1,5cmca (0,147kPA). I would like to undestand, why this values are so different, because I'm interested to use other sensors like mpx10dp, but I have to understand this issues.

[Kaique]

Ok Jozef,

With the accuracy its ok, thanks, its clear.

But with this information I can conclude that  this sensor only detects variations in 1 kpa, right?  Each variation in 1 kpa will increase Vout in 45mV. But, when I tested this sensor I did increases in 0.098 kpa and sensor detected, whith variations in Vout close to 1 mV. So, with this tests I can conclude that the sensibility is much less that the value in manual. It´s right?  

[JozefKozon · Accepted solution]

Hi Kaique,

I have discussed the pressure sensor sensitivity matter with my colleague. I misunderstood the sensitivity value in the datasheet. I apologize for my inconsistency. For the analog output pressure sensor there is no minimum value defined which the sensor will register. The sensitivity value in the Table 4. in the MPX5100 datasheet defines how much will the output voltage change with the applied pressure change. For the change of the applied pressure 1kPa the output voltage will change 45mV, for the change of the applied pressure 100Pa, the output voltage will change 4.5mV and so on.

With Best Regards,

Jozef

[JozefKozon]

Hi Kaique,

the accuracy and sensitivity are two different things, they have nothing in common. The accuracy defines the maximum deviation guaranteed for the part. The maximum accuracy is the +/-2.5%VSS, but it also could be 0%. Depends from part to part. It is guaranteed, that for the temperature from 0 to 85 °C will not be more, than +/-2.5%VSS. 

The sensitivity value in the Table 4. in the MPX5100 datasheet defines how much will the output voltage change with the applied pressure change.

With Best Regards,

Jozef