# Differential pressure sensor applications

I have two differential sensors and in my experiment I wish to measure the air pressure from below and on top of the ball that is levitated by air. These are my 3 possible setups. Considering the 3 setups what is the best and most accurate way of measuring $$P_1$$ and $$P_2$$ ?

Setup A

Utilizes only one differential sensor that measures the dynamic pressure from above the ball and below the ball.

Setup B

Utilizes two differential sensors and a Pitot tube to measure static and dynamic pressure and get its difference.

Setup C

Utilizes two differential sensors, with a similar concept as that of a pitot tube and gets the difference between the dynamic and static pressure from the top and below the ball. ## 2 Answers

Use setup "A" to measure differential pressure. Any drift in each pressure measurement will not be seen if you use one differential pressure cell, but any drift WILL be seen, and will be unpredictable, if you use two separate differential pressure cells to take your readings. Note - setup "A" is very commonly used in industry, where a LOT of differential pressure readings are taken every day (e.g., millions of readings).

If you also need a static pressure reading at the same time that you are getting a differential pressure reading, use a separate pressure measuring device to get that reading.

If your flow is not so fast, the pressure difference between up and down are not much (compared to atmospheric pressure). So setups B and C, that measure only difference between local static and dynamic pressure, are not very sensitive, as the air speed is almost the same before and after.

So I'll go for A, and use the second sensor on a Pitot tube to get airspeed.