Your transmitter measures two pressure values (static pressure and dynamic pressure), but there are actually three.

Types of pressure

Static pressure

Static pressure describes the force exerted on a fluid at rest. Imagine a bucket of water sitting on the ground with a rubber duck in it. As long as everything stays still, static pressure exists in that bucket. If you attached your transmitter, it would only give you the value for static pressure. You can consider it the default, as most transmitters measure it.

Total pressure

Dynamic pressure comes next, right? Not quite. Before we get to dynamic pressure, let’s talk about total pressure. Total pressure occurs when moving fluids stop. If you pick up the bucket, the water will slosh. The force exerted on the bucket by the sloshing water qualifies as total pressure.

Now, remember the duck? If you attached the transmitter to him instead of the bucket, he would still measure static pressure, because he moves with the water.

Dynamic pressure

However, he would also measure dynamic pressure, the difference between total and static pressure. Dynamic pressure means the kinetic energy of a fluid, which comes from the fluid’s velocity and density. So dynamic pressure happens in the movement between the point where the water started and the point where it stops.

Usually, you’ll find both sensors in multivariable devices like yours. The transmitter has static and differential sensors built in and working separately, sending their data to the control system.

To learn more about the difference between static pressure and dynamic pressure, click this link.

These vendors have multivariable transmitters:

Other resources on static and dynamic pressure that might interest you

Lower and upper range values of differential pressure transmitter
On my differential pressure transmitter, I have a range from 0 to 500 psi. We use an orifice plate for creating differential pressure. Maximum DP in our gas flow is about 200 psi but it’s not fixed. Can you tell me how to determine the lower and upper range values?

Pressure transmitter data
I bought a pressure transmitter S/N K219C601052 from Endress+Hauser, but I don’t know if the transmitter is providing the data I requested. Could you check for me?

Save money and time on pressure monitoring
You know pressure operators spend a lot of time checking measurements, making notes, and informing their control rooms about process conditions. Why should they spend all that time when it’s easier to send the information directly to the control room? There you can build a history of the whole day, month, and year.

Absolute, gauge, and differential pressure
I need to measure the pressure in a water pipe. Should I use a differential pressure transmitter or a gauge or absolute pressure transmitter?

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