Before we discuss the differential pressure gauge transmitter, you need to know the differential pressure (DP) transmitter. If you don’t know and want to learn just enough to hop back into this post, we have an article on it here.
The differential pressure gauge transmitter
Gauge pressure is the difference between absolute pressure and atmospheric pressure. You can learn more about the different types of pressure in this other post here.
A DP transmitter has two pressure chambers divided by a diaphragm. The transmitter reads the difference in pressure between these chambers.
A differential pressure gauge transmitter works the same way. However, one of the chambers, the low-pressure side, is open to the atmosphere, so you can’t apply any other pressure there. Therefore the device will always give the difference of the pressure applied to the high-pressure side and the atmospheric pressure.