In general, a differential pressure transducer is used to measure the variance, or the difference, between pressures on either side of an element such an orifice or a venturi. The pressure difference can be on either side depending on the flow and the type of system.
There is no set pressure measured against as seen in a gauge pressure measurement, which uses the atmosphere as the reference. The other option would be absolute pressure, which measures the change in pressure in relation to a vacuum.
Keep in mind that a differential pressure transducer and a transmitter will serve the same purpose in many applications, but they do have one difference, and that is in the type of electrical system that is generated to create the reading of the change in pressure.
The Electrical Signal Difference
A transducer is designed to measure the pressure difference and send a specific volt or millivolt signal to the controller. On the other hand, the transmitter will send an electronic signal in milliamps.
In most applications, a transducer in any application is ideal if there is a limited distance between the transducer, or the area where the pressure differential is being monitored, and the system. Additionally, the transducer tends to be much less sensitive to the existence and possible interference of other electronic components in a system. This makes them more resistant to electromagnetic types of interference.
There are several different options and models for a differential pressure transducer for a variety of different applications. There are those that are designed for measuring the differential pressure in gases or in liquids, also known as wet differential pressure transmitters or transducers.
These two devices can be designed for high pressures or more moderate to low pressures, and the specific application will determine which pressure level is required.
Ideally, for any solution, look for a transmitter or a transducer that is designed to have high levels of accuracy, solid state sensors, have shock and vibration ratings that match the requirements for the device.
Other factors to consider is the type of connection required, with different systems now using USB output options to allow for high-speed reading of data. This can include readings of up to 1000 per second.
Additionally, it is also possible to choose transducers with multiple field selectable ranges within one unit. These are often used for dry, clean air or in measuring pressure differentials in inert gases.