What is a Pressure Transducer?

A pressure transducer is a type of pressure sensor that consists of both a pressure-sensitive element, which creates a signal, and a signal-converting element. The transducer converts low-level electrical signals from input mechanical pressure (from a gas or liquid) into a proportional voltage or milli-amp output. To “transduce” means to “convert.”

What Does a Pressure Transducer Do?

The transducer reads the pressure in the fluid system. Then, the voltage or amperage outputs of the transducer can be delivered to remote locations for monitoring and to inform automated or manual control of the system. Analog output types include: 4 – 20mA, 0 – 5Vdc, 0 – 10Vdc, 1Vac, or 0.333Vac. If you’re using a digital pressure transducer (AKA a pressure transmitter), the more advanced electronics provide functionality to send signals through industry communication protocols such as Modbus or BACnet.

Types of Pressure Transducers

• Strain gauge pressure transducer: This type of transducer has a mounted strain gauge, sensor, and diaphragm. It converts a specific physical quantity, such as load, displacement, or pressure, into mechanical stress. This mechanical stress is sensed by the strain gauge and converted into electrical output.
• Capacitive pressure transducers: This transducer has a diaphragm and two capacitor plates. As the diaphragm is moved by electrical capacitance, the distance between the two plates narrows or widens. These changes are detected by the transducer, which measures the changes as differential pressure, absolute pressure, or gauge pressure.
• Piezoelectric pressure transducers: These transducers rely on quartz crystals or ceramic materials. When pressure is applied to the ceramic or crystal, an electrical charge is created that is proportional to the pressure. This charge is measured as voltage.
• Optical pressure transducers: An optical pressure transducer relies on changes to light to measure pressure. A diaphragm in the transducer will begin to block the light as the pressure increases.
• Resonant pressure transducers: The transducer has a vibrating wire in the diaphragm and will undergo varying tension. This tension is converted to resonant frequency. Digital counter circuits convert the frequency into an electrical signal.
• Potentiometric pressure transducer: This transducer has a pressure-sensitive element connected to a wiper, which is called a potentiometer. When pressure is applied to the element, the wiper changes its position. As the resistance value changes between the wiper and the element, it is proportionally measured.

What is the Difference between Pressure Sensors and Pressure Transducers?

The definitions for pressure sensor, switch, transducer, and transmitter can easily become confusing when they’re often used interchangeably in the facilities industry. However, understanding the differences between these terms, and the roles of each device in your building systems, can help you to ensure that you’re getting the right product for the job.

A pressure sensor will detect the varied pressure and convert it into an electrical signal. This concept differs from a pressure transducer, which continuously monitors and measures electrical signals and converts them into proportional voltage. Transducers are used more often for complex and sophisticated projects.

Meanwhile, a pressure switch is a simple device that measures pressure but not from a continuous output like a transducer. It performs a specific function, such as turning something on or off based on the pressure. A pressure transmitter is similar to a transducer in function, yet sends the electrical signals as volts or millivolts instead of milliamps.

Dry vs. Wet Pressure Transducers

A dry pressure transducer measures differential pressure within dry media (such as air or gas ductwork), whereas a wet media pressure transducer would allow for pressure sensing in wet systems (like plumbing runs).

Veris offers transducers of both varieties, such as our innovative PX3 differential pressure and air velocity transducer for dry media, and our PWR series of remote wet media transducers.

PX3 Series

The PX3 transducer gives you the freedom to measure air pressure or velocity with the flip of a switch. Built-in Bluetooth functionality paired with the intuitive and simple Veris Sensors App makes it easy to control the transducer without climbing any ladders to overhead ductwork. Applications include:

• Duct static pressure (Pressure mode)
• Building or room pressure (Pressure mode)
• Filter status (Pressure mode)
• Airflow measurement (Velocity mode)

Learn more about the capabilities of the PX3 here or take a closer look at the datasheet.

PWR Series

With remote probes and no need to run plumbing lines all the way to the transducer, the PWR series greatly reduces installation time and costs. Users will benefit from pushbutton zero calibration — no trim pots to adjust — and switch-selectable pressure ranges. Applications include:

• Monitoring and controlling pump differential pressure
• Chiller/boiler differential pressure drop
• CW/HW system differential pressure
• Browse the datasheet for the PWR series for further information.

Veris offers a variety of pressure sensors and transducers to fit the needs of your analog or digital system. To learn more about our pressure sensing products, visit our website or call to speak with our sales team at 1-800-354-8556 or +1 503.598.4564.