A pressure transducer is fitted in a heating and cooling or ventilation system. A pressure transducer measures the pressure in a specific location in a system and converts it into a signal which can be read by an instrument, e.g. resistance, inductance or capacitance.
The use of the signal
Sometimes the signal is used directly, for measuring and adjusting. Alternatively, the transducer may be connected to a transmitter, which converts the signal to a variable voltage or current signal, 0–10 V or 4–20 mA respectively. These signal ranges are used with a wide variety of building management system regulators.
Pressure measurement is used as part of system monitoring, or to control pumps/fans in order to achieve a required pressure at any given time.
There are various types of pressure transducers available:
1. A capacitive-type transducer acts like a capacitor where one plate of the capacitor is a pressure-sensitive membrane: Because the distance between the capacitor plates is variable, so is its capacity.
2. A strain gauge transducer is arranged as a long length of conductor arranged in a zigzag pattern. When it is compressed or stretched its cross-sectional area changes and thus its resistance changes.
3. A piezoelectric pressure sensor converts pressure into an electric signal when compressed.