PHD330 and PHM330｜What Is the Difference Between Piezoresistive and Hot-Wire Differential Pressure Sensing Principles?

In differential pressure measurement applications, it may appear to be simply a comparison of pressure levels between two pressure taps. However, behind different differential pressure sensing technologies lie fundamentally different physical measure

PHD330 Industrial Differential Pressure Transmitter adopts a piezoresistive differential pressure sensing technology. Its measurement principle is based on the piezoresistive effect: differential pressure applied to a silicon diaphragm causes minute deformation, which changes the resistance of the piezoresistive elements on the diaphragm. This change is then converted into an electrical signal output. This approach represents a differential pressure measurement method centered on direct pressure effects.

PHM330 Differential Pressure Transmitter uses hot-wire differential pressure measurement technology. When a pressure difference exists between the two sides, gas flow is generated within the internal channel of the transmitter. The gas velocity is measured through a heating element and temperature-sensing elements, and the flow velocity is then converted into differential pressure. Because it can measure extremely low gas flow rates, this technology is particularly sensitive to very small differential pressure changes and features low zero drift during long-term operation, helping maintain measurement stability.