- Bridge pressure sensors
- Current output pressure sensors
- Excitation 0 .. 24 V
- IEPE pressure sensors
- Excitation 4, 8 mA
- Bridge pressure sensors
- Current output pressure sensors
- Excitation 0 .. 24 V
How to measure pressure?
Pressure is measured as a difference betweent the measured pressure and the referecne pressure. The reference can be a vacuum (absolute pressure measurement), atmospheric pressure (gauge pressure measurement) or a user-specific part of the system (differential pressure measurement). Pressure sensors feature a diaphragm between the reference pressure and the measured pressure and sense the load acting on a diaphragm using strain gauges, piezoelectricity or change in capacitance. The load is proportional to the pressure difference from one side of the diaphragm to the other.
Bridge based pressure sensors
Bridge pressure sensors use strain gauges to measure the load on the diaphragm and require bridge signal conditioning: very accurate excitation, high impedance voltage input, lead wire compensation in case of long sensor cables, balancing possibility and shunt calibration. The accuracy of the measurement therefore depends a lot on the data acquisition system. But such sensors are the most common since they are very robust, usable in different applicaitons and not expensive.
Piezoelectric pressure sensors
Piezoelectric pressure sensors use piezoelectric crystal to sense the movement of the diaphragm in a similar way that a piezoelectric accelerometer senses the movement of a proof mass. Those sensors are appropriate for high frequency measurement and are oftenly available in IEPE / ICP version that requires a constant current excitaiton, a high pass filter and a +- 5 V differential voltage input.
Other types of pressure sensors
There are other types of pressure sensors available such as capacitive and optical pressure sensors. More expensive pressure sensors also include signal conditioning electronics in the package and output +-10 V voltage or 4-20 mA current.