Different Types of Pressure Sensors
Pressure Sensors can be found which measure gauge, absolute, differential and vacuum pressures. An absolute pressure sensor measures a pressure relative to a vacuum (0 psi of 0 Pa). A differential pressure sensor meausures the difference between 2 pressures. A gaauge pressure sensor measures the difference between the ambient pressure and pressure in a vessel. A differential pressure sensor can generally be configured in order to measure gauge pressure as well. A vacuum pressure sensor is used to measure pressures below atmospheric pressure (101 kPa or 14 psi). This page describes ways in which gauge or differential pressures can be measured.
Digital Pressure Sensor
A digital pressure sensor (Honeywell ASCX01DN) measures pressures from 0-1 psi and outout is in the form of a voltage proportional to either the differential pressure of the gauge pressure. It is also calibrated for use over a wide temperature range and .
The packaged sensor has 2 ports labelled A and B. B id the high pressure port for differential pressures or the pressure of interest for gauge pressures. The sensor must be supplied with a 5V supply (pin 3 ) and ground (pin 4). The output voltage is read from pin 3 and is directly proportional to the pressure being measured.