• Gauge – Reference to atmospheric pressure.

• Sealed – Referenced to a sealed chamber closed with atmospheric pressure (approximately 1bar).

• Absolute – The reference is a vacuum (0bar or no pressure).

• Differential – Where the sensor has two ports for the measurement of two different pressures.

All pressure measurements are made with respect to a reference pressure and are expressed in those main terms.

Gauge pressure sensors measure the input pressure (of your media) with reference to ambient atmospheric pressure (vented to atmosphere). Gauge is used to measure pressure relative to ambient conditions, such as with car tyre pressure. As the sensors are open to the atmosphere, they are susceptible to humidity. Care must be taken that units are installed in dry areas (otherwise internal circuitry can fail).

Measures the input pressure (of your media) with reference to a sealed chamber closed with atmospheric pressure (approximately 1bar). This protects the internal circuitry of the sensor from humidity. This range is normally restricted to minimum 7bar and above. Outside installations or where the equipment may be washed are good application examples.  Our industrial pressure sensors are ideal.

Absolute pressure sensors measure the input pressure (of your media) with reference to a vacuum chamber at 0bar (evacuated and hermetically sealed). Specified where absolute pressure measurements are required, eg barometric pressures, or where equipment needs to have all the air removed.

Here the reference pressure is neither ambient nor internal to the sensor. The sensor is supplied with two ports – high and low inputs – and will measure the difference between the two. Generally used for filter measurement applications.  See our range of differential pressure sensors.