Pressure Gauge
Instruments used to measure pressure are called pressure gauges or vacuum gauges. A pressure gauge is used to measure the pressure in a vacuum/line—which is further divided into two subcategories: high and low pressure. The applicable pressure ranges of many of the techniques used to measure vacuums have an overlap. .
Differential Pressure Transmitters
The most common and useful industrial pressure measuring instrument is the differential pressure transmitter. This equipment will sense the difference in pressure between two ports and produce an output signal with reference to a calibrated pressure range.
Pressure Transmitters
A pressure transducer, often called a pressure transmitter, is a transducer that converts pressure into an analog electrical signal. Although there are various types of pressure transducers, one of the most common is the strain-gage base transducer. The conversion of pressure into an electrical signal is achieved by the physical deformation of strain gages which are bonded into the diaphragm of the pressure transducer and wired into a wheat stone bridge configuration. Pressure applied to the pressure transducer produces a deflection of the diaphragm which introduces strain to the gages. The strain will produce an electrical resistance change proportional to the pressure.
Pressure Switches
A pressure switch is a form of switch that closes an electrical contact when a certain set pressure has been reached on its input. The switch may be designed to make contact either on pressure rise or on pressure fall.