ABSTRACT
Pressure Transducers. The most common type of transducer used to measure pressure is the traditional analog Bourdon sensor. These gages are found throughout most factories and are usually only equipped with a dial indicator readout for visual monitoring although units are available that operate with AC or DC systems. A simpler go/no go type of pressure gage is available for use in those applications where it is only necessary to be sure that a pressure level is above or below a certain value. Other types of pressure sensors may be used to provide a continuous output signal over a specific range. These unjts include variable reluctance transducers, piezo-resistive integrated circuits and fused quartz transducers. The variable reluctance transducers utilize a diaphram that is connected to electrical coils to translate diaphram motions caused by pressure differentials into an electrical output signal. These devices are used primarily in the lower pressure ranges. The solid-state transducers offer wider pressure ranges as well as insensitivity to wide temperature extremes. Measurement systems with digital output signals are available that can be readily interfaced with the electrical hardware used in digital monitoring and/or control systems. There are readily available devices that can measure pressures that vary from vacuum to thousands of pounds per square inch. These electronic pressure transducers can be interfaced with "intelligent" transmitters that provide improved calibration over the operating range, as well as offering the option for inferring fluid flow and level from the pressure measurements.
