Usual pressures in fluids - Sensors and Transmitters (Part 1)

Sensors and transmitters are ideal for static and/or dynamic measurements requiring evaluation in the form of an electrical signal. These instruments are endowed with properties, or even intrinsic functions, that enable information to be transmitted at greater or lesser distances. This criterion for differentiating between sensors and transmitters does not, of course, preclude local use limited solely to the digital display of pressure values (electronic pressure gauges). Finally, it should be remembered that standard pressure measurement ranges from a few hundred pascals to 50 MPa.

Following the example of the previous article [R 2 041] on mechanical pressure gauges, we present here the layout of the instruments, their potential and their limitations. Particular emphasis is placed on the essential link: the sensor (test body + detector). Whether in analog and/or digital output devices, with or without integrated logic functions, the sensor represents the heart of the system, giving it its intrinsic qualities. In this first part, we will take advantage of the presentation of conventional devices to offer an initial overview of their sensor technologies. The second part, [R 2 045] , will address aspects inherent in the miniaturization of instruments.