1.What are Sensors and Transducers? By-A K BARLA Sensors A sensor is a device that has a characteristic that changes in a predictable way when exposed to the stimulus it was designed to detect. When making process measurements we are not really measuring the value of the process variable. We are inferring the value of the process variable by measuring the response of a sensor to the process. Sensors have a physical property that changes in a measurable and consistent fashion. For example, when measuring temperature we are not directly measuring the temperature of an object, we are measuring a sensors change in resistance or the amount of voltage it produces from being exposed to a temperature. Transducers A transducer is a device that converts one form of energy into another. Transducers are used to convert the output of a sensor into a signal that a controller can use. The output of a sensor may be a mechanical movement, or a change in size or position, or a nonstandard electrical signal. The output of a sensor may even be nonlinear. A transducer will convert the output of the sensor into a standard signal that a controller can use. A sensor and transducer may be packaged together as shown in Figure 3-1. For the sake of convenience we will refer to any device that measures a process variable as an instrument, understanding that some signal processing will take place.
Posted on: Sat, 29 Mar 2014 15:34:15 +0000
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