Continuous Sensors

It is a device that converts one measured physical quantity to another that is proportional to the measured physical quantity. The measured physical quantity should be position, velocity or temperature; the converted proportional physical quantity is typically one that might be used in an electronic circuit, such like electrical resistance.  The concept of closed loop continuous control is shown in figure. The components of a sensing system & their relationship to a digital controller are illustrated in figure. The controller, a digital device, needs that the information provided by the sensor be converted to digital from before it might be acquired and recorded by the processor of the controller. The device that carries out this conversion is an analog to digital (A/D) converter. Likewise, to map out a relation among a digital output of the controller and an analog output, digital to (analog D/A) converter is utilized.

                                 Figure: Closed Loop Control with Analog to Digital and Digital to Analog Conversion

                                                       Figure: Components of Sensing System