Digital Transducers
A digital transducer is a measuring device that produces a digital output. A transducer whose output is a pulse signal may be considered in this category since the pulses can be counted and presented in the digital form using a counter.
Similarly, a transducer whose output is a frequency falls into the same category since it can use a frequency counter to generate a digital output.
Sensors and transducers are useful in many industrial applications within the general area of mechatronics.
Numerous examples are found in robotic manipulation, transit system, digital computers and accessories, process monitoring and control, material processing, fabrication, finishing, handling, inspection, testing, grading, and packaging.
Analog sensors and transducers. In this chapter we will study some useful types, concepts, operation, and utilization of digital transducers. Our discussion will primarily be limited to motion transducers. Note, however, that by using a suitable auxiliary front-end sensor, other measurand, such as force, torque, temperature, and pressure, may be converted into a motion and subsequently measured using a motion transducer.
For example, altitude (or pressure) measurements in aircraft and aerospace applications are made using a pressure-sensing front end, such as a bellows or diaphragm device, in conjunction with an optical encoder (which is a digital transducer) to measure the resulting displacement.
Similarly, a bimetallic element may be used to convert temperature into a displacement, which may be measured using a displacement sensor.
As we have done, it is acceptable to call an analog sensor an “analog transducer,” since both the sensor stage and the transducer stage are analog in this case.
The sensor stage of a digital transducer is typically analog as well. For example, motion, as manifested in physical systems, is continuous in time.
Therefore, we cannot generally speak of digital motion sensors. Actually, it is the transducer stage that generates the discrete output signal in a digital motion-measuring device. Hence, we have chosen to term the present category of devices as digital transducers rather than digital sensors.
Commercially available digital transducers are not as numerous as analog sensors, but what is available has found extensive application.
