47.1 Introduction

The word smart has been added as prefix to many things that are perceived to possess some form of intelligence. The term smart sensor was adopted in the mid-1980s in the sensor fields to differentiate this class of sensors from conventional sensors.1 A conventional sensor measures a physical, biological, or chemical parameters, such as displacement, acceleration, pressure, temperature, humidity, oxygen, or carbon monoxide content, and converts them into an electrical signal, either voltage or current. However, a smart sensor with some form of intelligence, provided by an additional microcontroller unit or microprocessor, can convert this raw signal into a level or form which makes it more convenient to use. This might include signal amplification, conditioning, processing, or conversion. In addition, over time, smart functions were not only built into sensors, but applied to actuators as well. Therefore, the term smart transducers as used in this chapter refers to smart sen- sors or smart actuators. Figure 47.1 illustrates the partitioning of a smart transducer s functions.

Figure 47.1: A smart transducer is either a sensor or an actuator that is instrumented or integrated with signal conditioning and conversion and a microcontroller or microprocessor to provide intelligent functions. Its output is migrating from an analog to a digital format for added capability to communicate with a host or a network.

A smart transducer provides value-added functions to a sensor or actuator and does more than just...