Chapter 10 – Intelligent Devices

This chapter introduces the subject of intelligent devices, which are distinguished from their nonintelligent counterparts by their computational processing capability. Discussion starts with a brief review of the main principles of digital computation and how the computation element in an intelligent device interfaces to other measurement system components. It is noted that intelligent devices have a number of names including intelligent instrument, intelligent sensor, smart sensor, and smart transmitter, but, since there are no universal definitions of these terms, devices with similar attributes but from different manufacturers may have different names. This chapter summarizes the common features of intelligent devices and explains the significant advantages that they have compared with nonintelligent devices, particularly in respect to improved measurement accuracy and their ability to perform functions like remote self-calibration and self-diagnosis of faults. This is followed by a discussion of the issues surrounding the communication between intelligent devices and other elements in a measurement/process control system, with coverage of local area networks and digital fieldbuses.