CHAPTER Industrial control networks 10 Most modern industrial control systems are embedded networks, relying on built-in, special-purpose, digital or numerical controllers and computers to perform real-time and distributed control applica- tions. They are used by controllers and computers to communicate with each other over dispersed locations, and to interact with large numbers of sensors and actuators. Embedded networks are common in aircraft, factories, chemical processing plants, and also in machines such as cars. The types of architecture most commonly used are controller area, supervisory control and data acquisition, industrial Ethernet, DeviceNet, HART field, and industrial local area networks. Their use raises many new practical and theoretical questions about network architecture, components, protocols, compatibility of operating systems, and ways to maximize the effectiveness of the embedded hardware. This part of the textbook provides students and engineers with a broad, comprehensive source of information and technological detail to enable them to address many questions and aspects of real-time and distributed control through use of embedded networks.