The Three Generations of Field-Level Networks - Evolution and Compatibility Issues

Field-level networks have been one of the keys to modern automation systems. Be it in factory, process, or building automation, networks allow for horizontal and vertical integration of distributed devices and functions. This paper reviews the evolution of field-level networks comprising fieldbus systems, industrial Ethernet, and recent industrial wireless networks. The main focus is on demonstrating the continuity in the development of the three generations that ensured backward compatibility at the expense of radical innovation. Given the wide set of modern communication technologies, this paper then discusses how architectures for future automation networks might look. Particular emphasis is put on hybrid architectures for combined wired/wireless networks. A generic concept for integration of multiple wireless segments will be presented that supports seamless roaming for mobile nodes in industrial environment.