ABSTRACT
PROFIBUS (process eld bus) is a standardized, open communication system for all areas of application in factory and process automation. The technology was introduced in the early 1990s and has been developed continuously ever since. From the historical point of view, the rst PROFIBUS protocol was PROFIBUS FMS (eldbus message specication), which was conceived as a universal data communication standard for machinery and plant. It did not prove successful in factory and process automation, among other reasons, because of its complexity. PROFIBUS DP (decentralized periphery), introduced in 1993, is an optimized variant for the quick and simple connection of input and output (I/O) units to a control system. PROFIBUS PA (process automation), which followed soon afterward, addresses the special requirements of process automation, in particular, the need for intrinsically safe bus powering of eld devices. PROFIBUS DP and PROFIBUS PA technologies are specied in the international standards EN 50170 [1] and IEC 61158 [2] and are suitable for replacement of conventional discrete and analog signals in control systems.
