From a technological viewpoint, the actual evolution of the fieldbus systems (its timeline is shown in Fig. 2) was heavily influenced by the development of computer networks, the key
contribution undoubtedly being the International Organization for Standardization (ISO)/Open Systems Interconnection (OSI) model. This reference model was (and still is) the starting point
for the development of many complex communication protocols. The first application of the OSI model to the domain of SAUTER: THREE GENERATIONS OF FIELD-LEVEL NETWORKS 3587
Fig. 2. Selection of important fieldbus systems and enabling technologies.
automation was the definition of the Manufacturing Automation
Protocol (MAP) in the wake of the CIM idea [7].