Main Paradigms as a Basis for Current Fieldbus Concepts

This paper discusses the main paradigms on fieldbuses from the applications requirements to the most common solutions derived to fulfill them. Temporal properties of the data to be exchanged are analyzed. Data are classified according to their criticality and their transmission frequency, for each of these types, the communication requirements are identified with emphasis on the realtime aspects. Two architectures are identified in order to design the applications, and an overview of their characteristics is presented. Main paradigms on fieldbuses are analysed at different levels of the architecture and in different contexts: synchronous vs asynchronous, periodic vs aperiodic, centralized vs distributed, static vs dynamic, deterministic vs nondeterministic. Several examples of the fieldbuses and the MAC protocols are analysed for each paradigm with regard to possible future fieldbuses.