Fieldbus application layer and real-time distributed systems

The author presents the application layer of Fieldbus as part of a real-time distributed system. The services of the layer must warrant the distributed process synchronization in real-time, and temporal and spatial data consistency. A model that fulfils these requirements is presented and a protocol with very low network and computational overhead is proposed. This protocol is intended to be used in low-cost Fieldbus for hard real-time applications. The proposed model is discussed in detail and compared with other application layer models intended for Fieldbus. The communication protocol that implements this model is also discussed in detail