2. Automated systems

In automated system architectures, we usually distinguish between the following networks: field network, cell network, plant network. But what lies behind these names? Firstly, a sort of hierarchical classification of devices and equipment, and a historical evolution. A field network connects sensors and actuators to PLCs, controllers and regulators, then a cell network connects the PLCs to a coordinator, the coordinators themselves being connected by a factory network to departments such as design, methods, management and procurement. But as we shall see, from the point of view of services, protocols and OSI model characteristics, this classification is not sufficient, as a network with a given profile can be used at different points in the architecture.

After recalling the main OSI concepts