A new solution for integrating control devices involved in computer integrated manufacturing

The paper deals with some of the problems which can appear when automation technologies are applied in the manufacturing sector. In particular, the communication via network of control equipment such as PLCs, CNC or robot controllers is established. In this paper, a new solution is described which allows the cell controller (represented by a PC under UNIX) to communicate with all of them, assuming that they follow the IEEE 802.3 standard at the lower level of its communication architecture. The solution presented is based on using the finite automata theory for formalising the particular protocol used by each device as well as the information exchange during each operation. Once this information is formalised as a finite state automaton, and making use of the software developed, the user can easily generate the complete application. Thus, the so called cell controller can not only be used for monitoring the processes controlled by the devices involved in the plant, but it can also be used as a central supervisor of single-loop controllers for sending new set-points.