Integration of supervisory control with SCADA system for a flexible manufacturing cell

This paper presents the integrated development of a SCADA system with the PLC code of supervisory control for a flexible manufacturing cell. A local modular approach of the Supervisory Control Theory is used for formal synthesis of optimal discrete-event systems supervisors, which are translated into PLC structured text code as a hierarchy of concurrent automata. The SCADA system provides a human-machine interface with complementary functionalities to the control system such as synoptic diagrams, high-level commands, historical reports, alarms, trends, recipes and interface to management systems. The control system design follows a methodology with several phases, including informational project, synthesis of supervisory control, emulation, implementation of PLC code, implementation of SCADA system and validation. The test bed application shows that, in addition to providing PLC supervisory control with valuable high-level functionalities, SCADA systems can take advantage of the automata based organization of modular supervisory control for a systematic, flexible and structured design.