Petri Net Based Hierarchical Coordinated Control For Industrial Process

Integrated hierarchical control structure has been widely used in industry control. As the modern industrial plants are expected to be highly task-integrated and flexible, the common hierarchical control solution which be designed with precedence diagram and programming language seems to be more and more complex.This paper proposes a new hierarchical control structure, which uses an extended Petri net-based translator to convey the control logic to command sequence directly and coordinate integrated tasks. This method provides a way to develop control system easily, integrally and flexibly. The approach to model Petri net-based control logic, which proposed in this paper, can make it easier to convey operating experience into an extended Petri net-based model, and to implement a coordinated control system directly by running the model.EPN-Tool, which is an ActiveX control developed under this conceptual, can be integrated into industry configuration control system. It provides a graphic editing environment, an extended Petri net runner, a common OPC data interface as well as a DataGate data interface for MPCE. The tool can execute control tasks according to the extended Petri-net based control logic.Finally, a simulation experiment on the automatic start-up process of polypropylene producing is implemented under the MPCE simulation environment. The study shows that the extended Petri-net based computer integrated hierarchal control structure is a convenient and effective method to establish a hybrid control system.