Integrated control for discrete event systems

This paper presents an integrated control approach for discrete event systems in industry. The integrated control involves two levels: basic control functions (PLC level) and higher supervision (SCADA Level). The considered discrete event system consists of three main groups: a chain of conveyors and a moving carriage to charge the tobacco material into silos (charging group), set of silos for temporary storage (silos group), and a chain of conveyors to discharge the material (discharging group). The system is analyzed using a sequential function chart (Grafcet tool) and discrete models are developed for both PLC level and SCADA level. Based on the developed model, a new control panel is designed using a PLC. The developed system is equipped by an industrial PC to visualize the industrial operation and to make the operator interact easily with the controlled system. The new system has the advantages of: high reliability in function operation, minimal downtime, and fault diagnosis capability in system components. The system is tested in applying standard commissioning procedures to ensure the quality and safety operation for the developed control panel. This application is running successfully and the required control objectives are maintained .