Design of Modular Hierarchical Discrete-Event Control Architectures for Complex Industrial Systems

This paper proposes a design strategy of hierarchical architectures for discrete-event control of complex industrial systems. The system behaviour complexity is addressed by modelling its operation in a two-dimensional space built by operation-mode (i.e., degree of user intervention) and operation-state (i.e., operational conditions) dimensions as proposed by the ISA-S88.01 control standards. Procedural control modules are synthesized using Procedural Control Theory. The notion of a "safe state" is employed to guarantee the system evolution along the two-dimension operation domain. To demonstrate the design strategy, a two-level architecture is built to operate a tubular continuous reactor. The architecture was implemented and tested with Stateflow in Simulink-MATLAB and translated to structured language in the Siemens TIA portal environment for an S1200-PLC following IEC61131 guidelines.