Initiation and inhibiting mechanisms for multi-tasking control in discrete event systems

A theoretical analysis is presented of sequential controller initiation (pre-check) and inhibition for concurrent operations within a formal Procedural Control Theory (PCT) framework. These aspects are essential to the safety and performance of multitasking sequential controllers at the design and operation stages. The pre–check mechanism ensures the correct initial state of the process when controller is synthesized. The inhibit function prevents nominated controllers potentially using shared devices from starting while another controller is already active. The ideas are explained via a small illustrative example.