Multicycle Polling Scheduling Algorithm

The paper deals with the scheduling of periodic information flow in FieldBus environment. The scheduling problem is defined from an analytical point of view, giving a brief survey of the most well-known solutions, and illustrating multicycle polling scheduling which is based on the hypothesis that all the production period of the periodic processes to be scheduled are harmonic. Although in some process control or manufacturing scenarios this hypothesis may be acceptable, there are many real industrial processes to which it cannot be applied. The aim of the paper is to make a contribution towards solving the scheduling problem. It essentially concerns extension of the theory on which multicycle polling scheduling is based to a much more realistic and general scenario, where the periods of all the processes to be scheduled have arbitrary values. We present a new formulation of multicycle polling scheduling, called extended multicycle polling scheduling, and demonstrate that it comprises the scenario currently considered in the literature. We then present an algorithmic solution to extended multicycle polling scheduling, demonstrating that it also coincides exactly with the solution given in the literature when the current restrictive hypotheses hold. Finally, some examples of scheduling further highlight the limits of the currently available algorithmic solution for multicycle polling scheduling and demonstrate the superiority of the solution proposed in the paper.