Period and priority assignment method for DCS design

초록

Distributed control systems (DCS) used in industry environments consist of sensors, actuators, and controllers that are connected with a fieldbus. It is difficult to design the DCS while guaranteeing the time-critical requirements because of both communication delays due to the fieldbus and computation delays due to many tasks executed in one node. This paper proposes a priority assignment method and a period assignment method that find the shortest periods of control loops and guarantee the end-to-end constraints such as precedence constraints and timing constraints. Also, a DCS design method is presented by using the proposed two assignment methods. The presented design method considers the worst-case response times of tasks and messages simultaneously and is applicable to a practical DCS, which consists of several constraints. The design method is validated by examples.

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