Period And Priority Assignment Method For Dcs Design

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.

[1]  Joseph Y.-T. Leung,et al.  On the complexity of fixed-priority scheduling of periodic, real-time tasks , 1982, Perform. Evaluation.

[2]  Pascal Lorenz,et al.  Real-Time Software Architecture: Application to FIP Fieldbus , 1995 .

[3]  Biao Chen,et al.  Properties of the Timed Token Protocol , 2004 .

[4]  David Lorge Parnas,et al.  Scheduling Processes with Release Times, Deadlines, Precedence, and Exclusion Relations , 1990, IEEE Trans. Software Eng..

[5]  M. Johnson,et al.  Proof that Timing Requirements of the FDDI Token Ring Protocol are Satisfied , 1987, IEEE Trans. Commun..

[6]  Wook Hyun Kwon,et al.  Network conscious design of distributed real-time systems , 1998, J. Syst. Archit..

[7]  Francisco Vasques,et al.  Pre-run-time schedulability analysis in Fieldbus networks , 1994, Proceedings of IECON'94 - 20th Annual Conference of IEEE Industrial Electronics.

[8]  Andy J. Wellings,et al.  Analysing real-time communications: controller area network (CAN) , 1994, 1994 Proceedings Real-Time Systems Symposium.

[9]  Alan Burns,et al.  Preemptive priority-based scheduling: an appropriate engineering approach , 1995 .

[10]  Richard Gerber,et al.  Guaranteeing Real-Time Requirements With Resource-Based Calibration of Periodic Processes , 1995, IEEE Trans. Software Eng..

[11]  Krithi Ramamritham,et al.  Scheduling algorithms and operating systems support for real-time systems , 1994, Proc. IEEE.

[12]  Neeraj Suri,et al.  Synchronization issues in real-time systems , 1994 .

[13]  A.-M. Deplanche,et al.  Heuristic techniques for allocating and scheduling communicating periodic tasks in distributed real-time systems , 2000, 2000 IEEE International Workshop on Factory Communication Systems. Proceedings (Cat. No.00TH8531).

[14]  John A. Clark,et al.  Holistic schedulability analysis for distributed hard real-time systems , 1994, Microprocess. Microprogramming.

[15]  A. Burns,et al.  Deadline monotonic scheduling theory and application , 1993 .