Redundancy Design Strategy of Control System Based on Component’s Fault Model*

Redundancy technology is one of the most efficient methods to improve the reliability of fault-tolerant control systems. However, unreasonable redundancy may degrade the reliability. Based on the characteristic of process control system, component’s fault model of typical device was analyzed in redundancy system.

By Control Engineering Staff August 2, 2006

Redundancy technology is one of the most efficient methods to improve the reliability of fault-tolerant control systems. However, unreasonable redundancy may degrade the reliability. Based on the characteristic of process control system, component’s fault model of typical device was analyzed in redundancy system. The faults of components were sorted according to the correlations between the faults of redundancy devices. The invalidation rate equation of the real redundancy system was brought forwards. Then, the design guide line and verify method of reliability based on the analysis of component’s fault model in redundancy system were proposed. At last, experiment data of field application was collected and these data has verified the conclusion above. Reliability is the primary characteristic of process control system. However, faults are inevitable, such as faults of sensors, actuators, and controllers. Element faults can degrade the reliability of control systems, and then cause serious problems of operation and safety. Therefore, fault tolerance has been one of the major issues in process control system [1]. The redundancy technology, a key issue in the reliability research, is widely used in the reliability design of process control system. The redundancy technology is one of the most efficient methods to enhance the reliability of control system. But, on the other side, too much redundancy may bring up a more complexity system and increase the difficulty of system design. Therefore, it is an issue of great importance to design and assess the redundancy in control system reasonably and effectively.

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