Fault-tolerant configuration of distributed discrete controllers

This paper presents a fault tolerant configuration for a multiple discrete control system. The distributed control nodes, such as programmable logic controllers, communicate over networks. The design methodology of an additional redundant controller using Galois field and an error-detecting code is proposed. The proposed method is implemented and tested on distributed controllers connected on a network. It is shown that the system is functional even if one of the controllers fails. From a reliability analysis, it is also shown that the proposed design method drastically improves the mean time to failure of the discrete control system.