Abstract: Abstract:The redundant I/O module technology used in maxDNA distributed control system to improe the system reliability was introduced. Aiming at different applications, there are two modes for the I/O module redundant configuration of the maxDNA system, which are the redundant I/O module redundancy and the mixed redundancy. In the mixed redundancy configuration mode, there are two mixed I/O switching over modules YMODULE and IMODULE, which provide different ways to connect nonredundant I/O modules into I/O bus network. In actual application, according to actual needs, it is able to adopt flexible redundancy configuration for the maxDNA system to improve the system reliability.

Key words: Keywords:distributed control system (DCS), redundancy, I/O module redundancy