What details should be considered in the redundant design of control systems?
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For a redundant control system, which parameter redundancies should be designed? How should it be designed? Could you recommend some professional books?
Redundancy setting: The CPU must be redundant, with at least a 2:1 ratio； IO card; AI is redundant in some cases and not redundant in others (depending on the importance of the IO points) ； AO, all redundant ； Some parts of DI are redundant, while others are not (depending on the importance of the IO points) ； DO (depending on the importance of the IO point) ； Communication cards need to be redundant ； The power supply must be redundant, sometimes at a ratio of 4:1
CPU switching time, how the values of the IO modules change during CPU switching, and so on. Generally, each DCS comes with its own specifications regarding redundancy
1# zuyuzu: What was said above is correct, but to achieve true redundancy, the elements that need to be redundant must be distributed across different cards in order for it to be considered redundancy!
The applications for redundancy vary, and so do the requirements regarding the level of redundancy. It depends on the owner’s requirements as well as the funding for the project. Starting from basic controller redundancy, to control networks and monitoring systems, power supply redundancy is also essential; only after that is signal redundancy considered. At the highest level, there is also redundancy in field devices (not just backups)… Different industries certainly have very different requirements regarding the level of redundancy, and different owners, with their varying understandings of redundancy, will have different demands as well!
Starting from basic controller redundancy, to control networks and monitoring systems, power supply redundancy is also essential; only after that is signal redundancy considered. At the highest level, there is also redundancy in field devices (not just backups)… Different industries certainly have very different requirements regarding the level of redundancy, and different owners, with their varying understandings of redundancy, will have different demands as well!
The SIL level makes it clear that the requirements for redundancy vary. For redundancy at the point level, different cards should be placed in different cabinets, with a power supply ratio of 2 to 1, etc