White Paper: How to Develop High Reliability Ethernet Control Systems Using Media Redundancy
Extending Ethernet redundancy schemes all the way down to the I/O
The key to using Ethernet on the plant floor is to make the implementation highly available. That means in practice, various means of redundancy are employed. A redundant system must be fault tolerant. We typically make systems redundant by duplicating system components that have high probabilities of failure, like power supplies, software file systems, and other computer hardware. We also add what is called “media redundancy” which refers to the formation of a backup communication path when part of a network is suddenly unavailable. A redundant media system can survive the break of a network cable or link by switching to alternate communication paths as soon as the break is detected.