Today, I want to introduce you to the A+B System (shared operation) which is a typical redundancy concept for onshore/offshore applications with increased safety requirements. It complies with DNV and NORSOK standards.
For this redundancy concept two independent systems work simultaneously (System A & System B). Often they are located in two different places so that a potential incident (e.g. fire, gas alarm) only affects one system. Both systems are synchronized and connected via redundant cable routes.
By default, all intercom stations and analog lines (e.g. contacts to fire & gas alarm systems) are connected to both systems. The speakers and beacons of the two systems are evenly distributed among the different speaker zones. There is always one speaker or beacon of each system installed per location to provide maximum protection against failures.
Usually, 50% of the amplifiers are connected to System A, the remaining ones are connected to System B. Under normal operation, the A+B System concept provides full sound coverage. Even in the worst case if one system fails, the sound level is only reduced by a maximum of 3 dB which is barely audible to human ears.
To provide additional protection, there is of course the option to protect main components by backup components in hot stand-by mode.
In conclusion, this redundancy concept provides maximum protection against failures and ensures highest system availability. There is no loss of any warning and alarm functions in case of failure. Due to the possibility to install the two synchronized systems in different locations, a potential incident affects only one system.
Continue to follow our blog and don’t miss the announcement of our brochure about redundancy concepts coming soon. It includes an overview on all individual concepts as well as more details on the different power supply variations.
If you want to read all previous articles about this topic, please refer to “Introducing INDUSTRONIC’s Redundancy Concepts”, “INDUSTRONIC’s Redundancy Concepts – Single System with N+1 Components”, and “INDUSTRONIC’s Redundancy Concepts – Duplicated Control System”.
