http://www.phoenixcontact.com/redundancy
The QUINT ORing redundancy module from Phoenix Contact is a perfect solution for machine building or the process industry. The QUINT ORing uses Auto Current Balancing (ACB) technology to ensure that redundant DIN rail DC power supplies are load-sharing evenly, which results in these power supplies being balanced. ACB technology - coupled with load current monitoring, remote diagnostics and visual indications - ensures maximum reliability in redundant power systems.
ACB technology automatically and symmetrically distributes the load current without regard to effects, such as temperature drift. With a balanced current draw, lifetime expectancy of each power supply may double. The Quint ORing redundancy module displays the status of the load sharing, generating an alarm in cases when the module nears a critical state or the redundancy is defeated.