Back-up power supply control system.Provides the back-up power supply to maintain the system in operation when there is no mains power supply. 24V input for external back-up batteries (not provided). Battery capacity 40 Ah. The built-in charger controls the power supply circuit when the AC supply operates correctly. In case of no mains power supply, all system devices will be automatically powered by the 24VDC batteries. The system controls the power supply circuit both for the mains power supply and for battery operation bycommunicating the power supply status and any faults to the unit. EN54-4 certified system 230V/50Hz power supply