Uninterruptible AC/DC power supplies. These devices provide AC output when there is mains power supply and DC output when there is not. The output voltage is 24V, but other values can be set.
Constituted by a battery charger, a watertight lead battery that provides the output voltage when there is a mains supply failure, a transformer that provides AC power and a contactor that performs the switching of the output to the transformer or battery.
Signals and alarms with LEDs