The B520 Auxiliary Power Supply Module is an auxiliary power supply expansion device that connects to compatible control panels through the SDI2 bus. This module is supervised and communicates all status changes to the control panel.Industrial, commercial, and institutional facilities are typical installations for the B520 module. The B520 address switches allow for easy device addressing. The SDI2 Out terminals provide auxiliary power for SDI2 expansion devices, such as keypads. The AUX PWR terminals provides added auxiliary power capabilities for additional devices such as PIR motion detectors.FunctionsSupervision monitoringThe module monitors and communicates status information over the SDI2 bus for the following: Operation (Heartbeat) Battery 1 (BATT 1) Battery 2 (BATT 2) AC input power (AC) Battery OK Low Battery Missing Battery Indicators Heartbeat [icon]. Blue LED flashing On and Off when system is operating normally. A steady On or Off LED indicates a system fault. Triple flash indicates communication failure. BATT 1 LED. Green steady On LED indicates the battery status of BATT 1 is operating normally. Flashing indicates low battery. Triple flash indicates battery charger failure. Off LED indicates a missing battery. BATT 2 LED. Green steady On LED indicates the battery status of BATT 2 is operating normally. Flashing indicates low battery. Triple flash indicates battery charger failure. Off LED indicates a missing battery. AC LED. Green steady On LED indicates the AC power is operational. A pulsating LED (3 pulses per second) occurs when a battery test is being performed. Flashing indicates low or failed AC. Battery chargingFully charged batteries, connected to the battery terminals, sustain power to the B520 in the event that the AC power fails.