Alpha Technologies Serial System Controller - Manual (Page 11)

1. System Overview
11
018-332-C0-002 Rev. B © 2001 TM
1.1 Theory of Operation, continued
1.1.3 Low battery Shutdown of Inverters
Each XM2 attempts to protect the batteries in a system from deep discharge that can
permanently damage them. The XM2 will disable its inverter when the battery voltage
drops below a threshold referred to as End of Discharge (EOD). The SSC will monitor
each XM2 for an EOD flag. If and when it receives an EOD indication, the SSC will
disable all inverters in the system simultaneously.
XM2s are equipped with a sleep mode that disables the logic power supply. This
protects the batteries from further discharge. The SSC monitors the DC bus voltage
after inverters have been disabled, and instructs all XM2s to enter sleep mode when
the voltage drops below a fixed value. At this point, all XM2s, the SSC and the digital
transponder are off, and will remain off until battery voltage recovers, or AC line
returns.
1.1.4 Enclosure Monitoring
The SSC monitors cabinet intrusion sensors and will report an alarm via the digital
transponder interface when a door opens. This alarm can be disabled by pressing
the Reset switch on the SSC 3 times within 30 seconds of opening the door. The
alarm can also be disabled by pressing the Tamper Disable software switch via the
digital transponder. The tamper alarm is reactivated when all doors on the cabinet
are closed, or after 60 minutes has elapsed.