Page 9
P O W E R I N G T E C H N O L O G Y
Document Number: MS0031-MAN rev. 7
guardian_access_ms31-man-rev7-0521.indd
2.2 Principal of Operation
The power system is normally configured with N+1 redundancy, with N as the number
of rectifier modules necessary for feeding the load and charging the battery and 1 as the
redundant rectifier module. In normal operation the rectifier modules are used to feed the
load and simultaneously maintain the batteries in a fully charged state.
Once the mains input power is failed, the rectifiers are shut down and the batteries feed
the load immediately. If the battery voltage drops below a preset level, the Low Voltage
Disconnection (LVD) circuit disconnects the batteries automatically to prevent over-discharge
of the battery to prolong battery life. When the mains input power is restored, the rectifiers
will start up automatically to feed the load, close LVD circuit and recharge the batteries.
System performance is supervised and controlled by the ACX Advanced controller. The DC
output voltage, alarm thresholds, LVD circuit operation, temperature compensated battery
charging can be set by the controller. Any malfunction will be indicated by LED, text in the
display and operation of dry contacts.
However, the system controller is not a single point of failure. In the event of controller
malfunction, basic tasks like feeding the load and charging batteries will be maintained by
the rectifier modules directly at preset default values.
The alarm and threshold setting of the power system can be set either through the buttons
and operation menu on the local controller, or remotely through the PowCom™ supervision
software.
Figure 2-2 Principal of Operation
