APC 900XL Power Supply User Manual


 
Page 20
5.0 Operation
5.4 Line voltage bar graph
The line voltage bar graph displays the UPS's input voltage in discrete steps. Line voltage
is displayed when the I/Test pushbutton is pressed and held. The example above shows
that the UPS's input line voltage is between 116 and 123 Vac (120 Vac version UPS, see
table for values for other versions). If no bars are illuminated, and the UPS is plugged into
a known working wall outlet, the line voltage is extremely low. Low input voltage could
be a result of an overloaded branch circuit, a misadjusted service pole transformer or
intentional local service brownout. The UPS will compensate for this problem by
boosting the load voltage supplied to your computer equipment. If all six bars are
illuminated, the line voltage is high and should be checked by a qualified electrician.
5.5 Audible alarm
The UPS contains a beeper that emits sound through the ventilation openings. Events
that cause the beeper to sound are listed below.
5.5.1 On-battery operation
The UPS emits four short beeps every 30 seconds following failure of the utility. The
audible alarm is silenced until the next utility failure when the I/Test pushbutton is
pressed.
5.5.2 Low battery
During an extended utility failure, the UPS will eventually emit continuous beeps to
indicate that the UPS will soon shut down due to battery capacity exhaustion. The low
battery warning cannot be muted.
Bar increments versus
version type
120 Vac 208 Vac
220/230/
240 Vac
130 237 260
123 225 246
116 212 232
110 200 220
104 187 208
98 175 196