Allen-Bradley controllogix 1756-L55M12, User Manual

Page: 124 / 142

Publication 1756-UM001G-EN-P - January 2007
124 Maintain the Battery
Check If the Battery Is Low
When the battery is about 95% discharged, the controller gives these
low-battery warnings:
•
Solid red BAT LED.
•
Minor fault (type 10, code 10).
Estimate 1756-BA1
Battery Life
To estimate how long a 1756-BA1 battery will support controller
memory on 1756-L55M
x (all series) and 1756-L6 x , series A controllers,
perform this procedure.
1. Determine the temperature 2.54 cm. (1 in.) below the chassis.
2. Determine the weekly percentage of time that the controller is
turned on.
3. Determine the estimated worst-case battery life before and after
the BAT LED turns on.
4. For each year of battery life, decrease the time before the BAT
LED turns on by the percentage that is shown in the table.
ATTENTION
To prevent possible battery leakage, even if the BAT LED is off,
replace a battery according to this schedule.
BAT LED
If the temperature 2.54 cm.
(1 in.) below the chassis is Replace the battery within
0...35 °C (32...95 °F) 3 years
36...40 °C (96.8...104 °F) 3 years
41...45 °C (105.8...113 °F) 2 years
46...50 °C (114.8...122 °F) 16 months
51...55 °C (123.8...131 °F) 11 months
56...60 °C (132.8...140 °F) 8 months
EXAMPLE
If a controller is off either :
•
8 hr/day during a 5-day work week.
•
all day Saturday and Sunday.
Then the controller is off 52% of the time:
•
Total hours per week = 7 x 24 = 168 hours
•
Total off hours per week = (5 days x 8 hr/day) + Sa
Sunday = 88 hours
•
Percentage off time = 88/168 = 52%