Rockwell Automation 1756-BATM ControlLogix Battery Module Installation Instructions - Manual (Page 20)

20 ControlLogix® Battery Module
Publication 1756-IN576B-EN-P - September 2003
Estimate Battery Life
When the battery is about 50 percent discharged, the controller provides the
following warnings:
• On the front of the controller, the BAT LED turns on (solid red).
• A minor fault occurs (type 10, code 10).
To estimate how long the battery will support the memory of the controller:
1. Determine the temperature (° C) 1 in. below the battery module.
2. Determine the percentage of time that the controller is powered off
per week.
4. Using “Table 1 Worst-case estimates of life for the 1756-BATA
battery” on page 21, determine the estimated worst-case battery life
before and after the BAT LED turns on.
5. For each year of battery life, decrease the time before the BAT LED
turns on by the percentage that is shown in the table. (Do not
decrease the time after the BAT LED turns on.)
EXAMPLE
If a controller is off:
• 8 hr/day during a 5-day work week
• all day Saturday and Sunday
Then the controller is off 52% of the time:
1. total hours per week = 7 x 24 +168 hours
2. total off hours per week = (5 days x 8 hr/day) +
Saturday + Sunday = 88 hours
3. percentage off time = 88/168 = 52%