Specifications
ControlLogix™ Controller and Memory Board 21
Publication
 1756-IN101H-EN-P - June 2003
Connect a Battery
To maintain the memory of the controller while the controller is 
without power, either use nonvolatile memory or connect a battery:
To connect a 1756-BATM battery module, see the ControlLogix 
Battery Module Installation Instructions, publication 1756-IN576.
!
WARNING
When you connect or disconnect the battery an 
electrical arc can occur. This could cause an 
explosion in hazardous location installations. Be 
sure that power is removed or the area is 
nonhazardous before proceeding. 
For Safety information on the handling of lithium 
batteries, including handling and disposal of 
leaking batteries, see Guidelines for Handling 
Lithium Batteries, publication AG 5-4.
ATTENTION
!
Connect only a 1756-BA1 battery or a 1756-BATM 
battery module to the controller. If you connect a 
different battery, you may damage the controller.
If your controller: And you want to: Then:
has nonvolatile 
memory
A battery is permitted but not 
required.
does not have 
nonvolatile 
memory
maintain memory only while the 
controller is in the chassis
Connect a 1756-BA1 battery or 
a 1756-BATM battery module.
maintain memory while the 
controller is out of the chassis
Connect a 1756-BA1 battery.










