Allen-Bradley controllogix 1756-L55M12 User Manual page 133

Color Description
Off No power is applied.
Flashing red If the controller is
a new controller
(just out of the box)
NOT a new controller
(previously in operation)
Solid red The controller detected a non-recoverable fault, so it
cleared the project from memory.
Solid green The controller is OK
Flashing green The controller is storing or loading a project to or from
nonvolatile memory.
OK LED Indicator
Then
The controller requires a
firmware update.
Major fault occurred.
Recommended Action
When ready, turn on power to the controller.
Update the controller with the correct firmware.
Clear the fault.
Clear the fault.
None
If the controller has a CompactFlash card, leave the card
in the controller until the OK LED turns solid green.
Publication 1756-UM001G-EN-P - January 2007
LED Indicators 133