Monitor controller status

Online-Offline toggle. The toggle is green when the controller is online. Slide the toggle to the right to go online with a controller. Slide it to the left to go offline with a controller.

A yellow triangle above the toggle indicates a warning:

A red circle above the toggle indicates a fault or error, and the Controller mode indicates the controller is in a fault state:

Key switch or toggle switch position on the physical controller.

If the physical controller's key switch or toggle switch is set to REM (Remote), you can use FactoryTalk Design Studio or the Logix Designer application to change the controller mode. If the controller mode switch is set to RUN or PROG, you cannot change the controller mode from FactoryTalk Design Studio or the Logix Designer application.

Current controller mode:

Program mode: logic is not executing, outputs are not controlled, and you can edit the project.
Run mode: the controller schedules tasks, scans programs, scans routines, and reads and writes I/O. You can change a limited subset of project elements.
Faulted: the controller is in a fault state and requires correction.

Controller LED lights:

OK. Indicates power and overall status of the controller.
I/O. Indicates input-output communication status.
ES. The Energy Storage LED. Indicates status of the energy storage module, if present.