After switching on the controller (or after a power failure), a short animation of the logo with the name of the controller is displayed by default. This animation can be turned off in Settings (Introductory logo).

 

At the same time, the controller checks its status and settings. These checks take approximately 1 second. If it detects a problem in the controller’s memory, it will use an earlier backup. If the older backup is also corrupted, it will display instructions to initialize the controller.

 

The controller also checks whether the program has been started and whether there has been a power failure. During the running of the program, it saves information about its status every second so that it can continue the interrupted program in the event of a power failure. The behavior of the controller after a power failure can be influenced in the Settings (article Continuation on failure)). Here, it is possible to choose whether the controller should continue the program after a blackout or set the duration of the power outage until which it will continue. If the blackout is longer than the set time, then the program is terminated immediately after the blackout.

 

The controller also reads information from the real-time clock circuit, which is backed up by a battery with a lifespan of about 50 years. This clock operation with help of calibration can reach an accuracy of 1 ppm (about 1 second in 11 days) and is unaffected by a power failure.