Each step is associated a step flag which indicates whether a step is active or inactive. Step flags can be used in action programs. They are represented by the logic value of a Boolean structure element ***.X, where *** is the step name.
As soon as a step is activated, the corresponding step flag will be set to TRUE. It will be reset to FALSE once the transition after the step is set to TRUE. In the next scan, the step is processed one more time before the next step is processed. So a step is always processed at least twice.
Step flags can be used to reset Boolean variables in action programs when changing from one step to the next.
It is also possible to evaluate step flags of other steps than the current one.
If step flags are used in actions, using these actions in other steps or renaming the steps can lead to unexpected behavior.