A state machine is an abstraction of a machine that can be in one of a finite number of states at any given time, wherein in each state there are actions and transitions. Actions are means for the machine to interact with the system, while transitions are certain conditions to be achieved in order to move from one step to another.
This is a companion discussion topic for the original entry at https://www.solisplc.com/tutorials/programming-a-state-machine-in-ladder-logic