Automation encompasses a wide range of technologies designed to reduce human intervention in industrial processes. This is achieved by predetermining decision criteria, subprocess relationships, and related actions, which are then implemented in machines. One simple form of control is on-off control, as seen in thermostats for household appliances that either open or close an electrical contact. (Originally, thermostats were developed as true feedback control mechanisms, more complex than the simple on-off thermostats used in common household appliances today.)

Sequential control can either follow a fixed sequence or be logical, performing different actions based on various system states. An example of a fixed sequence is a timer on an automatic lawn sprinkler system. In automation, states refer to the different conditions that can occur in a process or system. A common example is an elevator, which uses logic based on the system’s state to perform specific actions in response to its current state and operator input.