Finite State Machine

A finite state machine is a model of a control system.

A finite state machine describes the behavior of a control system using states, transitions and actions.

The state stores information about the past, i.e. it reflects the input changes from the system start to the present moment.

A transition indicates a state change and is described by a condition that must be fulfilled to enable the transition.

An action is a description of an activity that is to be performed at a given moment. There are several action types:

• Entry action,
• Exit action,
• Input action and
• Transition action.

Depending on the actions used we have different finite state machine models, as for instance:

• Moore model (only entry actions) or
• Mealy model (only input actions).

Take a look at the Example or read Moore or Mealy model?