Extensions.StateMachineProcedure

Classification

Name	StateMachineProcedure
Short Description	Description of a behavior model with states, transactions and actions
Class	OTX Extension
Base Extension	-
Pre-Conditions	-
Specified by	ISO 13209-4

Introduction

A finite-state machine (FSM) or simply a state machine, is conceived as an abstract machine that can be in one of a finite number of states. The machine is in only one state at a time; the state it is in at any given time is called the current state. It can change from one state to another when initiated by a triggering event or condition; this is called a transition. A particular FSM is defined by a list of its states, and the triggering condition for each transition. Each state machine shall have one mandatory state which is marked as the initial state (State I in Figure 96). It can have one optional state which is marked as the completed state. The initial state and the completed state shall be different. Every state has 1 to n triggers. Each trigger has 1 to n event sources. If an event source, specified inside the triggers of the current state fires an event, the wait state of the current state will be terminated. If a trigger terminates its wait state, all transitions (in order of XML occurrence) which refer to this trigger will check their condition. The first transition whose condition is true or which has no condition will be executed. All further transitions will be ignored. If a transition is active the optional flow of that transition shall be executed first. Only then will the target state of the transition shall be reached.