The output names trigger actions entry actions, exit actions, input actions or transition actions. The virtual conditions are built using the positive logic algebra. The input names build virtual conditions to perform state transitions or input actions. state names, as defined for each of the states of the FSM.output names represent the available actions on the variables.input names represent the control properties of all available variables.The virtual environment characterises the runtime environment in which a virtual machine operates. A timer which is both: an input and output variable can be triggered by actions like: Start, Stop or Reset.įigure 1: VFSM in the Virtual Environment A numerical (analog) output variable has an action: Set. For instance, a digital output has two actions: True and False. Other state variables in the VFSM environment may be activated by actions-in such a case it is an output variable. A timer can have its OVER state (time-out occurred) as its most significant control value other values could be STOPPED or RUNNING. A numerical (analog) input variable has control properties such as: LOW, HIGH, OK, BAD, UNKNOWN according to its range of desired values. For instance, a digital variable could provide three control properties: TRUE, FALSE and UNKNOWN according to its possible boolean values. Control properties are not necessarily specific data values but are rather certain states of the variable. Those values are the control properties of this variable.
Finite state automata unity software#
In addition input signals can be unknown due to errors or malfunctions, meaning even digital input signals (considered as classical Boolean values) are in fact 3 values: Low, High, Unknown.Ī Positive Logical Algebra solves this problem via virtualization, by creating a Virtual Environment which allows specification of state machines for software using multivalued variables.Ī state variable in the VFSM environment may have one or more values which are relevant for the Control-in such a case it is an input variable. In a hierarchical control system the subordinate state machines can have many states that are used as conditions of the superior state machine.Commands may have several values: Init, Start, Stop, Break, Continue.In contrast state machines specified and implemented in software require logical conditions that are per se multivalued: In the hardware environment, where state machines found their original use, this is trivial: all signals are Boolean. Implementing a state machine necessitates the generation of logical conditions (state transition conditions and action conditions).
0 kommentar(er)
