LabVIEW – State Machines
Gary Boorman
Finite State Machine I
•A Finite State Machine (FSM or State Machine)
is a behavioural model used to design computer
programs.
•It is composed of a finite number of states
associated with transitions.
•A transition is a set of actions that starts from
one state and ends in another (or the same)
state.
•A transition is started by a trigger, and a trigger
can be an event or a condition.
Post-Grad LabVIEW Course G Boorman
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Finite State Machine II
Post-Grad LabVIEW Course G Boorman
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Simple SM Implementation
•Uses a While loop with Shift Register, Case
Structure and Enum
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Finite State Machine III
•State Machines are extremely useful in
Control, DAQ and Analysis systems
•Easily constructed in Labview
•Easily scaled to larger state machines – more
states, choice of next-state
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Simple Traffic Light FSM
FSM operates to defined pattern
Traffic
waiting?
Red
red:T; amber:F;
green:F
Timer=3s
Amber
RedAmber
r:F; a:T; g:F
Start Timer
r:T; a:T; g:F
Start Timer
Green
Timer=2s
r:F; a:F; g:T
Start Timer
Timer=20s
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Simple Traffic Light FSM
•FSM has a choice of next state
Red
r:T; a:F; g:F
Run Normal
Amber
Run Backwards
Green
r:F; a:T; g:F
Start Timer
Timer=20s
r:F; a:F; g:T
Start Timer
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