# PLCs – A counter PLC as a function

Any automaton can be seen as a function $$f: Sigma ^ * to {0,1 }$$, namely, let $$f$$ to be the characteristic function of the language that he accepts; or in other words, define $$f (x) = 1$$ if the word $$x$$ is accepted by the automaton, otherwise $$f (x) = 0$$. This is true for only one finite automaton.