JPS57202894A - Stop operation detector - Google Patents

Abstract

PURPOSE:To enable to accurately and effectively detect a superlow speed of a motor by outputting a stop operation detection signal when a time corresponding to the pulse width of a pulse synchronized with the rotation of a motor becomes longer than a set time. CONSTITUTION:A delay timer 20 outputs a signal after a delay of the prescribed time from the application of an operation signal S to the timer. Thus, an AND gate 13 outputs a pulse b corresponding to a pulse a from a pulse generator 12. A delay timer 14 outputs a signal d after a set time from the rise of a pulse b. AND gate 15 receives the output signal d of the timer 14 and a pulse b, and produces an output of the AND logic of both the inputs. NOR gate 12, a delay timer 17, and AND gate similarly output a signal when the pulse width of the pulse b is longer than a set time T2. An OR gate 19 outputs the outputs of AND gates 15, 18 as a stop operation signal X.