JPS5746687A - Stop controlling method for dc motor - Google Patents

Abstract

PURPOSE:To allow a DC motor to be stopped within allowable error limits, by a method wherein a time detecting point is provided in the halfway part of the moving angle, the time at said moving angle is compared with a reference time, and from the difference therebetween the reverse voltage application to the DC motor is corrected. CONSTITUTION:Timing pulse outputs P2, P3 of the code plate provided on the shaft of a DC motor, together with a given decelerating time T1, are fed to a flip- flop 13 through AND circuits 11, 12. When it is set, an AND circuit 14 is opened. With a clock pulse c as one input of an OR circuit 15, a counting clock pulse CL from the OR circuit 15 is fed to an up/down counter 16 so as to be counted up during a time T1 or until the AND circuit 14 is closed, and the count output (A) thereof is fed to a comparator 17 to compare with a digital value B on a reference timer t1'. Until A=B is reached, t clock pulses are delivered, and the up/down counter 16 counts them down through the OR circuit 15. Thereby, deceleration control time is corrected by means of a retriggerable monostable circuit 19 set by the t clock pulses.