| 摘要 |
PURPOSE:To provide positional control with high reliability even under disturbances by noises by additionally adding a prohibition circuit and a control circuit to a control device, and effecting stop control of a closed circuit by a counter only when an one-revolution pulse is properly obtained from its original point. CONSTITUTION:An one-revolution pulse RP1 is generated, a stop position command is loaded to a counter 104, and a positional pulse ABP is counted. Then, even if the counter 104 is overflowed, switching to a closed loop by counter 104 control is effected. When the counter 104 is again subjected to the stop position command, generation of an one-revolution pulse RP2 is detected to open a gate 112b. And, a switching circuit 106 is switched by the overflow of the counter 104, allowing stop control by the closed loop to be started. Accordingly, even if any noise NS2 is produced of the one-revolution pulse RP1 and it is delivered from a gate 110b, a flip-flop 112a is not set unless a comparison coincidence output COMP from a comparator 111 is provided, whereby erroneous operation is prevented from being caused. |
