| 摘要 |
PURPOSE:To prevent a malfunction due to noises, by reading an encoder output signal of double phases as a feedback signal and shifting the reading timing in accordance with the revolving direction of a servomotor. CONSTITUTION:A servomotor revolution indicating signal consisting of the information on the revolving direction and revolving quantity given from a CPU (not shown in the diagram) is fed to a buffer 1. The information on the revolving quantity is supplied to a counter 2 from the buffer 1. The outputs of the buffer 1 and counter 2 are supplied to a servomotor driving circuit 3, and a servomotor 4 is rotated in a desired direction. When the motor 4 starts its revolution, output signals A and B are delivered from an encoder 5 and then read by an encoder feedback circuit 6. In the case of the counterclockwise revolution of the motor 4, the signal B is read with a delay of time different from an integer-fold value of the noise period given by a timer. With a combination of levels of signals A and B and the forward and backward revolutions of the motor, the counter 2 performs subtration. Then the motor 4 is stopped when the count value of the counter 2 is set at 0. |
