| 摘要 |
1. A system for controlling the rotation of the shaft (2) of a motor (1) so as to provide automatically an oscillatory motion of this shaft to one and the other side of a predetermined angular position (R) which remains fixed with the course of time the said system comprising contactors which determined the direction of rotation of the said motor, characterized in that it further comprises a disk (3) which accurately follows the rotation of the said shaft and is provided at its circumference with regularly spaced detection zones (4), two sensors (5) which are associated with a pulse-shaping unit (6) to detect the said zones and to translate their passage into calibrated electric pulses as well as their direction of passage into an electric signal, and also comprises an up/down counter (10) for the delayed said calibrated pulses, whose count is a number having a variable value (N), a display device (13) displaying a predetermined fixed nimber N', and, in a logic device (17) when receives the numbers N and N' as well as the said electric signal, a comparator (19) for comparing the numbers N and N', a detector (18) for detecting when the number N attains zero, a control unit (20) for changing the direction of rotation of the said motor and a control unit (21) for changing the counting direction of the said up/down counter (10). |
