| 摘要 |
PURPOSE:To prevent previously the runaway of a servomotor by protecting the servo system with outputs of both the 1st detecting circuit for absolute value of a current command signal and the 2nd detecting circuit for detection of frequency of a position feedback signal. CONSTITUTION:A deviation counter 1 obtains a deviation between a position command pulse S1 of a servo system and a position feedback signal S2 given from a rotary encoder 9. This deviation is applied to a PWM control circuit 5 via a D/A converter 2, etc. Thus the impressed voltage of a servomotor 6 is controlled for positioning control. The 1st and 2nd detection circuits 10 and 11 are provided to detect faults of the servo system. In addition, the circuit 10 detects that a current command signal S5 given from a speed control amplifier 3 exceeds a certain detection level. While the circuit 11 detects that the frequency of the signal S2 is lower than a certain level. The logic of both detection signals is obtained by an output circuit 12 to actuate a protection circuit for servo system. |
