| 摘要 |
PURPOSE:To detect abnormality such as locking of motor and to stop the motor by setting a first time limit longer than the period of pulse signal during normal operation of a motor, interrupting provision of a command signal to a motor drive circuit and stopping the motor forcibly. CONSTITUTION:When a motor 4 is locked abruptly, a first counter 2 is not kept at zero count but counts up subsequently to produce a High level signal so as to pull down the output from an inverter 10 to Low level. Consequently, output from an AND gate 11 goes to Low level and a delay circuit 7 starts time limit operation. Subsequently, the delay circuit 7 outputs a Low level signal to close the gate of an AND gate 8. Since no command signal is provided to the transistor TR3 in a motor drive circuit 9, the motor 4 is stopped forcibly. |
