| 摘要 |
PURPOSE:To protect the locking of a motor by suitably setting the output pulse width of a monostable multivibrator which inputs the logic product output of a motor drive command and a pulse width control signal, thereby enabling normal and reverse rotation without control of the motor drive command. CONSTITUTION:When a motor drive command MS and a pulse width control signal PS become ''H'' at the starting time, the output Q of a monostable multivibrator 21 becomes ''H'', and a drive pulse OP becomes equal to the signal PS. The signal PS becomes ''H'' during the prescribed period at the reverse rotation time, the command MS does not alter but maintains ''H''. Accordingly, the output Q of the multivibrator 21 becomes ''H'' during the reverse rotation period. When the motor is locked during the operation and the pulse width of the signal PS becomes wider than that of the output Q of the multivibrator 21, an AND circuit is interrupted, the drive pulse OP is not outputted, and the motor is abruptly stopped. |
