Emergency stop circuit

Two emergency stop lines (A,B) are provided in an emergency stop circuit for a motor (12). Due to contacts being opened by commands from emergency stop factors (14,15) and from first and second CPUs (10a,10b), conduction to first and second contactors (Ca,Cb) is stopped. Contacts of the contactors (Ca,Cb) are opened, and power supply to the motor (12) is interrupted, whereby an emergency stop is performed. Further, the first CPU (10a) on the first line (A) transmits an abnormality signal to the second CPU (10b) when the states of the contacts on the self emergency stop line, detected by digital inputs, are abnormal, and the second CPU (10b) opens a contact on the self emergency stop line so as to cause the contactor to be non-excited to thereby stop power supply to the motot (12).