Malfunction determination device for motor control system

A malfunction determination device for a motor control system that includes position signal output means for outputting a position signal that indicates a moved position of a movable member of a motor and direction signal output means for outputting a direction signal that indicates a movement direction of the movable member to execute operation control of the motor, the malfunction determination device comprising:

• malfunction determination means for determining a malfunction has occurred if a relationship between the position signal and the direction signal differs from that when no malfunction has occurred in the motor control system,
• wherein:
• the position signal output means outputs a pulse signal that varies periodically along with variations in the moved position of the movable member as the position signal,
• the direction signal output means outputs a periodic pulse signal in the same phase with the position signal as the direction signal if the movable member is moving in one of a forward direction and a reverse direction, and
• the direction signal output means outputs a periodic pulse signal in an opposite phase to the position signal as the direction signal if the movable member is moving in the other of the forward direction and the reverse direction.

A malfunction determination method for a motor control system that executes operation control of a motor, the method comprising:

• outputting, as a position signal that indicates a moved position of a movable member of the motor, a pulse signal that varies periodically along with variations in the moved position of the movable member;
• outputting a periodic pulse signal in the same phase with the position signal as a direction signal that indicates a movement direction of the movable member if the movable member is moving in one of a forward direction and a reverse direction;
• outputting a periodic pulse signal in an opposite phase to the position signal as the direction signal that indicates the movement direction of the movable member if the movable member is moving in the other of the forward direction and the reverse direction;
• and
• determining that a malfunction has occurred if a relationship between the position signal and the direction signal differs from that when no malfunction has occurred in the motor control system.