système de commande numérique en boucle fermée

CONT: The closed loop system is similar to the open loop system with the exception that a feedback unit is introduced in the electrical circuit. This feedback unit, generally called a transducer, compares the amount the machine table has been moved by the servo motor with the signal sent by the control unit. The control unit instructs the servo motor to make whatever adjustments are necessary until both the signal from the control unit and the one from the servo unit are equal.... Closed loop numerical control systems are very accurate because the accuracy of the command signal is recorded and there is an automatic compensation for error.