The servo controller is the "brains" of the system. The servo controller can be something as simple as an ON/OFF switch or a dial controlled by an operator and as sophisticated as a multi-axis controller that actively servos several drives and monitors I/O while maintaining all of the programming for the machine. Typically, the servo controller sends a signal to the drive; the drive provides power to the motor; and the feedback from the motor is sent back to the controller, which analyzes the feedback signal and sends a new signal to the amplifier to correct for errors. The servo controller is considered to be the intelligent part of the system.