In closed-loop control, the motor (evaluation kit) is supplied with a factory-fitted encoder and motion control software. The driver PCB supplied with the close-loop system includes an additional daughter PCB, which is mounted on top of the driver PCB. Feedback from the motor encoder is transmitted to the daughter board and used to close the loop. The position and speed of the motor can be controlled through an elaborate set of commands via either a USB port (through Piezo Motion's GUI) or serial (RS 232) port commands. 

The daughter board performs two key functions. Firstly, it enables the communication between the encoder installed on the motor and the driver PCB microprocessor, which provides for precision linear or rotational closed-loop control. Secondly, the daughter board's communications unit allows piezo motor motion control via external devices using a USB or Serial Port (RS 232) interface. 

During the installation of the daughter board, the microcontroller is factory-programmed with proprietary encoder motion control algorithms. Once the daughter board is installed, the driver PCB will no longer work as a standalone driver. However, manual control of motor movement can still be achieved by pushing the Manual Control Buttons of the driver PCB.