The Mitsubishi MELSERVO-J3 series general-purpose AC servo is based on the MELSERVO-J2-Super series and has further higher performance and higher functions. It has position control, speed control and torque control modes. Further, it can perform operation with the control modes changed, e.g. position/speed control, speed/torque control and torque/position control. Hence, it is applicable to a wide range of fields, not only precision positioning and smooth speed control of machine tools and general industrial machines but also line control and tension control. As this new series has the USB or RS-422 serial communication function, a MR Configurator installed personal computer or the like can be used to perform parameter setting, test operation, status display monitoring, gain adjustment, etc. With real-time auto tuning, you can automatically adjust the servo gains according to the machine. The MELSERVO-J3 series servo motor with an absolute position encoder which has the resolution of 262144 pulses/rev to ensure more accurate control as compared to the MELSERVO-J2-Super series. Simply adding a battery to the servo amplifier makes up an absolute position detection system. This makes home position return unnecessary at power-on or alarm occurrence by setting a home position once.