The MD series electric actuator adopts AC servo motor as the driving device, and the matching position locator PM-2 control board receives the 4 ~ 20mA DC control signal of the regulating system, and compares it with the position feedback signal of the position transmitter. After comparison, the signal deviation is amplified to turn on the power stage, and the motor rotates to drive the output of the actuator to move in the direction of reducing this deviation (the position transmitter continuously converts the output actual position into an electrical signal-the position residual feedback signal is sent to the position locator) until the deviation signal is less than the set value. At this time, the output of the actuator is stabilized at a position corresponding to the input signal.