The YT1000 series of electric locators and pneumatic control valves are used to form the closed-loop control loop. The dc current signal given by the control system is converted into the gas signal to drive the regulating valve and the action of the control valve is controlled. The valve position can be correctly positioned according to the control signal of the system according to the opening of the control valve. The electric positioner can be used for single acting type (spring reset type) and double acting pneumatic actuator.