Understanding Control Valve Positioners vs. Actuators – What’s the Difference? In process control, control valves are essential for regulating flow, pressure, and level. However, two important components often cause confusion: the actuator and the positioner. Actuator = The muscle The actuator provides the force needed to move the valve stem in response to a control signal. It is responsible for physically opening or closing the valve. Positioner = The brain The positioner ensures that the valve