Madho controls offers pneumatic valve positioners used to increase or decrease the air pressure operating the diaphragm actuator until the valve stem reaches the position called for by the instrument controller. . It is mounted on the side of the diaphragm actuator and valve positioner is connected mechanically to the valve stem: so that stem position can be compared with the position dictated by the controller. A separate air supply is brought into the positioner for positioning the valve at exactly the point called for by the controller. The split range of the valve positioner available is 3-15 psig.
