The positioner, option 4R is mounted to a pneumatic valve and allows you to operate the valve as a proportional valve and can be mounted to three different actuator sizes 50, 80 and 125. The positioner can be mounted to the actuator without having to disconnect the valve from the medium line. The positioner contains an optical LED seven-segment display which shows the valve stroke position in %. In addition, the input and output signals can be manually set on the positioner.