The Type 8630 works as an electropneumatic positioner for pneumatically actuated control valves with piston actuators, e.g. the series 2702, 2712, 2730, 2731 and 2731K, as well as ball and butterfly valves with pneumatic rotary actuators. It forms an optical and functional unit. With its numerous software functions, Top Control Continuous Type 8630 may also be used as a process controller with PID characteristics. In this case a process control loop is superposed upon the positioner loop in a cascade structure. The process value is led directly to the Top Control as a standard current signal, frequency or PT-100 signal.