Valve positioners are most often used for converting 4...20mA current signals into proportional pneumatic output signals for a pneumatic actuator or for driving a motor-operated actuator stepwise in the direction desired.
Digital bus signals such as Profibus, Fieldbus Foundation or ASI can also be used as control signals.
A digital positioner as a stock model
The SIPART PS2 digital valve positioner can be used in the case of both linear-motion and rotary-motion single-acting or double-acting pneumatic actuators. HART communication protocol is available as an option, which allows diagnostics acquisition from the valve and tuning with the help of a programming device.
Digital and electropneumatic positioners by from other manufacturers are also available.