Method and device to operate a positioner that communicates in digital and in analogue way over a single current loop

摘要

The regulator (10) has a pneumatic output unit (20) connected with an adjusting drive (16) of a safety positioner (12). A current source (26) is connected to a voltage source (30) of a power system (14) via a single two wire-current loop (28). The power source is controllably designed and impresses current into the loop based on measurement parameters. A position sensor (24) is connected with the current source. A computing unit (22) and the output unit are supplied with energy by the voltage source. A digital communication unit (32) evaluates and transmits digital commands via the loop. An independent claim is also included for a method for operating a position regulator.