| 摘要 |
<p>A position controller for a pressure medium-operated servo drive with a pilot stage (6, 7, 8) based on the principle of current/pressure conversion (I/P conversion), preferably a pneumatic pilot stage, and a main stage (5) which can be actuated through the latter and by means of which a final control element (1) can be acted upon by a pressure medium to execute a control movement, the pilot stage comprising an electronics unit (2) by means of which the pilot stage can be actuated. In order to be able to produce rapid venting of the pressure medium with the "intrinsically safe" type of ignition protection, the invention proposes that in the electrical actuation path between the electronics (2) and the pilot stage (6, 7, 8) there is a switching element (13) which cuts the electrical actuating signal to the pilot stage in the event of a malfunction, and in that in this case the pilot stage adopts a fail-safe position such that the control volume (1) of the final control element is vented through the main stage (5). <IMAGE></p> |
