Patent ID: 8282071
Filing Date: 2012-10-09
Classification: F15B,Y10T

Abstract:
1. A method of activating an electropneumatic valve of a pressure medium-operated position controller to achieve a blocking fail-safe behavior in the event of a failure of a pressure medium, the electropneumatic valve being activated by an electrical signal as a manipulated variable within a process regulation and control loop, so as to act with a pilot control pressure upon a booster stage of a position controller downstream of the electropneumatic valve, the method comprising: detecting a current position of the booster stage after action with the pilot control pressure and assignment of a manipulated variable corresponding to the detected current position; continuously measuring at least one of a regulation variable and a process variable to be influenced by the position controller; determining an expected directional reaction of the at least one of the regulation variable and process variable to the assigned manipulated variable; comparing the determined expected directional reaction with the measured actual directional reaction of the at least one of the regulation variable and process variable; determining existence of a pressure medium failure, upon detecting that the expected directional reaction does not coincide with the actual directional reaction; and assigning an electrical emergency signal generating the blocking fail-safe behavior of the electropneumatic valve as a new manipulated variable.