Method and device for driving a electropneumatic valve of a pressure medium-actuated position regulator

摘要

Device for driving a electropneumatic 3 / 3 - valve (3) of a hydraulically operated position regulator (1), in which an electrical signal as a manipulated variable (y) within a process as a rule is - and control loop the electropneumatic 3 / 3 - valve (3) in order, which acts as an actuating drive is connected downstream of the booster stage (4) of the position regulator (1) with a pilot control pressure, wherein in order to achieve a blocking breakdown behaviour as a result of pressure means of case means for detecting the current position of the booster stage (4) according to the action of the pilot control pressure and associating the this position corresponding manipulated variable (y) are provided, and that sensor means for continuous measurement of at least one through the position regulator (1) as a rule, - or process parameter to be influenced are provided, wherein an evaluation unit (6) an expected directional - reaction (x '') of the rule - or process parameter to the predetermined control variable (y) is determined, and this expected directional - reaction (x'') with the measured actual directional - reaction (x) compares, as a rule, - or process parameter, and then a pressure means of a failure to signal as the case of a fault, if the expected direction - reaction (x '') are not connected to the actual directional - reaction (x) and a blocking failure behavior of the electropneumatic valve (3) generating electric emergency signal as a new correcting variable (y'') for the 3 / 3 - valve (3) to be prescribed.