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A device for activating an electropneumatic valve of a pressure medium-operated position controller, in which the valve is activated by a manipulated variable. To achieve a blocking fail-safe behavior in case of a failure of a pressure medium, the device includes means for detecting the current posi

A device for activating an electropneumatic valve of a pressure medium-operated position controller, in which the valve is activated by a manipulated variable. To achieve a blocking fail-safe behavior in case of a failure of a pressure medium, the device includes means for detecting the current position of a booster stage downstream of the valve and assigning the manipulated variable based on the detected position, and means for measuring a first variable to be influenced by the position controller. The device includes an evaluation unit configured to determine an expected directional reaction of the first variable to the assigned manipulated variable, compare the expected reaction with the measured reaction, determine a pressure medium failure as a fault situation if the expected reaction does not coincide with the measured reaction, and assign, as a new manipulated variable for the valve, an emergency signal generating a blocking fail-safe behavior of the valve.

대표청구항 ▼

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

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; andassigning an electrical emergency signal generating the blocking fail-safe behavior of the electropneumatic valve as a new manipulated variable. 2. The method as claimed in claim 1, comprising discharging, via an electrical activation signal, the pressure medium acting upon the booster stage to a surrounding atmosphere via an exhaust air duct of the electropneumatic valve, to achieve a reversal of activation opposite to an original direction of the activation. 3. The method as claimed in claim 1, comprising enclosing, via the electrical emergency signal, the pressure medium acting upon the booster stage via a neutral position of the electropneumatic valve, to achieve a leaktight closure. 4. The method as claimed in claim 1, wherein the expected directional reaction is constituted by a mathematical relationship of a first derivative of an expected speed signal, wherein the comparing comprises comparing the expected directional reaction with a measured speed signal. 5. The method as claimed in claim 4, wherein the measured speed signal and the expected speed signal possess the same direction, and wherein the method comprises establishing a pressure medium failure as a fault situation when the expected directional reaction does not correspond to a measured direction of the actuating drive. 6. The method as claimed in claim 5, comprising applying, in the measured speed signal, a tolerance band corresponding to a system-induced induced quantization noise, to prevent an unwanted detection of a pressure medium failure. 7. The method of claim 1, wherein the electropneumatic valve is an electropneumatic 3/3-way valve. 8. A device for the activation of an electropneumatic valve of a pressure medium-operated position controller, the electropneumatic valve being configured to be activated by an electrical signal constituting a manipulated variable within a process regulation and control loop, to act with a pilot control pressure upon a booster stage downstream of the electropneumatic valve to actuate an acutating drive, the device being configured to achieve a blocking fail-safe behavior as a result of the failure of a pressure medium, the device comprising: detecting means for detecting a current position of the booster stage after action with the pilot control pressure and assigning the manipulated variable to correspond to the detected current position;sensor means for continuously measuring at least one of a regulation variable and a process variable to be influenced by the position controller;evaluation means for determining an expected directional reaction of the at least one of the regulation variable and process variable to the assigned manipulated variable, and to compare the expected directional reaction with the measured actual directional reaction of the at least one of the regulation variable and process variable;determining means for determining existence of a pressure medium failure upon the evaluation means determining that the expected directional reaction does not coincide with the actual directional reaction; andassigning means for assigning an electrical emergency signal generating a blocking fail-safe behavior of the electropneumatic valve as a new manipulated variable for the electropneumatic valve. 9. The device as claimed in claim 8, wherein the detecting means for detecting the current position of the booster stage comprises a contactlessly operating inductive or capacitive position sensor. 10. The device as claimed in claim 8, wherein the sensor means for continuously measuring the at least one of the regulation variable and process variable to be influenced by the position controller comprises a displacement sensor configured to detect a position of the actuating drive. 11. A pressure medium-operated position controller for a fitting, comprising an electropneumatic 3/3-way valve configured to actuate a booster stage downstream of the electropneumatic 3/3-way valve via a pilot control pressure, and a device as claimed in claim 10, to achieve a blocking fail-safe behavior as a result of the failure of a pressure medium. 12. A pressure medium-operated position controller for a fitting, comprising an electropneumatic 3/3-way valve configured to actuate a booster stage downstream of the electropneumatic 3/3-way valve via a pilot control pressure, and a device as claimed in claim 8, to achieve a blocking fail-safe behavior as a result of the failure of a pressure medium. 13. The device as claimed in claim 8, wherein the electropneumatic valve is an electropneumatic 3/3-way valve. 14. A device configured to activate an electropneumatic valve of a pressure medium-operated position controller, the electropneumatic valve being configured to be activated by an electrical signal constituting a manipulated variable within a process regulation and control loop, to act with a pilot control pressure upon a booster stage downstream of the electropneumatic valve to actuate an acutating drive, the device being configured to achieve a blocking fail-safe behavior as a result of the failure of a pressure medium, the device comprising: a detector configured to detect a current position of the booster stage after action with the pilot control pressure and assign the manipulated variable to correspond to the detected current position;a sensor configured to continuously measure at least one of a regulation variable and a process variable to be influenced by the position controller; andan evaluation unit configured to determine an expected directional reaction of the at least one of the regulation variable and process variable to the assigned manipulated variable, to compare the expected directional reaction with the measured actual directional reaction of the at least one of the regulation variable and process variable, to determine existence of a pressure medium failure upon the evaluation unit determining that the expected directional reaction does not coincide with the actual directional reaction, and to assign an electrical emergency signal generating a blocking fail-safe behavior of the electropneumatic valve as a new manipulated variable for the electropneumatic valve.