POSITIONER FOR DOUBLE-ACTING PNEUMATIC ACTUATOR, DOUBLE-ACTING PNEUMATIC ACTUATOR AND METHOD FOR OPERATING THE DOUBLE-ACTING PNEUMATIC ACTUATOR

摘要

In a positioner for a double-acting pneumatic actuator having first and second pneumatically loadable working chambers as well as a movable working part which is shiftable for an actuating movement at a pressure difference in the first and second working chambers, the positioner comprises first and second pneumatic control signals output to the first and second working chambers, respectively. At least one adjusting device for adjusting the first pneumatic control signal for the first working chamber is provided. The adjusting device is designed such that the adjustment of the first control signal according to a control leaves the second control signal unaffected. In a method for operating the double-acting pneumatic actuator, an average pressure value of the first and the second working chambers is determined in a fully regulated state of the actuator. For increasing or reducing respectively a stiffness of the actuator, the average pressure value of the working chambers is increased or decreased, respectively.