Device and method for regulating a state variable in a process

摘要

The device has a fine controller (1) for comparing a reference variable (w1) with a control variable (x1) to determine a control variable (y1). The former control variable is dependent on a measured value of state variable. The reference variable gives a desired value of state variable. A coarse controller (3) compares other reference variable (w2) with control variable (x2) to determine the control variable (y2). The variable (y1) is supplied to fine control member (2) and other variable (y2) is supplied to coarse control member (4). The state variable is influenced by the control members. Independent claims are also included for the following: (1) a differential pressure controlling device comprising two connected measuring points (2) a method for regulating state variable of a process.