METHOD TO CONTROL A PROCESS VARIABLE

A method to control a process variable in a process using a control unit includes sequential determination of values of a reference variable to be supplied to the control unit based on values of a first measurand, and sequential determination of values of a regulating variable using values for the reference variable and sequentially determined values for the process variable. A current value for the reference variable is determined by sequentially saving values of the first measurand in a first FIFO memory having a number K of memory locations for saving one value respectively, and by using only the n oldest values saved in the first FIFO memory to determine the current value for the reference variable, with n being a number of values that is smaller than the number K of the values saved in the memory locations of the first FIFO memory and greater or equal 1.