the optimation is immediately adapted to the distances the changes of the point of autolevelling application may be 3 mm between to measured values cv 1 and cv 2 the distances to the other measured values can be identical in order to obtain distance constant scanning only when the measurement of the cv value is effected with a sufficiently large number of individual measurements is a secured value for the storage as quality measured value of function a r and b k available with this method in the setting run the quality function a r and b k can thereby be determined in a continuous manner without stopping and setting the sliver the method is thus extremely fast operator friendly and very quiet for the actual production operation with the best adapted parameters the hardware or software realization in the control 11 to change the point of autolevelling application r of the pilot control is realized with variable memory length measured values originating from the thickness measurement d 0 n are continuously entered into these memory cells located in the memory they represent the momentary values of the sliver thickness going currently through the input scanner roller pair the memory in which the above mentioned length discrete measured values are stored has a variable length or shown in a circle an inflating and reducing circumference if the same distance between memory values are assumed on the circumference of the circle in the real memory area linear and one after the other the measured values are entered via indication of a pointer value in the memory and are read out at that same location the delay between two reading and writing cycles for a memory cell corresponds to the distance covered.