Patent ID: 8206554

Claim:
A method for controlling a manufacturing or finishing process of a fiber web during a transition stage of the manufacturing or finishing process, wherein before the transition stage, a last actuator profile, or a last control signal are stored in a memory, the method comprising the steps of: when the transition stage begins, selecting a plurality of correction profiles stored in the memory which correspond to an earlier corresponding transition stage; determining a first corrected error profile by selecting one of said plurality of correction profiles from the memory, or by selecting an error profile obtained from the memory, the error profile selected from memory being an error profile determined before the transition stage, or a zero profile; obtaining from the memory the last control signal used before the transition stage, or the last actuator profile; forming a control signal based on the first corrected error profile, and the last control signal, or the last actuator profile; transmitting the control signal to at least one actuator, and storing the control signal in the memory; measuring the fiber web in a cross machine direction to obtain measurement results, and transmitting the measurement results at intervals to a control unit; comparing in the control unit the measurement results to target values to determine an error profile; correcting the error profile by using a selected corresponding one of said plurality of correction profiles from memory to form a corrected error profile; obtaining from the memory the control signal in the memory which was previously stored; or the last actuator profile; forming a control signal based on the corrected error profile and the control signal in the memory which was previously stored, or the last actuator profile; transmitting the control signal to the at least one actuator, and storing the control signal in the memory; repeating the steps of measuring the fiber web in the cross machine direction to the step of transmitting the control signal to at least one actuator until the transition stage is complete, whereupon the error profile without correction is used as a basis for forming the control signal.