A method for monitoring the operation of a machine comprising: a. providing at least a function linking at least one control parameter to at least one operating parameter; b. operating the machine and measuring the at least one control parameter and the at least one operating parameter while the machine is operating; c. on the basis of the at least one measured operating parameter, calculating by means of the at least a function the at least one control parameter; d. comparing the at least one measured control parameter with the at least one calculated control parameter and generating an alarm when they do not match, e. defining a fitting time window; f. adjusting the at least a function based on the at least a measured operating parameter and at least a measured control parameter measured through the fitting time window; g. defining an operating time window, which is temporally shifted after the fitting time window; and h. using over the whole operating time window the at least a function adjusted based on the fitting time window; characterized by: - defining a temporally longer fitting time window and a temporally shorter fitting time window, - calculating at least one longer control parameter and at least one shorter control parameter on the basis of the longer and shorter fitting time windows; - comparing the at least one measured control parameter with the at least one calculated longer and shorter control parameter; - generating an alarm when at least one of the at least one calculated longer and shorter control parameters does not match with the at least one measured control parameter; and further characterized in that the longer fitting time window is timely removed from an actual operating time of the machine and the shorter fitting time window is timely closer to the actual operating time; and the longer fitting time window and the shorter fitting time window are temporally shifted over time according to the actual operating time. a. providing at least a function linking at least one control parameter to at least one operating parameter; b. operating the machine and measuring the at least one control parameter and the at least one operating parameter while the machine is operating; c. on the basis of the at least one measured operating parameter, calculating by means of the at least a function the at least one control parameter; d. comparing the at least one measured control parameter with the at least one calculated control parameter and generating an alarm when they do not match, e. defining a fitting time window; f. adjusting the at least a function based on the at least a measured operating parameter and at least a measured control parameter measured through the fitting time window; g. defining an operating time window, which is temporally shifted after the fitting time window; and h. using over the whole operating time window the at least a function adjusted based on the fitting time window; - defining a temporally longer fitting time window and a temporally shorter fitting time window, - calculating at least one longer control parameter and at least one shorter control parameter on the basis of the longer and shorter fitting time windows; - comparing the at least one measured control parameter with the at least one calculated longer and shorter control parameter; - generating an alarm when at least one of the at least one calculated longer and shorter control parameters does not match with the at least one measured control parameter; and further characterized in that the longer fitting time window is timely removed from an actual operating time of the machine and the shorter fitting time window is timely closer to the actual operating time; and the longer fitting time window and the shorter fitting time window are temporally shifted over time according to the actual operating time.