1. Method for controlling systems and/or machines ( 20 ), particularly decanters and separators, having the following steps, detecting operating conditions ( 30 - 36 ), such as current consumption, temperature, conveying speeds, etc. at the machine ( 20 ), collecting and storing the detected data in a data bank of a first computer ( 5 ), transmitting the data to a memory of a second computer ( 10 ), preferably to a computer ( 10 ) of the manufacturer of the machine ( 20 ), analyzing the data and comparison with the mathematical model of the machine ( 20 ), detecting the actual condition and generating a fault message if the actual condition deviates from the mathematical model, an automatic output of the fault message by the second computer ( 10 ) to a peripheral unit and/or to another computer.