Abstract: A method for monitoring an IO link system and/or at least one IO link device of the IO link system and/or a plant, a plant part and/or a process that works together with the IO link system is suggested. The current (Im), the voltage (Um) and/or the electrical power (Pm) are here recorded (42) at at least one port of an IO link master of the IO link system. A monitoring of a condition (Z) and/or a detection of anomalies, errors, deviations and/or maintenance indicators and/or a prediction of a maintenance requirement, an error and/or an outage of the IO link system and/or of the at least one IO link device and/or of the plant, of the plant part and/or of the process in the IO link master occurs by means of a model (M) for the current, the voltage and/or the electrical power previously learned via machine learning.