Method for monitoring a rotating machine which is provided with a plurality of sensors for capturing physical parameters and is operated in a plurality of variable operating states, wherein the machine is a wind energy installation, and wherein: starting sensor data are obtained in at least one basic operating state (A, B, C) of the machine; a starting model for the machine is established in a knowledge-based manner on the basis of the starting sensor data using a set of rules for carrying out the monitoring process, which set of rules determines which parameters are intended to be monitored in which manner and with which weighting and which sensor data are intended to be obtained and used for this purpose; a reference SOM is created on the basis of the set of rules using sensor data which are selected on the basis of the set of rules and are obtained in a reference operating phase of the machine, wherein SOM is used to denote a self-organizing map; the temporal profile of the quantization error of the sensor data selected on the basis of the set of rules is tracked with respect to the reference SOM during a monitoring operating phase; troubleshooting is started if the quantization error satisfies a criterion predefined by the set of rules, at least one first diagnostic SOM is created on the basis of the set of rules using a subset of the sensor data obtained in the monitoring operating phase with regard to measuring times and/or the number of sensors and optionally using sensor data obtained in the reference operating phase, at least one 3-D diagram of the first diagnostic SOM(s) is created and is evaluated with the aid of the set of rules in order to identify the cause of a fault; if it is not possible to identify the cause of a fault from the evaluation of the first diagnostic SOM(s), at least one second diagnostic SOM is created using another subset of the sensor data obtained in the monitoring operating phase with regard to measuring times and/or the number of sensors and optionally using sensor data obtained in the reference operating phase and is evaluated in order to identify the cause of a fault; the starting model - and therefore the set of rules - is checked and modified on the basis of evaluations of the reference SOMs and/or the diagnostic SOMs provided that additional sensor data, on the one hand, and additional knowledge of the operating behaviour of the machine, on the other hand, are obtained. starting sensor data are obtained in at least one basic operating state (A, B, C) of the machine; a starting model for the machine is established in a knowledge-based manner on the basis of the starting sensor data using a set of rules for carrying out the monitoring process, which set of rules determines which parameters are intended to be monitored in which manner and with which weighting and which sensor data are intended to be obtained and used for this purpose; a reference SOM is created on the basis of the set of rules using sensor data which are selected on the basis of the set of rules and are obtained in a reference operating phase of the machine, wherein SOM is used to denote a self-organizing map; the temporal profile of the quantization error of the sensor data selected on the basis of the set of rules is tracked with respect to the reference SOM during a monitoring operating phase; troubleshooting is started if the quantization error satisfies a criterion predefined by the set of rules, at least one first diagnostic SOM is created on the basis of the set of rules using a subset of the sensor data obtained in the monitoring operating phase with regard to measuring times and/or the number of sensors and optionally using sensor data obtained in the reference operating phase, at least one 3-D diagram of the first diagnostic SOM(s) is created and is evaluated with the aid of the set of rules in order to identify the cause of a fault; if it is not possible to identify the cause of a fault from the evaluation of the first diagnostic SOM(s), at least one second diagnostic SOM is created using another subset of the sensor data obtained in the monitoring operating phase with regard to measuring times and/or the number of sensors and optionally using sensor data obtained in the reference operating phase and is evaluated in order to identify the cause of a fault; the starting model - and therefore the set of rules - is checked and modified on the basis of evaluations of the reference SOMs and/or the diagnostic SOMs provided that additional sensor data, on the one hand, and additional knowledge of the operating behaviour of the machine, on the other hand, are obtained.