A controller for a wind turbine with an operating software for operating the wind turbine , wherein the operating software is set up to regulate or control at least an electrical output of a wind turbine generator, a speed of a wind turbine rotor , an azimuth angle of a wind turbine nacelle , and a pitch angle of at least one rotor blade of the wind turbine rotor , wherein the operating software comprises a core module and at least one customer application , wherein the customer application is set up to determine a parameter , in particular a control variable, in particular a target value, depending on at least one function of the customer application , and provide it for the core module , and wherein the core module is set up to - Detect and/or predict a load acting on the wind turbine during an operation of the wind turbine , - In a case where a detected or predicted load lies below a predefined load limit , to operate the wind turbine as a function of the parameter provided by the customer application , and - In a case where a detected or predicted load exceeds the predefined load limit , to adjust the prepared parameter and leave the wind turbine unconsidered as a function of the adjusted parameter or the provided parameter , and operate the wind turbine with a parameter determined in the core module , wherein the controller further has a first programming interface and a second programming interface , wherein the first programming interface is set up to program the core module , in particular the load limits , and wherein the second programming interface is set up to program the customer applications , in particular their function , and prevent the core module from being reprogrammed via the second programming interface . wherein the customer application is set up to determine a parameter , in particular a control variable, in particular a target value, depending on at least one function of the customer application , and provide it for the core module , and wherein the core module is set up to - Detect and/or predict a load acting on the wind turbine during an operation of the wind turbine , - In a case where a detected or predicted load lies below a predefined load limit , to operate the wind turbine as a function of the parameter provided by the customer application , and - In a case where a detected or predicted load exceeds the predefined load limit , to adjust the prepared parameter and leave the wind turbine unconsidered as a function of the adjusted parameter or the provided parameter , and operate the wind turbine with a parameter determined in the core module , - Detect and/or predict a load acting on the wind turbine during an operation of the wind turbine , - In a case where a detected or predicted load lies below a predefined load limit , to operate the wind turbine as a function of the parameter provided by the customer application , and - In a case where a detected or predicted load exceeds the predefined load limit , to adjust the prepared parameter and leave the wind turbine unconsidered as a function of the adjusted parameter or the provided parameter , and operate the wind turbine with a parameter determined in the core module , wherein the controller further has a first programming interface and a second programming interface , wherein the first programming interface is set up to program the core module , in particular the load limits , and wherein the second programming interface is set up to program the customer applications , in particular their function , and prevent the core module from being reprogrammed via the second programming interface . <EOS>