Operating a programmable logic controller

A method for updating and operating a programmable logic controller, the method comprising:

• generating a list of allowed actuator output parameters by recording all sensor input data and actuator output parameters of an initial application logic and correlating the recorded sensor input data and actuator output parameters to generate the list of allowed actuator output parameters;
• receiving application logic update data in an update checking layer of the programmable logic controller, wherein the application logic update data contains information for updating the initial application logic of the programmable logic controller;
• checking the application logic update data by the update checking layer, to assess whether the application logic update data is allowed application logic update data by verifying that every application logic update defined by the application logic update data corresponds to an application logic update from a list of allowed application logic updates;
• and
• updating the initial application logic with the application logic update data only if the application logic update data is allowed application logic update data;
• receiving sensor input data from at least one sensor coupled to the programmable logic controller;
• processing the sensor input data with the updated initial application logic stored in the programmable logic controller to generate an actuator output parameter;
• receiving the actuator output parameter in an output checking layer of the programmable logic controller;
• checking, during runtime, the actuator output parameter by the output checking layer, to assess whether the actuator output parameter is an allowed actuator output parameter by verifying whether the actuator output parameter corresponds to the list of allowed actuator output parameters;
• and
• outputting only an allowed actuator output parameter to an actuator coupled to the programmable logic controller.