A sensor unit includes at least one sensor for detecting and converting measured quantities into sensor signals; at least one microprocessor; at least one memory for program modules for processing sensor signals, the program modules being executable on the microprocessor; and at least one communications interface to an external application processor, the program modules being able to be activated and deactivated via this communications interface, and further program modules are able to be loaded into the memory via this communications interface. The microprocessor includes at least one closed environment for executing plug-in program modules.