The invention relates to methods and appropriate devices for safely, unequivocally and exclusively, temporarily assigning the command authority of an operator (1) to a controllable technical system (60) using a mobile control device (2) which is technically suitable for periodically controlling a plurality of controllable technical systems (60), which is equipped as standard with safety switch elements (38, 39) such as an emergency stop switch, ok key and operating mode selection switches and for a data coupling with the controllable technical system (60) in spite of having only normal transmission means (6) or network technologies without any particular features specific to safety function.