Abstract: The invention relates to a drive unit for a power operated tool for the generation of a screw pretensioning force, with a pump unit (2), a valve unit (3) arranged on the pump unit with a pressure-restricting pressure valve (4) and a control unit (2) for activating the pump unit. In order to provide a drive unit that eliminates the risk of an incorrect setting of the setting parameter, it is provided that a processing unit (5) with an output unit and a data capturing unit (6) connected and/or integrated with the processing unit are provided, wherein the processing unit is designed for the output of the value to be set on the pressure valve based on the screw connection process parameters determined with the data capturing unit.