A method to control a unit of a technical apparatus, where the apparatus can be operated in a plurality of operating circumstances in which the unit is controlled with a control command belonging to respective operating circumstance in order to active an operating mode associated with the operating circumstance The apparatus comprises a control unit having a program installed, this control program defining a framework comprising fundamental logical components with which information to describe the operating circumstances are prepared. A file describing the unit is present that comprises a logic unit comprising a logical expression as well as the associated control command, the logical expression defining one of the operating circumstances. The logical expression is read from the file into the control unit; a query of the logical expression identifies the operating circumstance, the logical expression defining one of the operating circumstances. The corresponding control command is subsequently output.