In an apparatus and method for operating an apparatus having a mobile part which is movable on a movement plane and has a measuring unit, and a measuring body which is set apart from the movement plane and from the plane parallel to the movement plane that includes the measuring unit, for example, and is situated as far as possible from the movement plane, the measuring unit is adapted to determine the distance between the measuring body and the measuring unit in a normal direction to the movement plane, and the measuring body is shaped such that in the projection of the measuring body perpendicular onto the plane, e.g., the projection surface, an individual distance value is bijectively allocated to the, or to the plurality of, partial surface regions of the projection surface, which particularly do not overlap one another.