A bus system has a bus, a number of units which can be connected to one another via the bus, and a bus controller. The inventive method is characterized in that the space located behind the side of the porous support, which is not to be coated, is filled with an inert fluid during the production of the solid layer on the porous support, \u201cbehind\u201d being from the perspective of the support. The method may include determining a subset of screens associated with the behavior.