if the output signal from the first and second measurement indicators is greater than zero i e both running gears are resting on the ground in this case the evaluation unit 22 can also generate a second control signal that indicates a controlled lowering of the building machine however a signal evaluation of this type is to be understood as being only one of a number of possible embodiments as the generation of corresponding signals and their evaluation belongs as such to the state of the art the signaling unit 30 comprises an acoustic and or a visual and or a tactile signal emitter 20 a 20 b 20 c if the signaling unit 30 receives a control signal from the evaluation unit 22 indicating an uncontrolled lowering of the building machine during the operating mode selected by the machine operator for adjusting the cutting depth the signaling unit sends the machine operator an acoustic and or a visual and or a tactile signal so that he can take the necessary steps to restore the machine to a controlled state by way of example it is assumed that in the operating mode for adjusting the cutting depth the machine operator lowers the machine frame more quickly that the cutting roller can penetrate the ground consequently at least one of the two running gears loses contact with the ground so that the evaluation unit 22 generates a signal indicating an uncontrolled lowering of the building machine this is immediately communicated.