Abstract: The present invention relates to a compressed air processing system. The compressed air processing system includes an inlet connection, a pressure control unit, a multi-circuit protection valve, a plurality of outlet connections, a parking brake connection, an electronic control unit and a valve arrangement. The inlet connection is connected to a conduit coming from a compressor. Each of the outlet connections is connected to a circuit (I, II, and so forth). The parking brake connection is connected to a conduit coming from a parking brake cylinder. The electronic control unit includes an electric input connection for a control signal. The valve arrangement aerates and locks the parking brake connection in a controlled way due to a signal being generated by the electronic control unit. The valve arrangement also deaerates the parking brake connection due to a signal being generated by the electronic control unit.