Compressed air conditioning apparatus comprising the following components: - an electrically actuable valve device having a feed inlet connectable to a compressed air source and a working outlet, - an apparatus outlet, which is connectable to an external consumer device and connected to the working outlet of the valve device via an outlet passage, - sensor means, at least in the form of a flow sensor for measuring the outlet flow in the outlet passage and of an outlet pressure sensor for measuring the outlet pressure in the outlet passage, - and an internal electronic control unit, which is connected in terms of signal technology both to the valve device and to the sensor means and which is designed to generate an electric valve control signal for the valve device as a function of the state values of the compressed air measured by the sensor means, characterised in that - the valve device is designed as an electrically actuable proportional pressure control valve, which is capable of controlling the outlet pressure in the outlet passage to produce different outlet pressure values as a function of the electric valve control signal applied to it, wherein it can be operated both in a working mode in which it controls the outlet pressure to produce a working pressure value and in a standby mode in which it controls the outlet pressure to produce a standby pressure lower than the working pressure value, - and in that the electronic control unit is designed such that it (a) automatically outputs an electric valve control signal which transfers the proportional pressure control valve from the working mode to the standby mode if the flow sensor detects over a preset or presettable period of time a flow value corresponding to or undershooting a preset or presettable switch-off flow limit value, and that it (b) also automatically outputs an electric valve control signal which resets the proportional pressure control valve from the standby mode to the working mode if the flow sensor detects during the standby mode a flow value corresponding to or exceeding a preset or presettable switch-on flow limit value. - an electrically actuable valve device having a feed inlet connectable to a compressed air source and a working outlet, - an apparatus outlet, which is connectable to an external consumer device and connected to the working outlet of the valve device via an outlet passage, - sensor means, at least in the form of a flow sensor for measuring the outlet flow in the outlet passage and of an outlet pressure sensor for measuring the outlet pressure in the outlet passage, - and an internal electronic control unit, which is connected in terms of signal technology both to the valve device and to the sensor means and which is designed to generate an electric valve control signal for the valve device as a function of the state values of the compressed air measured by the sensor means, - the valve device is designed as an electrically actuable proportional pressure control valve, which is capable of controlling the outlet pressure in the outlet passage to produce different outlet pressure values as a function of the electric valve control signal applied to it, wherein it can be operated both in a working mode in which it controls the outlet pressure to produce a working pressure value and in a standby mode in which it controls the outlet pressure to produce a standby pressure lower than the working pressure value, - and in that the electronic control unit is designed such that it (a) automatically outputs an electric valve control signal which transfers the proportional pressure control valve from the working mode to the standby mode if the flow sensor detects over a preset or presettable period of time a flow value corresponding to or undershooting a preset or presettable switch-off flow limit value, and that it (b) also automatically outputs an electric valve control signal which resets the proportional pressure control valve from the standby mode to the working mode if the flow sensor detects during the standby mode a flow value corresponding to or exceeding a preset or presettable switch-on flow limit value. (a) automatically outputs an electric valve control signal which transfers the proportional pressure control valve from the working mode to the standby mode if the flow sensor detects over a preset or presettable period of time a flow value corresponding to or undershooting a preset or presettable switch-off flow limit value, and that it (b) also automatically outputs an electric valve control signal which resets the proportional pressure control valve from the standby mode to the working mode if the flow sensor detects during the standby mode a flow value corresponding to or exceeding a preset or presettable switch-on flow limit value.