The air quality transducer FS1300 registers CO2, VOC, humidity and temperature. The measuring transducer converts the measured values into a digital output signal.In the register the switching threshold, hysteresis, offset value etc can be specified. A zero point adjustment can be performed using a command.The air quality sensor performs an automatic recalibration at regular interval, thus ensuring a long-term stable CO2 measurement.As special equipment a potential-free alternating contact and/or a backlit display are available The contents of the display can be rotated in steps of 90° by using a command.As special functions a series of defined measured values from other bus-participants (also cross-manufacturers) can be shown in the display. To display measured values from other bus-participants these are entered into the corresponding register by the bus-Master. The optional alternating contact can be configurated for measured values from other bus-participants.The configuration of address, transmission mode/speed, terminating resistor and master/slave function of the bus-devices can easily be done using the innovative DIP switch technology. Thus devices can quickly and easily integrated into the system and later parameterised via the master.The bus-devices can even be reset to the works settings during operation of the master. Thus the basic functionality of the device is recreated in a matter of seconds. This can be necessary in the event of incorrect parameterisations of, e.g. offset, switching threshold, display modes etc..By means of the FS master/slave topology autarkic nodes without additional SPS master can be installed within the device series. Hereby a bus-device assumes the master function in the node. This requests the measured values from other bus-participants, automatically enters these into the corresponding register and shows them in the internal display. Furthermore the master can evaluate and operate additional actuators in the device series (analogue in- and outputs, relay station).