The disclosure relates to a device and a method for monitoring the data traffic on a fieldbus of a process automation system which comprises a plurality of field devices for carrying out a process function, which field devices can be controlled via at least one higher-level control unit, with a monitoring appliance for the data traffic and for passing on information contained in the data traffic to the higher-level control unit being connected to the fieldbus. The invention proposes that the monitoring appliance continuously records quality parameters of the data traffic and communicates them directly via a data radio channel to the level of the higher-level control unit which analyzes the quality parameters of the data traffic.