The increasing spread of fieldbus installations in industrial environment leads to increased amount of information and a large number of new innovative functionalities. These are not only important for classical tasks of process control engineering (like plant and process supervision or process control), but also for advanced functions, like synthesised plant data for the economical optimisation of technical system support. The concept of the Asset Management Box (AMBox) is considered, which realises an additional information channel between field and plant control level. This contribution describes the AMBox as an open, configuration-free and manufacturer-independent access to field device functionality for the PROFIBUS-PA fieldbus. Since the configuration data of field devices to perform their functional role is kept, exchanging field devices is possible without need for reconfiguration. Finally, some Asset Management applications of the AMBox are discussed.