Patent ID: 8279038

Claim:
A method for operating a field device of automation technology capable of special-functionalities, which can be enabled with the assistance of an enabling code, comprising the steps of: storing, in a superordinated, key-management unit, an enabling code set having a plurality of enabling codes, wherein associated with said enabling codes of said enabling code set is an attribute “free” or “blocked”; transmitting a data packet from a query unit to the key-management unit with a query for an enabling code having attribute “free”; testing whether an enabling code having attribute “free” is present in said enabling code set of the key-management unit; in case an enabling code with attribute “free” is present, transmitting a data packet with this free enabling code from the key-management unit to the query unit; changing the attribute of the transmitted enabling code from “free” to “blocked” in the key-management unit; and enabling special-functionalities associated with the transmitted enabling code in the field device.