Method for providing an expanded name service for an industrial automation system, in which - in a name service system comprising at least one name service server, name-address assignments between device names and communication network addresses are registered for automation devices and/or communication devices, on the basis of which an assigned communication network address is provided in response to a name resolution request, wherein device names registered in the name service system have a hierarchical structure represented by a tree structure, and the tree structure comprises a root node, internal nodes and end nodes, characterized in that, - in addition to the name-address assignments, assignments between device names and plant identification codes in accordance with DIN 40719-2 or EN 81346 for automation devices and/or communication devices are registered in the name service system, - the device names and the plant identification codes of automation devices and/or communication devices of an automation plant are administered within separate plant-specific partial trees (121, 122) of the tree structure, and the root node of the partial tree for the device names comprises a reference to the assigned root node of the partial tree for the plant identification codes, - the plant identification codes are registered within the same tree structure as the device names, and end nodes which are respectively assigned to the plant identification codes in the tree structure contain a reference to end nodes which are respectively assigned to the device names, - when a plant identification code is registered, the assigned device name is determined, - the root node of the partial tree for the device names is determined on the basis of the determined device name, - the assigned root node of the partial tree for the plant identification codes is determined on the basis of the determined root node of the partial tree for the device names, - an end node below the determined root node of the partial tree for the plant identification codes is generated for the plant identification code to be registered, - when there is a request to resolve a plant identification code a device name is determined on the basis of the assignments between the device names and plant identification codes and a name resolution request for the determination of an assigned communication network address is made for said device name. - in a name service system comprising at least one name service server, name-address assignments between device names and communication network addresses are registered for automation devices and/or communication devices, on the basis of which an assigned communication network address is provided in response to a name resolution request, wherein device names registered in the name service system have a hierarchical structure represented by a tree structure, and the tree structure comprises a root node, internal nodes and end nodes, - in addition to the name-address assignments, assignments between device names and plant identification codes in accordance with DIN 40719-2 or EN 81346 for automation devices and/or communication devices are registered in the name service system, - the device names and the plant identification codes of automation devices and/or communication devices of an automation plant are administered within separate plant-specific partial trees (121, 122) of the tree structure, and the root node of the partial tree for the device names comprises a reference to the assigned root node of the partial tree for the plant identification codes, - the plant identification codes are registered within the same tree structure as the device names, and end nodes which are respectively assigned to the plant identification codes in the tree structure contain a reference to end nodes which are respectively assigned to the device names, - when a plant identification code is registered, the assigned device name is determined, - the root node of the partial tree for the device names is determined on the basis of the determined device name, - the assigned root node of the partial tree for the plant identification codes is determined on the basis of the determined root node of the partial tree for the device names, - an end node below the determined root node of the partial tree for the plant identification codes is generated for the plant identification code to be registered, - when there is a request to resolve a plant identification code a device name is determined on the basis of the assignments between the device names and plant identification codes and a name resolution request for the determination of an assigned communication network address is made for said device name.