A method for operating an automation system having automation units, a computer program for implementing the method and a computer system having such a computer program, wherein technology-oriented plant description data is stored in the automation system, the plant description data is organized in an object tree with nodes and edges, and wherein the plant description data comprises references to program data in individual automation programs and nodes of the object tree (36) containing references to program data are stored in or at least also in that automation unit which provides the respective program data.