The invention relates to a method for the exchange of engineering data (RED) between independent engineering tools (ET1 . . . ETx) of an engineering system (ESY) and to an engineering system, wherein engineering data (ET1PD . . . ETxPD) of each of the engineering tools (ET1 . . . ETx), which is associated with a project such as a production system, a switching system or a robot cell, is stored in a tool-specific data format in a data memory (SR, SPMR) associated with the engineering tool, and wherein user-selected engineering data (ET1D . . . ETxD) of the engineering tools, which is associated with a system function (SF1 . . . SFn) such as a project management function, a topology management function, a variable exchange function or a diagnosis function and which is of interest for at least an additional one of the engineering tools, is converted by means of a converting unit (ETC1 . . . ETCx) into a standardized data format and is stored in a standardized common data memory (CC). In order to optimize the exchange of engineering data at engineering time and in order to achieve minimal redundancy without change of the existing data models of the engineering tools, it is provided that changes of the selected engineering data (ET1D . . . ETxD) of the individual engineering tools (ET1D . . . ETxD), which is associated with a system function (SF1 . . . SFn), are continuously cached in the standardized common data memory (CC) and are read as needed at any time by one of the engineering tools (ET1 . . . ETx), and that, for a temporary access to all the engineering data (ET1PD . . . ET1XPD) associated with the project by a requesting engineering tool, a start of the providing engineering tool is carried out.