A data loading process is disclosed for coupling a supplementary system (ZAS) to an automation total system (ABS) provided with a basic system (BAS). The contents of the main memory (HSB) of the basic system (BAS) are transmitted by reading and writing them section by section into the main memory (HSB) of the supplementary system (ZAS). While the data are read section by section and written out of or into the main memory (HSB) of the basic system (BAS), the same data are written into a temporary memory (ZSB) and transmitted from the temporary memory (ZSB) to the main memory (HSB) of the supplementary system (ZAS).
