A method of drafting a program code of control and instrumentation technology for operating a plant is disclosed using industrial components. The program code, in its graphical representation, comprises a plurality of sub-plans. The program code of the control and instrumentation technology and the industrial components are represented together in a machine-readable technology plan. The sub-plans, especially the functional plans of the individual plane, are automatically generated from the technology plan, and the individual sequences of the program code are generated from the functional plans. The method makes manual drafting or manual correction project planning superfluous.