Patent ID: 7139618

Claim:
A method of operation for a central unit in an automation system, the central unit repeatedly executing a control program that is stored in the central unit, a single instance of the execution of the control program occurring within a cycle time which is set by the control program, the control program comprising at least two subprograms, wherein only one of the subprograms is activated at a time, the central unit executing only an activated subprogram, the cycle time being independent of the activated subprogram, shorter than the time required in order to execute all of the subprograms, and at least as long as the longest of the times periods required in order to execute one of the subprograms once, the method comprising the steps of: (a) communicating via a bus with a plurality of peripheral modules during the execution of the control program; (b) splitting the cycle time into a plurality of time slices, wherein the number of time slices is smaller than the plurality of peripheral modules; (c) assigning each of the plurality of peripheral modules to a maximum of one of the time slices in activating one of the subprograms; and (d) communicating with a single one of the plurality of peripheral modules within each time slice, wherein the peripheral modules are associated with the time slice during the execution of the activated subprogram.