Patent ID: 7411966

Claim:
An industrial control system for transmitting data by means of a first data network being an isochronous real-time Ethernet and comprising means for transmitting data in at least one first transmission cycle within the first data network, said transmission cycle being subdivided into a first area for transmitting real-time-critical data at defined times between defined users and a second area for transmitting non-real-time-critical data, means of a second data network having a communication protocol different from that of the first data network and comprising means for transmitting data in at least one second transmission cycle, said transmission cycle being subdivided into a third area for transmitting real-time-critical data and into a fourth area for transmitting non-real-time-critical data, a switching unit coupling the first data network and the second data network, wherein the switching unit is operable to identify a next beginning of a second transmission cycle in the second data network for allocating real-time-critical data of the first area into the third area, a machine coupled with the second network and being controlled by loop control using said real-time-critical data; and a first master clock for the first data network for sending out real-time-critical cycle synchronization messages for synchronizing local relative clocks of users of the first data network, the switching unit transmitting the real-time-critical cycle synchronization messages from the first area of the one transmission cycle into the third area of the second transmission cycle.