System and method for the parallel transmission of real-time-critical and non-real-time critical data via switched data networks, especially the Ethernet

• US 20020064157A1
• Filed: 02/22/2001
• Published: 05/30/2002
• Est. Priority Date: 11/24/2000
• Status: Abandoned Application

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Krause, Karl-Heinz
• Application Number:
  US09/790,998
• Publication Number:
  US 20020064157A1
• Time in Patent Office: Days
• US Class Current: 370/393
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6454 Random, e.g. Ethernet
• CPC Class Codes: H04L 2012/6462 Movable boundaries in packets or frames

Abstract

A system and a method provides both for a real-time-critical communication and a non-real-time-critical communication in a switched data network consisting of users and switching units, for example a distributed automation system, by means of a cyclic operation. In a so-called transmission cycle (12), there exists for all users and switching units of the switched data network in each case at least one section (13) for transmitting real-time-critical data and at least one section (14) for transmitting non-real-time-critical data, as a result of which the real-time-critical communication is separated from the non-real-time-critical communication. Since all users and switching units are always synchronized to a common time base, the respective sections for transmitting data in each case take place at the same time for all users and switching units, i.e. the real-time-critical communication takes place independently in time from the non-real-time-critical communication and is, therefore, not influenced by the latter.

Claims

1. A method for transmitting data via switched data networks in the field of industrial systems, in which real-time-critical and non-real-time-critical data are transmitted, the switched data network being set up between at least two users, especially a transmitter and a receiver, the data being transmitted in at least one transmission cycle (12) with adjustable period (17), each transmission cycle (12) being subdivided into at least one first section (13) for the transmission of real-time-critical data for real-time control and at least one second section (14) for the transmission of non-real-time-critical data.

2. The method as claimed in claim 1, wherein each user is allocated a switching unit which is provided for transmitting and/or receiving and/or forwarding the data to be transmitted.

3. The method as claimed in claim 1, wherein all users and switching units of the switched data network always exhibit a common synchronous time base due to mutual timing synchronization.

4. The method as claimed in claim 1, wherein all non-real-time-critical data which are intended to be transmitted during the section (13) of a transmission cycle (12) which is provided for the real-time-critical communication are temporarily stored by the respective switching unit and are transmitted during the section (14) of this or a subsequent transmission cycle which is intended for the non-real-time-critical communication.

5. The method as claimed in claim 1, wherein all non-real-time-critical data which cannot be transmitted during the section (14) of a transmission cycle (12) intended for the transmission of the non-real-time-critical data are temporarily stored by the respective switching unit and transmitted during the section (14) of a later transmission cycle which is intended for the transmission of the non-real-time-critical data.

6. The method as claimed in claim 1, wherein the period of the section (14) for the transmission of non-real-time-critical data within a transmission cycle (12) is automatically established by the period of the section (13) for the transmission of real-time-critical data.

7. The method as claimed in claim 1, wherein the period of the section (13) for the transmission of real-time-critical data within a transmission cycle (12) is in each case determined by the data to be transmitted in a connection-oriented manner.

8. The method as claimed in claim 1, wherein the period (17) of a transmission cycle (12) is established at least once before the respective data transmission takes place.

9. The method as claimed in claim 1, wherein the period (17) of a transmission cycle (12) and/or the period of the section (13) for the transmission of real-time-critical data of a transmission cycle (12) can be changed.

10. The method as claimed in claim 1, wherein the period (17) of a transmission cycle (12) is between 1 microsecond and 10 seconds.

11. The method as claimed in claim 1, wherein the real-time communication can be newly planned at any time during active operation of an automation system.

12. The method as claimed in claim 1, wherein the period (17) of a transmission cycle (12) can be changed by newly planning the real-time communication.

13. The method as claimed in claim 1, wherein a part of the section (13) of the transmission cycle (12) intended for the transmission of the real-time-critical data is intended for the transmission of data for the organization of the data transmission (15).

14. The method as claimed in claim 1, wherein the data for the organization of the data transmission (15) are transmitted at the beginning of the section (13) for the transmission of real-time-critical data of the transmission cycle (12).

15. The method as claimed in claim 1, wherein the data for the organization of the data transmission (15) contain data for the timing synchronization of the users and switching units of the data network and/or data for recognizing the topology of the network.

16. The method as claimed in claim 1, wherein the transmitting and receiving time for all real-time-critical data telegrams to be transmitted are noted at the transmitter and/or receiver before the beginning of the respective performance of the data transmission.

17. The method as claimed in claim 1, wherein all switching units involved in each case, all times for forwarding the real-time-critical data telegrams and the respective associated links via which the real-time-critical data telegrams are forwarded are noted before the beginning of the respective performance of the data transmission for all real-time-critical data telegrams to be transmitted.

18. The method as claimed in claim 1, wherein each real-time-critical data telegram arrives at the corresponding switching unit at the latest at the forwarding time or earlier.

19. The method as claimed in claim 1, wherein the real-time-critical data telegrams are transmitted or, respectively, forwarded immediately without time interval.

20. The method as claimed in claim 1, wherein links of a switched data network which must not be used for the non-real-time-critical communication are used in the real-time-critical communication.

21. The method as claimed in claim 1, wherein at least one user of a switched data network can perform a real-time-critical communication and/or a non-real-time-critical communication, especially an Internet communication, in parallel in the same switched data network, wherein the non-real-time-critical communication taking place does not influence the real-time-critical communication taking place in parallel.

22. The method as claimed in claim 1, wherein at least one arbitrary user, especially a user having the capability for open Internet-capable communication, with or without associated switching unit, can be added to a switched data network.

24. The system as claimed in claim 23, wherein the system exhibits at least one means which allocates to each user one switching unit which is intended for transmitting and/or receiving and/or forwarding the data to be transmitted.

25. The system as claimed in claim 23, wherein the system exhibits at least one means which always supplies all users and switching units of the switched data network with a common synchronous time base by means of mutual timing synchronization.

26. The system as claimed in claim 23, wherein the system exhibits at least one means which ensures that all non-real-time-critical data which are to be transmitted during the section (13) of a transmission cycle (12) intended for the real-time-critical communication are temporarily stored by the respective switching unit and are transmitted during the section (14), intended for the non-real-time-critical communication, of this or a subsequent transmission cycle.

27. The system as claimed in claim 23, wherein the system exhibits at least one means which ensures that all non-real-time-critical data which cannot be transmitted during the section (14) of a transmission cycle (12) intended for the transmission of the non-real-time-critical data are temporarily stored by the respective switching unit and are transmitted during the section (14), intended for the transmission of the non-real-time-critical data, of a later transmission cycle.

28. The system as claimed in claim 23, wherein the system exhibits at least one means which automatically establishes the period of the section (14) for the transmission of non-real-time-critical data within a transmission cycle (12) by means of the period of the section (13) for transmitting real-time-critical data.

29. The system as claimed in claim 23, wherein the system exhibits at least one means which in each case determines the period of the section (13) for transmitting real-time-critical data within a transmission cycle (12) by means of the data to be transmitted in a connection-oriented manner.

30. The system as claimed in claim 23, wherein the system exhibits at least one means which establishes the period (17) of a transmission cycle (12) at least once before the respective performance of the data transmission.

31. The system as claimed in claim 23, wherein the system exhibits at least one means which changes the period (17) of a transmission cycle (12) and/or the period of the section (13) for the transmission of real-time-critical data of a transmission cycle (12).

32. The system as claimed in claim 23, wherein the system exhibits at least one means which newly plans the real-time communication at any time during active operation of an automation system.

33. The system as claimed in claim 23, wherein the system exhibits at least one means which changes the period (17) of a transmission cycle (12) by newly planning the real-time communication.

34. The system as claimed in claim 23, wherein the system exhibits at least one means which provides a part of the section (13) of the transmission cycle (12) provided for the transmission of the real-time-critical data for the transmission of data for the organization of the data transmission (15).

35. The system as claimed in claim 23, wherein the system exhibits at least one means which transmits the data for the organization of the data transmission (15) at the beginning of the section (13) for the transmission of the real-time-critical data of the transmission cycle (12).

36. The system as claimed in claim 23, wherein the system exhibits at least one means which notes the transmitting and receiving time at the transmitter and/or receiver for all real-time-critical data telegrams to be transmitted before the beginning of the respective performance of the data transmission.

37. The system as claimed in claim 23, wherein the system exhibits at least one means which notes all times for the forwarding of the real-time-critical data telegrams and the respective associated links via which the real-time-critical data telegrams are forwarded for all real-time-critical data telegrams to be transmitted in all switching units in each case involved, before the beginning of the respective performance of the data transmission.

38. The system as claimed in claim 23, wherein the system exhibits at least one means which ensures that each real-time-critical data telegram arrives at the corresponding switching unit at the latest at the forwarding time or earlier.

39. The system as claimed in claim 23, wherein the system exhibits at least one means which transmits or forwards the real-time-critical data telegrams immediately without time interval.

40. The system as claimed in claim 23, wherein the system exhibits at least one means which ensures that links of a switched data network which must not be used for the non-real-time-critical communication are used in the real-time-critical communication.

41. The system as claimed in claim 23, wherein a switching unit is integrated in a user.

42. The system as claimed in claim 23, wherein a switching unit has two separate accesses to the respective user, one access being intended for exchanging real-time-critical data and the other access being intended for exchanging non-real-time-critical data.

43. The system as claimed in claim 23, wherein the system exhibits at least one means which ensures that at least one user of a switched data network can perform a real-time-critical communication and/or a non-real-time-critical communication, especially an Internet communication, in parallel in the same switched data network, wherein the non-real-time-critical communication taking place does not influence the real-time-critical communication taking place in parallel.

44. The system as claimed in claim 23, wherein the system exhibits at least one means which ensures that at least one arbitrary user, especially a user with the capability for open Internet-capable communication, with or without associated switching unit, can be added to a switched data network.

45. A user for a method as claimed in claim 1.

46. The user as claimed in claim 45, wherein the user is a user of an automation system.

47. The user as claimed in claim 45, wherein the user exhibits at least one means for transmitting real-time-critical and non-real-time-critical data, the data being transmitted in at least one transmission cycle (12) with adjustable period (17), each transmission cycle (12) being subdivided into at least one first section (13) for transmitting real-time-critical data for real-time control and at least one second section (14) for transmitting non-real-time-critical data.

48. A user for a system as claimed in claim 23.

49. The user as claimed in claim 48, wherein the user is a user of an automation system.

50. The user as claimed in claim 48, wherein the user exhibits at least one means for transmitting real-time-critical and non-real-time-critical data, the data being transmitted in at least one transmission cycle (12) with adjustable period (17), each transmission cycle (12) being subdivided into at least one first section (13) for transmitting real-time-critical data for real-time control and at least one second section (14) for transmitting non-real-time-critical data.

23. A system for transmitting data via switched data networks in the field of industrial systems, comprising at least one data processing device which can be coupled to a switched data network and which transmits real-time-critical and non-real-time-critical data, the switched data network being set up between at least two users, especially a transmitter and a receiver, the system exhibiting at least one means for transmitting data in at least one transmission cycle (12) with adjustable period (17), each transmission cycle (12) being subdivided into at least one first section (13) for transmitting real-time-critical data for real-time control and at least one second section (14) for transmitting non-real-time-critical data.