Communications system and method for synchronizing a communications cycle

• US 20040249982A1
• Filed: 03/26/2004
• Published: 12/09/2004
• Est. Priority Date: 09/26/2001
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Krause, Karl-Heinz, Klotz, Dieter, Bruckner, Dieter, Schimmer, Jurgen, Gotz, Franz-Josef, Arnold, Johann, Bernecker, Herbert, Muller, Christiane, Scheithauer, Gerhard
• Granted Patent: US 7,441,048 B2
• Time in Patent Office: Days
• US Class Current: 709/248
• CPC Class Codes: G05B 2219/25479 Synchronize controllers using messages, add transmission time afterwards
• CPC Class Codes: G06F 1/14 Time supervision arrangements, e.g. real time clock
• CPC Class Codes: H04J 3/0655 using timestamps

Abstract

The invention relates to a method for synchronizing a communications cycle and a communications node in a network. Said node comprises: devices for receiving a desired value for a time base of a communications cycle of the communications node in a communications link to an additional communications node of the network; devices for determining a system deviation between the desired value and an actual value of the time base; and a device for generating a manipulated variable for correcting the time base in accordance with the system deviation.

Claims

1-20. -20. (canceled)

21. A method for operating a first node in a network comprising:

processing a send list and a receive list during a communication cycle;

receiving a desired value for a time base of the communication cycle in the first node of the network;

determining a system deviation from the desired value and an actual value of the time base; and

generating a manipulated value for adjusting the time base corresponding to the system deviation, the desired value sent by a clock pulse generator node of the network by a data telegram to the first node, and the desired value determined by the clock pulse generator node from a reference time base of the clock pulse generator node taking account of the delay time of the data telegram to the first node.

22. A method in accordance with claim 21, wherein a point-to-point connection between the first node and a second node of the network exists during the communication cycle.

23. A method in accordance with claim 21, wherein the network is a switched data network.

24. A method in accordance with claim 21, wherein the first and/or the second node having a switching matrix for establishing a switched point-to-point connection.

25. A method in accordance with claim 21, wherein the desired value is received from the first node via the network.

26. A method in accordance with claim 21, wherein the manipulated variable involves a number of clocks of the time base per communication cycle.

27. A method in accordance with claim 26, wherein the number of clock for adjusting the length of the communication cycle is uniformly distributed over the current or a subsequent communication cycle.

28. A method in accordance with claim 26, wherein the manipulated variable having a first parameter and a second parameter, the first parameter defining a number of clocks distributed uniformly over a communication cycle and the second parameter defining whether the clocks defined by the first parameter is to be repeated or not executed.

29. A method in accordance with claim 21, further comprising:

providing a first adjustment rule for creating a manipulated variable during an initialization phase;

providing a second adjustment rule for creating the manipulated variable during operation.

37. A method in accordance with claim 21, wherein the network is a realtime Ethernet network.

38. A method in accordance with claim 22, wherein the network is a switched data network.

39. A method in accordance with claim 22, wherein the first and/or the second node has a switching matrix for establishing a switched point-to-point connection.

30. A computer program product adapted to execute a method for operating a first node in a network, the method comprising:

processing a send list and a receive list during a communication cycle;

receiving a desired value for a time base of the communication cycle in the first node of the network;

determining a system deviation from the desired value and an actual value of the time base; and

generating a manipulated value for adjusting the time base corresponding to the system deviation, the desired value sent by a clock pulse generator node of the network by a data telegram to the first node, and the desired value determined by the clock pulse generator node from a reference time base of the clock pulse generator node taking account of the delay time of the data telegram to the first node.

31. A communication system having communication nodes and a clock pulse generator node, the communication node comprising:

a send list and a receive list for processing during a communication cycle;

a device for receiving a desired value for a time base of the communication cycle of the communication node of a communication connection with a further communication node of the network;

a device for determining a system deviation from the desired value and an actual value of the time base; and

a device for generating a manipulated value for adjusting the time base corresponding to the system deviation,

wherein the clock pulse generator node includesa device for sending a data telegram with the desired value to a relevant communication node, and the desired value is determined from an actual value of a clock pulse generator base and a delay time of the data telegram from the clock pulse generator node to the relevant communication node,

wherein the network establishes point-to-point connections in synchronized communication cycles.

32. A communication system in accordance with claim 31, wherein the communication connection is a point-to-point connection.

33. A communication system in accordance with claim 31 for the receiving and/or sending realtime data via the communication connection.

34. communication system in accordance with claim 31, wherein the device for generating a manipulated value provides that the adjustment of the time base is distributed uniformly over a communication cycle.

35. A communication system in accordance with claim 31, wherein the device for generating a manipulated variable is adapted to generate a first parameter and a second parameter of the manipulated variable, the first parameter defining a number of clocks of the time base and the second parameter defining whether the clocks defined by the first parameter are to be repeated or not executed.

36. A communication system in accordance with claim 31, wherein the communication system is useed in an automation system.

40. A communication system in accordance with claim 31, wherein the communication connection is a switched data network.