Communication system and method for synchronization of the same

• US 8,170,066 B2
• Filed: 10/11/2005
• Issued: 05/01/2012
• Est. Priority Date: 10/15/2004
• Status: Expired due to Fees

• Current Assignee: Bosch Rexroth AG (Robert Bosch GmbH)
• Original Assignee: Bosch Rexroth AG (Robert Bosch GmbH)
• Inventors: Kynast, Rigobert, Leurs, Ludwig, Schmid, Thomas, Schultze, Stephan
• Primary Examiner(s): Wu, Jianye
• Application Number:
  US11/247,673
• Publication Number:
  US 20060083213A1
• Time in Patent Office: 2,394 Days
• Field of Search: 370/350, 370/503, 379/350, 379/503
• US Class Current: 370/503
• CPC Class Codes: H04J 3/0664 unidirectional timestamps
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 7/04 Speed or phase control by synchronisation signals H04L7/0075 takes precedence

Abstract

With a method for synchronization in a communication system that includes a central participant and at least one further participant, at least one of the further participants being synchronized with the central participant, and, to this end, a telegram with synchronization information being transmitted by the central participant to the at least one further participant, particularly efficient synchronization of the at least one participant with the central participant results due to the fact that the telegram is a data telegram.

Claims

1. A method for synchronization in a serial, real-time communication system including a central participant and at least one further participant, comprising the steps of:

synchronizing the at least one further participant with the central participant by transmitting a Master Data Telegram formed to comprise operating or process data, including setpoint values for process interfaces controlled by the at least one further participant, and synchronization information including at least a dedicated checksum;

wherein said synchronization information is embedded in one or more subfields of a plurality of subfields comprising a data field of said Master Data Telegram,

and wherein in a case where multiple subfields are required to embed all said synchronization information, each of the multiple subfields comprising said synchronization information are positioned either separated from or concatenated with each other within said data field, such that a portion of said Master Data Telegram is protected from a beginning up to and including the synchronization information, and wherein each position of the multiple subfields comprising said synchronization information within the data field is separately and unambiguously positioned in a predefined manner from subfield positions within said data field dedicated for data transmission only; and

evaluating immediately after receipt of said Master Data Telegram only a portion of the bit string up to and including the one or more subfields comprising said synchronization information to obviate a need to first receive and then check the entire Master Data Telegram for corruption thereby expediting synchronization.

2. A method as defined in claim 1;

and further comprising forming the at least one subfield containing the synchronization information as a first entry in the data field.

3. A method as defined in claim 1;

and further comprising ending the at least one subfield containing the synchronization information at a specified time interval after a beginning of the data telegram.

4. A method as defined in claim 3;

and further comprising using the specified time interval of substantially 2;

s.

5. A method as defined in claim 3;

and further comprising using the specified time interval of substantially 2.24;

s.

6. A method as defined in claim 3;

and further comprising making the specified time interval independent of a total length of the data telegram.

7. A method as defined in claim 1;

and further comprising forming the checksum used to protect the synchronization information contained in the data telegram as a cyclic redundancy check.

8. A method as defined in claim 1;

and further comprising covering by the checksum a beginning of the data telegram up to and including the synchronization information.

9. A method as defined in claim 1;

and further comprising performing an evaluation of the checksum by the at least one further participant via a comparison with previously-stored checksums for known data telegram entries.

10. A method as defined in claim 1;

and further comprising locating the checksum after the at least one subfield containing the synchronization information.

11. A method as defined in claim 1;

and further comprising locating the checksum directly at an end of the at least one subfield containing the synchronization information.

12. A method as defined in claim 1;

and further comprising providing a beginning of the data telegram with a fixed reference to an instant of synchronization in the central participant.

13. A method as defined in claim 1;

and further comprising including in the data telegram a plurality of fields containing a preamble field, a destination address field, a source address field, a type field, a data field, and a checksum field, wherein a subfield with the synchronization information is located at a beginning of the data field, and a checksum field of the data telegram includes a checksum for an entire data telegram.

14. A method as defined in claim 1;

and further comprising including in the at least one subfield with the synchronization information fields a type field, a phase field, and a checksum field, wherein the checksum field of the at least one subfield includes a checksum that covers a beginning of a data telegram up to and including the phase field.

15. A method as defined in claim 1;

and further comprising evaluating the synchronization also when a checksum field of the at least one subfield is valid and the checksum field of the data telegram is invalid.

16. A method as defined in claim 1;

and further comprising forming the data telegram as an amplifier telegram.

17. A method as defined in claim 7;

and further comprising forming the data telegrams as Ethernet telegrams.

18. A communication system configured for serial, real-time communication, comprising

a central participant;

at least one further participant that is synchronized with a central participant by transmitting a Master Data Telegram formed to comprise operating or process data, including setpoint values for process interfaces controlled by the at least one further participant and synchronization information including at least a dedicated checksum,

wherein said synchronization information is embedded in at least one subfield of a plurality of subfields comprising a data field of said Master Data Telegram,

wherein in a case where multiple subfields are required to embed all said synchronization information, each of the multiple subfields are positioned either separated from or concatenated with each other within said data field such that a portion of said Master Data Telegram is protected from the beginning up to and including the plurality of subfields comprising the synchronization information,

wherein each position of each subfield of the multiple subfields comprising said synchronization information precedes and is separated unambiguously and in a predefined manner from subfield positions within said data field dedicated for data transmission only and

wherein the multiple subfields comprising said synchronization information are evaluated immediately after receipt of said Master Data Telegram until an end of said synchronization information to obviate a need to first receive and then check the entire Master Data Telegram for corruption thereby expediting synchronization.

19. A communication system as defined in claim 18, wherein a communication system is a distributed communication system for decentralized control with a master-slave structure.

20. A communication system as defined in claim 18, wherein the communication system is located in a structure selected from the group consisting of a ring structure, a linear bus topology, and a star topology.

21. A communication system as defined in claim 18, wherein the communication system is based on Ethernet physics.

22. An automation system, comprising a communication system configured for serial, real-time communication including a central participant and at least one further participant synchronized with a central participant by transmitting a Master Data Telegram formed to comprise operating or process data, including setpoint values for process interfaces controlled by the at least one further participant and synchronization information including at least a dedicated checksum,

wherein said synchronization information is embedded in at least one subfield of a plurality of subfields comprising a data field of said Master Data Telegram,

wherein in a case where multiple subfields are required to embed all said synchronization information, said multiple subfields are positioned either separated from or concatenated with each other within said data field,

wherein each position of said at least one subfield comprising said synchronization information is arranged to precede and is separated unambiguously and in a predefined manner from subfield positions in said data field comprising data only and

wherein only the at least one subfield comprising said synchronization information is evaluated immediately after receipt of said Master Data Telegram to obviate a need to first receive and then check the entire Master Data Telegram for corruption thereby expediting synchronization;

a control unit; and

at least one further unit selected from the group consisting of an amplifier unit, an input unit, and an output unit, wherein said control unit is connected with the central participant, and at least one of said further units is connected with one of further participants.