US20020126582A1 - Network subscriber station having a feature that prevents inaccuracies in time messages - Google Patents
Network subscriber station having a feature that prevents inaccuracies in time messages Download PDFInfo
- Publication number
- US20020126582A1 US20020126582A1 US09/849,349 US84934901A US2002126582A1 US 20020126582 A1 US20020126582 A1 US 20020126582A1 US 84934901 A US84934901 A US 84934901A US 2002126582 A1 US2002126582 A1 US 2002126582A1
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- United States
- Prior art keywords
- time
- message
- network user
- user station
- instant
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
- H04J3/0658—Clock or time synchronisation among packet nodes
- H04J3/0673—Clock or time synchronisation among packet nodes using intermediate nodes, e.g. modification of a received timestamp before further transmission to the next packet node, e.g. including internal delay time or residence time into the packet
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/04—Generating or distributing clock signals or signals derived directly therefrom
- G06F1/14—Time supervision arrangements, e.g. real time clock
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0685—Clock or time synchronisation in a node; Intranode synchronisation
- H04J3/0697—Synchronisation in a packet node
Definitions
- the invention relates to a network user station, which can be connected with another network user station and which, in a transmitting mode, transmits telegrams to the other network user station and in a receiving mode receives telegrams from the other network user station.
- These telegrams contain messages of identical message length in a message string.
- One of these messages is a time message provided with a time of day.
- Such a network user station is known from the Siemens catalog ST 70, chapter 12, 1997 edition.
- This network user station is suitable for use in a distributed automation system including a plurality of automation components, which must be synchronized for controlling a technical process in accordance with an automation task.
- a time transmitter connected to the network cyclically transmits via broadcasting or multicasting a time message which forms part of a message string comprising a plurality of messages.
- the automation components use this transmitted time message to synchronize their clocks. Due to different dwell times of a time message in the transmitter and/or receiver of the network user station, it can occur that the times stored in the time message are erroneous with respect to the transmittal and/or receive time in the transmitting and/or receiving mode.
- One object of the invention is thus to create a network user station of the initially mentioned type which substantially prevents inaccuracies with respect to a transmittal and/or processing instant of the time of day.
- the messages in the message string are processed in the sequence in which they are deposited in said message string.
- An underlying idea of the invention is to detect the time delay that is caused by a delayed processing of the time message within the message string and accordingly to correct the time stored in the time message. If the network user station operates in a transmitting mode, the algorithm/component of the network user station detects a first delay time between the instant when the time message is entered in the message string and the instant when transmission of the time message starts and adjusts the time stored in the time message based on this detected first delay time. If the network user station operates in a receiving mode, the algorithm/component detects a second delay time between the instant when the time message is received and the instant when the time message is processed and adjusts the time stored in the time message based on this detected second delay time.
- the algorithm/component in the transmitting mode provides the time message to be transmitted with an identification code.
- the algorithm/component analyzes the code, which indicates to a network user station operating in receiving mode whether the time stored in the time message has been adjusted. This makes it possible for the receiving network user station to introduce corresponding measures, e.g., in such a way that a non-adjusted time of a time message is not further processed.
- FIG. 1 is a schematic diagram of a preferred embodiment of the network of the present invention showing time adjustment by the transmitting unit;
- FIG. 2 is a schematic diagram of another embodiment of the network user station of the present invention showing time adjustment by the receiving unit;
- FIG. 3 is a schematic diagram of an integrated network of the present invention showing a network junction connecting multiple networks.
- reference numeral 1 identifies a network, e.g., a local area network (LAN).
- a plurality of network user stations 2 a , 2 b , 2 c , . . . is connected to the network 1 , each of which has a receiver 3 a , 3 b , 3 c , . . . and a transmitter 4 a , 4 b , 4 c , . . . .
- the present example assumes that the transmitter 4 a of the network user station 2 a is to transmit to receiver 3 c of network user station 2 c messages 5 a , 5 b , 5 c , 5 d , 5 e in a message string 6 , via a network connection 23 .
- Message 5 d is a time message.
- the time message 5 d contains the time of day of a timer 7 of the network user station 2 a , which can be externally synchronized by a signal 8 .
- a timer 9 of network user station 2 c must be synchronized with the time of day entered in time message 5 d at an input instant.
- a network controller 10 of the transmitter 4 a transmits messages 5 a , 5 b , 5 c , 5 d , 5 e to receiver 3 c in the time sequence in which they were deposited in the message string 6 , the time entered in the time message 5 d deviates from the actual time of day at the instant when transmission begins.
- five processing cycles pass between the moment when the time of day is entered in time message 5 d and the moment when this time message 5 d is transmitted to the receiver 3 c by the network controller 10 .
- the time stored in time message 5 d must be corrected by this delay time of five processing cycles.
- the network controller 10 transmits a message 5 a , 5 b , . . . to the receiver 3 c .
- the delay time is recorded and the time of day is adjusted according to the delay time by a recording and adjusting unit 11 of the transmitter 4 a .
- the time of day is supplied to the unit 11 at the moment when the time is entered in the time message 5 d .
- the unit 11 records the delay time in the form of the number of processing cycles up to the instant when the time message 5 d is transmitted and finally adjusts the time of day in the time message 5 d according to the delay time.
- FIG. 2 which depicts another schematic diagram of a network, will now be described.
- Transmitter 4 a of user station 2 a transmits messages 5 a , . . . of message string 6 to a network controller 12 and a recording and adjusting unit 13 of the receiver 3 c of the user station 2 c via a network connection 23 .
- This recording and adjusting unit 13 decodes messages 5 a , 5 b , . . . , detects the time message and records the number of processing cycles required between the instant when time message 5 d is received and the instant when time message 5 d is forwarded to the timer 9 . According to this number of processing cycles, the unit 13 adjusts the time of day and enters this corrected time in time message 5 d , so that a correct time of day is supplied to timer 9 for its synchronization.
- FIG. 3 shows an integrated network 16 formed of two networks 14 , 15 .
- a network user station 18 e.g., a network user station in the form of a gateway, a router, a relay, or a bridge, forms the network junction and provides the connection between the two networks 14 , 15 .
- This network user station 18 has recording and adjusting units 19 , 20 . If a user station 21 of the network 14 transmits a time message to user station 22 of network 15 , recording and adjusting unit 19 adjusts the time to be received from user station 21 and the recording and adjusting unit 20 adjusts the time in the time message to be transmitted to user station 22 .
- the recording and adjusting unit 19 adjusts the time of day to be received from user 22 and recording and adjusting unit 20 adjusts the time in the time message to be transmitted to user station 21 .
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- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
- Computer And Data Communications (AREA)
- Medicines Containing Material From Animals Or Micro-Organisms (AREA)
- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
Abstract
Description
- This is a Continuation of International Application PCT/DE99/03443, with an international filing date of Oct. 28, 1999, which was published under PCT Article 21(2) in German, and the complete disclosure of which is incorporated into this application by reference.
- The invention relates to a network user station, which can be connected with another network user station and which, in a transmitting mode, transmits telegrams to the other network user station and in a receiving mode receives telegrams from the other network user station. These telegrams contain messages of identical message length in a message string. One of these messages is a time message provided with a time of day.
- Such a network user station is known from the Siemens catalog ST 70,
chapter 12, 1997 edition. This network user station is suitable for use in a distributed automation system including a plurality of automation components, which must be synchronized for controlling a technical process in accordance with an automation task. To this end, a time transmitter connected to the network cyclically transmits via broadcasting or multicasting a time message which forms part of a message string comprising a plurality of messages. The automation components use this transmitted time message to synchronize their clocks. Due to different dwell times of a time message in the transmitter and/or receiver of the network user station, it can occur that the times stored in the time message are erroneous with respect to the transmittal and/or receive time in the transmitting and/or receiving mode. - One object of the invention is thus to create a network user station of the initially mentioned type which substantially prevents inaccuracies with respect to a transmittal and/or processing instant of the time of day.
- This and other objects are solved providing an algorithm and/or a component, which in transmitting mode records a first delay time between the instant when the time message is input in the message string and the instant when transmission of the time message begins, and which adjusts the time of the time message corresponding to this recorded first delay time.
- The messages in the message string are processed in the sequence in which they are deposited in said message string. An underlying idea of the invention is to detect the time delay that is caused by a delayed processing of the time message within the message string and accordingly to correct the time stored in the time message. If the network user station operates in a transmitting mode, the algorithm/component of the network user station detects a first delay time between the instant when the time message is entered in the message string and the instant when transmission of the time message starts and adjusts the time stored in the time message based on this detected first delay time. If the network user station operates in a receiving mode, the algorithm/component detects a second delay time between the instant when the time message is received and the instant when the time message is processed and adjusts the time stored in the time message based on this detected second delay time.
- This ensures that the time stored in the time message is the correct time of day at the transmitting instant of the time message. It further ensures that the time to be processed in the receiver is the correct time of day at the processing instant.
- In preferred embodiments of the invention, the algorithm/component in the transmitting mode provides the time message to be transmitted with an identification code. In a receiving mode the algorithm/component analyzes the code, which indicates to a network user station operating in receiving mode whether the time stored in the time message has been adjusted. This makes it possible for the receiving network user station to introduce corresponding measures, e.g., in such a way that a non-adjusted time of a time message is not further processed.
- The invention as well as embodiments and advantages thereof are described below in greater detail, by way of example, with reference to the drawings in which:
- FIG. 1 is a schematic diagram of a preferred embodiment of the network of the present invention showing time adjustment by the transmitting unit;
- FIG. 2 is a schematic diagram of another embodiment of the network user station of the present invention showing time adjustment by the receiving unit; and
- FIG. 3 is a schematic diagram of an integrated network of the present invention showing a network junction connecting multiple networks.
- In FIG. 1, reference numeral1 identifies a network, e.g., a local area network (LAN). A plurality of
network user stations receiver transmitter transmitter 4 a of thenetwork user station 2 a is to transmit to receiver 3 c ofnetwork user station 2c messages message string 6, via anetwork connection 23.Message 5 d is a time message. Thetime message 5 d contains the time of day of atimer 7 of thenetwork user station 2 a, which can be externally synchronized by asignal 8. Atimer 9 ofnetwork user station 2 c must be synchronized with the time of day entered intime message 5 d at an input instant. Due to the fact that anetwork controller 10 of thetransmitter 4 a transmitsmessages message string 6, the time entered in thetime message 5 d deviates from the actual time of day at the instant when transmission begins. In the present example, five processing cycles pass between the moment when the time of day is entered intime message 5 d and the moment when thistime message 5 d is transmitted to the receiver 3 c by thenetwork controller 10. As a result, the time stored intime message 5 d must be corrected by this delay time of five processing cycles. It is assumed that for each processing cycle thenetwork controller 10 transmits amessage unit 11 of thetransmitter 4 a. The time of day is supplied to theunit 11 at the moment when the time is entered in thetime message 5 d. First, theunit 11 records the delay time in the form of the number of processing cycles up to the instant when thetime message 5 d is transmitted and finally adjusts the time of day in thetime message 5 d according to the delay time. - FIG. 2, which depicts another schematic diagram of a network, will now be described. The parts that are identical in FIGS. 1 and 2 are provided with identical reference numbers.
Transmitter 4 a ofuser station 2 a transmitsmessages 5 a, . . . ofmessage string 6 to anetwork controller 12 and a recording and adjustingunit 13 of the receiver 3 c of theuser station 2 c via anetwork connection 23. This recording and adjustingunit 13 decodesmessages time message 5 d is received and the instant whentime message 5 d is forwarded to thetimer 9. According to this number of processing cycles, theunit 13 adjusts the time of day and enters this corrected time intime message 5 d, so that a correct time of day is supplied totimer 9 for its synchronization. - FIG. 3 shows an integrated
network 16 formed of twonetworks network user station 18, e.g., a network user station in the form of a gateway, a router, a relay, or a bridge, forms the network junction and provides the connection between the twonetworks network user station 18 has recording and adjustingunits user station 21 of thenetwork 14 transmits a time message touser station 22 ofnetwork 15, recording and adjustingunit 19 adjusts the time to be received fromuser station 21 and the recording and adjustingunit 20 adjusts the time in the time message to be transmitted touser station 22. If theuser station 22 ofnetwork 15 transmits a time message to theuser station 21 ofnetwork 14, the recording and adjustingunit 19 adjusts the time of day to be received fromuser 22 and recording and adjustingunit 20 adjusts the time in the time message to be transmitted touser station 21. - The above description of the preferred embodiments has been given by way of example. From the disclosure given, those skilled in the art will not only understand the present invention and its attendant advantages, but will also find apparent various changes and modifications to the structures and methods disclosed. It is sought, therefore, to cover all such changes and modifications as fall within the spirit and scope of the invention, as defined by the appended claims, and equivalents thereof.
Claims (14)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE29819806U | 1998-11-05 | ||
DE29819806.1 | 1998-11-05 | ||
DE29819806U DE29819806U1 (en) | 1998-11-05 | 1998-11-05 | Network participants |
PCT/DE1999/003443 WO2000028400A1 (en) | 1998-11-05 | 1999-10-28 | Network subscriber station |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DE1999/003443 Continuation WO2000028400A1 (en) | 1998-11-05 | 1999-10-28 | Network subscriber station |
Publications (2)
Publication Number | Publication Date |
---|---|
US6449220B1 US6449220B1 (en) | 2002-09-10 |
US20020126582A1 true US20020126582A1 (en) | 2002-09-12 |
Family
ID=8064933
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/849,349 Expired - Fee Related US6449220B1 (en) | 1998-11-05 | 2001-05-07 | Network subscriber station having a feature that prevents inaccuracies in time messages |
Country Status (6)
Country | Link |
---|---|
US (1) | US6449220B1 (en) |
EP (1) | EP1125184B1 (en) |
AT (1) | ATE230499T1 (en) |
DE (2) | DE29819806U1 (en) |
ES (1) | ES2190278T3 (en) |
WO (1) | WO2000028400A1 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE29820339U1 (en) | 1998-11-13 | 2000-01-20 | Siemens Ag | Network participants |
DE10004425A1 (en) * | 2000-02-02 | 2002-01-17 | Siemens Ag | Network with subscriber device, esp. field device, enables transmitter, receiver transmission, reception time delays to be taken into account for time synchronisation |
US7463643B2 (en) | 2001-03-16 | 2008-12-09 | Siemens Aktiengesellschaft | Applications of a switched data network for real-time and non-real time communication |
US6760687B2 (en) * | 2001-05-31 | 2004-07-06 | Fisher-Rosemount Systems, Inc. | Sequence of events detection in a process control system |
DE50200454D1 (en) | 2001-06-07 | 2004-06-24 | Siemens Ag | Method for transmitting time information over a data packet network |
US6873573B2 (en) * | 2001-09-21 | 2005-03-29 | Quartex, Inc. | Wireless synchronous time system |
US6826123B1 (en) * | 2003-10-14 | 2004-11-30 | International Business Machines Corporation | Global recovery for time of day synchronization |
DE102004035194B4 (en) * | 2004-07-21 | 2006-12-07 | Görlitz Ag | Method for forwarding time information |
JP2008064474A (en) * | 2006-09-04 | 2008-03-21 | Sharp Corp | Clock apparatus, clock system, synchronization method, clock apparatus control program, and communication apparatus |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4337463A (en) * | 1980-08-22 | 1982-06-29 | Control Data Corporation | Time synchronization master station and remote station system |
DE3638947C2 (en) * | 1986-11-14 | 1995-08-31 | Bosch Gmbh Robert | Process for the synchronization of computers of a multi-computer system and multi-computer system |
JPH03296684A (en) * | 1990-04-16 | 1991-12-27 | Toshiba Corp | Synchronizing system of time of network station |
DE59108895D1 (en) * | 1991-12-18 | 1998-01-08 | Siemens Ag | Procedures for keeping the time in computer networks |
US5327468A (en) * | 1992-06-19 | 1994-07-05 | Westinghouse Electric Corp. | Synchronization of time-of-day clocks in a distributed processing network system |
US5712867A (en) * | 1992-10-15 | 1998-01-27 | Nexus 1994 Limited | Two-way paging apparatus having highly accurate frequency hopping synchronization |
US5384563A (en) * | 1993-02-22 | 1995-01-24 | Honeywell Inc. | Method and apparatus for time synchronization of bus type local area networks including hierarchical networks |
EP0703514B1 (en) * | 1994-09-24 | 1998-07-22 | Eta SA Fabriques d'Ebauches | Time measurement in a communications system, a communications system and a receiver for use in such a system |
US6236623B1 (en) * | 1998-10-16 | 2001-05-22 | Moore Industries | System and method for synchronizing clocks in a plurality of devices across a communication channel |
-
1998
- 1998-11-05 DE DE29819806U patent/DE29819806U1/en not_active Expired - Lifetime
-
1999
- 1999-10-28 AT AT99962042T patent/ATE230499T1/en active
- 1999-10-28 EP EP99962042A patent/EP1125184B1/en not_active Expired - Lifetime
- 1999-10-28 WO PCT/DE1999/003443 patent/WO2000028400A1/en active IP Right Grant
- 1999-10-28 ES ES99962042T patent/ES2190278T3/en not_active Expired - Lifetime
- 1999-10-28 DE DE59903931T patent/DE59903931D1/en not_active Expired - Lifetime
-
2001
- 2001-05-07 US US09/849,349 patent/US6449220B1/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
US6449220B1 (en) | 2002-09-10 |
DE59903931D1 (en) | 2003-02-06 |
EP1125184B1 (en) | 2003-01-02 |
ATE230499T1 (en) | 2003-01-15 |
WO2000028400A1 (en) | 2000-05-18 |
ES2190278T3 (en) | 2003-07-16 |
EP1125184A1 (en) | 2001-08-22 |
DE29819806U1 (en) | 2000-03-16 |
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