WO2001058067A1 - Synchronisation d'horloge dans un reseau, et poste d'abonne au reseau, en particulier dispositif de terrain, pour un tel reseau - Google Patents

Synchronisation d'horloge dans un reseau, et poste d'abonne au reseau, en particulier dispositif de terrain, pour un tel reseau Download PDF

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Publication number
WO2001058067A1
WO2001058067A1 PCT/DE2001/000413 DE0100413W WO0158067A1 WO 2001058067 A1 WO2001058067 A1 WO 2001058067A1 DE 0100413 W DE0100413 W DE 0100413W WO 0158067 A1 WO0158067 A1 WO 0158067A1
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WO
WIPO (PCT)
Prior art keywords
network
telegram
time
port
participant
Prior art date
Application number
PCT/DE2001/000413
Other languages
German (de)
English (en)
Inventor
Karl Glas
Dieter Klotz
Christoph MÜNCH
Original Assignee
Siemens Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE2000104426 external-priority patent/DE10004426A1/de
Priority claimed from DE2000104425 external-priority patent/DE10004425A1/de
Application filed by Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO2001058067A1 publication Critical patent/WO2001058067A1/fr

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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
    • H04J3/0679—Clock or time synchronisation in a network by determining clock distribution path in a network
    • 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
    • H04J3/0661—Clock or time synchronisation among packet nodes using timestamps
    • H04J3/0664—Clock or time synchronisation among packet nodes using timestamps unidirectional timestamps
    • 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
    • H04J3/0682—Clock or time synchronisation in a network by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L12/40006—Architecture of a communication node
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L12/40143—Bus networks involving priority mechanisms
    • H04L12/4015—Bus networks involving priority mechanisms by scheduling the transmission of messages at the communication node
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L12/40169—Flexible bus arrangements
    • H04L12/40176—Flexible bus arrangements involving redundancy
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L2012/4026—Bus for use in automation systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/28—Timers or timing mechanisms used in protocols

Definitions

  • the invention relates to a network according to the preamble of claim 1 and to a network participant, in particular a field device, for such a network.
  • Such a network is, for example, from the
  • the object of the invention is to create a network and a subscriber, in particular a field device, for such a network, which are characterized by improved accuracy with regard to time synchronization.
  • the new network of the type mentioned has the features specified in the characterizing part of claim 1.
  • a network participant, in particular a field device, for such a network and advantageous refinements of the invention are described in claim 11 and in the dependent claims.
  • the invention has the advantage that a transmission time delay in the transmitter and a reception time delay in the receiver, which can be variable, are taken into account in the time synchronization.
  • a first network subscriber sends a first telegram to a second network subscriber, which contains the time of the first network subscriber corrected by a transmission time delay.
  • the telegram transit time is stored in the second subscriber as a throughput time over the physical transmission link between the first network subscriber and the second network subscriber. For example, it can be entered manually or by another
  • Telegram traffic must have been measured beforehand.
  • the second network participant measures the time delay since receipt of the first telegram and corrects the time received in the first telegram by the throughput time and the measured reception time delay.
  • the second network participant is therefore advantageously able at any time to obtain a synchronized time from the sum of the time received in the telegram and to determine the delay in reception time supplemented by the transit time. Variable transmission and reception delays have no effect on the result of the synchronization.
  • the second network participant is also designed to send a second telegram for time synchronization to a third network participant, which contains a received time corrected for the running time and the delay time between receipt of the first telegram and transmission of the second telegram, then iterative forwarding of the respective one corrected time from network participants to network participants possible.
  • Identical correction mechanisms can be applied in the receiving network participants.
  • the runtime stored in each case in a network subscriber corresponds to the runtime over the physical transmission link between the last sending and receiving network subscriber.
  • time synchronization with two telegrams can also take place.
  • the first network participant sends a first telegram for time synchronization to a second network participant and at the same time stores a time of the first network participant corrected for the transmission time delay.
  • the transit time of the telegram is stored in the second network participant over the physical transmission link between the first network participant and the second network participant.
  • the second network participant measures the time delay since receipt of the first telegram without, however, stopping the timer used for this.
  • the first network participant now sends a second telegram, which contains the time of the first network participant corrected for the transmission time delay, to the second network participant.
  • the second network subscriber corrects the time received in the second telegram for the runtime and the Reception time delay, which is measured in relation to the reception of the first telegram.
  • This procedure with two telegrams has the same advantages that are also associated with the procedure for time synchronization with only one telegram.
  • the process with two telegrams can also be continued in an iterative process.
  • the second network participant forwards the first telegram to a third network participant and measures its delay time for the telegram forwarding.
  • the second network participant sends a received time to the third network participant, corrected for the running time and the delay time of the telegram forwarding of the first telegram.
  • the actual transmission time delay in the time synchronization is advantageously taken into account if the first network subscriber has a first timer for determining the transmission time delay, which he starts a list of the transmission orders when a telegram m is entered and after the telegram is made available for physical transmission as a value reads out the transmission time delay by which the time of the telegram entry is to be corrected.
  • the actual reception time delay during transmission is advantageously taken into account if the second network subscriber has a second timer for determining the reception time delay, which he starts when a first telegram is received from a physical transmission link.
  • the runtime of the telegram over the physical transmission link between the first network subscriber and the second network subscriber can be the second as the starting value
  • the timer must be saved before it starts. This has the advantage that the sum of the transit time and the delay in reception time can be determined by only one timer.
  • the start and end of the runtime of a telegram can each be determined as the point in time at which a characteristic field of a telegram leaves a media-independent interface of the first network subscriber at a fixed distance from the start of the telegram or into a media-independent interface of the second network participant arrives.
  • the type field can advantageously be used as the characteristic field of the telegram.
  • the second network participant upon receipt of the type field, it is known that it is a telegram that is used for time synchronization, and the necessary mechanisms can be initiated.
  • the data field is located behind the type field and can be changed in the sender until the type field is output to the media independence interface. This makes it possible to transmit the time corrected for the transmission time delay in the same telegram.
  • the runtime of a telegram over the physical transmission link can be exactly determined by the first network participant sending a first telegram to a second network participant for determining the runtime and starting a response time timer after the telegram has been provided for the physical transmission.
  • the second network participant After receiving the first telegram to determine the running time, the second network participant starts a timer to measure the time spent in the vehicle and stops the timer after providing a second telegram for physical transmission to the first Network participants.
  • the measured residence tent is transmitted to the first network participant in the second telegram for determining the running time.
  • the first network participant stops the response time timer and calculates the duration of a telegram over the physical transmission path as half the difference between the measured response time and the residence tent in the second network participant.
  • a network subscriber in particular a field device, can advantageously be equipped with a plurality of ports, in particular four ports, for connecting further network components.
  • an interface a so-called micro- processor interface, for connecting the ports to a subscriber-internal processor bus, and a control unit, a so-called ⁇ Switch control, are provided, which performs a Telegrammweglenkung between the ports and the microprocessor interface.
  • Fieldbuses can be connected as usual in a line structure.
  • a separate switch as would be required with a star-shaped structure, is not required.
  • the invention enables the construction of a network of large extent, since only the distance between two network components may not exceed certain limits, but the length of the line structure is unlimited .
  • the integration of switch functions in the network participants has the advantage that the CSMA / CD access control can be deactivated, in particular in the case of Ethernet, and the network receives a deterministic behavior.
  • the area of application of the network participants and the network is thus expanded to include application cases in which real-time behavior is required.
  • ports may be part ⁇ participants are interconnected to form a two or three dimensional network structure, since at these two ports for the integration of the network station m a line two in each case to connect the line with another line can be used.
  • An embodiment of the interfaces implemented by the ports according to the Ethernet or Fast Ethernet specification has the advantage that, for example, a fieldbus with network components of this type can be made use of technology knowledge already available from other areas. In this way, a continuous network is obtained for the office, control, line and field levels, which enables transparent access to any data.
  • a gateway for coupling network areas with different physics and different protocols is advantageously not required.
  • networks based on the Ethernet specification are characterized by high data transmission performance. They offer cost advantages thanks to a widely available technology and components that are available in high numbers of pieces. It is possible to connect a large number of network participants to a network.
  • the advantages of the preferred line or bus structure of the network e.g. the advantage of simple interconnection of the participants, combined with the advantages of networks mentioned above based on the Ethernet specification according to IEEE 802.3.
  • the switch functions integrated into the network participants assume the function of a previously separately installed network component, for example a switch, which is no longer required.
  • a further improvement in applications in automation technology, in particular in the use in time-critical applications, is achieved if the control unit of the Switch function is designed such that a transmission priority of the telegrams to be sent is evaluated and telegrams with high priority are sent before telegrams with low priority.
  • a microprocessor for correcting an internal clock using m telegrams of time information received has the advantage that the time synchronization can largely be implemented without additional hardware expenditure.
  • FIG. 1 shows a communication structure of an automation system
  • FIG. 2 shows a block diagram of an interface of a network participant
  • FIG. 3 shows a series connection of network participants with a linear network topology
  • FIG. 4 shows a series connection of network participants with two communication channels
  • FIG. 5 shows a two-dimensional connection of network participants
  • Figure 6 shows a two-dimensional interconnection with redundant
  • Figure 7 shows a two-dimensional network after redundancy management
  • Figure 8 shows a three-dimensional network after redundancy management
  • Figure 9 shows the basic structure of a telegram
  • Figure 10 shows the structure of an order list.
  • FIG. 1 shows the structure of a communication structure in an automation system. Communication takes place continuously at the control, line and field level a network whose data transmission complies with the Fast Ethernet standard according to IEEE 802. u.
  • a sensor 1 for example a pressure transducer, a sensor 2, here an ultrasonic flow transducer, an actuator 3, a control valve for setting a flow, and a programmable logic controller 4 with twisted-pair lines 5, 6 and 7 interconnected in bus form.
  • the programmable logic controller 4 forms, together with the two sensors 1 and 2 and the actuator 3, a control loop, in which the position of the control valve m is predetermined as a function of the measured values of the pressure transducer and the flow transducer.
  • the programmable logic controller 4 is connected to a switch 9 via a twisted pair line 8.
  • a cell computer 10, a master computer 11 and a firewall 12, with which a secure Ethernet access is implemented, are also connected to the switch 9 in a star-shaped topology. With a line 13, further cell computers, not shown in the figure for the sake of clarity, from adjacent cells of the automation system are connected to the switch 9.
  • FIG. 1 clearly shows the advantage of high data transparency across all levels.
  • the same transmission standard is used for control, line and field level.
  • the field devices 1, 2 and 3 are connected to the programmable logic controller 4 m in the manner customary in the user m of a linear topology.
  • Another advantage is the consistent use of uniform addresses for the individual network participants. An address conversion, as would be required if different standards were used at the different levels, can be omitted in the new network and the new network participants in an automation system.
  • FIG. 2 shows the basic structure of the communication interface of a network participant, for example sensor 2 in FIG. 1.
  • Application-specific circuit parts le such as a supply mechanical-electrical transducer element, means for signal preprocessing, and aponsver ⁇ , of clarity, are not shown because.
  • the parts combined in a rectangle 20 can be integrated in an ASIC (Application Specific Integrated Circuit).
  • ASIC Application Specific Integrated Circuit
  • Communication with the application-specific circuit points of the network subscriber takes place via a microprocessor bus 21, to which a RAM 22, a microprocessor 23 and a microprocessor interface 25 are connected.
  • Broken lines in the representation of the microprocessor 23 indicate that the integration into the ASIC is optional. Its functions could be taken over by an external processor.
  • the task of the microprocessor 23 is the execution of user programs and communication functions, for example the handling of TCP / IP. Another task can be the management of send and receive lists of telegrams of different priority in the external RAM 22.
  • the microprocessor 23 selects an order from a send list in the external RAM 22 and starts a DMA controller 26, which is referred to as DMA 1 control, via a microprocessor interface 25, after having previously assigned the number of times to the DMA controller 26 sending data bytes and a pointer that points to the data byte to be sent. Is the send order by the DMA controller 26 completely m one
  • Transmit buffer 27 transmitted the microprocessor 23 removes this send job from the send list in the RAM 22 and processes the next send job, provided the send list is not empty and free memory space is still available in the transmit buffer 27.
  • Ethernet controllers 28, 29, 30 and 31 are also integrated in the ASIC 20. Each of these Ethernet controllers enters the data bytes of a completely received telegram via a multiplexer 32, a DMA controller 33, which is also referred to as DMA 2 control, and the microprocessor interface 25 m a receive list in RAM 22.
  • the micro Processor 23 accesses the reception list and evaluates the received data in accordance with an application program.
  • the microprocessor interface 25 forms the essential
  • the microprocessor interface 25 decides on the access rights of the two DMA channels. Via the microprocessor interface 25, the microprocessor 23 can also write parameter registers 34 which are required for operating the communication interface of the network subscriber.
  • Examples include a pomter on the start of the high-priority memory area in a transmit buffer of an Ethernet controller, a pointer on the start of the high-priority memory area in each of the receive buffers of the Ethernet controller, an operating mode register for general control bits, and an address of the series to which the network participant belongs, called a cycle time for so-called port select telegrams and settings for various monitoring time intervals.
  • the transmit buffer 27 has a size of more than three kilobytes and is divided into a memory area for high-pore and a memory area for low-priority telegrams. The ratio of the two memory areas can be parameterized.
  • the memory areas of the transmit buffer for high and low priority data are each implemented as a ring buffer. Sending the data from the transmit buffer 27 via one or more Ethernet controllers 28 ... 31 begins when the number of bytes entered in a telegram is greater than the parameterizable fill level or when a complete telegram from the RAM 22 m the transmit buffer 27 pated and at least one Ethernet controller 28 ... 31 is free for transmission.
  • the Ethernet controllers 28 ... 31 are constructed identically. Their structure is explained in more detail using the example of the Ethernet controller.
  • a device 40 which is referred to as Transmit Control, contains a control unit which is responsible for the transmission of telegrams, for repetitions, transmission abort etc. It forms the interface between the internal controller clock and the send clock.
  • a transmit status register m of the device 40 is provided in each case for storing transmit status information for low-priority and high-priority telegrams. If a telegram was sent without errors via the port, a corresponding interrupt is generated.
  • MII Media Independent Interface 41
  • the MII 41 also contains a transmit function block 42 and a receive function block 43.
  • a MAC control block (not shown in FIG. 2), an address filter, a statistic payer and a host interface are integrated , Control and configuration data can be transmitted to the module 36 and status information can be read from it via the media-independent interface.
  • the individual functions of the transmit function block 42 are: mapping of the bytes to be sent, detection of collisions in half-duplex operation and execution of a back-off algorithm, provision of transmit status information to the device 40 after termination of one Transmission process, compliance with the idle time inter-packet gap (IPG) between two telegrams, supplementing the transmission data with a preamble, a start-off-frame delimeter (SFD) and a parameterizable cyclic redundancy check word (CRC) , Filling a telegram with pad Bytes if the telegram length would be ⁇ 60 bytes, and abort of a send operation on request.
  • IPG idle time inter-packet gap
  • SFD start-off-frame delimeter
  • CRC parameterizable cyclic redundancy check word
  • the receive function block 43 makes the received bytes available to a device 44, which is referred to as receive control.
  • the receive function block 43 recognizes the start-of-frame delimeter and a VLAN frame. He checks the Langenfeld and the CRC word in telegrams. After the reception process has ended, receive status information is made available to the device 44.
  • Block 43 recognizes and removes preambles and start-of-frame delimeters in the case of telegrams. If the free memory space in a receive buffer 45 of the Ethernet controller 28 falls below a predetermined threshold in full duplex mode, the MAC control block sends a pause control telegram for flow control via the module 36.
  • This telegram causes the connected network subscriber to send no data telegrams to the Ethernet controller 28 until the time interval sent with the pause control telegram has expired.
  • the address filter carries out telegram filtering in accordance with unicast, multicast and broadcast addresses. To do this, the destination address (DA) received in a telegram is compared with filter addresses.
  • the statistic payers store statistical information about sending and receiving operations.
  • the host interface allows access to parameter registers and statistics payer of the Ethernet controller 28 by the neighboring network participants.
  • the device 44 contains a control unit which is responsible for receiving telegrams. It forms the interface between the internal clock of the Ethernet controller 28 and the receive clock.
  • the receive buffer 45 has a size of more than 3 kilobytes. It is divided into a memory area for high priority and m a memory area for low priority telegrams. The The ratio of the two memory areas can be parameterized.
  • the memory areas are each implemented as a ring buffer.
  • the DMA controller 33 controls the DMA transfer from one of the receive buffers m the Ethernet controllers 28 ... 31 to the RAM 22.
  • the DMA transfer begins when m of the receive buffers, for example in the receive Buffer 45, the number of data bytes received has reached a parameterizable minimum fill level or a telegram has been completely received. At the same time, this receive buffer must be selected for the DMA transfer by a module 46, which is referred to as switch control.
  • a multiplexer 47 is connected upstream of the device 40, which is controlled by a control unit 46, which is referred to as switch control.
  • Switch-Control 46 controls the forwarding of data between the Ethernet controllers 28 ... 31 and the storage of received data if they are intended for the respective network participant. Since the application of the invention is not limited to networks according to the Ethernet specification, the Ethernet controllers 28 ... 31 are also generally referred to below as port 1, port 2, port 3 or port 4. Which ports are released for the forwarding of received data depends on the network structure m the participant is involved in. Switch-Control 46 controls the following actions as a function of the operating state, the network structure, the received destination address and the telegram p ⁇ o ⁇ tat:
  • the received telegram is transmitted via the microprocessor interface 25 m to the RAM 22 without forwarding it to other ports. - If a broadcast telegram is received at a port, the telegram m is transferred to the RAM 22 and the other released ports for sending.
  • a telegram with a multicast address that corresponds to one of the multicast addresses stored in a filter table 48 is received at a port, the telegram is transferred to the RAM 22 and made available to the other released ports for transmission. If the received destination address is different from the own subscriber address and the multicast addresses, the telegram is made available to the other released ports for sending without being saved for further processing.
  • Eight priority levels are available for telegrams with so-called VLAN bytes, for example. If several telegrams are waiting to be sent, the transmission order of the telegrams is determined according to their transmission priority.
  • Telegram forwarding taking into account a modified spanning tree algorithm.
  • Switch-Control 46 contains other parameters, the meanings of which will be explained in more detail later:
  • Row address R P3 which corresponds to the row connected to port 3, a row address Rp 4 , which represents the address of the row connected to port 4, a number N Ri of the transmission links to port 1, a number N R2 of the transmission links to port 3 , a value
  • Root_ID.Cost .Transm ⁇ tter_ID.Port_ID P4 for port 4, a best received combination (Root_ID. Cost. Transm ⁇ tter_ID. Post_ID) R of the series, a message interval counter for a cycle time of port select telegrams, a timeout Payer for a timeout interval on port 1, a timeout payer for a timeout interval on port 2, a timeout payer for a timeout interval on port 3, an active time payer for a time interval beginning with the last one Receipt of a port select telegram on port 4 begins, a combination aging counter for a maximum time interval within which a configuration telegram must be received, otherwise the stored combination Root_ID. Cost. Transm ⁇ tter_IC.
  • Port_ID is deleted, a payer for a time interval after which a port 3 of a series switches from inactive to active, which corresponds to twice the worst case throughput time of a port select telegram through the series, and a payer for a time interval ⁇ t ne rdeiay / after which a port from potentially active to is actively switched and which corresponds to twice the worst case throughput time of a configuration telegram through the network.
  • the user can enter multicast and virtual LAN identification addresses, so-called VLAN addresses, in the filter table 48.
  • Telegram is only accepted if the received address matches one of the addresses m of the filter table 48.
  • a device 50 for redundancy control is intended to ensure in a network that detected physical errors do not impair communication between the network components. Firstly, there is redundancy within each row formed with network participants. To do this, the network participants connected in series must form a ring that is open at one point in the event of a fault, in the
  • the device 50 includes a cycle time register with a parameterized cycle time for test telegrams, a cycle time counter for generating a cycle time interval, a control unit for switching over to a redundant communication channel and for initiating the sending of so-called Lmk Up or link-down telegrams, a row runtime register with a parameterized worst case throughput time of a telegram through a row and a row runtime counter used to generate a row runtime.
  • interrupt control which is also referred to as interrupt control.
  • interrupt control is also referred to as interrupt control.
  • the device 51 contains an interrupt request register, an interrupt mask register, an interrupt register and an interrupt acknowledge register. Every event is stored in the interrupt request register. Individual events can be suppressed via the interrupt mask register. Only the events from the
  • Interrupt mask registers cannot be masked.
  • the entry m the interrupt request register is independent of the interrupt mask in the interrupt mask register. Bits in the interrupt request register can be reset with write access to the interrupt acknowledge register.
  • a module 52 contains special user functions that m the communication interface of the network participant are integrate.
  • a partial function is implemented with a module 53 for time synchronization, another with a module 54 for aquidistance, which will be explained in more detail later.
  • a delay timer 1 to 4 with the reference numerals 57, 58, 59 and 60 is provided for ports 1 to 4, which determines the transmission time between the respective network subscriber and the network subscriber connected via the respective port.
  • the respective delay timer is also used as a lead time timer (DLZ timer) for the respective port.
  • DLZ timer lead time timer
  • Aquidistance timer an auxiliary timer for a transmission time .DELTA.t x via the respective port and a parameter .DELTA.t DLjZ are provided, which corresponds to the sum of the throughput times in the send and receive direction and the cable runtime between the communication interface and the network subscriber connected via the respective port , There is also a local clock 37 m from the network subscriber, the time of which can be read and set via the microprocessor bus 21.
  • An integrated serial-peripheral interface (SPI) 55 is a simple but powerful serial bus system for connecting peripheral components, e.g. EEPROMs.
  • An integrated I / O interface 56 is a parallel interface with 12 configurable inputs and outputs. About these
  • Interface can be used to control LEDs for status display, for example.
  • Each port of the communication interface can be parameterized operated in half-duplex or in full-duplex mode. While half-duplex mode is set on one port, full-duplex mode can be parameterized on another port at the same time. In full duplex mode, telegrams can be sent and received at the same time. This is not possible in half-duplex mode.
  • An application-specific application program which can be stored, for example, on the RAM 22, contributes sending data m an order list in RAM 22.
  • the DMA controller 26 copies data from this job list into the transmit buffer 27.
  • Compiled telegrams are passed on to the released Ethernet controllers 28 ... 31. If a transmission conflict occurs because other telegrams are currently being routed through the communication interface, controlled by switch control 46, the transmit buffer 27 should be able to store two complete Ethernet telegrams.
  • the transmission of the data from the transmit buffer 27 begins when a number of data bytes to be parameterized or a complete telegram from the RAM 22 m has been transmitted to the transmit buffer 27 and at least one Ethernet controller is free.
  • the telegram remains stored in the transmit buffer 27 until it has been sent via all released Ethernet controllers 28 ... 31.
  • the number of data bytes of a telegram, which must at least be stored in the transmit buffer 27 before being sent, must be parameterized in such a way that a seamless transmission of the telegram is guaranteed. Otherwise the telegram will be received incorrectly by other network participants. If telegrams of different priorities are stored in the transmit buffer, the telegrams are sent in accordance with their transmission priority.
  • Figure 3 shows an example of an interconnection of three
  • Network participants 61, 62 and 63 m linear structure.
  • the ports 1 to 4 of the communication interface of the network participants 61, 62 and 63 m are subdivided into circuit locations T1 to T4 for the transmission direction and circuit parts R1 to R4 for the reception direction.
  • port 2 can also be referred to as port T2 / R2.
  • Network participant 63 connected. Data is transferred using a twisted pair cable for each transmission tragungscardi.
  • the ports involved can thus be operated in full duplex mode. End devices can optionally be connected to the open ports T3 / R3 and T4 / R4 in FIG. 3 and to the port T1 / R1 of the network subscriber 61 or the port T2 / R2 of the network subscriber 63 and thus coupled to the network.
  • FIG. 4 shows a number of network participants 70, 71, 72 and 73, each of which can exchange some data via two communication channels.
  • the communication channels are each realized by connecting the port T2 / R2 to the port T1 / R1 of the adjacent network subscriber and the port T4 / R4 to the port T3 / R3 of the adjacent network subscriber m in the manner shown.
  • a high-pore and a low-pore communication channel can be set up and the data throughput doubled.
  • There is no data exchange between the communication channels i.e. a telegram received at the switching point R1 can - if necessary - only be forwarded by the switching part T2. Both communication channels are operated in full duplex mode.
  • FIG. 5 shows an example of a two-dimensional interconnection of the network subscribers.
  • Network subscribers 80, 81 and 82 are interconnected in a row in the manner already described with reference to FIG.
  • network participants 83, 84 and 85 form a series and network participants 86, 87 and 88 form a series.
  • 7Terminals 89, 90 and 91 are connected to ports T4 / R4 of network participants 80, 81 and 84, and terminals 92, 93 and 94 are connected to ports T3 / R3 of network participants 83, 84 and 87.
  • Ports T4 / R4 of network participant 82 with port T3 / R3 of network participant 85 provide a communication channel between the respective rows.
  • two communication channels are formed between the network participants 83 and 86 and between the network participants 85 and 88. So that loop freedom in Network is, however, allowed to be activated only one commu ⁇ nikationskanal at a time from them.
  • the rows formed from the participants 80 to 82, 83 to 85 and 86 to 88 are each assigned a unique row address R], which is stored in a parameter register “row address *”.
  • FIG. 6 A further two-dimensional network is shown in FIG. 6 to clarify the redundancy control. 8 each
  • Network nodes 100 ... 107, 110 ... 117, 120 ... 127 and 130 ... 137 are connected in a row. Both the broken lines and the solid lines between the network participants represent communication channels. However, it must be ensured that only one communication path is used between any two network participants in the entire network. Loops would occur with several possible communication paths, ie telegrams would multiply and circulate. The Spannmg-Tree algorithm has been developed to avoid such situations. Data telegrams are only received by ports, forwarded to ports and sent by ports that are contained in the voltage tree. The remaining ports are deactivated. Deactivated communication channels are shown with broken lines in FIG. 6, activated with solid lines.
  • the two line ends are connected to one another, for example at network participants 100 and 107.
  • the communication channel created in this way is deactivated, and in the case of an error m the active state is set.
  • This redundancy requires an uninterrupted line structure. Since the spanning tree algorithm may have also interrupted a connection via the ports T1 / R1 and T2 / R2, it cannot be used unchanged.
  • a method is presented that is used for a network of interconnected rows of network participants Ensures loop freedom without having to break a row. If necessary, only ports T3 / R3 are deactivated. Only one communication channel may be active between two rows at a time, ie data telegrams are exchanged via this communication path. There is no data exchange via the other communication paths between two rows. The selection of the only active communication channel between two rows takes place with the help of port select telegrams. These are telegrams that are only forwarded within a row. There is no exchange between the rows.
  • the task of these port select telegrams is to find a network participant that is connected to an adjacent row via port T3 / R3 and is as far away from both ends of the line structure as possible based on the number of network participants, i.e. has the smallest distance from the center of the row.
  • These properties define the only network participant in the series that is actively connected to an adjacent series via port T3 / R3. All other connections via ports T3 / R3 from network participants of the same row to this neighboring row are deactivated. No data telegrams are exchanged via deactivated communication channels.
  • Port select telegrams are clearly identified by an identifier in the type field.
  • FIG. 7 shows the result of the redundancy control in a two-dimensional network in a different type of representation.
  • the number entered in the individual boxes corresponds to the respective address of the network participant.
  • Port Tl / Rl is on the left, port T2 / R2 on the right, port T3 / R3 on the top and port T4 / R4 on the bottom of the network participants.
  • With two solid parallel lines between two participants there is an active one, operated in full duplex mode Communication channel shown.
  • the machines with two through broche ⁇ lines drawn communication channels are deactivated.
  • the data area of port select telegrams that are received by a network participant via port T2 / R2 contains information about the number N R of the transmission links between port Tl / Rl of the network participant on the “right” edge of the row and the port T2 / R2 of the respective network subscriber and contains the number N Ri of the subscriber who was the last to forward or send the received port select telegram.
  • the data area of port select telegrams that are received via port T1 / R1 contains the number N r of transmission links between port T2 / R2 of the network participant at the "left * edge of the row and the port T1 / R1 of the respective network participant as well the number N R that is valid for the network participant that was the last to forward or send the received port select telegram.
  • the port via which a port select telegram was received it contains the value IN R] - N R In ⁇ t - latoI at the initiator of the received port select telegram, the 16 bit address R t (0 ⁇ k ⁇ p, p number of rows) of the row to which the initiator of the port select telegram belongs, and a valid bit V for the received value of
  • V 0 means that the received values are invalid.
  • Network participants also send port select telegrams to be forwarded or compiled themselves via their port T3 / R3.
  • each network participant Upon receipt of a port select telegram via port T3 / R3, each network participant recognizes whether it is connected to another row via this port. Network participants set the valid bit V to one if a port select telegram has been received via port T3 / R3.
  • Port select telegrams received on port T3 / R3 are sent back to the sender unchanged.
  • the network participant previously saves the address R n received with the port select telegram of the row connected via port T3 / R3.
  • a timeout counter is assigned to port T3 / R3, which is incremented with an adjustable clock.
  • Port T3 / R3 received port select telegram resets this payer.
  • the network participant sets the valid bit V to zero when lrnerrenz a paramet ⁇ erbaren timeout interval ⁇ tt-m eo - is gen no port select message are received, ⁇ .
  • Network participants also send port select telegrams to be forwarded or compiled themselves via port T4 / R4.
  • Port select telegrams received on port T4 / R4 are sent back to the sender unchanged.
  • the network participant previously saves the address R r received with the port select telegram of the row connected via port T4 / R4.
  • a timeout counter is assigned to port T2 / R2, which is incremented with an adjustable clock.
  • Each port select telegram or data telegram received on port T2 / R2 resets this payer. 8.3 via port Tl / Rl with (N R2e m F f + 1) and port T2 / R2 with (N R ⁇ + 1), if a port select telegram is received at port T2 / R2 with the received value not equal to the stored value of N R2 .
  • N R2e mpf is stored.
  • Communication channel are connected to another row via port T3 / R3 and receive a port select telegram with a valid bit V set to one, compare IN RI - N R2 limtiaor of the received port select telegram with amount
  • the network participant saves
  • a IriltI3tor is the source address of the received port select telegram. The value
  • N RI - N R is the distance of the receiving station from the center of the row. 9. 2 I st
  • N R1 - N R2 li m tiato r IN Ri - N R2 , Aimtiator is compared with its own station address A s :
  • the port select telegram is forwarded with IN Ri - N R2 limtiator without changing the data field.
  • the network participant saves
  • a st ored Aim ti ator -
  • An active port T3 / R3 of a network participant is deactivated if the network participant does not receive a port select telegram from another row within the timeout interval ⁇ t t i m eout.
  • the algorithmu ⁇ nikationskanal through the port T3 / R3 is in the other row as not operational.
  • An active port T3 / R3 is also deactivated when the network participant receives a port select telegram with
  • Network nodes that are connected to another row via an operational communication channel via port T3 / R3 send their own port select telegrams cyclically in each message interval ⁇ t M.
  • mn IN Ri - N R2
  • s and A s t or ed A s is saved.
  • each network subscriber in the row knows the network subscriber who is connected to an adjacent row via his port T3 / R3 and has the smallest distance from the row center. Data telegrams are only exchanged between the two rows via this active communication channel. The connections of the other network participants to the next row are deactivated.
  • FIG. 7 shows a network in this steady state.
  • FIG. 8 shows a network with a three-dimensional structure.
  • the arrangement of the ports on the individual boxes, which each represent a network participant with the entered address, is the same as in the illustration in FIG. 7.
  • the communication channels are also shown in the same way.
  • a series m of linear structure is built up with several network participants by connecting the ports T1 / R1 and T2 / R2.
  • Several of these rows are interconnected to form a three-dimensional structure, as shown in FIG. 8. To do this, there must be at least one communication channel between ports T3 / R3 and T4 / R4 between every two rows. Multiple communication paths between two rows are permitted.
  • terminal devices can be connected between rows.
  • Each row is assigned a unique row address Ry with 0 ⁇ k ⁇ p, where p is the number of rows in the selected network structure.
  • the respective row addresses are shown on the left side of FIG. 8 next to the respective row.
  • the associated address of the row is stored in the parameter register "Row address *" in each network node.
  • the data area of the port select telegrams is expanded by the address R n of the adjacent row to which the port T3 / R3 or the port T4 / R4 of the network subscriber who compiled the telegram is connected.
  • the task of the port select telegrams expanded by the row address R r of the adjacent row is to find a network subscriber which is connected to a row with the address R via port T3 / R3 and in relation to the number of
  • Network subscriber is as far as possible from both ends of its row, ie has the smallest distance from the middle of the row. This defines the only network participant in the row that is potentially actively connected to the adjacent row with the address R r via port T3 / R3. Port T3 / R3 is switched from potentially active to active if the modified Spanmng tree algorithm also switches this port active. Data telegrams are only exchanged via active communication channels between the rows. With the method previously described for the two-dimensional network structure, it is possible to find the network subscriber who has the smallest distance from the center of the row and whose port T3 / R3 is connected to the row with the address R N.
  • the port select telegrams ensure that between two rows that are directly connected to each other via communication channels, only one communication channel is potentially active at any time via port T3 / R3.
  • a modified tension tree method ensures that no loop occurs across the entire three-dimensional network. Characteristics of the modified voltage tree method are that each row is regarded as a virtual switch, with the potentially active communication channels via ports T3 / R3 or via ports T4 / R4 to other rows as ports of the virtual switch and that a communication channel via a port T4 / R4 is potentially active if it is connected to a potentially active port T3 / R3 of another row, which is also regarded as a virtual switch.
  • the following entries are provided in the data field for configuration telegrams: 1. Root_ID: A 64 bit address R R of the virtual switch, which is assumed to be “Root w ”.
  • Transm ⁇ tter_ID A 64 bit address R ⁇ of the virtual switch to which the sending network participant belongs.
  • the addresses R ⁇ and R ⁇ each correspond to the address of the row that is regarded as a virtual switch.
  • Port_ID A 16 bit address P ID of the port via which the sending virtual switch sends the configuration telegram.
  • R F ID is equal to the address R n of the row that is connected to the port via which the virtual switch sends with the Transm ⁇ tter_ID.
  • the Spannmg-Tree algorithm can be applied to a network of virtual switches. It is based on the described configuration telegrams that are sent and received by virtual switches. Only the potentially active or active ports T3 / R3 or T4 / R4 of a row, ie a virtual switch, evaluate received configuration telegrams. The deactivated ports T3 / R3 or T4 / R4 evaluate the configuration telegrams and then filter them. The voltage tree method switches the ports T3 / R3 or T4 / R4 from potentially active to active, which ensure that there is only one communication path between any two network participants in the network and therefore no loops occur. The remaining ports T3 / R3 or T4 / R4 remain potentially active or deactivated. Data telegrams are only exchanged via active communication channels between the rows.
  • a virtual switch is constantly on at its ports for
  • Configuration telegrams ready to receive and save the configuration message for each port with the "best * combination of Root_ID. Cost. Transm ⁇ tter_ID. Port_ID. Not only are the received combinations compared for each port, but also the combination that the virtual switch has sent to this port is compared.
  • Transm ⁇ tter__ID of Kl ⁇ Transm ⁇ tter_ID of K2 or 4.
  • Transm ⁇ tter_ID of Kl Transm ⁇ tter_ID of K2 and Port_ID of Kl ⁇ Port_ID of K2.
  • the root port of a virtual switch is the port with the "best * received combination
  • the root port is the port of a virtual switch with the shortest distance to the Rooc_ID.
  • Root_ID (Cost + 1) .Transm ⁇ tter_ID.Port_ID from the root port
  • Root_ID Cost. Transm ⁇ tter_ID. Port_ID of the considered port.
  • the payer is reset and restarted with every received or forwarded configuration telegram.
  • the combination aging counter is therefore only activated for the potentially active or active ports in a row and is incremented with a parameterizable time cycle. If the combination aging counter reaches the parameterizable threshold value for a potentially active or an active port "Maximum age *, the combination Root_ID saved for this port becomes. Cost. Transm ⁇ tter_ID. Port_ID deleted and recalculated.
  • Switches that is to say within a number of network participants with a linear structure, are carried out using port select telegrams which are similar to the above described port select telegrams of a network with a two-dimensional structure.
  • the data area of the port select telegrams of a network with a three-dimensional structure is expanded independently of the receiving port compared to the data area of the port select telegrams for a network with a two-dimensional structure by a 16 bit address R r of the one connected via port T3 / R3 virtual switches, ie the neighboring ones
  • an active timer is transmitted in the port select telegrams at the time of transmission.
  • the data area of port select telegrams for three-dimensional network structure contains the best received combination for this port
  • K E Root_ID.Cost .Transm ⁇ tter_ID. Port_ID that was sent or forwarded in the data field of a configuration telegram from a row connected to a potentially active or active port T3 / R3 or T4 / R4 with the address R n or Ri.
  • K R Root_ID.Cost .Transm ⁇ tter_ID.Port_ID.
  • the ports T4 / R4 are each assigned an active timer, which is incremented with an adjustable clock.
  • Received port select telegrams with P PA 0 reset the active timer without starting it.
  • a network participant with a potentially active or active port T4 / R4 deactivates this port if 1.
  • each network participant with a potentially active communication channel via the port T3 / R3 to a row with the address R n when it receives a configuration telegram via port T3 / R3,
  • Each network participant, whose port T4 / R4 is switched from deactivated to potentially active or active, sends a parameterizable number of port select telegrams with P pA 1.
  • All receivers of a port select telegram with a deactivated communication channel to another row store the values K E and K R sent by the associated potentially active or active port of the virtual switch.
  • FIG. 8 shows the result of using the port select telegrams in combination with the modified voltage tree method on each row of the three-dimensional network shown.
  • Redundancy in the network is intended to ensure that physical errors, electromagnetic interference, network expansions or component replacement ensure communication between the network components.
  • the prerequisite for this is not only rapid detection of errors or network modifications and quick network reconfiguration, but also a network area that is as small as possible, which is affected by the effects of the error or network modification during the reconfiguration time.
  • the redundancy of a redundancy management is a network within each row, the posted communication ⁇ ducts interconnected between each two rows and redundancy with respect to the entire network possible.
  • the modified Spannmg-Tree algorithm guarantees freedom from loops.
  • This type of redundancy advantageously enables short reconfiguration times with minimal hardware expenditure and can therefore be implemented with little effort.
  • the network area is limited which is affected by the effects of an error or a network configuration during the reconfiguration time.
  • a ring is formed, as is the case in FIG. 6 with the network subscribers, for example
  • a network subscriber for example network subscriber 100, which is located at one end of the row, must be operated in redundancy mode. It acts as a redundancy manager.
  • this network participant By setting a redundancy bit in the parameter register, this network participant is switched to the redundancy mode. To check the series, it cyclically sends a Testl telegram to port 1 with the MAC address of port 1 as the source address.
  • the cycle time is, for example, 10 ms.
  • Test 2 is sent cyclically on port 2 with the MAC address of port 2 as the source address.
  • the cycle time is c ⁇ ) > M - * t- 1
  • Network participants have not been interrupted for a certain minimum time of, for example, 1.6 s.
  • an "lmk-up *" telegram is sent to ports 1 and 2 of the redundancy manager in order to inform all other network participants in the series about the new ring structure.
  • Test frames will continue det cyclically verses ⁇ .
  • Each network participant in the series resets the registers necessary for the telegram forwarding when it receives an "lmk-up * or" lmk-down * telegram.
  • a redundant implementation of the communication channels between two rows requires at least two separate communication paths. However, a maximum of one path may be used for data exchange between the rows. This potentially active communication channel between two rows is selected with the help of port select telegrams. If a potentially active communication channel is identified as faulty, it is deactivated and another communication path is switched to potentially active. The following applies to the switchover time from deactivated to potentially active:
  • ⁇ t imeoit is the timeout interval and ⁇ t r oweiay corresponds to twice the worst case throughput time of a port select telegram through the series.
  • the switchover time therefore depends on the number of network participants that form a row. It is, for example, for a series of 50 network participants in the order of 200 ms, if a timeout interval of 150 ms is assumed.
  • Redundancy in a three-dimensional network is also possible. If the loop structure already provides freedom from loops, ie there is no network redundancy, every potentially active communication path between two rows is also active. In this case, it is not necessary to use the modified tension tree algorithm described. In the case of network redundancy, the modified Spannmg tree algorithm places loop-free between the Rows sure. A reconfiguration of a network with the modified spanning tree algorithm is only necessary in the event of errors or network modifications that are not processed by the redundancy within a row or the redundancy of the communication channels between two rows.
  • the transmission time from the transmitter to the receiver depends on the number of network participants via which a telegram is forwarded and cannot be neglected.
  • the transmission time of a telegram increases for everyone
  • Network subscriber who forwards the telegram by a subscriber-specific delay time ⁇ ti, which is composed of the following times:
  • This time is, for example, 21 T B ⁇ t for DP83843 PHYTER of NSC, wherein T and Blt ns at 100 Mbps transmission rate corresponds to 10 at 10 Mbps transmission rate 100 ns.
  • This lead time is, for example, for DP83843 PHYTER from NSC 6 T B ⁇ t. 4. Runtime over the lines between two neighboring network participants. The sum of the times specified under 1, 3 and 4 is a fixed quantity and is referred to as the throughput time ⁇ t DlJ z. It can either be parameterized or measured by the network participants. A change in this throughput time ⁇ t D "is only possible if a network subscriber is removed from the network or added to the network or if the cabling is changed.
  • the throughput time ⁇ t D Lz can be determined with the following sequence of telegrams, which network participants execute, for example after initialization or on request:
  • Each network subscriber who is newly added to the network sends his or her neighboring network subscriber a so-called DLZ telegram, i.e. em first telegram for running time determination.
  • This telegram is clearly identified in the 16 bit type address.
  • the new network participant starts a DLZ timer 1 after the last nibble of the type field of the DLZ telegram has been made available to the media independent interface (MII) of port 1 for sending. Accordingly, he starts a DLZ timer 2, 3 and 4 for sending via ports 2, 3 and 4. 3.
  • MII media independent interface
  • Each of the maximum of 4 neighboring network participants starts after receiving the last nibble of the type field of the DLZ telegram on his MII its DLZ timer of the respective port.
  • the received DLZ telegram is not forwarded, but is sent back to the sender supplemented by the residence tent in the respective Ethernet controller of the network participant.
  • this neighboring network participant If this neighboring network participant has passed the last nibble of the type field of the DLZ telegram modified in this way to its MII directed to the newly connected network participant, it stops the DLZ timer and sends the stay tent stored in the DLZ timer with the data field of the telegram to the newly connected network participant.
  • the network subscriber newly added to the network stops the assigned DLZ timer 1, 2, 3 or 4 when he receives the last nibble of the type field at his MII of the respective port.
  • the throughput times ⁇ t D ⁇ _z, ⁇ t D LZi and ⁇ t D Z4 are calculated in a corresponding manner for the remaining ports of the network subscriber newly added to the network.
  • the flow tents determined in this way are stored as parameters in module 52 (FIG. 2).
  • the newly connected network participant sends the measured throughput times to the neighboring network participants via the respectively assigned port.
  • the described determination of the throughput times is only necessary for every second network participant when initializing a network.
  • Time synchronization has the task of synchronizing the clocks of several or all network participants.
  • the communication channels between network participants are advantageously operated in full duplex mode so that the transmission of telegrams exhibits deterministic behavior.
  • the transmission time from a sender to a receiver in a network depends on the number of network participants over which the telegram is routed and cannot be neglected. Time synchronization can be carried out with two special telegrams, for example.
  • Figure 9 shows the general structure of a telegram.
  • the first field 140 contains a destination address, ie an address of the subscribers to whom the telegram is directed, for example 48 bits long.
  • the second field 141 contains a source address, the address of the sending network subscriber, the length of which is also 48 bits, for example.
  • An identifier of the telegram is transmitted in a type field 142 with, for example, 16 bits.
  • the user data of the telegram are sent in a data field 143 of variable length.
  • Telegrams for time synchronization can be identified by a special multicast address as destination address 140 and / or by a new type address to be defined in type field 142.
  • FIG. 10 shows an order list which can be stored, for example, in the RAM 22 in FIG. 2. Telegrams that are to be transmitted via the network are entered in such an order list. If the transmission is not prioritized, the telegram below is transmitted next. It can therefore happen that, for example, a completed telegram 151 is only transmitted when two telegrams 152 and 153 previously entered in the job list have been transmitted. Depending on the number of pending orders, the delay in sending a telegram m a network subscriber after its entry m the order list is variable. In the following a possibility is described how the influence of the transmission time delay in the time synchronization can be avoided: 1.
  • a nibble is defined as half a byte, i.e. it is a sequence of 4 bits.
  • the stored delay times of the ports each correspond to the transmission time ⁇ ti defined above for this network participant.
  • the delay of the telegram via the physical transmission has already been added by the start value ⁇ t D ⁇ _z P of the delay timer.
  • the time master then enters an SM-Timel telegram, which contains the start time of the delay timers in the data field, in the job list.
  • P 1, 2, 3, 4
  • it replaces the start time of the delay timers with the time at which the last nibble of the type field of the SM-TimeO telegram the MII of this port for sending Grouting was made, ie by the sum of the start ⁇ the delay timer and the measured delay time time of each port P.
  • the SM Timel telegram is thus corrected by the time Sendezeitverzog für carry emge-.
  • SM-Timel telegrams are only accepted by the network participant that previously sent an SM-TimeO telegram.
  • the time slave When the SM-Timel telegram is received, the time slave knows, i.e. the neighboring network participant, the start time of his delay timer.
  • the synchronized time is the sum of the time received in the SM-Timel telegram and the delay time of the time slave for the respective receiving port.
  • the neighboring network subscriber thus corrects the time received in the second telegram by the runtime and the reception time delay.
  • the time master starts the delay timers assigned to the ports and carries the time telegram with the start time of these timers m the job list em.
  • the network participant then adds the ones in the time frame specified start time of the delay timer for the value of the delay timer of the respective port P and sends this sum as the time corrected by the transmission time delay with a first telegram for time synchronization via the respective port P.
  • Each neighboring network participant starts after receiving the last nibble of the type field of the first telegram for time synchronization on a port P,
  • the value of the delay timer which is assigned to this port is stored. However, the delay timers continue to run. The stored delay times assigned to the individual ports each correspond to the transmission time ⁇ ti of this network subscriber. It is added to the received start time of the delay timer and with a second telegram for time synchronization via another port to the next, i.e. forwarded to a third, network participant.
  • the time slave knows the start time of its delay timer in time synchronization.
  • the synchronized time results from the sum of the time received in a first or second telegram and the delay time of the time slave for the receiving port P.
  • the described possibilities for time synchronization can be used in a corresponding manner for the synchronization of interval timers in the network participants.
  • the task of aquidistance timers is to enable several or all network participants to perform specified actions aquidistantly. This function is common in control systems referred to as "electronic wave *.
  • a clock beat For all network participants that are connected to one another via the network, a clock beat should be generated, with the clock of which respective target values are transferred and actual values are queried.
  • An application example is the measurement of the electrical power if the required current and voltage measured values are recorded by separate transmitters and queried via a network.
  • an aquidistant cycle is controlled by only one aquidistance master.
  • the network participant that takes over the function of an aquidistance master has a timer that is loaded at the start with the parameterizable value of the aquidistance interval.
  • the timer is free running and is decremented with every bit clock. When the timer has expired, it is loaded again with the parameterized value of the aquidistance interval and a new cycle begins.
  • the difference between an aquidistance timer and a watch is the direction of travel.
  • Time delays are not added as with the time, but are subtracted.
  • time synchronization * used above should therefore be understood to include the synchronization of aquidistance timers.
  • each network participant After receiving the last nibble of the type field of the aquidistance telegram at the MII of a port, ie when receiving the aquidistance telegram from the physical transmission link, each network participant starts an auxiliary timer with the value of the throughput time ⁇ t D _.zp -
  • the value of the auxiliary timer is saved at the point in time at which the neighboring network subscriber creates the last nibble of the type field from the aquidistance telegram for forwarding to the MII of another port.
  • the stored value of the auxiliary timer corresponds to the transmission time ⁇ ti of this network participant for port P. This stored time ⁇ t x is subtracted from the received remaining time ⁇ t AqJ ⁇ until the next cycle begins .
  • the neighboring network participant forwards the corrected remaining time ( ⁇ t Aqu ⁇ - ⁇ t with the aquidistance telegram via the other port to the next neighboring network participant. In addition, he loads the corrected remaining time into his aquidistance timer, which is decremented with each cycle. 4.
  • Aquidistanz-Timer of an Aquidistanz-Slave If the Aquidistanz-Timer of an Aquidistanz-Slave has expired, it is first loaded with the parameterized value of the Aquidistanz-Interval and decremented with every bit clock in the manner described, the remaining time ( ⁇ t AqJ1 - ⁇ t 2 ) until the next cycle begins m the aquidistance timer.
  • the maximum transmission time between a transmitter and a receiver in the network should be less than the length of the aquidistance interval.
  • a network was described according to the Ethernet specification.
  • the invention is also readily applicable to Fast Ethernet, Gigabit Ethernet or other types of networks.

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Abstract

L'invention concerne un réseau comportant plusieurs postes d'abonnés au réseau (1, 2, 3, 4, 10, 11, 12). Un premier poste d'abonné au réseau envoie, à un second poste d'abonné au réseau, dans un télégramme destiné à la synchronisation d'horloge, une heure corrigée du retard du temps d'émission. Dans le second poste d'abonné au réseau est mémorisé le temps du parcours du trajet de transmission physique. Ce second poste d'abonné corrige l'heure reçue de la valeur du temps de parcours et de la valeur de son retard de temps de réception. On obtient ainsi une précision élevée de la synchronisation d'horloge.
PCT/DE2001/000413 2000-02-02 2001-02-02 Synchronisation d'horloge dans un reseau, et poste d'abonne au reseau, en particulier dispositif de terrain, pour un tel reseau WO2001058067A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE2000104426 DE10004426A1 (de) 2000-02-02 2000-02-02 Netzwerkteilnehmer, insbesondere Feldgerät, sowie Netzwerk mit einem derartigen Netzwerkteilnehmer
DE10004426.3 2000-02-02
DE2000104425 DE10004425A1 (de) 2000-02-02 2000-02-02 Netzwerk sowie Netzwerkteilnehmer, insbesondere Feldgerät, für ein derartiges Netzwerk
DE10004425.5 2000-02-02

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WO2001058067A1 true WO2001058067A1 (fr) 2001-08-09

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003036832A3 (fr) * 2001-10-17 2003-08-21 Siemens Ag Procede permettant a un abonne terminal de se servir d'un systeme de communication cyclique isochrone
WO2003085921A2 (fr) * 2002-04-02 2003-10-16 Schneider Automation, Inc. Methode et appareil relatifs a la synchronisation d'horloge de dispositif ethernet avec classement par ordre de priorite
DE102004061343A1 (de) * 2004-12-20 2006-06-29 Siemens Ag Netzwerk mit mehreren Stationen, Station für ein derartiges Netzwerk sowie Verfahren zur Synchronisierung von Stationen
DE10332551B4 (de) * 2003-07-17 2006-11-09 Jülg, Thomas, Dipl.-Ing. Dr. Verfahren zur Positionsbestimmung
CN102591291A (zh) * 2012-02-27 2012-07-18 固高科技(深圳)有限公司 工业控制器与人机界面双向数据传输系统和方法
CN104135533A (zh) * 2014-08-13 2014-11-05 北京金鸿泰科技有限公司 一种工业数据传输的系统和方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0389754A2 (fr) * 1989-02-28 1990-10-03 Hewlett-Packard Company Appareil de localisation de station de diffusion dans un réseau local
US5546385A (en) * 1995-01-19 1996-08-13 Intel Corporation Flexible switching hub for a communication network
US5602992A (en) * 1993-11-29 1997-02-11 Intel Corporation System for synchronizing data stream transferred from server to client by initializing clock when first packet is received and comparing packet time information with clock
US5802082A (en) * 1995-07-25 1998-09-01 Deutsche Telekom Ag Method and device for measuring cell propagation time in ATM networks
DE19710971A1 (de) * 1997-03-17 1998-09-24 Siemens Ag Verfahren zur Bestimmung der Laufzeit eines Telegramms sowie Teilnehmer zur Durchführung des Verfahrens
US5926461A (en) * 1996-04-22 1999-07-20 Deutsche Telekom Ag Process for measuring switching delays
WO1999062230A1 (fr) * 1998-05-22 1999-12-02 Winnet Mcs, Inc. Commutateur ethernet dans un terminal pour reseau radio metropolitain

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0389754A2 (fr) * 1989-02-28 1990-10-03 Hewlett-Packard Company Appareil de localisation de station de diffusion dans un réseau local
US5602992A (en) * 1993-11-29 1997-02-11 Intel Corporation System for synchronizing data stream transferred from server to client by initializing clock when first packet is received and comparing packet time information with clock
US5546385A (en) * 1995-01-19 1996-08-13 Intel Corporation Flexible switching hub for a communication network
US5802082A (en) * 1995-07-25 1998-09-01 Deutsche Telekom Ag Method and device for measuring cell propagation time in ATM networks
US5926461A (en) * 1996-04-22 1999-07-20 Deutsche Telekom Ag Process for measuring switching delays
DE19710971A1 (de) * 1997-03-17 1998-09-24 Siemens Ag Verfahren zur Bestimmung der Laufzeit eines Telegramms sowie Teilnehmer zur Durchführung des Verfahrens
WO1999062230A1 (fr) * 1998-05-22 1999-12-02 Winnet Mcs, Inc. Commutateur ethernet dans un terminal pour reseau radio metropolitain

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
BUCHWITZ M ET AL: "DAS NETZ IST DIE STEUERUNG TECHNOLOGIESPRUNG IN DER STEUERUNGSTECHNIK", ELEKTRONIK,FRANZIS VERLAG GMBH. MUNCHEN,DE, vol. 48, no. 8, 20 April 1999 (1999-04-20), pages 38,51 - 52,54-56, XP000902697, ISSN: 0013-5658 *
GOLDBERG L: "SPEED DOES MATTER: GIGABIT SWITCH CHIP RAISES THE BAR", ELECTRONIC DESIGN,PENTON PUBLISHING, CLEVELAND, OH,US, vol. 46, no. 17, 20 July 1998 (1998-07-20), pages 53 - 54,56,58, XP000849214, ISSN: 0013-4872 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003036832A3 (fr) * 2001-10-17 2003-08-21 Siemens Ag Procede permettant a un abonne terminal de se servir d'un systeme de communication cyclique isochrone
WO2003085921A2 (fr) * 2002-04-02 2003-10-16 Schneider Automation, Inc. Methode et appareil relatifs a la synchronisation d'horloge de dispositif ethernet avec classement par ordre de priorite
WO2003085921A3 (fr) * 2002-04-02 2003-12-18 Schneider Automation Methode et appareil relatifs a la synchronisation d'horloge de dispositif ethernet avec classement par ordre de priorite
DE10332551B4 (de) * 2003-07-17 2006-11-09 Jülg, Thomas, Dipl.-Ing. Dr. Verfahren zur Positionsbestimmung
DE102004061343A1 (de) * 2004-12-20 2006-06-29 Siemens Ag Netzwerk mit mehreren Stationen, Station für ein derartiges Netzwerk sowie Verfahren zur Synchronisierung von Stationen
DE102004061343B4 (de) * 2004-12-20 2007-11-22 Siemens Ag Netzwerk mit mehreren Stationen, Station für ein derartiges Netzwerk sowie Verfahren zur Synchronisierung von Stationen
CN102591291A (zh) * 2012-02-27 2012-07-18 固高科技(深圳)有限公司 工业控制器与人机界面双向数据传输系统和方法
CN104135533A (zh) * 2014-08-13 2014-11-05 北京金鸿泰科技有限公司 一种工业数据传输的系统和方法

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