WO2008101394A1 - Procédé synchrone en temps réel et réseau synchrone reposant sur le standard ethernet - Google Patents

Procédé synchrone en temps réel et réseau synchrone reposant sur le standard ethernet Download PDF

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Publication number
WO2008101394A1
WO2008101394A1 PCT/CN2008/000268 CN2008000268W WO2008101394A1 WO 2008101394 A1 WO2008101394 A1 WO 2008101394A1 CN 2008000268 W CN2008000268 W CN 2008000268W WO 2008101394 A1 WO2008101394 A1 WO 2008101394A1
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Prior art keywords
node
slave node
slave
message
data
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PCT/CN2008/000268
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English (en)
Chinese (zh)
Inventor
Chengrui Zhang
Jinjiang Wang
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Shan Dong University
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Priority claimed from CN200710013313A external-priority patent/CN101018115B/zh
Priority claimed from CNB2007100144192A external-priority patent/CN100561904C/zh
Application filed by Shan Dong University filed Critical Shan Dong University
Publication of WO2008101394A1 publication Critical patent/WO2008101394A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/66—Arrangements for connecting between networks having differing types of switching systems, e.g. gateways

Definitions

  • the invention relates to a real-time synchronous communication network for industrial field level communication, in particular to a real-time synchronization method based on standard Ethernet and a synchronization network, which is used for solving communication problems in a field-level communication system, that is, how to solve Ethernet Real-time communication and accurate homology of the system when the field-level communication system is used.
  • Fieldbus is currently the mainstream solution in field-level communication systems in the field of factory automation and process automation.
  • traditional fieldbus has increasingly shown its limitations.
  • control becomes more and more dispersed, and control data needs to be continuously exchanged between smart devices distributed throughout the plant and between smart devices and plant control layers.
  • the exchange of data between devices is growing rapidly.
  • enterprises hope to integrate the underlying production information into a unified plant-wide information management system, so the enterprise information management system needs to read the site.
  • Ethernet technology began to penetrate from the information management layer of factories and enterprises to the bottom layer, and Ethernet technology began to be widely used in the control level communication of factories.
  • Ethernet technology began to be widely used in the control level communication of factories.
  • Bus-based control is the development direction of current control systems, and industrial Ethernet bus is widely regarded as the best solution for future control networks.
  • the replacement of fieldbus by industrial Ethernet is an inevitable trend in the development of industrial control networks.
  • the promotion and application of industrial Ethernet will greatly simplify the structure of the plant control system and save the cost of system implementation and maintenance.
  • Ethernet Since Ethernet uses CSMA/CD collision detection, that is, when a slave node on a network needs to send data, it first listens to the channel, and if the channel is busy, it waits until it hears that the channel is idle. The data is sent out. If two or more slave nodes are listening and waiting to transmit data, when the channel is idle, the slave nodes start transmitting data almost immediately (almost simultaneously), and a collision occurs. If a slave detects a collision during transmission, it stops transmitting immediately and sends a "crowded" signal to the channel to ensure that all other slaves on the network also find a collision.
  • CSMA/CD collision detection that is, when a slave node on a network needs to send data, it first listens to the channel, and if the channel is busy, it waits until it hears that the channel is idle. The data is sent out. If two or more slave nodes are listening and waiting to transmit data, when the channel is idle, the slave nodes start transmitting data almost immediately (almost simultaneously), and a collision
  • each slave node uses the Binary Exponential Back-Off (BEB) algorithm to handle collisions, but this method has the drawback of conflicting delay uncertainty.
  • BEB Binary Exponential Back-Off
  • the network load is large, the uncertainty of network transmission can not meet the real-time requirements of industrial control. Therefore, traditional Ethernet technology is difficult to meet the real-time requirements of the control system for accurate timing communication, and has been regarded as a non-deterministic network.
  • the industrial control network is a typical real-time application system in which tasks (such as the execution of function blocks) usually start at a certain time interval and have a deadline for the execution time of the task.
  • This task is called a periodic task.
  • This task is called aperiodic. Tasks, non-periodic tasks are randomly triggered.
  • These two tasks are reflected in industrial control network communication, which is two types of communication information: periodic communication information and aperiodic communication information.
  • the periodic communication information and the aperiodic communication information have different time characteristics.
  • Periodic communication information is real-time information. Once the system configuration is completed, the transmission of periodic communication information is time-deterministic.
  • Non-periodic communication information is often bursty information and is uncertain in time.
  • Improved Ethernet MAC protocol in Ethernet
  • the network layer increases the transmission control mechanism.
  • C ⁇ MA/DCR Deterministic Collision Resolution
  • the deterministic binary tree addressing method is used, and the CSMA/DCR resolves the collision according to the pre-order traversal from the node address.
  • the low priority slave node stops competing for the channel, while the high priority slave node continues to contend for the channel until successful transmission.
  • this method of modifying the Ethernet MAC protocol can greatly improve the deterministic problem of Ethernet communication, it is at the cost of changing Ethernet firmware (Ethernet master node hardware and software), and it is difficult to communicate with standard commercial Ethernet. Network compatible and increased development costs.
  • TDMA Time Division Multiple Access
  • TDMA allocates a certain bandwidth for each slave node, and each slave node sends information in a fixed time slice to The information of each slave node is guaranteed to have a certain transmission time. Since TDMA does not need to transmit additional control information, the network bandwidth usage is relatively low. However, TDMA is based on the slave node method and cannot reflect the actual bandwidth requirements of each slave node. It cannot guarantee the timely transmission of non-cycle information.
  • Another method to increase transmission control in the upper layer of Ethernet is the master-slave transmission control mode. This is a centralized transmission control method.
  • the above methods all improve the real-time and certainty of Ethernet transmission to a certain extent, it is at the cost of changing the Ethernet structure (such as CSMA/DCR), or at a lower network level (such as the MAC layer).
  • the upper layer) implementation the biggest shortcoming of these methods is that it is difficult to implement, often involves hardware, is not compatible with traditional standard Ethernet, and cannot meet the two-cycle information (ie real-time information) in the industrial control network.
  • Acyclic information usually non-real-time information). Special requirements for simultaneous processing.
  • the communication rate of Ethernet increases from 10M, 100M to 1000M and 10G today.
  • the increase of communication rate means the reduction of network load and the reduction of network transmission delay, that is, the probability of collision is greatly increased. decline.
  • the switch uses a star network topology, divides the network into several network segments. Because the Ethernet switch has the function of data storage and forwarding, the data frames input and output between the ports can be buffered, no collision occurs, and the switch can filter the data transmitted on the network to make the slave nodes in each network segment.
  • full-duplex communication allows two pairs of twisted pairs (or two pairs of fibers) to receive and transmit message frames simultaneously between ports without conflict. Therefore, the use of switching hubs and full-duplex communication can make the collision domain on the network no longer exist (full-duplex communication), or the collision probability is greatly reduced (half-duplex), thus making the Ethernet communication deterministic and real-time greatly improve.
  • full-duplex switched Ethernet the CSMA/CD mechanism is changed, and the communication speed and efficiency of the network will depend on the switch.
  • Some systems also have strict requirements on the synchronization of communication slave nodes. For example, in motion control, the synchronism of each axis is also a very important factor.
  • the existing solution is that all sites on the network must achieve accurate synchronous real-time Ethernet through precise clock synchronization. For example: Internet Time Protocol NTP (Network Time ProtocaD, Simple Network Time Protocal), IEEE1588 Standard Time Protocol (PTP), periodic transmission of synchronous packets with timestamp protocol Synchronization of communication loops.
  • NTP Network Time ProtocaD, Simple Network Time Protocal
  • PTP Standard Time Protocol
  • periodic transmission of synchronous packets with timestamp protocol Synchronization of communication loops In the case where the synchronization accuracy is required to be in the microsecond range, it is impossible to achieve such high synchronization timing by software alone, and must rely on hardware support in the second layer (data link layer) of the network. , that is, an isochronous real-time ASIC chip.
  • Ethernet for field-level communication
  • the upper computer is a dedicated control network card that is bursting out by itself.
  • Real-time communication of Ethernet It is difficult to be compatible with standard Ethernet, and it is difficult to interchange with devices developed by other manufacturers to form a separate communication system.
  • PR MNET, Eth e rnet/IP, PowerLink, EtherCAT, SY ⁇ T, SERCOS III, etc.
  • PROFINET is a typical switched Ethernet network.
  • the switch uses an address-based information forwarding mechanism.
  • the communication speed and efficiency of the network will depend on the switch. In order to reduce the impact of the switch on the speed and efficiency of the entire network, it is necessary to avoid communication across multiple switches when networking, and put devices that frequently exchange data in a network segment. This will increase the difficulty of networking and is not conducive to future systems. Extension.
  • the system cannot enumerate and configure each device.
  • PROFINET realizes synchronous real-time Ethernet through precise clock synchronization, and realizes synchronization of communication loops through regular synchronous data. Its precision can reach microsecond level. Such high synchronization level cannot be realized by software alone. Accurate synchronization in real time, must rely on the hardware support in the second layer of the network, namely Siemens IRT isochronous real-time ASIC chip, increasing the system cost.
  • Ethernet/IP The protocol of Ethernet/IP consists of three parts: IEEE 802. 3 physical layer and data link layer standard, TCP/IP protocol group and Control Information Protocol (CIP). The first two parts are standards.
  • the Ethernet technology is characterized by the CIP part called the Control and Information Protocol.
  • Ethernet/IP networks use commercial Ethernet communication chips, physical media, and star topologies. Ethernet switches are used to implement point-to-point connections between nodes. The system cannot enumerate and configure devices.
  • the latest version of the Ethernet/IP specification includes CIP Sync.
  • the CIP Sync time synchronization scheme is based on the IEEE1588 standard.
  • the main processor (or slave) periodically transmits a real-time clock synchronization message signal for other slave processing.
  • the device (or slave) can be accurately synchronized.
  • PowerLink By using the Hub to implement any network topology, networking through the Hub makes it difficult to enumerate and configure each device. In order to avoid conflicts, PowerLink tries to use bandwidth to reorganize the site information interaction mechanism in the network, and introduces a time slot management mechanism based on CSMA/CD.
  • One site on the network acts as a management station to manage network communication and gives synchronization to other sites. Beats, assigned to each station to publish permissions, each station can only post information after getting the publishing permission. This time slot management mechanism avoids communication conflicts on the network, but also prevents non-cyclical real-time data (such as alarms) of each device from being notified to the system in time.
  • EtherCAT Breaks through the technology of receiving Ethernet packets, decoding them and then copying the process data to each device.
  • the EtherCAT slave device reads the corresponding addressing data as it passes through the slave node. The same input data is also inserted into the message as it passes. The entire process is only a few nanoseconds of time delay. So performance is improved compared to other Ethernet solutions.
  • the last module in the network segment ends the entire data transfer operation, forming a logical and physical ring structure. All transmission data is compatible with Ethernet protocols and works in full-duplex transmission, improving transmission efficiency. Each device converts these Ethernet protocols into an internal bus protocol.
  • EtherCAT is an optimized protocol for process data.
  • the EtherCAT protocol can include several EtherCAT messages.
  • Each message serves a specific memory area of a ⁇ ⁇ process image area.
  • the data order does not depend on the physical order of the Ethernet terminals in the network. , can be arbitrarily addressed.
  • EtherCAT supports topological types such as line, tree, and star.
  • EtherCAT uses distributed clock technology to achieve accurate synchronization, and external synchronization with the factory, using the IEEE1588 standard.
  • SYNQNET It is a ring network structure with fault tolerance.
  • the master node implements a real Bf synchronization network through a dedicated control network card developed by itself, and modifies the data link layer MC protocol to achieve a high-performance synchronous motion.
  • the network because it is its own dedicated control network card and modified the data link layer MAC protocol, makes it difficult to be compatible with other vendors and standard Ethernet.
  • SERCOS III It is a ring or line topology.
  • the master node realizes real-time synchronization network through its own dedicated control network card.
  • the communication protocol is divided into real-time communication channel and non-real-time communication channel.
  • the real-time communication channel transmits real-time data for displaying and inputting all control internal parameters, data and diagnostic information.
  • Non-real-time channels use standard Ethernet frames Transfer non-real time data. I did not suggest ways to enumerate and configure each device in the system.
  • real-time and synchronicity are two basic features of many control systems (especially motion control systems), and Ethernet itself does not have these two features.
  • people's habitual thinking is to solve the real-time synchronization problem from the master node.
  • the solution includes real-time operating system and hardware interrupts, but the current best-performing real-time extended system interrupt latency uncertainty also takes a few microseconds, which is still not high-precision for real-time synchronization requirements.
  • the current real-time synchronization solution is to initiate a synchronous broadcast communication by the hardware at the master node to complete the synchronization. Therefore, the master node needs to use a dedicated network card or an accurate clock synchronization protocol. Have hardware support.
  • the purpose of the present invention is to solve the problem that when the Ethernet is used in a field-level communication system, the real-time communication of the existing network equipment and the accurate synchronization of the system are difficult to guarantee, and the addition of dedicated hardware causes cost increase and openness reduction.
  • the problem is to provide a real-time synchronization method based on standard Ethernet and a synchronous network with simple structure and low cost, real-time synchronization using existing common standard network cards.
  • a real-time synchronization network based on standard Ethernet comprising at least one master node and at least one slave node, each node transmitting data through a transmission protocol, the network may be a chain network or a ring network, and one of the slave nodes is selected Synchronization signal source;
  • the master node When the network is a chain network, the master node has at least one data line interface, and each slave node has at least two data line interfaces, and is connected to each other in series, that is, the data line interface of the master node is connected through the data line. from a data line to the interface node, and connected via a data line & another data from the interface node to the next node data interface from a sequentially connected to form a chain network, real-time synchronization of full duplex communication;
  • each of the master nodes has at least two data line interfaces
  • each slave node has at least two data line interfaces
  • one data line interface of the master node is connected to one data of the slave node through the data line.
  • another data line interface of the slave node is connected to a data interface of the next slave node through the data line, so that the cascade is continued, and the last slave node is connected to the data line interface of the last slave node.
  • Another data line interface is connected to another data line interface of the master node through the data line to form a ring network for real-time synchronous full-duplex communication.
  • the slave node is provided with two timers, which are a periodic timer and a delay timer respectively;
  • the master node is a standard network card, and the control message sent by the slave node is a packet structure of a standard Ethernet transmission protocol IEEE802.3 protocol specification;
  • Each slave node adopts a standard PHY chip and an FPGA with a MAC IP core as a network communication interface (or can be made into a dedicated ASIC);
  • each PLL has a PLL circuit, and each crystal oscillator signal passes through the PLL circuit to generate a clock.
  • the data segment of the IEEE802.3 frame protocol includes periodic data and non-periodic data
  • the periodic data is data in industrial control
  • the task is usually issued at a certain time interval, and the execution time of the task has a cutoff requirement
  • the periodic data is only generated when a specific event is triggered; the control message can also be applied to user-defined or other well-known transport protocol forms.
  • the synchronization signal source is any one of the slave nodes, the synchronization signal source is responsible for strict timing and synchronization message transmission, the other slave nodes are responsible for receiving synchronization messages, and each slave node is provided with a synchronization message delay parameter register. (Also a delay timer), used to set the time delay of the synchronization message on the transmission line.
  • the synchronization message delay parameter sends a delay measurement command message through the master node, and each slave node automatically measures the form of the time delay.
  • the synchronization signal source periodically sends the synchronization message, and the slave node receives the synchronization message and delays the operation for a certain period of time to realize the synchronization of the actions between the slave nodes; the synchronization mode can also use the installation synchronization signal.
  • the line connects the sync signal source with the remaining slave nodes;
  • the slave node When the synchronization signal source is set, the slave node may be arbitrarily designated by the software as a synchronization signal source according to the manner in which the master node sends a command message, or may be determined by setting a dial switch device or any other known manner on any one of the slave nodes.
  • the slave node is the sync signal source.
  • the data line includes a data transmission line and a data receiving line, and there is no conflict between two adjacent nodes to achieve full-duplex communication, and the transmission medium of the data line can be either a twisted pair or a Optical fiber
  • each slave node In full-duplex communication, each slave node has the function of storing and forwarding data and directly forwarding data.
  • the master node and the slave node enter When communicating, the guest slave node forwards the information of the master node, and the whole system communication does not conflict.
  • each slave node communicates with the master node, if the slave node has data sent to the master node, it will first send its own data to the master node. At the same time, the data sent by the latter slave node to the master node is received and stored, and after waiting for the data transmission to the master node to complete, the stored data of the slave node is sent to the master node, and the slave node is not sent to the master node. The data will directly forward the data sent by the latter slave node to the master node, avoiding communication conflicts and realizing full-duplex communication of the entire system.
  • the master node After the system is powered on, for the chain network, the master node performs a self-test on each slave node, and the master node sends a query message.
  • the first slave node first receives the query message, and then forwards the query.
  • the message, and send its own response message initialize its own node number to 0; each slave node forwards the query message in turn after receiving the query message, and sends its own response message and its own node.
  • the number is initialized to 0 until the last slave node; the last slave node can be determined by a DIP switch or other device.
  • the last slave node After receiving the query message, the last slave node sends its own response message, including The last slave node information, and initialize its own node number to 0, 'The master node receives the response message of the last slave node, indicating that the system connection is reliable and each node works normally; if the master node sends the query After the message, the response message of the last slave node will not be received within the set time, and an error will be reported, indicating that there is a fault;
  • the master node For the ring network, the master node sends a query message. After the first slave node receives it, it forwards it to the next slave node, and initializes its own node number to 0. Each slave node forwards it in turn and initializes its own node number to 0, until the last slave node, the last slave node forwards the query message to the master node, and initializes its own node number to 0. After receiving the query message, the master node indicates that the system connection is reliable and each node works. Normal; if the master node still cannot receive this query message within the set time, it indicates that the system connection is not reliable or a node is not working properly;
  • the master node After the self-test is passed, the master node enumerates and configures each slave node;
  • the master node sends a control message measuring the network time delay to each slave node, and the first slave node sends a specific message, and each slave node forwards the specific message, and measures the self and the last slave node.
  • the first slave node periodically sends a synchronization message, and each slave node will forward the synchronization message to the next slave node after receiving the synchronization message, and each slave node After receiving the synchronization message, delay a certain time to compensate for the network time delay, and then act to achieve synchronization of motion between the nodes;
  • the delay timers of the other slave nodes also set an initial parameter value, which is a network time delay of measuring the slave node relative to the last slave node measured from the inter-node network time delay; After receiving the synchronization message, the node triggers the late timer. The delay timer starts to count under the driving of the clock signal. After the initial parameter is set, an interrupt signal is generated, and the slave node latches according to the interrupt signal. The current state is in accordance with the command of the control message, and the current state information is sent to the master node in the form of a message; the master node receives the state information of each slave node, then performs data planning, and plans the data.
  • an initial parameter value which is a network time delay of measuring the slave node relative to the last slave node measured from the inter-node network time delay
  • each slave node In the form of a data message, it is sent to each slave node in the cycle; after receiving the data message, each slave node operates in the same manner in the next cycle; thus, the cycle is repeated, and the normal cycle data exchange and synchronization action of the system are realized. .
  • the master node enumerates and configures the slave nodes, and after receiving the response message of the last slave node, the master node starts to send the configuration packet, followed by the master.
  • the first slave node connected to the node. If the node number is 0, the configuration packet will be received first. After receiving the configuration packet, the configuration packet will not be forwarded to the next slave node.
  • the first slave node Set its own node number to 1, and send a response message, including its own node number, the function and role of the slave node. After the primary node is configured with the first slave node, it will send another configuration report. The first slave node will forward the configuration packet to the second slave node. The node number is 0.
  • the second slave node will not forward the configuration packet to the next one after receiving the configuration packet.
  • the second slave node sets its own node number to 2, and sends a response message, including its own node number, the function and role of the slave node, and so on; until the last one is configured.
  • Point so that each has its own unique reference node, the master node also create a table node from the node, the node contains the node number of each node from the function and role, and the like;
  • the master node starts sending configuration messages through a data interface, and the first slave connected to the master node The node, when the node number is 0, will receive the configuration packet first. After receiving the configuration packet, the configuration packet will not be forwarded to the next slave node.
  • the first slave node sets its own node number to 1, at the same time send a response message, including its own node number, the function and role of the slave node, the master node will send another configuration message after the first slave node is configured, the first slave node The configuration packet will be forwarded to the second slave node. The node number is 0.
  • the second slave node will not forward the configuration packet to the next slave node.
  • the second slave sets its own node number to
  • the control packet structure for measuring the network time delay in the step 3) is a 802.32 protocol specification, and the composition includes a preamble of 7 bytes, a separator of 1 byte, a destination address of 6 bytes, a source address of 6 bytes, a length/type field of 2 bytes, and a data segment 46.
  • Step 3) The method for measuring the time delay between the slave nodes is that after each slave node receives the control message, the delay timer is cleared, and the first slave node sends a specific message to the next slave node, and Triggering its own delay timer to start timing; the second slave node forwards the message to the next slave node after receiving the specific message, and triggers its own delay timing.
  • the device starts timing; this is forwarded down until the end A slave node; after receiving the specific packet, the last slave node forwards the specific packet to the upper slave node, and the last slave node receives the specific packet and then forwards the specific packet upward, and triggers its own delay.
  • the timer stops counting, thus forwarding up and triggering its own delay timer to stop timing until:: the first slave node; the first slave node will trigger its own delay timer to stop timing after receiving the specific message, and The specific text is no longer forwarded; thus, each slave node can obtain the network time delay between itself and the last slave node, that is, the delay timer When half of the form will register the timing of the delay timer parameters stored on each slave node.
  • the specific delay measurement message is sent by the last slave node, and the time delay of each slave node and the first slave node is measured, and the working method is similar to the above.
  • each slave node latches the current state of the current slave node while the action is active, and simultaneously operates the command message of the master node received in the previous cycle, and the slave node
  • the status information is sent to the master node in the form of a message.
  • the master node analyzes the state information of each slave node, and uniformly plans the actions of the slave nodes in the next cycle, and transmits the action information in the form of a command message to the slave node.
  • the synchronization of the actions of the slave nodes is implemented; periodically sending a synchronization message refers to the initial parameter of the first slave node's cycle timer, and the initial parameter is the communication cycle of the periodic communication.
  • the cycle timer starts to be driven by the first slave node clock signal. ⁇ When the timer value reaches the set initial parameter, the cycle timer generates an interrupt signal and clears the cycle timer and restarts the timer. When the first slave receives the interrupt signal, it will send a specific synchronization message downward, so that the cycle reciprocates and the periodicity is realized.
  • the cycle timer of the last slave node is specified to set the initial parameter to the communication cycle of the weekly communication, and the cycle timer of the last slave node generates an interrupt to transmit the specific ' Synchronize messages to each slave node.
  • the working method is similar to the above.
  • step 4 the slave node is delayed by a certain time, and then the action method is a delay timer in each slave node, and each delay timer can set an initial parameter value, and the initial parameter is from the node to the network time of the last slave node.
  • Delay after receiving the synchronization message, each slave node triggers a delay timer, which is driven by the clock signal, starts timing, and after generating the initial parameter, generates an interrupt signal, and the slave node according to the The interrupt signal latches the current state and acts according to the command of the control message, and sends the current state information to the master node in the form of a message.
  • the idea of the invention is to use a standard network card at the primary node, without any proprietary hardware, but in a network-controlled slave node Select one (such as the first slave) as the sync source.
  • the system measures the network transmission time delay (including device delay, transmission line delay, and potassium jitter delay from the node) of each network slave node and the last network slave node during the configuration phase, and The form of the register parameters is stored on the delay timer of the network slave node, and its accuracy can reach ns level.
  • the synchronization signal source is periodically and accurately according to the time parameter of the system configuration (depending on the clock of the slave node.
  • each network slave node operates according to the measured transmission delay time when receiving the synchronization message, realizing the real-time synchronization of the actions of each network slave node. It combines FPGA (Field Programmable Gate Array) technology to implement a new real-time synchronous Ethernet network for field-level communication.
  • the nodes in Ethernet are divided into master nodes and slave nodes, which are suitable for distributed control systems.
  • the network topology of full duplex communication in Ethernet is given, and the method of automatic enumeration and configuration of slave nodes by the master node, as well as the method of realizing network real-time communication and synchronous action between slave nodes are given.
  • the invention has the advantages of reducing the real-time requirement of the main node of the system, and the main node can adopt a standard network card without real-time operating system support, which truly realizes the openness of the control system hardware and reduces the system cost.
  • FIG. 2 is a structural diagram of an example of the Ethernet connection of FIG. 1;
  • FIG. 3 is a structural diagram of another embodiment of the Ethernet connection of FIG. 1;
  • Figure 4 is a ring topology diagram of the system
  • FIG. 5 is a structural diagram of an example of an Ethernet connection of 4.
  • Figure 6 is a diagram of a method for implementing accurate synchronization from a node
  • Figure 7 is a format diagram of a data transmission protocol
  • Figure 8 is another format diagram of the data transmission protocol
  • Figure 9 is a working flow chart of the system.
  • master node 2. slave node, 3. data transmission line, 4. data receiving line, 5. common standard network card, 6. network transformer, 7. PHY chip, 8. FPGA with MAC IP core, 9 Signal sync line, 10. Timer.
  • the communication between the master node 1 and the slave node 2 is completed by the data transmission line 3 and the data reception line 4, respectively, and the communication between the slave nodes 2 is also completed by the data transmission line 3 and the data reception line 4, thus realizing Full duplex communication of data between nodes.
  • the slave node has the functions of store-and-forward and direct-forward. When the data sent by the master node 1 passes through the slave node 2, it is received from the node 2 and directly forwarded to the next slave node 2.
  • the slave node 2 When the data of the slave node 2 is sent to the master node 1, if The slave node 2 has data to be sent to the master node 1, and the slave U slave node 2 stores the data of the next slave node 2 first, and after the data sent from the node 2 to the master node 1 is transmitted, the next slave node 2 is forwarded.
  • the data if the slave node 2 has no data to be sent to the master node 1, the slave node 2 directly forwards the data of the next slave node 2. This achieves full duplex communication of the system.
  • This topology is not only applicable to Ethernet, but also to user-defined or other well-known transport protocol forms, except that the protocols of the IP cores in the FPGA are different.
  • Figure 2 The detailed structure of Figure 1 is shown in Figure 2, where 1 is the master node, 2 is the slave node, 5 is the common standard network card, 6 is the network transformer, 7 is the PHY chip, and 8 is the FPGA with the MAC IP core.
  • the master node 1 can automatically detect whether the system is reliably connected and working normally. In the last slave node 2, through a dial configuration switch or other known means, it is indicated as the last slave node. After the master node 1 automatically detects the slave node, the master node 1 sends a query message, and the first slave node 2 first receives the query message, and the first slave node 2 will forward the query message, and Send its own response message and initialize its own node number to 0. After the next slave node 2, that is, the last slave node receives the query message, it sends its own response message (including the information of the last slave node). ), and initialize its own node number to 0.
  • Master node 1 receives the last slave node 2 After the message is answered, the system connection is reliable and the nodes work normally. If the master node 1 waits for a period of time after sending the query message (this time is twice the maximum time of detecting the maximum number of slave nodes under normal conditions), the response packet of the last node 2 is still not received. An error will be reported stating that there is a failure.
  • the master node 1 can automatically enumerate and configure each slave node 2. After the master node 1 detects the reliable connection and normal operation of the system, after the master node 1 receives the response packet of the last slave node 2, it starts to send the configuration packet, and the first slave node 2 connected to the master node 1 ( At this time, the node number is 0). The configuration packet will be received first. After receiving this configuration, the configuration packet will not be forwarded to the next slave node 2. The first slave node 2 will set its own node number.
  • a response message is sent at the same time, including its own node number, the function and function of the slave node, and the master node 1 sends another configuration message after the first slave node 2 is configured.
  • Slave node 2 (the node number is not 0 at this time) will forward this configuration message to the second slave node 2 (the node number is 0 at this time), and the second slave node, that is, the last slave node 2, is received.
  • This configuration message sets its own node number to 2, and sends a response message, including its own node number, the function and function of the slave node.
  • each slave node 2 has its own unique node label, and the master node 1 also establishes a node table containing the node numbers of the nodes, including the functions and functions of the nodes.
  • Example 2 Example 2:
  • FIG. 3 an Ethernet embodiment with a timer 10 in a chain structure.
  • each slave node 2 measures the network time delay between itself and the last slave node 2.
  • the first slave node 2 periodically sends a synchronization message, and each slave node 2 forwards the synchronization message to the next slave node 2 after receiving the synchronization message, and each slave node 2 After receiving the synchronization message, delay a certain time to compensate for the network time delay, and then act, thus achieving synchronization of motion between nodes 2.
  • the master node 1 selects the standard network card 5 as the network communication interface, and each slave node uses the dual PHY 7 and the FPGA 8 with the MAC IP core! / network communication interface, such that the master node 1 has a communication interface, and each slave node has two communication interfaces, the communication interface of the master node 1 is connected to one communication interface of the slave node through the data line, and the other node of the slave node The communication interface is connected to a communication interface of the next slave node through a data line, and thus connected to each other to form a chain-like network structure.
  • the control message structure sent by the master node 1 conforms to the IEEE802.3 message structure protocol specification.
  • the first two words in the IEEE802.3 message structure data area is represented by 0X55 as the format of the control message, and the following one byte is used to distinguish different control information of the control message.
  • 0X11 indicates the control message measuring the time delay between the nodes, and the rest is the control message. Data area.
  • the entire message consists of a preamble of 7 bytes, a separator of 1 byte, a destination address of 6 bytes, a source address of 6 bytes, a length/type field of 2 bytes, a data section of 46-1500 bytes, and a frame check sequence of 4 bytes.
  • the data segment is further divided into two bytes.
  • the master node message flag, followed by a byte is used to distinguish the control type flag of the different control information of the control message, and the rest is the data information of the control message.
  • the first synchronization message periodically sent from the node 2 the synchronization message is transmitted between the slave nodes 2, and the structure protocol does not have to conform to the long message structure protocol specification of IEEE802.3, due to the synchronization message relationship.
  • the accuracy to synchronization, so the synchronization message should be as short as possible.
  • the synchronization message is represented by two bytes 0XM55.
  • each crystal oscillator has a certain deviation in manufacturing, this is also allowed.
  • each slave node is provided with a PLL circuit, and each crystal oscillator signal passes through the PLL circuit to generate a clock signal.
  • the phase ⁇ 1 fixed loop circuit eliminates the influence of the clock signal jitter of each slave node.
  • the master node 1 After the system is powered on, the master node 1 performs a self-test on each slave node 2, and the master node 1 sends a query message, and the first slave node 2 first receives the query message, and the first slave node 2
  • the query message will be forwarded, and its own response message will be sent and its own node number will be initialized to 0.
  • the second slave node 2 will receive the query message and will forward the query message. Send its own response message and initialize its own node number to 0 until the last slave node 2, the last slave node 2 can be determined by the DIP switch or other device, the last slave node 2 receives this check
  • the response message is sent, including the information of the last slave node, and its own node number is initialized to 0.
  • the master node 1 After the master node 1 receives the response message of the last slave node 2, the system is described. The connection is reliable and the nodes work normally; if the master node 1 waits for a period of time after sending the query i text, this time is twice the maximum time of enumerating the maximum number of slave nodes under normal conditions, and still does not receive the last time. A response message from node 2 will report an error indicating a fault.
  • the master node 1 After the self-test is passed, the master node 1 enumerates and configures each slave node 2, that is, after receiving the response packet of the last slave node 2, the master node 1 starts to send a configuration message and is connected to the master node 1.
  • the first slave node 2 when the node number is 0, will receive the configuration packet first. After receiving the configuration packet, the configuration packet will not be forwarded to the next slave node 2, the first slave node. 2 Set its own node number to 1, and send a response message, including its own node number, the function and function of the slave node, and the master node 1 will send the next one after configuring the first slave node. Configure the packet.
  • the first slave node 2 (the node number is not 0) will forward the configuration packet to the second slave node 2.
  • the second slave node 2 will not forward the packet after receiving the configuration packet.
  • This configuration message is sent to the next slave node 2, and the second slave node 2 sets its own node number to 2, and simultaneously sends a response message, including its own node number, the function and role of the slave node; Analogy, until configuration to the last one Node 2; thus each slave node 2 has its own unique node label, and the master node 1 also establishes a node table, including the node number of each slave node, the function and role of each slave node, and the like;
  • each slave node 2 includes a delay timer, and the first slave node 2 receives itself after receiving the control message measuring the network time delay.
  • delay timer is cleared, and the measurement control message forwarding network time delay after each received this message from the control node, will own delay timer is cleared Q
  • the first slave node 2 sends a specific control message to the second slave node 2, and triggers its own delay timer to start timing, and the second slave node 2 receives the specific message backward.
  • the third slave node 2 forwards the message and triggers its own delay timer to start timing.
  • the last slave node 2 After the last slave node 2 receives the specific message, it will forward the specific message to the previous slave node 2, and the previous slave node 2 After receiving the specific message, the specific message will be forwarded, and its own delay timer will be triggered to stop timing.
  • the first slave node 2 will trigger its own message after receiving the specific message.
  • the delay timer stops counting and the specific message is no longer forwarded.
  • each slave node 2 can know the network time delay between itself and the last slave node 2, that is, half of the delay timer, and the timing of the delay timer will be stored in the register parameters in the slave nodes.
  • the system enters the periodic communication phase, and the first slave node 2 periodically transmits a synchronization message, and the cycle timer in the first slave node 2 can set an initial parameter, which is a periodic communication.
  • the communication cycle the cycle timer starts to be driven by the first slave node 2 clock signal.
  • the cycle timer generates an interrupt signal and clears the cycle timer. And then start timing, the first one receives the interrupt letter from node 2, and sends a specific synchronization message downward.
  • Each slave node will forward the synchronization message. In this way, the cycle is repeated, and the method of transmitting the synchronization message in the cycle 4 is realized.
  • the delay timer in each slave node 2 sets an initial parameter value for measuring the network time delay of the slave node relative to the last slave node measured from the inter-node network time delay.
  • the third slave node forwards the synchronization message
  • the fourth slave node receives the synchronization message
  • a delay timer is triggered, and the delay timer 10 starts timing after being driven by the clock signal.
  • an interrupt signal is generated, and the slave node 2 latches the current state according to the interrupt signal and acts according to the command of the control message, and sends the current state information to the master node in the form of a message.
  • the master node 1 After receiving the status information of each slave node, the master node 1 performs data planning, and sends the planned data to the slave nodes 2 in the form of data packets. This cycle reciprocates to achieve normal cycle data exchange and synchronization actions.
  • Each slave node 2 includes a transformer 6, a DUAL PHY 7 and an FPGA with a MAC IP core. 8. Two timers 10, one of which is a delay timer and the other is a periodic timer.
  • Example 3
  • the ring topology of the system is shown in Figure 4. 1 is the master node, and 2 is the slave node.
  • the communication line between the master node 1. and the slave node 2 has two data transmission lines 3 and two data reception lines 4, and communication between the two slave nodes 2 is also completed by the data transmission line 3 and the data reception line 4. , so that the full-duplex communication of data is realized between adjacent nodes.
  • the slave node has the functions of store-and-forward and direct-forward. When the data sent by the master node passes through the first slave node 2, it is received from the node 2 and directly forwarded to the next slave node 2.
  • the slave node 2 When the data of the slave node 2 is sent to the master node 1, If the slave node 2 has data to be sent to the master node 1, the slave node 2 first stores the data of the next slave node 2, and after the data sent from the node 2 to the master node 1 is transmitted, the next slave node is forwarded.
  • the data of 2 if the slave node 2 has no data to be sent to the master node 1, the slave node 2 directly forwards the data of the next slave node 2.
  • the master node 1 can also communicate with the slave node 2 via another data line 3, 4 in the same manner as the master node 1 mentioned above through the data transmission line 3 and the data receiving line 4 and the slave node 2 communication method.
  • the topology has a fault tolerance function, that is, if the data line connection between the two slave nodes 2 is disconnected, the slave node 2 can pass the data transmission line 3
  • the data receiving line 4 communicates with the master node 1, and the next slave node 2 can communicate with the master node 1 via another data transmitting line 3 and data receiving line 4.
  • This topology is not only applicable to Ethernet, but also to the form of a user-defined or other well-known transport protocol, except that the protocol of the IP core in the FPGA is different.
  • Figure 5 The internal detailed structure of Figure 4 is shown in Figure 5.
  • 1 is the master node
  • 2 is the slave node
  • 5 is the common standard network card as the communication data interface of the master node
  • 6 is the network transformer
  • 7 is the PHY chip
  • 8 is the FPGA with the MAC IP core.
  • the master node 1 can automatically detect whether the system is reliably connected and working normally.
  • the master node 1 sends a query message through the data transmission line 3 and the data receiving line 4, and the first node is forwarded to the next slave node 2 after receiving it from the node 2, and initializes its own node number to 0, and the next slave
  • the node that is, the last slave node 2 forwards the query message to the master node 1 through the data transmission line 3 and the data receiving line 4, and initializes its own node number to 0.
  • the master node 1 indicates that the system connection is reliable and each node works normally.
  • the master node 1 waits for a period of time (this time is twice the maximum time of detecting the maximum number of slave nodes under normal conditions), the query message is still not received, indicating that the system connection is unreliable or a node is abnormal. jobs.
  • the master node 1 has two data interfaces, and each slave node 2 can be automatically enumerated and configured. After the master node 1 detects the reliable connection and normal operation of the system, the master node 1 starts to send the configuration message through the data transmission line 3 and the data receiving line 4, and the first slave node 2 connected to the master node 1 (the node number is 0 at this time). The configuration packet will be received first. After receiving this configuration packet, the configuration packet will not be forwarded to the next slave node 2. The first slave node 2 sets its own node number to 1, and sends a response at the same time.
  • the packet contains its own node number, the function and role of the slave node, and the master node 1 will send the next configuration message after the first slave node 2 is configured.
  • the first slave node 2 will forward the packet.
  • the configuration packet is sent to the second slave node 2 (the node number is 0), and the second slave node 2 does not forward the configuration packet to the next slave node 2 after receiving the configuration packet.
  • the slave node 2 sets its own node number to 2, and simultaneously sends a response message, including its own node number, the function and function of the slave node.
  • each slave node 2 has its own node number (the node number is not 0 at this time), and each slave node 2 will forward the configuration packet, and the last slave node 2 will forward the packet.
  • Configure the packet to another data line interface on the primary node 1.
  • master node 1 indicates that the entire system will be configured.
  • each slave node 2 has its own unique node label, and the master node 1 also establishes a node table, which includes the node numbers of the slave nodes 2, including the functions and functions of the nodes.
  • 1 is a master node
  • 2 is a slave node
  • 3 is a data transmission line
  • 4 is a data reception line
  • 9 is a synchronization signal line.
  • one slave node can be selected as the synchronization signal source, and the last one is given.
  • the last slave node 2 is responsible for the strict timing and synchronization signal transmission, and periodically transmits the synchronization signal through the synchronization signal line 9.
  • the other slave node 2 receives the synchronization signal.
  • each slave node 2 will simultaneously receive the synchronization signal and operate at the same time to realize the synchronization of the actions of the slave nodes 2. If the line delay of the transmission line is considered, the on-line delay time of each slave node 2 receiving the synchronization signal is fixed, and a time delay is set in each slave node 2 according to the transmission line length of each node and the transmission delay of the device in the configuration phase.
  • the parameter register (which may also be a delay timer), after receiving the synchronization signal, is delayed by a certain time each time, so that the precise synchronization action of each slave node 2 is realized.
  • the transmission protocol and packet format of the data communication between the master node and each slave node mainly include the master node configuration packet, the master node data, and the slave node data packet.
  • the data communication protocol between the master node and the slave nodes and the slave nodes conforms to the Ethernet frame protocol specification, and the Ethernet ⁇ 802.3 frame protocol format is taken as an example, as shown in FIG. 7, including the preamble, the separator, the destination address, and the source.
  • the data segment includes non-periodic data and periodic data.
  • the periodic data is data in industrial control, and tasks (such as the execution of function blocks) are usually issued at certain time intervals and have deadlines for the execution time of the tasks.
  • Acyclic data is only generated when a specific event is triggered, such as node configuration, fault diagnosis, program upload/download, operation log, alarm processing, and so on.
  • FIG. 8 shows another control message structure sent by the master node 1, which also conforms to the 802.3 message structure protocol specification, in order to distinguish from the TCP/IP message format sent by the master node 1, ⁇ 802.3
  • the first two bytes in the message structure data area are represented by 0 ⁇ 55 ⁇ as the format of the control message, and the following one byte is used to distinguish different control information of the control message.
  • 0X11 indicates the time between nodes.
  • the delayed control message, the rest is the data area of the control message.
  • the entire message consists of a preamble of 7 bytes, a separator of 1 byte, a destination address of 6 bytes, a source address of 6 bytes, a length/type field of 2 bytes, a data section of 46-1500 bytes, and a frame check sequence of 4 bytes.
  • the data segment is further divided into two bytes.
  • the master node message flag, followed by a byte is used to distinguish the control type flag of the different control information of the control message, and the rest is the data information of the control message.
  • Master node configuration (query) message After the system is powered on or after the system is reconfigured, the master node sends the packet to complete the system detection and automatic enumeration and configuration of each slave node.
  • the master node data message is used to send instruction data to the slave node.
  • the master node sends a primary node period data packet, and receives its own data from the node after receiving it.
  • the slave node data message is used to reflect the running status of the node to the master node.
  • the slave node sends a slave node data message to the master node.
  • the master node 1 After the system completes the automatic enumeration and configuration process of the slave node, taking the chain structure as an example, as shown in FIG. 6, the master node 1 sends a periodic data packet, and ensures that each slave node 2 receives the master node 1 period.
  • the synchronization signal source that is, the last slave node 2 periodically transmits a synchronization signal through the signal synchronization line 9, and after receiving the signal, each slave node 2 passes the set delay time value and then locks.
  • the current working state is stored, and the received data of the master node 1 period is simultaneously operated, and the current working state is sent from the node period data message to the master node 1.
  • FIG. 9 shows the process of the system of the present invention.
  • the master node After the system is powered on, for the chain network, the master node performs a self-test on each slave node, and the master node sends a query message.
  • the first slave node first receives the query message, and then forwards the query.
  • the message, and send its own response message initialize its own node number to 0; each slave node forwards the query message in turn after receiving the query message, and sends its own response message and its own node.
  • the number is initialized to 0 until the last slave node; the last slave node can be determined by a DIP switch or other device.
  • the last slave node After receiving the query message, the last slave node sends its own response message, including the last.
  • the master node After the master node receives the response message of the last slave node, it indicates that the system connection is reliable and the nodes work normally; if the master node sends the query message After that, the response message of the last slave node is not received within the set time, and an error is reported, indicating that there is a fault; For the ring network, the master node sends a query message, the first slave node receives it and then forwards it to the next slave node, 'at the same time, initializes its own node number to 0, and each slave node forwards it in turn and initializes its own node number. 0, until the last slave node, the last slave node forwards the query message to the master node, and initializes its own node number to 0. After receiving the query message, the master node indicates that the system connection is reliable and each The node works normally. If the master node still cannot receive the query message within the set time, the system connection is unreliable or a node is not working properly.
  • the master node After the self-test is passed, the master node enumerates and configures each slave node;
  • the master node sends a control message measuring the network time delay to notify each slave node, the first slave node sends a specific message, each slave node forwards the specific message, and measures itself and the last slave node.
  • the first slave node periodically sends a synchronization message, and each slave node will forward the synchronization message to the next slave node after receiving the synchronization message, and each slave node After receiving the synchronization message, delay a certain time to compensate for the network time delay, and then act to achieve synchronization of motion between the nodes;
  • the delay timers of the other slave nodes also set an initial parameter value, which is a network time delay of measuring the slave node relative to the last slave node measured from the inter-node network time delay; After receiving the synchronization message, the node triggers a delay timer, which is driven by the clock signal to start timing. After the initial parameter is set, an interrupt signal is generated, and the slave latches the current according to the interrupt signal.
  • the state is in accordance with the command of the control message, and the current state information is sent to the master node in the form of a message; after receiving the state information of each slave node, the master node performs data planning, and the planned data is The form of the data message is sent to each slave node in the cycle; after receiving the data message, each slave node operates in the same manner in the next cycle; in this way, the cycle is repeated to realize the normal cycle data exchange and synchronization action of the system.
  • the master node enumerates and configures the slave nodes, and after receiving the response packet of the last slave node, the master node starts to send the configuration packet, and the master node
  • the configuration packet will not be forwarded to the next slave node.
  • the first slave node will The node number of the node is set to 1, and a response packet is sent, including its own node number, the function and function of the slave node, and the master node sends another configuration packet after the first slave node is configured.
  • the first slave node will forward the configuration packet to the second slave node.
  • the node number is 0.
  • the second slave node will not forward the configuration packet to the next slave after receiving the configuration packet.
  • the second slave node sets its own node number to 2, and sends a response message, including its own node number, the function and role of the slave node, and so on; until the last one is configured.
  • the master node so that each has its own unique 'reference node, the master node also create a node from the node table contains the node number of the sections, each of the function and role of the other node;
  • the master node sends a configuration packet through a data interface, and the first slave node connected to the master node.
  • the configuration packet is received first.
  • the configuration packet will not be forwarded to the next slave node.
  • the first slave node sets its own node number to 1, and sends a response packet, including its own node number, the function and role of the slave node, and so on.
  • the node sends another configuration packet.
  • the first slave node 3 forwards the configuration packet to the second slave node.
  • the node number is 0, and the second slave After receiving the configuration packet, the node will not forward the configuration packet to the next slave node.
  • the second slave node sets its own node number to
  • the master node simultaneously send a response message, including its own node number, the function and role of the slave node, and so on, and so on: until the last slave node is configured; at this time, the master node retransmits the configuration message, each slave node Each node has its own node number, and each slave node will forward the configuration packet. The last slave node will forward the configuration packet to another data line interface of the master node. After receiving the 1* configuration packet, the master node receives the packet. , indicating that the entire system will be configured, so that each slave node has its own unique node label, and the master node also establishes a node table, including the node number of each slave node, the function and role of each slave node.
  • the control message structure for measuring the network time delay in the step 3) is an IEEE802.3 protocol specification, and the composition includes a preamble 7byt s, a separator lbyte, a destination address of 6 bytes, a source address of 6 bytes, a length/type field of 2 bytes, and a data segment. 46- 15 & 00bytes, frame check sequence field 4bytes, where the data segment is divided into two bytes of the master node message mark Zhi, followed by a byte used to distinguish the control type flag of the different control information of the control message, and the rest is the data information of the control message;
  • step 3 the method for measuring the time delay between nodes is: after each slave node receives the control message, the delay timer is cleared, and the second slave node sends a specific message to the next slave node, and triggers The own delay timer starts. Timing; the second slave node forwards the message to the next slave node after receiving the specific message, and triggers its own delay timing. The device starts timing; this is forwarded down until the end. a slave node; after the last slave node receives the specific message, 'will forward the particular message to the upper slave node, and the last slave node receives the specific message and then forwards the specific message upward, and triggers itself.
  • the delay timer stops counting, so that it forwards up and triggers its own delay timer to stop timing until the first slave node; the first slave node will trigger its own delay timer to stop timing after receiving the specific message.
  • the specific message is no longer forwarded; thus, each slave node can obtain the network time delay between itself and the last slave node, that is, the delay timer Half will form the timing register of the delay timer parameters stored in the respective slave node.
  • the specific delay measurement message is sent by the last slave node, and the time delay of each slave node and the first slave node is measured, and the working method is similar to the above.
  • each slave node latches the current state of the current slave node while the action is active, and simultaneously operates the command message of the master node received in the previous cycle, and the slave node
  • the status information is sent to the master node in the form of a message.
  • the master node analyzes the state information of each slave node, and uniformly plans the actions of the slave nodes in the next cycle, and transmits the action information in the form of a command message to the slave node.
  • the synchronization of the actions of each slave node is implemented; '.
  • Periodically sending a synchronization message refers to the communication of the periodic communication after the initial parameter of the first slave node's cycle timer is set.
  • the cycle timer starts to be driven by the first slave node clock signal.
  • the cycle timer When the timer value reaches the set initial parameter, the cycle timer generates an interrupt signal and clears the cycle timer and restarts timing.
  • the first slave node receives the interrupt signal and sends a specific synchronization message downward, so that the cycle reciprocates and the periodicity is realized.
  • step [4] the slave node is delayed for a certain period of time, and then the action method is to include a delay timer for each slave node, and each delay timer can set an initial parameter value, which is from the node relative to the last one.
  • each slave node triggers a delay timer after receiving the synchronization message.
  • the delay timer starts timing after the clock signal is driven, and generates an interrupt signal after the initial parameter is set.
  • the slave latches the current state according to the interrupt signal and acts according to the command of the control message, and sends the current state information to the master node in the form of a message.
  • the cycle timer of the last slave node is specified to set the initial parameter to the communication cycle of the periodic communication, and the cycle timer of the last slave node generates an interrupt to transmit the specific
  • the synchronization message is sent to each slave node.
  • the working method is similar to the above.
  • the selected signal source is not a slave node at both ends but an arbitrarily selected one from among the slave nodes between them, the synchronization 'method is basically the same as the foregoing, except that it should be simultaneously forward and backward according to the aforementioned working method.
  • the slave sends a signal.
  • each slave node should send a specific delay measurement message to the slave nodes in front of and behind it, and measure the time delay of each of the preceding slave nodes and the first slave node, and also measure the time of each slave node and the last slave node.
  • Delay the specific process is as described above. After the measurement is completed, the delay time of each slave node is sent to the master node, and the master node calculates the delay time of each slave node according to the maximum delay time, and then sends it to each slave node for storage to the delay timer 10 as each slave node. Delay time. Then, an interrupt is generated by the cycle timer of the slave node selected as the signal source, and a synchronization message is sent to the slave nodes in front of and behind the slave node. After receiving the synchronization message, each slave node delays the delay timer. Time to perform the corresponding action to complete the synchronization process.

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Abstract

L'invention concerne un procédé synchrone en temps réel et un réseau synchrone reposant sur la norme Ethernet. Le réseau synchrone résout le problème suivant : lors de l'utilisation d'Ethernet en tant que système de communication en direct, la performance de communication en temps réel de la communication des nœuds du réseau et la performance synchrone précise du système ne peuvent pas être garanties. Du fait de l'ajout de matériels spéciaux, le coût va augmenter et la capacité d'ouverture sera réduite. La présente invention offre notamment les avantages d'une configuration simple, d'un faible coût et de l'utilité de la carte réseau standard ordinaire existante. La configuration du réseau synchrone est la suivante : elle comprend au moins un nœud maître et au moins un nœud esclave ; les données sont transmises entre les nœuds grâce à un protocole de transmission ; le réseau peut être un réseau de connexion ou un réseau en anneau ; un nœud sélectionné de manière aléatoire parmi les nœuds peut être la ressource synchrone, de manière à pouvoir effectuer une communication entièrement bidirectionnelle, synchrone et en temps réel.
PCT/CN2008/000268 2007-02-13 2008-02-02 Procédé synchrone en temps réel et réseau synchrone reposant sur le standard ethernet WO2008101394A1 (fr)

Applications Claiming Priority (4)

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CN200710013313.0 2007-02-13
CN200710013313A CN101018115B (zh) 2007-02-13 2007-02-13 基于标准以太网的实时同步网络及其工作方法
CN200710014419.2 2007-04-29
CNB2007100144192A CN100561904C (zh) 2007-04-29 2007-04-29 一种实现以太网链状网络节点间同步的装置和方法

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US11380190B2 (en) * 2020-04-30 2022-07-05 Kone Corporation Safety communication in an elevator communication system
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CN107872362A (zh) * 2016-09-28 2018-04-03 阿姆有限公司 通信网络中的错误检测
CN114051712A (zh) * 2019-09-23 2022-02-15 倍福自动化有限公司 用于在基于以太网的网络中进行时间同步的方法
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CN111478834A (zh) * 2020-03-25 2020-07-31 武汉迈信电气技术有限公司 一种基于非实时系统的EtherCAT主站同步方法
US11380190B2 (en) * 2020-04-30 2022-07-05 Kone Corporation Safety communication in an elevator communication system
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CN112817904A (zh) * 2021-02-22 2021-05-18 中国人民解放军93114部队 一种MilCAN总线动态数据时序对准方法
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CN113225151B (zh) * 2021-04-19 2023-08-25 杭州康吉森自动化科技有限公司 一种基于can总线的时钟同步系统、方法和装置
CN113467454A (zh) * 2021-07-05 2021-10-01 中国科学院半导体研究所 一种应用于喷灌机的塔车节点控制装置及控制方法
CN113645170A (zh) * 2021-07-12 2021-11-12 鹏城实验室 Wfrft混合载波系统收发端参数同步方法及相关设备
CN113645170B (zh) * 2021-07-12 2023-08-18 鹏城实验室 Wfrft混合载波系统收发端参数同步方法及相关设备
CN114089662A (zh) * 2021-11-17 2022-02-25 湖南力行动力科技有限公司 一种新型高性能电子轴传动控制系统实现方法
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CN114448801A (zh) * 2021-12-23 2022-05-06 东莞市李群自动化技术有限公司 实时通道组创建的方法、网络拓扑、设备及存储介质
CN114786248B (zh) * 2022-03-18 2022-10-25 哈尔滨工业大学 一种无线传感器链式组网及时钟同步方法
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CN115426070A (zh) * 2022-11-02 2022-12-02 浙江国利信安科技有限公司 用于进行时钟再同步的方法、设备和存储介质
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