EtherCAT system with hot link slave station

Abstract

The utility model relates to the technical field of industrial control automation, and provides an EtherCAT system with a hot link slave station. An EtherCAT master station comprising a first master station network port and a second master station network port and N EtherCAT slave stations are constructed in the system, a signal output port of the first master station network port is connected with a signal input port of the first slave station, and a signal input port of the second master station network port is connected with a signal output port of the Nth slave station. The signal output port of the ith slave station is connected with the signal input port of the (i + 1) th slave station, and at least one group of hot link slave stations are arranged in the N EtherCAT slave stations, so that network equipment or nodes serving as the EtherCAT slave stations are flexibly added, deleted or replaced in the EtherCAT ring network networking, the networking flexibility is improved, and the expansibility and the maintainability of the EtherCAT system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial control automation, and in particular to an EtherCAT system with hot-linking slave stations. BACKGROUND

[0002] With the rapid development of science and technology, intelligent manufacturing and industrial control are facing new development trends and challenges. Higher requirements are also put forward for the reliability and flexibility of industrial control systems. EtherCAT bus technology stands out in the industrial Ethernet communication protocol with its high-speed data transmission capability. The ring network and hot-linking function in the EtherCAT bus meet the requirements of reliability and flexibility of the industrial 4.0 control system.

[0003] In the industrial control system of the EtherCAT ring network, there is no solution to how to dynamically add, delete or replace devices or nodes in the network without affecting the entire system and network when a node or link fails. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the embodiments of the present application provide an EtherCAT system with hot-linking slave stations to solve the problem of how to dynamically add, delete or replace network devices and nodes in the EtherCAT ring network.

[0005] In a first aspect, the embodiments of the present application provide an EtherCAT system with hot-linking slave stations, comprising:

[0006] an EtherCAT master station, comprising a first master station network port and a second master station network port, both of which are connected to a receiving unit and a sending unit of the EtherCAT master station;

[0007] N EtherCAT slave stations, each of which comprises a signal input port and a signal output port, and N is a positive integer;

[0008] The first master station network port is a signal output port of the EtherCAT master station and is connected to the signal input port of the first slave station, and the second master station network port is a signal input port of the EtherCAT master station and is connected to the signal output port of the Nth slave station, the signal output port of the ith slave station is connected to the signal input port of the (i+1)th slave station, and i is a positive integer greater than 1 and less than N;

[0009] Among the N EtherCAT slave stations, at least one group of hot-linking slave stations is included, and each group of hot-linking slave stations includes at least one EtherCAT slave station.

[0010] In some embodiments, the EtherCAT master station stores the unique identifier of each hot-linking slave station; and

[0011] The EtherCAT master station updates the saved unique identifier of each hot-linking slave station when updating the hot-linking configuration.

[0012] In some embodiments, the unique identifier of each slave station is saved in the electrically erasable programmable read-only memory (EEPROM) of each slave station, or is the corresponding code of the dial switch of each slave station.

[0013] In some embodiments, before or during the operation of the system, if the EtherCAT master station detects that one or a group of hot-linking slave stations are disconnected from other network modules in the system, the signal transmission is completed by using the network topology formed by the remaining network modules in the system.

[0014] In some embodiments, before or during the operation of the system, if the EtherCAT master station detects that one or more hot-linking slave stations are added to the system, the signal transmission is completed by using the network topology formed after the hot-linking slave stations are added to the system.

[0015] In some embodiments, under the condition that a single point failure occurs in N EtherCAT slave stations, the second master network port is switched to the signal output port of the EtherCAT master station, connected to the signal input port of the Nth slave station, the first master network port is switched to the signal input port of the EtherCAT master station, connected to the signal output port of the first slave station, and the signal output port of the (i+1)th slave station is connected to the signal input port of the ith slave station.

[0016] In some embodiments, each EtherCAT slave station includes at least two signal input ports and two signal output ports.

[0017] The signal output port of the first master network port is connected to the first signal input port of the first slave station, the signal input port of the second master station is connected to the first signal output port of the Nth slave station, and the first signal output port of the ith slave station is connected to the first signal input port of the (i+1)th slave station.

[0018] The signal output port of the second master network port is connected to the second signal input port of the Nth slave station, the signal input port of the first master station is connected to the second signal output port of the first slave station, and the second signal input port of the ith slave station is connected to the second signal output port of the (i+1)th slave station.

[0019] The beneficial effects of the embodiments of the present application compared with the prior art are that the embodiments of the present application construct an EtherCAT master station including a first master station network port and a second master station network port, the first master station network port and the second master station network port are connected with a receiving unit and a sending unit of EtherCAT respectively, a signal output port of the first master station network port is connected with a signal input port of a first slave station, a signal input port of the second master station network port is connected with a signal output port of an Nth slave station, a signal output port of an ith slave station is connected with a signal input port of an (i+1)th slave station, and at least one group of hot-linked slave stations is arranged in the N EtherCAT slave stations, so that the network devices or nodes serving as the EtherCAT slave stations can be flexibly added, deleted or replaced in the EtherCAT ring network, the network flexibility is improved, and the expansibility and maintainability of the EtherCAT system are improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0021] Figure 1 is a structural schematic diagram of an EtherCAT system with hot-linked slave stations provided by the embodiments of the present application.

[0022] Figure 2 is a flowchart of initialization configuration of an EtherCAT master station provided by the embodiments of the present application.

[0023] Figure 3 is a structural schematic diagram of an EtherCAT system with redundant ring network provided by the embodiments of the present application. DETAILED DESCRIPTION

[0024] In the following description, specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. However, persons skilled in the art will understand that the present application can be practiced without these specific details. In other instances, well-known systems, devices, circuits and methods have not been described in detail so as not to obscure the description of the present application.

[0025] As mentioned above, in the industrial control system with EtherCAT ring network, there is no solution to dynamically add, delete or replace the devices or nodes in the network without affecting the whole system and network when a node or link fails.

[0026] In view of this, the embodiment of the present application provides an EtherCAT system with hot-linked slaves, in which an EtherCAT master station including a first master network port and a second master network port is constructed, and N EtherCAT slaves are connected, the first master network port and the second master network port are connected to a receiving unit and a sending unit of the EtherCAT respectively, a signal output port of the first master network port is connected to a signal input port of a first slave, a signal input port of the second master network port is connected to a signal output port of an Nth slave, a signal output port of an ith slave is connected to a signal input port of an (i+1)th slave, and at least one group of hot-linked slaves is arranged in the N EtherCAT slaves, so that the network device or node serving as the EtherCAT slave can be flexibly added, deleted or replaced in the EtherCAT ring network, the networking flexibility is improved, and the expansibility and maintainability of the EtherCAT system are improved.

[0027] Figure 1 is a structural schematic diagram of an EtherCAT system with hot-linked slaves provided by the embodiment of the present application. As shown in the figure, Figure 1 the system includes an EtherCAT master station and N EtherCAT slaves. The N EtherCAT slaves can be EtherCAT slaves 11 to mn, and a servo device, and m and n are both positive integers. Among them, the slaves 21 to mn can constitute a hot-linked group 1, and the servo device can constitute a hot-linked group 2.

[0028] In an example, the EtherCAT master station can include a first master network port MAC1 and a second master network port MAC2, and the first master network port and the second master network port are both connected to a receiving unit and a sending unit of the EtherCAT master station, the receiving unit is used for processing received information, and the sending unit is used for processing sent information. That is, the first master network port and the second master network port can exchange information through the receiving unit and the sending unit of the EtherCAT master station.

[0029] In another example, each of the N EtherCAT slaves can include a signal input port and a signal output port. Among them, each EtherCAT slave can correspond to a node, and one or more network devices can be connected under the node, and each EtherCAT slave and each network device connected thereto also has a master-slave relationship.

[0030] The first master station network port can be set as the signal output port of the EtherCAT master station and connected to the signal input port of the first slave station. The second master station network port can be set as the signal input port of the EtherCAT master station and connected to the signal output port of the Nth slave station. The signal output port of the i-th slave station can be connected to the signal input port of the (i+1)-th slave station, thereby forming a ring network.

[0031] Among the N EtherCAT slaves, there is at least one set of hot-linked slaves, and each set of hot-linked slaves includes at least one EtherCAT slave. Figure 1 The example shown is of N EtherCAT slaves including two groups of hot-linked slaves, where the first group of hot-linked slaves includes two hot-linked slaves and the second group of hot-linked slaves includes one hot-linked slave.

[0032] Understandably, the number of hot link sub-site groups, and the number of sub-sites in each hot link sub-site group, can be set according to actual needs, and there is no limit here.

[0033] According to the technical solution provided in the embodiments of this application, by constructing an EtherCAT master station including a first master station network port and a second master station network port and N EtherCAT slave stations in the system, the signal output port of the first master station network port is connected to the signal input port of the first slave station, the signal input port of the second master station network port is connected to the signal output port of the Nth slave station, the signal output port of the i-th slave station is connected to the signal input port of the (i+1)-th slave station, and at least one set of hot-linked slave stations is set among the N EtherCAT slave stations, thereby realizing the flexible addition, deletion or replacement of network devices or nodes used as EtherCAT slave stations in the EtherCAT ring network, improving the networking flexibility, and enhancing the scalability and maintainability of the EtherCAT system.

[0034] In some embodiments of this application, the EtherCAT master station can store the unique identifier of each hot-link slave station; and the EtherCAT master station updates the stored unique identifier of each hot-link slave station when the hot-link configuration is updated.

[0035] In other words, the EtherCAT master can store which slaves are configured as hot-linked slaves, and which hot-linked slaves are configured as a group. The configuration of hot-linked slaves can be updated as needed; for example, users can configure a target slave as a hot-linked slave or deconfigure it as such. The updated configuration is still stored in the EtherCAT master.

[0036] In some embodiments, the unique identification of each slave station can be stored in the EEPROM (Electrically Erasable Programmable read only memory) of each slave station, or the code corresponding to the dial switch of each slave station.

[0037] In some embodiments of the present application, before or during the operation of the system, if the EtherCAT master station detects that a single or a group of hot-linking slave stations are disconnected from the rest of the network modules in the system, the network topology formed by the rest of the network modules in the system is used to complete the signal transmission.

[0038] On the other hand, before or during the operation of the system, if the EtherCAT master station detects that one or more hot-linking slave stations are added to the system, the network topology formed after the hot-linking slave stations are added to the system is used to complete the signal transmission.

[0039] That is, in order to make the EtherCAT system more flexible, the hot-linking function allows the pre-configured part of the network to be deleted or added from the EtherCAT network before the system is started or during the operation of the system, without affecting the communication with the other part of the network.

[0040] Before enabling hot-linking, a unique identification ID (Identity Document) needs to be configured for the slave station to be hot-linked. This ID can be stored in the EEPROM of the slave station, or it can be the dial switch of the slave station itself. After setting the ID of the slave station, a configuration file can be generated using the corresponding hot-linking information, so that the master station can address the slave station and perform configuration when initializing.

[0041] Figure 1 In the illustrated embodiment, two hot-linking groups are configured in the ring network. The ring network can ensure that a single point failure in the network does not affect data transmission, and the hot-linking slave station device can access any idle port as needed without considering any factors such as network connection order and connection position. The hot-linking slave station unit can be connected or disconnected from the fixed network in any state of the network, and can be powered on or off at any time when the network is working. Therefore, according to the use scenario, the slave stations that are prone to wear and tear and need regular maintenance can be set as hot-linking, so that when a single point failure occurs or a single or a group of slave stations need to be maintained during the operation of the system, the normal operation of the system will not be affected.

[0042] Figure 2 is a flowchart of the initialization and configuration of the EtherCAT master station provided by an embodiment of the present application. As shown in Figure 2As shown, the EtherCAT master station can first acquire the master-slave station configuration file and parse the master-slave station configuration information. The parsing of the master station configuration information can include acquiring the master station bus cycle, acquiring the master station ring network state, and acquiring the master station cycle data size, etc. The parsing of the slave station configuration information can include acquiring the number of slave stations, acquiring slave station information, generating a slave station register initialization command, and generating a slave station mailbox initialization command, etc.

[0043] After the parsing is completed, the EtherCAT master station determines whether the configuration data is accurate. If not, it prompts the protocol stack initialization failure and returns the corresponding error code. If yes, it creates an EtherCAT master station thread, including a protocol stack diagnosis thread, a protocol stack cycle real-time thread, and a data receiving thread.

[0044] If the thread creation fails, it prompts the protocol stack initialization failure and returns the corresponding error code. Otherwise, if the creation is successful, it acquires the link topology. Next, it determines whether the acquisition of the link topology is timed out. If yes, it prompts the protocol stack initialization failure and returns the corresponding error code. If not, it further determines whether the acquisition of the link topology is correct. If not, it continues to determine whether the acquisition of the link topology is timed out, and reacquires when it is not timed out. Otherwise, if the acquisition of the link topology is correct, it sets the slave station state machine and performs the slave station state machine conversion.

[0045] During the conversion, it can be determined whether the slave station state machine is timed out. If yes, it prompts the protocol stack initialization failure and returns the corresponding error code. If not, it further determines whether the slave station state machine is converted successfully. If not, it continues to determine whether the slave station state machine is timed out, and performs the conversion again when it is not timed out, and determines whether the slave station state machine is converted successfully. If the slave station state machine is converted successfully, it determines that the slave station initialization is successful.

[0046] It can be further determined whether the bus cycle starts. If yes, it acquires the slave station cycle data, and repeatedly performs the operation of acquiring the slave station cycle data after the bus cycle starts. If not, it detects the link topology, determines whether the topology changes, and if not, it detects the slave station state, determines whether the slave station state changes. If the slave station state changes, it recovers the slave station and detects the link topology again.

[0047] If the link topology changes, it connects the Link (connection between the slave station and the master station) state of the slave station. If the Link of the PHY (physical layer) chip of the slave station is in the up state, indicating that the PHY chip of the slave station is configured and configured successfully, it can open the slave station port message to acquire the slave station information, determine whether the slave station information is consistent with the slave station configuration information, if yes, recover the slave station, if not, re-detect the Link state of the slave station. On the other hand, if the Link of the PHY chip of the slave station is not in the up state, it also needs to re-detect the Link state of the slave station.

[0048] That is, the configuration file can include three parts of configuration information: master configuration information, slave configuration information and periodic data information.

[0049] The master configuration information is less and mainly includes master identity information, ring network information, network card information and bus period.

[0050] The slave configuration information is the most important and complex part in the configuration file, which includes address and identity information of each slave, register, mailbox and periodic input and output data offset configuration parameters, connection mode between slaves, topology structure and the like. In addition, the slave configuration information can also include some parameter settings for specific applications, such as periodic time, synchronization mode and the like.

[0051] The periodic data information mainly includes command frame information of periodic data, which is used to output data to the slave and acquire input data of the slave after all the slaves enter the periodic mode.

[0052] After the configuration file is parsed, the parsed configuration information and commands can be used to correctly configure the EtherCAT network, and then realize communication and data exchange of each slave in the network. If the network connection and the description in the configuration file do not match, it may cause the failure of initialization and operation information. If the failure occurs in the initialization stage, the master will be terminated immediately, and an error code of response failure will be returned, and the user can troubleshoot according to the error code.

[0053] The EtherCAT master can create three threads during initialization: bus period real-time thread, diagnosis thread and data receiving thread. The priority of the three threads is: data receiving thread > bus period real-time thread > diagnosis thread.

[0054] The data receiving thread can be used to receive data on the link and put it into the receiving queue. The bus period real-time thread can be used for periodic data transmission and analysis, and the output data of each slave on the link is transmitted according to the bus period, and the input data of each slave on the link is acquired. The priority of the bus period real-time thread needs to be paid attention to, and if it is not set reasonably, the bus period may be unstable.

[0055] The diagnosis thread is used for link topology, slave LINK state and slave online state management, and provides diagnosis information of the master and each slave for the application layer, and is responsible for recovering the slave when the state of the slave changes. The diagnosis thread is a periodic thread, and the setting of the periodic time will affect the speed of recovery of the slave.

[0056] In some embodiments of the present application, each EtherCAT slave station can also include at least two signal input ports and two signal output ports. At this time, the signal output port of the first master station network port is connected with the first signal input port of the first slave station, the signal input port of the second master station is connected with the first signal output port of the Nth slave station, and the first signal output port of the ith slave station is connected with the first signal input port of the (i+1)th slave station.

[0057] Meanwhile, the signal output port of the second master station network port is connected with the second signal input port of the Nth slave station, the signal input port of the first master station is connected with the second signal output port of the first slave station, and the second signal input port of the ith slave station is connected with the second signal output port of the (i+1)th slave station.

[0058] That is, when the EtherCAT ring network is formed, each network port of the EtherCAT master station can also include a signal output port and a signal input port respectively, and each EtherCAT slave station can include two signal input ports and two signal output ports, so as to realize the redundant ring network.

[0059] Figure 3 is a structure diagram of the EtherCAT system provided by the embodiments of the present application. As shown in Figure 3 , in the system, the EtherCAT master station includes two network ports, namely MAC1 and MAC2. The master station initiates data transmission through the MAC1 interface and receives corresponding data frames through the MAC2 interface. When the line interruption occurs, only two automatic recovery timeouts are needed to diagnose the interruption and start transmitting data through the MAC2 interface and receiving corresponding data frames through the MAC1 interface.

[0060] That is, when the link is interrupted, MAC1 and MAC2 start to work independently and transmit and receive data respectively. The cable redundancy mode is single fault-tolerant, that is, if the cable is interrupted at one place, the communication of the system will not be affected. However, the ring network cannot tolerate multiple faults in the link.

[0061] When there is no fault, all EtherCAT slave stations will process the data forwarded from the EtherCAT master station. The IN port of the MAC1 is connected with the slave station, and the EtherCAT slave station will process the data transmitted from the MAC1. The OUT port of the MAC2 is connected with the slave station, and the data forwarded after receiving the data of the MAC1 will not be processed by the EtherCAT slave station.

[0062] When a fault occurs, the IN port of the slave station in the link is not linked, the data sent by MAC1 is looped back to MAC1 at the slave station where the link is disconnected, and the data sent by MAC2 is processed by the slave station and looped back to MAC2 from the slave station where the link is disconnected, and the data is received by the master station for data combination. At this time, the two network cards start working at the same time, and all the slave stations in the link receive the data of the master station, and the master station also receives the data of all the slave stations, so the link communication is normal and is not affected.

[0063] The technical scheme provided in the embodiments of the present application realizes the combination of the ring network networking and the hot link function of the EtherCAT system. The ring network requires that the EtherCAT master station has at least two Ethernet ports, the first network port is connected from the signal input port of the EtherCAT slave station, and the signal output port of the last EtherCAT slave station in the link is looped back to the second network port. This means that when a certain node or link in the network fails, data can still be transmitted through other paths, thereby ensuring the continuous operation of the system. The hot link is that the EtherCAT master station configures a unique identifier for the EtherCAT slave station that sets the hot link, and uses the identifier as the addressing address of the slave station. The EtherCAT master station uses this address to identify the slave station that sets the hot link in the link, and uses sequential addressing to identify other slave stations, thereby obtaining the correct link topology.

[0064] The technical scheme provided in the embodiments of the present application utilizes the hot link function of EtherCAT to allow devices to be dynamically added, removed or reconfigured during network operation without the need to close the entire network or interrupt data transmission, so that the system can flexibly cope with configuration changes and improve the scalability of the system.

[0065] At the same time, when a fault occurs in a path in the ring network of EtherCAT, data can continue to be transmitted through another path, thereby not affecting the normal operation of the system, and the slave station with the hot link function allows replacement and reconfiguration during normal operation. Therefore, when the hot link module in the ring link fails, the module can be replaced and repaired without affecting the operation of the system, thereby realizing disturbance-free maintenance.

[0066] All the optional technical schemes described above can be combined in any way to form optional embodiments of the present application, which will not be described here one by one.

[0067] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is taken as an example, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of software functional unit.

[0068] If the integrated module / unit is realized in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, all or part of the processes in the above embodiment methods can also be completed by a computer program instructing related hardware, and the computer program can be stored in a computer readable storage medium. The computer program can be executed by a processor to implement the steps of each method embodiment. The computer program can include computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium can include any entity or device capable of carrying computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc.

[0069] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. An EtherCAT system with hot-linked slave stations, characterized in that, The system includes: The EtherCAT master station includes a first master station network port and a second master station network port. Both the first master station network port and the second master station network port are connected to the receiving unit and the sending unit of the EtherCAT master station. The receiving unit is used to process received information, and the sending unit is used to process sent information. There are N EtherCAT slave stations, each of which includes a signal input port and a signal output port, where N is a positive integer; The first master station network port is the signal output port of the EtherCAT master station and is connected to the signal input port of the first slave station. The second master station network port is the signal input port of the EtherCAT master station and is connected to the signal output port of the Nth slave station. The signal output port of the i-th slave station is connected to the signal input port of the (i+1)-th slave station. i is a positive integer greater than 1 and less than N. Among the N EtherCAT slaves, at least one group of hot-linked slaves is included, and each group of hot-linked slaves includes at least one EtherCAT slave.

2. The system according to claim 1, characterized in that, The EtherCAT master station stores the unique identifier of each hot-link slave station; and When the EtherCAT master station updates the configuration of hot links, it updates and saves the unique identifiers of each hot link slave station.

3. The system according to claim 2, characterized in that, The unique identifier of each slave station is stored in the electrically erasable programmable read-only memory (EEPROM) of each slave station, or is the code corresponding to the DIP switch of each slave station.

4. The system according to claim 1, characterized in that, Before or during system operation, if the EtherCAT master station detects that a single or group of hot-linked slave stations have disconnected from other network modules in the system, it will use the network topology formed by the remaining network modules in the system to complete signal transmission.

5. The system according to claim 1, characterized in that, Before or during system operation, if the EtherCAT master station detects one or more hot-link slave stations joining the system, it uses the network topology formed after the hot-link slave stations join the system to complete signal transmission.

6. The system according to claim 1, characterized in that, Under the condition that a single point of failure occurs in the N EtherCAT slave stations, the network port of the second master station is switched to the signal output port of the EtherCAT master station and connected to the signal input port of the Nth slave station. The network port of the first master station is switched to the signal input port of the EtherCAT master station and connected to the signal output port of the first slave station. The signal output port of the (i+1)th slave station is connected to the signal input port of the ith slave station.

7. The system according to claim 1, characterized in that, Each EtherCAT slave station includes at least two signal input ports and two signal output ports; The signal output port of the first master station's network port is connected to the first signal input port of the first slave station, the signal input port of the second master station is connected to the first signal output port of the Nth slave station, and the first signal output port of the i-th slave station is connected to the first signal input port of the (i+1)-th slave station. The signal output port of the second master station network port is connected to the second signal input port of the Nth slave station, the signal input port of the first master station is connected to the second signal output port of the first slave station, and the second signal input port of the i-th slave station is connected to the second signal output port of the (i+1)-th slave station.

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