Relay unit, communication system, data relay method, and program

Abstract

A relay unit (10) relays device data between a time-synchronized network in which transmission and reception of time-synchronized synchronous communication frames are performed, and a non-time-synchronized network in which transmission and reception of asynchronous communication frames that are not time-synchronized are performed, the device data being data to be used in an application of a device connected to the time-synchronized network or the non-time-synchronized network. A reception unit (112) receives a synchronous communication frame to be received from the time-synchronized network, and acquires, from the synchronous communication frame, the device data of a device connected to the time-synchronized network. A reception buffer (115) stores the device data acquired by the reception unit (112). A transmission unit (123) transmits the device data stored in the reception buffer (115) by encapsulating the device data in an asynchronous communication frame of the non-time-synchronized network.

Description

Relay unit, communication system, data relay method and program

[0001] The present disclosure relates to a relay unit, a communication system, a data relay method, and a program.

[0002] In the field of factory automation (FA), there are often multiple industrial networks with different communication cycles or communication methods. At the boundaries between such networks, a process is required to relay communication frames that are transmitted and received.

[0003] For example, in a TSN (Time-Sensitive Networking) network that synchronizes time between communication devices within the network, communication frames are transmitted and received in accordance with line occupancy rights that are separated by extremely short time periods called time slots for each communication type or device. At the boundary between such a TSN network and a non-TSN network, for example, in order to transmit a communication frame received from the non-TSN network to a device on the TSN network, a communication frame relay process is required, such as holding the communication frame until a time slot where the communication frame can be transmitted and transmitting the communication frame using that time slot (for example, Patent Document 1).

[0004] The device connected to the TSN switch described in Patent Document 1 creates a gate control list (GCL) based on a mapping that associates the frame type, traffic class, and time slot of the TSN stream with each other and the network topology, and the TSN switch transmits the GCL frame.It is explained that this makes it possible to transmit a data stream with guaranteed end-to-end delay.

[0005] JP 2022-167764 A

[0006] A device connected to the TSN switch described in Patent Document 1 buffers received communication frames in multiple queues when relaying communication frames from a non-TSN network to a TSN network. Similarly, communication frames are also buffered in multiple queues when relaying from a TSN network to a non-TSN network. For this reason, for example, when a large number of devices are connected to a TSN network with a short communication cycle, when the communication frame size is large, or when each device transmits a multicast frame, the buffering capacity of the queues becomes large. As a result, the queue capacity may be depleted, potentially leading to missed communication frames.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a relay unit, a communication system, a data relay method, and a program that can reduce buffering capacity when relaying between a time-synchronized network and a non-time-synchronized network.

[0008] To achieve the above object, a relay unit of the present disclosure relays device data, which is data used in applications of devices connected to a time-synchronized network or an asynchronous network, between a time-synchronized network in which time-synchronized synchronous communication frames are transmitted and received and an asynchronous network in which non-time-synchronized asynchronous communication frames are transmitted and received. The relay unit includes a first receiving unit that receives the synchronous communication frames from the time-synchronized network and acquires device data of the devices connected to the time-synchronized network from the synchronous communication frames, a first receiving buffer that temporarily stores the device data acquired by the first receiving unit, and a first transmitting unit that stores the device data temporarily stored in the first receiving buffer in an asynchronous communication frame and transmits it.

[0009] According to the present disclosure, it is possible to reduce the buffering capacity when relaying between a time-synchronized network and a non-time-synchronized network.

[0010] FIG. 1 is a block diagram showing an example of the overall configuration of a communication system according to an embodiment; FIG. 2 is a block diagram showing an example of the functional configuration of a relay unit; FIG. 3 is a block diagram showing an example of the hardware configuration of a relay unit; FIG. 4 is a diagram showing an example of the frame format of a TSN frame;

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals.

[0012] 1 is a block diagram showing an example of the overall configuration of a communication system 100 according to this embodiment. The communication system 100 is, for example, an industrial network system, and includes a time-synchronized network in which time-synchronized synchronous communication frames are transmitted and received, and an asynchronous network in which non-time-synchronized asynchronous communication frames are transmitted and received. The communication system 100 further includes a relay unit 10 that relays between the time-synchronized network and the asynchronous network.

[0013] The relay unit 10 relays device data, which is data used in applications of devices included in a time-synchronized network or a non-time-synchronized network. Specifically, the relay unit 10 has a function of receiving a communication frame transmitted in one network, storing the device data included in the communication frame in a communication frame of the other network, and transmitting the received data.

[0014] A time synchronization network is a network that can maintain a certain level of synchronization between devices within the network using any method. Examples of the time synchronization network include TSN networks such as CC-Link IE / TSN (registered trademark) and EtherCAT (registered trademark). In this embodiment, a case will be described in which the time synchronization network is a TSN network 210 that complies with the Ethernet TSN standard.

[0015] 1, in a TSN network 210, TSN-compatible devices 21, which are device stations (slave stations), maintain a certain level of synchronization with each other through time synchronization processing with a TSN master unit 20 as the master station. Any time synchronization method may be used, and for example, a synchronization method based on a measured value of transmission path delay from the TSN master unit 20 to each TSN-compatible device 21 is used.

[0016] A non-time-synchronized network is a network that has a longer communication cycle than a time-synchronized network and does not guarantee a certain level of synchronism, such as a general-purpose network such as Ethernet (registered trademark), EtherNet / IP (registered trademark), or DeviceNet (registered trademark). In this embodiment, a case will be described in which the non-time-synchronized network is a non-TSN network 220.

[0017] 1, devices included in a TSN network 210, which is a time-synchronized network, are called TSN-compatible devices 21, and devices included in a non-TSN network 220, which is a non-time-synchronized network, are called TSN-incompatible devices 22. The TSN-compatible devices 21 and the TSN-incompatible devices 22 are any devices, such as robots, sensors, cameras, inverters, servos, displays, and industrial computers.

[0018] The device data is data used in the applications of the TSN-compatible device 21 and the TSN-incompatible device 22, and includes, for example, control data for a robot, inverter, or servo, sensor data, image data, monitor data, and the like.

[0019] 1 illustrates a case in which the TSN master unit 20 and TSN-compatible devices 21 of the TSN network 210, the relay unit 10, and the non-TSN-compatible devices 22 of the non-TSN network 220 are connected by line, but the network connection topology is arbitrary. Note that in the following description, the TSN-compatible devices 21 may also include the TSN master unit 20.

[0020] 2 is a block diagram showing an example of the functional configuration of the relay unit 10. As shown in FIG. 2, the relay unit 10 includes a TSN function unit 11 and a non-TSN function unit 12. The TSN function unit 11 of the relay unit 10 has the function of receiving a TSN frame, which is a synchronous communication frame, from a TSN-compatible device 21 of the TSN network 210, extracting and acquiring device data of the TSN-compatible device 21 stored in the TSN frame, and buffering the data. Here, the TSN frame is a communication frame transmitted in TSN-controlled communication and is used in communication within the TSN network 210.

[0021] The non-TSN function unit 12 of the relay unit 10 stores the device data buffered by the TSN function unit 11 in a non-TSN frame, which is an asynchronous communication frame, and transmits it to the TSN-incompatible device 22 of the non-TSN network 220. Here, the non-TSN frame is a communication frame transmitted in communication that is not TSN controlled, and is a communication frame used in communication within the non-TSN network 220.

[0022] The non-TSN function unit 12 of the relay unit 10 further has the function of receiving non-TSN frames, which are asynchronous communication frames, from the TSN-incompatible equipment 22 of the non-TSN network 220, extracting and acquiring the equipment data of the TSN-incompatible equipment 22 stored in the non-TSN frames, and buffering them. Also, the TSN function unit 11 of the relay unit 10 stores the equipment data buffered by the non-TSN function unit 12 in TSN frames, and transmits them to the TSN-compatible equipment 21 of the TSN network 210.

[0023] Fig. 3 is a block diagram showing an example of the hardware configuration of the relay unit 10. In the example of Fig. 3, the relay unit 10 includes a TSN processing circuit 1101, a non-TSN processing circuit 1201, a TSN RAM (Random Access Memory) 1103, a non-TSN RAM 1203, a ROM (Read Only Memory) 1104, a TSN communication interface (indicated as I / F in the figure) 111, and a non-TSN communication interface 121.

[0024] The TSN processing circuit 1101 and the non-TSN processing circuit 1201 are any arithmetic processing circuits, and include, for example, an ASIC (Application Specific Integrated Circuit). At least one of the TSN processing circuit 1101 and the non-TSN processing circuit 1201 includes a CPU (Central Processing Unit) 1105. The CPU 1105 realizes the functions of the TSN processing circuit 1101 and the non-TSN processing circuit 1201 by reading and executing a control program stored in a ROM 1104. Figure 3 shows a case where the CPU 1105 is built into the TSN processing circuit 1101.

[0025] The RAM 1103 functions as a working memory for the TSN processing circuit 1101, and the RAM 1203 functions as a working memory for the non-TSN processing circuit 1201. The RAM 1103 also temporarily stores a control program read from the ROM 1104 and executes it by the CPU 1105.

[0026] The ROM 1104 is a storage unit including a nonvolatile memory such as an EEPROM (Electrically Erasable and Programmable Read Only Memory), a flash memory, etc. The ROM 1104 stores the control program executed by the CPU 1105, as well as data, parameters, etc. used in the arithmetic processing in the TSN processing circuit 1101 and the non-TSN processing circuit 1201.

[0027] More specifically, ROM 1104 stores relay information associated with identification information of TSN master unit 20 or TSN-compatible device 21 of TSN network 210, which is the source of the device data to be relayed, and identification information of non-TSN-compatible device 22 of destination non-TSN network 220. The relay information includes, for example, buffer information indicating the addresses and sizes of receive buffer 115 and transmit buffer 126 that temporarily store the device data of the TSN frame received from TSN master unit 20 or TSN-compatible device 21, destination information indicating to which non-TSN-compatible device 22 connected to non-TSN network 220 each device data is to be transmitted, and transmission type information indicating whether the transmission is to be performed as a multicast frame or a unicast frame.

[0028] ROM 1104 also stores relay information associated with identification information of non-TSN compatible device 22 of non-TSN network 220, which is the source of the device data to be relayed, and identification information of TSN master unit 20 or TSN compatible device 21 of destination TSN network 210. The relay information includes, for example, buffer information indicating the addresses and sizes of receive buffer 125 and transmit buffer 116 that temporarily store device data of non-TSN frames received from non-TSN compatible device 22 of non-TSN network 220, destination information indicating to which device of TSN master unit 20 or TSN compatible device 21 connected to TSN network 210 each device data is to be transmitted, and transmission type information indicating whether the transmission is to be performed as a multicast frame or a unicast frame.

[0029] The TSN communication interface 111 is an interface for transmitting and receiving data to and from the TSN-compatible device 21, and includes a communication device that complies with the TSN standard. The non-TSN communication interface 121 is an interface for transmitting and receiving data to and from the TSN-incompatible device 22, and includes a communication device that complies with the same communication standard as the communication interface of the TSN-incompatible device 22.

[0030] The number of TSN communication interfaces 111 and the number of non-TSN communication interfaces 121 are arbitrary, but they correspond to the number of ports connecting TSN-compatible devices 21 and the number of ports connecting TSN-incompatible devices 22, respectively. Fig. 3 shows a configuration with two TSN communication interfaces 111 and one non-TSN communication interface 121.

[0031] In the hardware configuration example shown in Fig. 3, the TSN processing circuit 1101, RAM 1103, and TSN communication interface 111 of the relay unit 10 work together to function as the TSN function unit 11 shown in Fig. 2. Also, the non-TSN processing circuit 1201, RAM 1203, and non-TSN communication interface 121 of the relay unit 10 work together to function as the non-TSN function unit 12 shown in Fig. 2.

[0032] 2, the TSN function unit 11 includes a receiving unit 112, which is a first receiving unit that receives TSN frames from the TSN-compatible device 21 via the TSN communication interface 111 and extracts and acquires the device data stored in the TSN frames, and a receiving buffer 115, which is a first receiving buffer that temporarily stores the acquired device data. The non-TSN function unit 12 includes a transmitting buffer 126, which is a first transmitting buffer that temporarily stores device data that has been temporarily stored in the receiving buffer 115 of the TSN function unit 11 and then transferred, and a transmitting unit 123, which is a first transmitting unit that stores the device data in the transmitting buffer 126 in a non-TSN frame and transmits the non-TSN frame from the non-TSN communication interface 121 in accordance with the communication cycle of the non-TSN network 220.

[0033] The non-TSN functional unit 12 further includes a receiving unit 122, which is a second receiving unit that receives non-TSN frames from the non-TSN-compatible device 22 via the non-TSN communication interface 121 and extracts and acquires the device data stored in the non-TSN frames, and a receiving buffer 125, which is a second receiving buffer that temporarily stores the acquired device data. The TSN functional unit 11 further includes a transmitting buffer 116, which is a second transmitting buffer that temporarily stores device data that has been temporarily stored in the receiving buffer 125 of the non-TSN functional unit 12 and then transferred, and a transmitting unit 113, which is a second transmitting unit that stores the device data in the transmitting buffer 116 in a TSN frame and transmits it from the TSN communication interface 111. The TSN functional unit 11 further includes a TSN control unit 114 that instructs the transmitting unit 113 to transmit the TSN frame in a time slot allocated for transmitting the TSN frame in the TSN network 210.

[0034] The TSN frame transmitted and received by the TSN communication interface 111 of the TSN function unit 11 has a frame format according to the communication protocol used in the TSN network 210. Fig. 4 shows an example of the frame format of a TSN frame. As shown in Fig. 4, the TSN frame has an Ethernet (registered trademark) header 501, an FA protocol header 502, and a data section 503 following these. Device data is stored in a portion of the data section 503.

[0035] In addition, in the TSN network 210, TSN frames are transmitted and received by unicast and multicast, so the TSN communication interface 111, the receiving unit 112, and the transmitting unit 113 are configured to be able to transmit and receive both unicast and multicast frames.

[0036] The receiving unit 112 of the TSN function unit 11 receives a TSN frame from the TSN master unit 20 or the TSN-compatible device 21 via the TSN communication interface 111, and extracts and acquires the device data stored in the TSN frame. The acquired device data is temporarily stored in the receiving buffer 115.

[0037] More specifically, the receiving unit 112 of the TSN function unit 11 refers to the buffer information of the relay information stored in the ROM 1104, and stores the device data acquired from the TSN frame in a buffer D of an address and size assigned in the receiving buffer 115. Ｒ１ ~D ＲＮ The data will be temporarily saved in the following order.

[0038] The device data temporarily stored in the receiving buffer 115 is transferred to the transmitting buffer 126 of the non-TSN function unit 12. At this time, based on the buffer information of the relay information stored in the ROM 1104, the device data temporarily stored in the receiving buffer 115 is transferred to the buffer D of the address and size assigned in the transmitting buffer 126. Ｔ１ ~D Ｔｍ are temporarily saved in the

[0039] The transmitter 123 stores the temporarily saved device data in a non-TSN frame. At this time, the transmitter 123 references the transmission type information of the relay information stored in the ROM 1104 and selects whether to transmit the data as a multicast frame or a unicast frame. The transmitter 123 then transmits the non-TSN frame to the destination non-TSN device 22 via the non-TSN communication interface 121 in accordance with the communication cycle of the non-TSN network 220.

[0040] The non-TSN frames transmitted and received by the non-TSN communication interface 121 of the non-TSN functional unit 12 have a frame format according to the communication protocol used in the non-TSN network 220. The non-TSN frame has a header according to the communication protocol followed by a data section, with device data stored in part of the data section. The non-TSN communication interface 121, receiving unit 122, and transmitting unit 123 are configured to be able to transmit and receive both unicast frames and multicast frames.

[0041] The receiving unit 122 of the non-TSN function unit 12 receives the non-TSN frame from the non-TSN compatible device 22 via the non-TSN communication interface 121, and extracts and acquires the device data stored in the non-TSN frame. The acquired device data is temporarily stored in the receiving buffer 125.

[0042] More specifically, the receiving unit 122 of the non-TSN function unit 12 refers to the buffer information of the relay information stored in the ROM 1104, and stores the device data acquired from the non-TSN frame in the buffer U of the address assigned in the receiving buffer 125. Ｒ１ ~U ＲＭ The data will be temporarily saved in the following order.

[0043] The device data temporarily stored in the receiving buffer 125 is transferred to the transmitting buffer 116 of the TSN function unit 11. At this time, based on the buffer information of the relay information stored in the ROM 1104, the device data temporarily stored in the receiving buffer 125 is transferred to the buffer U of the address and size assigned in the transmitting buffer 116. Ｔ１ ~U Ｔｎ are temporarily saved in the

[0044] The transmitter 113 stores the temporarily saved device data in a TSN frame. At this time, the transmitter 113 references the transmission type information of the relay information stored in the ROM 1104 and selects whether to transmit the data as a multicast frame or a unicast frame. The TSN controller 114 then issues an instruction to transmit the TSN frame in the time slot allocated for transmitting the TSN frame in the TSN network 210. Based on this instruction, the transmitter 113 transmits the TSN frame from the TSN communication interface 111 to the destination TSN master unit 20 or TSN-compatible device 21.

[0045] Here, when performing the above-described transfer operation, the total capacity of each of the receive buffer 115, transmit buffer 116, receive buffer 125, and transmit buffer 126 is preferably equal to the maximum number of non-TSN-compatible devices 22 that can be connected to the non-TSN network 220 multiplied by the maximum amount of device data that can be stored in a non-TSN frame. By setting the total capacity of each buffer in this manner, it is possible to prevent buffer depletion and the resulting loss of device data during relay between the TSN network 210 and the non-TSN network 220. Furthermore, it is possible to reduce the total capacity of each buffer compared to storing the entire TSN frame or non-TSN frame.

[0046] The operation of the relay unit 10 having the configuration described above will be described with reference to the flowcharts of Figures 5 and 6. Figure 5 is a flowchart of the TSN frame relay process executed by the relay unit 10, and Figure 6 is a flowchart of the non-TSN frame relay process executed by the relay unit 10. First, the operation when a TSN frame arrives at the relay unit 10 from the TSN-compatible device 21 of the TSN network 210 will be described with reference to Figure 5.

[0047] In the TSN function section 11 of the relay unit 10, first, the receiving section 112 receives a TSN frame from the TSN master unit 20 or TSN-compatible device 21 of the TSN network 210 via the TSN communication interface 111 (step S101), and extracts and obtains device data from the received TSN frame (step S102).

[0048] The receiving unit 112 stores the device data acquired in step S102 in the receiving buffer 115 of the TSN function unit 11 (step S103). At this time, the device data is stored in the buffer D of the address assigned in the receiving buffer 115 based on the buffer information of the relay information stored in the ROM 1104. Ｒ１ ~D ＲＮ are temporarily saved in the

[0049] The device data temporarily stored in the receiving buffer 115 is transferred to the transmitting buffer 126 of the non-TSN function unit 12 (step S104). At this time, the device data is transferred to the buffer D of the transmitting buffer 126 based on the buffer information of the relay information stored in the ROM 1104. Ｔ１ ~D Ｔｍ Thereafter, the non-TSN network 220 waits until it is time to transmit a non-TSN frame to the non-TSN compatible device 22 (step S105: No).

[0050] When it is time to transmit a non-TSN frame to the TSN-incompatible device 22 (step S105: Yes), the transmitter 123 stores the device data stored in the transmission buffer 126 in a non-TSN frame and transmits it (step S106). At this time, the transmission type information of the relay information stored in the ROM 1104 is referenced, and either a multicast frame or a unicast frame is selected for transmission, and the non-TSN frame is transmitted.

[0051] An example of the operation of relaying device data from the TSN network 210 to the non-TSN network 220 will be described with reference to Figures 7A, 7B, 8A, and 8B. Figures 7A and 8A are diagrams showing an example of the operation of relaying communication frames by TSN frame relay processing, and Figures 7B and 8B are diagrams showing data transfer from a receive buffer to a transmit buffer.

[0052] The relaying of equipment data is performed in accordance with the following information: buffer information included in the relay information, which indicates the addresses and sizes of the receive buffer 115 and the transmit buffer 126 that temporarily store the equipment data of the TSN frames received from the TSN master unit 20 or the TSN-compatible equipment 21 of the TSN network 210; destination information indicating to which of the TSN-incompatible equipment 22 connected to the non-TSN network 220 each piece of equipment data should be sent; and transmission type information indicating whether the data should be sent as a multicast frame or a unicast frame.

[0053] For example, as shown in Figure 7A, when a unicast TSN frame F1 is transmitted from the TSN master unit 20(A) of the TSN network 210, the receiving unit 112 of the relay unit 10 extracts the device data from the TSN frame F1 and stores it in the receiving buffer 115 according to the buffer information of the relay information, as shown in Figure 7B. Thereafter, the stored device data is transferred to the transmitting buffer 126 according to the buffer information as device data addressed to the TSN non-compatible device 22(D), device data addressed to the TSN non-compatible device 22(E), and device data addressed to the TSN non-compatible device 22(F). The transmitting unit 123 of the relay unit 10 stores each device data in non-TSN frames F2, F3, and F4 and transmits them as unicast frames to the TSN non-compatible devices 22(D, E, F). That is, device data transmitted by unicast from the TSN network 210 can be transmitted to a plurality of non-TSN compatible devices 22 on the non-TSN network 220 .

[0054] 8A shows a case where a multicast TSN frame F5 is transmitted from the TSN master unit 20(A) of the TSN network 210, a multicast TSN frame F6 is transmitted from the TSN-compatible device 21(B), and a multicast TSN frame F7 is transmitted from the TSN-compatible device 21(C). As shown in FIG. 8B, the receiving unit 112 of the relay unit 10 extracts the equipment data from the TSN frames F5, F6, and F7 and stores them in the receiving buffer 115 according to the buffer information in the relay information. The stored equipment data is then transferred to the transmitting buffer 126 as equipment data addressed to the TSN-incompatible device 22(D) according to the buffer information. The transmitting unit 123 of the relay unit 10 stores the transferred equipment data in a non-TSN frame F8 and transmits it to the TSN-incompatible device 22(D) as a multicast frame. That is, device data transmitted by multicast from a plurality of TSN-compatible devices 21 on the TSN network 210 can be transmitted to one TSN-incompatible device 22 on the non-TSN network 220 .

[0055] Next, the operation when a non-TSN frame arrives at the relay unit 10 from the TSN non-compatible device 22 of the non-TSN network 220 will be described with reference to FIG.

[0056] In the non-TSN function section 12 of the relay unit 10, first, the receiving section 122 receives a non-TSN frame from a TSN-incompatible device 22 of the non-TSN network 220 via the non-TSN communication interface 121 (step S201), and extracts and obtains device data from the received non-TSN frame (step S202).

[0057] The receiving unit 122 stores the device data acquired in step S202 in the receiving buffer 125 of the non-TSN function unit 12 (step S203). At this time, the device data is stored in the buffer U of the address assigned in the receiving buffer 125 based on the buffer information of the relay information stored in the ROM 1104. Ｒ１ ~U ＲＭ are temporarily saved in the

[0058] The device data temporarily stored in the receiving buffer 125 is transferred to the transmitting buffer 116 of the TSN function unit 11 (step S204). At this time, the device data is transferred to the buffer U of the transmitting buffer 116 based on the buffer information of the relay information stored in the ROM 1104. Ｔ１ ~U Ｔｎ Thereafter, if the TSN control unit 114 determines that the time slot is not allocated for transmitting a TSN frame from the relay unit 10 in the TSN network 210 (step S205: No), the TSN control unit 114 waits.

[0059] When the TSN control unit 114 determines that the time slot is allocated for transmitting a TSN frame (step S205: Yes), the transmitting unit 113 stores the device data stored in the transmission buffer 116 in a TSN frame and transmits it (step S206). At this time, the transmission type information of the relay information stored in the ROM 1104 is referenced, and either a multicast frame or a unicast frame is selected for transmission, and the TSN frame is transmitted.

[0060] An example of the operation of relaying device data from non-TSN network 220 to TSN network 210 will be described with reference to Figures 9A, 9B, 10A, and 10B. Figures 9A and 10A show an example of the operation of relaying communication frames by non-TSN frame relay processing, and Figures 9B and 10B show data transfer from a receive buffer to a transmit buffer.

[0061] The relaying of equipment data is performed in accordance with the following information: buffer information included in the relay information, which indicates the addresses and sizes of the receive buffer 125 and transmit buffer 116 that temporarily store equipment data of non-TSN frames received from non-TSN compatible equipment 22 of the non-TSN network 220; destination information indicating to which of the TSN master unit 20 and TSN compatible equipment 21 connected to the TSN network 210 each piece of equipment data is to be sent; and transmission type information indicating whether the data is to be sent as a multicast frame or a unicast frame.

[0062] For example, Figure 9A shows a case where a unicast non-TSN frame F9 is transmitted from a TSN-incompatible device 22(D) of the non-TSN network 220, a unicast non-TSN frame F10 is transmitted from a TSN-incompatible device 22(E), and a unicast non-TSN frame F11 is transmitted from a TSN-incompatible device 22(F). As shown in Figure 9B, the receiving unit 122 of the relay unit 10 extracts equipment data from the non-TSN frames F9, F10, and F11 and stores them in the receiving buffer 125 according to the buffer information in the relay information. Thereafter, the stored equipment data is transferred to the transmitting buffer 116 as equipment data addressed to the TSN master unit 20(A) according to the buffer information. The transmitting unit 113 of the relay unit 10 stores the transferred equipment data in a TSN frame F12 and transmits it to the TSN master unit 20(A) as a unicast frame. In other words, device data transmitted by unicast from multiple TSN-incompatible devices 22 in the non-TSN network 220 can be transmitted to one TSN master unit 20 or one TSN-compatible device 21 in the TSN network 210.

[0063] As shown in Figure 10A, when a multicast non-TSN frame F13 is transmitted from the TSN non-compatible device 22(D) of the non-TSN network 220 and a unicast non-TSN frame F14 is transmitted from the TSN non-compatible device 22(E), the receiving unit 122 of the relay unit 10 extracts equipment data from the non-TSN frames F13 and F14 and stores them in the receiving buffer 125 according to the buffer information of the relay information. Thereafter, as shown in Figure 10B, the stored equipment data is transferred to the transmitting buffer 116 as equipment data addressed to the TSN master unit 20(A) and the TSN compatible device 21(B) according to the buffer information. The transmitting unit 113 of the relay unit 10 stores the transferred equipment data in a TSN frame F15 and transmits it to the TSN master unit 20(A) and the TSN compatible device 21(B) as a multicast frame. That is, device data transmitted by multicast or unicast from the non-TSN compatible device 22 of the non-TSN network 220 can be transmitted to the TSN master unit 20 and the TSN compatible device 21 of the TSN network 210 .

[0064] As described above, in the communication system 100 according to the present embodiment, the relay unit 10 connects the TSN network 210 and the non-TSN network 220, and relays device data, which is data used in applications of devices included in the TSN network 210 or the non-TSN network 220. The receiving unit 112 of the TSN function unit 11 of the relay unit 10 receives TSN frames from the TSN network 210, extracts the device data stored in the TSN frames, and temporarily stores the data in the receiving buffer 115. Then, the transmitting unit 123 of the non-TSN function unit 12 stores the device data transferred from the receiving buffer 115 and temporarily stored in the transmitting buffer 126 in a non-TSN frame and transmits it. This makes it possible to reduce the buffering capacity when relaying from a TSN network to a non-TSN network.

[0065] Furthermore, the receiving unit 122 of the non-TSN function unit 12 of the relay unit 10 receives non-TSN frames from the non-TSN network 220, extracts the equipment data stored in the non-TSN frames, and temporarily stores it in the receiving buffer 125. Then, the transmitting unit 113 of the TSN function unit 11 stores the equipment data transferred from the receiving buffer 125 and temporarily stored in the transmitting buffer 116 in a TSN frame and transmits it. This makes it possible to reduce the buffering capacity when relaying from the non-TSN network 220 to the TSN network 210.

[0066] Furthermore, when relaying device data in a TSN frame transmitted from the TSN network 210, the relay is performed in accordance with relay information that includes pre-stored destination information indicating to which non-TSN compatible device 22 connected to the non-TSN network 220 the data should be transmitted, and transmission type information indicating whether the data should be transmitted as a multicast frame or a unicast frame. This makes it possible to relay device data transmitted by multicast from the TSN network 210 even if the non-TSN compatible device 22 does not support multicast.

[0067] Furthermore, when relaying device data in a non-TSN frame transmitted from the non-TSN network 220, relaying is performed in accordance with relay information that includes pre-stored destination information indicating to which of the TSN master unit 20 and TSN-compatible devices 21 connected to the TSN network 210 the data should be transmitted, and transmission type information indicating whether the data should be transmitted as a multicast frame or a unicast frame. This makes it possible to transmit data to the TSN network 210 by multicast even if the non-TSN-compatible device 22 does not support multicast.

[0068] The network configuration, hardware configuration, and flowchart shown in the above embodiment are merely examples, and can be modified and applied as desired. For example, in the above embodiment, the TSN-compatible devices 21 are connected in a line via the TSN communication interface 111 of the relay unit 10, and the TSN-incompatible devices 22 are connected in a line via the non-TSN communication interface 121 of the relay unit 10, but the network configuration may be any other configuration. For example, as shown in Figure 11A, the relay unit 10 may be provided with two or more TSN communication interfaces 111, and the TSN-compatible devices 21 may be connected in a line via each TSN communication interface 111, forming a star connection.

[0069] 11B, the relay unit 10 may be provided with two or more TSN communication interfaces 111, and the TSN-compatible devices 21 may be connected in a ring shape via the two TSN communication interfaces 111. Alternatively, as shown in FIG. 11C, the relay unit 10 may be connected to a star or mesh connection in which the TSN-compatible devices 21 are connected via a TSN-compatible hub 31, or the TSN-incompatible devices 22 are connected via a hub 32. Here, the hub 32 may be compatible with the communication method of the non-TSN network, and may be, for example, the same as the TSN-compatible hub 31, or may be a general-purpose Ethernet hub.

[0070] Furthermore, in the above embodiment, the relay unit 10 relays equipment data between the TSN network 210 and the non-TSN network 220, but the network relayed by the relay unit 10 may be any other network as long as the networks have different communication cycles, communication methods, time synchronization levels, etc.

[0071] Furthermore, in the above embodiment, the division of functions realized by the TSN processing circuit 1101, non-TSN processing circuit 1201, and CPU 1105 of the relay unit 10 is an example, and the division may be changed arbitrarily. For example, in the relay unit 10, a part that relays equipment data of a TSN frame received from the TSN-compatible device 21 to the non-TSN network 220, or a part that relays equipment data of a non-TSN frame received from the TSN-incompatible device 22 to the TSN network 210 may be realized by a single ASIC. In this case, the relay unit 10 may be configured not to have a transmission buffer 126. That is, the transmitter 123 may store equipment data temporarily stored in the receive buffer 115 in a non-TSN frame and transmit it. Similarly, the relay unit 10 may be configured not to have a transmission buffer 116, and the transmitter 113 may store equipment data temporarily stored in the receive buffer 125 in a TSN frame and transmit it.

[0072] Furthermore, the functions realized by the TSN processing circuit 1101, the non-TSN processing circuit 1201, and the CPU 1105 can be realized using a normal computer system, rather than a dedicated system. In this case, a program for executing the operations of the embodiment may be stored and distributed on a computer-readable recording medium such as a CD-ROM (Compact Disc Read-Only Memory), a DVD (Digital Versatile Disc), an MO (Magneto Optical Disc), or a memory card, and the program may be installed on a computer to configure a computer that can realize each function. Then, when each function is realized by sharing the work between an OS (Operating System) and an application, or by cooperation between the OS and an application, only the parts other than the OS may be stored on the recording medium.

[0073] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to explain the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of equivalent disclosures are considered to be within the scope of the present disclosure.

[0074] 10 relay unit, 11 TSN function unit, 12 non-TSN function unit, 100 communication system, 111 TSN communication interface, 112, 122 receiving unit, 113, 123 transmitting unit, 114 TSN control unit, 115, 125 receiving buffer, 116, 126 transmitting buffer, 121 non-TSN communication interface, 20 TSN master unit, 21 TSN compatible device, 22 TSN non-compatible device, 31, 32 HUB, 210 TSN network, 220 non-TSN network, 501 Ethernet header, 502 FA protocol header, 503 data unit, 1101 TSN processing circuit, 1103, 1203 RAM, 1104 ROM, 1105 CPU, 1201 non-TSN processing circuit.

Claims

1. A relay unit that relays device data, which is data used in applications of devices connected to a time-synchronized network or a non-time-synchronized network, between a time-synchronized network where time-synchronized synchronous communication frames are transmitted and received and a non-time-synchronized network where non-time-synchronized asynchronous communication frames are transmitted and received, the relay unit comprising: a first receiving unit that receives the synchronous communication frames from the time-synchronized network and acquires the device data of the devices connected to the time-synchronized network from the synchronous communication frames; a first receiving buffer that temporarily stores the device data acquired by the first receiving unit; and a first transmitting unit that stores the device data temporarily stored in the first receiving buffer in the asynchronous communication frame and transmits it.

2. The relay unit according to claim 1, wherein the first receiving buffer has a capacity obtained by multiplying the maximum capacity of the device data that can be stored in the asynchronous communication frame by the number of devices that can be connected to the non-time-synchronized network.

3. A relay unit as described in claim 1 or claim 2, further comprising a first transmission buffer to which the device data temporarily stored in the first reception buffer is transferred and temporarily stored for transmission to the device connected to the non-time-synchronized network, and the first transmission unit stores the device data temporarily stored in the first transmission buffer in the asynchronous communication frame and transmits it.

4. A relay unit as described in claim 3, further comprising a memory unit that stores relay information including at least one of the following information: buffer information indicating the addresses and sizes of the first receive buffer and the first transmit buffer that temporarily store the device data included in the synchronous communication frame received by the first receive unit; destination information indicating to which device connected to the asynchronous network each device data is to be sent; and transmission type information indicating whether the data is to be sent as a multicast frame or a unicast frame; and based on the relay information, the device data temporarily stored in the first receive buffer and transferred to the first transmit buffer is stored in the asynchronous communication frame and transmitted.

5. A relay unit that relays device data, which is data used in an application of a device connected to a time-synchronized network or the non-time-synchronized network, between a time-synchronized network where time-synchronized synchronous communication frames are transmitted and received and a non-time-synchronized network where non-time-synchronized asynchronous communication frames are transmitted and received, the relay unit comprising: a second receiving unit that receives the asynchronous communication frames from the non-time-synchronized network and acquires the device data of the device connected to the non-time-synchronized network from the asynchronous communication frames; a second receiving buffer that temporarily stores the device data acquired by the second receiving unit; and a second transmitting unit that stores the device data temporarily stored in the second receiving buffer in the synchronous communication frame and transmits the synchronous communication frame using a time slot allocated by the time-synchronized network.

6. The relay unit according to claim 5, wherein the second receive buffer has a capacity obtained by multiplying the maximum capacity of the device data that can be stored in the asynchronous communication frame by the number of devices that can be connected to the non-time-synchronized network.

7. A relay unit as described in claim 5 or claim 6, further comprising a second transmission buffer to which the device data temporarily stored in the second reception buffer is transferred and temporarily stored for transmission to the device connected to the time synchronization network, and the second transmission unit stores the device data temporarily stored in the second transmission buffer in the synchronous communication frame and transmits it.

8. A relay unit as described in claim 7, further comprising a memory unit that stores relay information including at least one of the following information: buffer information indicating the addresses and sizes of the second receive buffer and the second transmit buffer that temporarily store the equipment data included in the asynchronous communication frame received by the second receive unit; destination information indicating to which equipment connected to the time synchronization network each piece of equipment data is to be sent; and transmission type information indicating whether the data is to be sent as a multicast frame or a unicast frame; and based on the relay information, the equipment data temporarily stored in the second receive buffer and transferred to the second transmit buffer is stored in the synchronous communication frame and transmitted.

9. The relay unit according to any one of claims 1 to 8, wherein the time-synchronized network is a TSN (Time-Sensitive Networking) network, and the non-time-synchronized network is a non-TSN network.

10. A communication system comprising a relay unit according to any one of claims 1 to 9.

11. A data relay method for relaying device data, which is data used in an application of a device connected to a time-synchronized network or a non-time-synchronized network, between a time-synchronized network where time-synchronized synchronous communication frames are transmitted and received and a non-time-synchronized network where non-time-synchronized asynchronous communication frames are transmitted and received, the data relay method comprising: temporarily storing the device data contained in the synchronous communication frame received from the device connected to the time-synchronized network; storing the temporarily stored device data in the asynchronous communication frame; and transmitting the data to the non-time-synchronized network.

12. A data relay method for relaying device data, which is data used in an application of a device connected to a time-synchronized network or a non-time-synchronized network, between a time-synchronized network where time-synchronized synchronous communication frames are transmitted and received and a non-time-synchronized network where non-time-synchronized asynchronous communication frames are transmitted and received, the data relay method comprising: temporarily storing the device data contained in the asynchronous communication frame received from the device connected to the non-time-synchronized network; storing the temporarily stored device data in the synchronous communication frame; and transmitting the synchronous communication frame using a time slot allocated by the time-synchronized network.

13. A program for causing a computer that relays device data, which is data used in applications of devices connected to a time-synchronized network or a non-time-synchronized network between the time-synchronized network where time-synchronized synchronous communication frames are sent and received, and the non-time-synchronized network where non-time-synchronized asynchronous communication frames are sent and received, to function as: a first receiving unit that receives the synchronous communication frames from the devices connected to the time-synchronized network and temporarily stores the device data obtained from the synchronous communication frames in a first receiving buffer; and a first transmitting unit that stores the device data temporarily stored in the first receiving buffer in the asynchronous communication frame and transmits it to the non-time-synchronized network.

14. A program for causing a computer that relays device data, which is data used in applications of devices connected to a time-synchronized network or a non-time-synchronized network between the time-synchronized network where time-synchronized synchronous communication frames are sent and received, and the non-time-synchronized network where non-time-synchronized asynchronous communication frames are sent and received, to function as: a second receiving unit that receives the asynchronous communication frames from the devices connected to the non-time-synchronized network and temporarily stores the device data obtained from the asynchronous communication frames in a second receiving buffer; and a second transmitting unit that stores the device data temporarily stored in the second receiving buffer in the synchronous communication frame and transmits the synchronous communication frame using a time slot allocated by the time-synchronized network.

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