Communication system, communication device and communication interface

Abstract

The invention relates to a communication system, a communication device and a communication interface. A frame collision can be avoided in communication using a bidirectional path in a daisy chain connection. Each of the plurality of communication devices, when receiving a first frame, forwards the first frame via the second port if it is identified, on the basis of the first information, that itself is not the first communication device, on the other hand, does not forwards the first frame if it is identified, and, when receiving a second frame, forwards the second frame via the second port if it is identified that itself is the first communication device. The second frame is forwarded via the first port in a case where it is identified based on second information that itself is not the second communication device, and the second frame is not forwarded in a case where it is identified that itself is the second communication device.

Description

Technical Field

[0001] The present disclosure relates to a communication system, a communication device and a communication interface. Background Art

[0002] Conventionally, there is a technology related to monitoring the state of a cell using a communication method of a daisy chain connection in which a plurality of cells are connected in series.

[0003] For example, there is a technology related to a daisy chain communication bus and a protocol (see Patent Document 1). In this technology, a communication circuit transmits cell status data to a circuit on a first side via a first connection node in one direction of a bidirectional data path. In addition, in response to a display that the bidirectional data path is incomplete, the cell status data is transmitted to a circuit on a second side via a second connection node along the other direction of the bidirectional data path.

[0004] Prior art literature Patent document: Japanese Patent Application Publication No. 2015-076890. Summary of the invention

[0005] Problems to be solved by the invention In the prior art, an example of a battery management system is disclosed in which a plurality of communication circuits mounted on battery cells are daisy-chained for bidirectional communication and managed by a battery manager. Normally, the battery manager communicates in one direction, and when an abnormality such as disconnection between any of the cells occurs, communication is performed in the opposite direction, thereby enabling management of the battery cells even when an abnormality occurs.

[0006] In the prior art, communication is performed using a unilateral path, and when communication is not possible, communication is switched to using a path in the other direction. However, in the prior art, although bidirectional paths can be used, there is no research on specific communication control when using bidirectional paths, and frame conflicts may occur.

[0007] Therefore, in the technology disclosed herein, an object is to provide a communication system, a communication device, and a communication interface capable of avoiding collision of frames in communication using a bidirectional path in a daisy chain connection.

[0008] Solutions to Solve Problems The communication system of the present disclosure includes: a communication device group, which connects a plurality of communication devices each having a first port and a second port in a daisy-chain manner so that the first port and the second port are connected between adjacent devices; and a communication interface, which connects the communication device group to a network, wherein the communication interface, when receiving a first frame into which first information capable of identifying a first communication device that restricts forwarding of a frame is inserted and a second frame into which second information capable of identifying a second communication device that restricts forwarding of a frame is inserted via the network, transmits the first frame to the first port of a communication device constituting one end of the daisy-chain connection, and transmits the second frame to the second port of a communication device constituting the other end of the daisy-chain connection, wherein each of the plurality of communication devices: when receiving the first frame, forwards the first frame via the second port if it is recognized that the device is not the first communication device based on the first information, and does not forward the first frame if it is recognized that the device is the first communication device, and when receiving the second frame, forwards the second frame via the first port if it is recognized that the device is not the second communication device based on the second information, and does not forward the second frame if it is recognized that the device is the second communication device.

[0009] The communication device disclosed in the present invention is a communication device constituting a communication device group, wherein the communication device group connects a plurality of communication devices having a first port and a second port respectively in a daisy chain manner by connecting the first port and the second port between adjacent devices, wherein when a first frame into which first information of a first communication device capable of identifying frame forwarding is inserted is received, if the device recognizes that it is not the first communication device based on the first information, the first frame is forwarded via the second port, and on the other hand, if the device recognizes that it is the first communication device, the first frame is not forwarded, and when a second frame into which second information of a second communication device capable of identifying frame forwarding is received, if the device recognizes that it is not the second communication device based on the second information, the second frame is forwarded via the first port, and on the other hand, if the device recognizes that it is the second communication device, the second frame is not forwarded.

[0010] The communication device disclosed in the present invention is a communication device constituting a communication device group, wherein a plurality of communication devices respectively having a first port and a second port are daisy-chained in a manner of connecting the first port and the second port between adjacent devices, wherein, when the communication device group identifies itself as the designated communication device based on a frame having designated information indicating the designated communication device received via either the first port or the second port, the frame is not forwarded.

[0011] The communication interface disclosed in the present invention is a communication interface for connecting a communication device group to a network, wherein the communication device group connects a plurality of communication devices having a first port and a second port, respectively, in a daisy-chain manner by connecting the first port and the second port between adjacent devices, wherein when a first frame having first information of a first communication device capable of identifying forwarding of a restricted frame inserted therein and a second frame having second information of a second communication device capable of identifying forwarding of a restricted frame inserted therein are received via the network, the first frame is sent to the first port of a communication device constituting one end of the daisy-chain connection, and the second frame is sent to the second port of a communication device constituting the other end of the daisy-chain connection.

[0012] Effects of the Invention According to the technology of the present disclosure, an effect is achieved in which a collision of frames can be avoided in communication using a bidirectional path in a daisy chain connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing an example of a schematic configuration of a battery management system 10 according to the present embodiment. Figure 2 This is a diagram showing an example of frame processing executed by the communication interface 110 according to the present embodiment. Figure 3 This is a diagram showing an example of frame processing executed by the communication device 120 according to the first embodiment. Figure 4 This is a diagram showing an example of frame transfer according to the first embodiment. Figure 5 This is a diagram showing an example of data transfer corresponding to frame transfer according to the present embodiment. Figure 6 This is a diagram showing an example of frame processing executed by the communication device 120 according to the second embodiment. Figure 7 This is a diagram showing an example of frame transfer according to the second embodiment. Figure 8 This is a diagram showing an example of frame processing executed by the communication device 120 according to the third embodiment. Fig. 9 This is a diagram showing an example of frame transfer according to the third embodiment. DETAILED DESCRIPTION

[0014] Hereinafter, an example of an embodiment of the present disclosure will be described with reference to the accompanying drawings. In addition, in each of the drawings, the same reference numerals are used for the same or equivalent components and parts. In addition, for the sake of convenience of description, the dimensional ratios of the drawings are sometimes exaggerated and different from the actual ratios.

[0015] Additionally, although the term "connection" is used hereinbefore, the term may be broadly interpreted as referring to an electrical connection, including not only a direct connection but also an indirect connection (eg, connection via a passive component).

[0016] Figure 1 1 is a diagram showing an example of a schematic configuration of a battery management system 10 according to the present embodiment. The battery management system 10 includes a battery manager 30 , a network 50 , and a communication system 100 .

[0017] The battery manager 30 requests and collects monitoring data, and performs various controls based on the monitoring data.

[0018] The network 50 connects the battery manager 30 and the communication system 100. As an example, the network 50 may be a CAN (Controller Area Network) bus.

[0019] The communication system 100 is communicably connected to the battery manager 30 via the network 50. The communication system 100 includes a communication interface 110 and a communication device group consisting of a plurality of communication devices 120a, 120b, 120c, and 120d (collectively referred to as "communication devices 120").

[0020] The communication interface 110 connects the communication device group to the network 50 and transmits communication between the battery manager 30 and the communication device group. Previously, the case where the communication interface 110 is implemented by a dedicated circuit is described as an example, but it is not limited to this. The communication interface 110 can also be implemented by a computer with a processor. In addition, a program that enables the computer to function as the communication interface 110 by being executed by the processor can also be provided. In addition, a non-temporary recording medium that records such a program can also be provided. The communication interface 110 has a first connection port 111 and a second connection port 112.

[0021] The communication device 120 transmits monitoring data in response to a request from the battery manager 30. Previously, the case where the communication device 120 is implemented by an integrated circuit is described as an example, but the present invention is not limited thereto. The communication device 120 may also be implemented by a computer having a processor. In addition, a program that is executed by the processor and causes the computer to function as the communication device 120 may also be provided. In addition, a non-transitory recording medium that records such a program may also be provided.

[0022] The communication device 120a has a first port 121a, a second port 122a, a communication unit 123a, a battery cell 124a, and a monitoring unit 125a. The first port 121a and the second port 122a are ports for communicating with other devices, and the communication unit 123a communicates with other devices via at least one of the first port 121a or the second port 122a. As an example, the battery cell 124a may be a lithium-ion battery cell. However, it is not limited thereto, and the battery cell 124a may also be a storage cell such as an electric double layer capacitor. The monitoring unit 125a monitors various states of the battery cell 124a, such as current, voltage, or temperature.

[0023] In such a communication device 120a, monitoring data showing the state of the battery cell 124a is transmitted in response to a request from the battery manager 30. The structures of the communication devices 120b, 120c and 120d may be the same as the communication device 120a, and thus detailed descriptions are omitted here.

[0024] In this way, a plurality of communication devices 120 each having a first port 121 and a second port 122 are daisy-chain connected such that the first port 121 and the second port 122 are connected between adjacent devices, thereby forming a communication device group.

[0025] That is, the second port 122a of the communication device 120a is connected to the first port 121b of the communication device 120b, the second port 122b of the communication device 120b is connected to the first port 121c of the communication device 120c, and the second port 122c of the communication device 120c is connected to the first port 121d of the communication device 120d, thereby forming a daisy chain.

[0026] Then, the first connection port 111 of the communication interface 110 is connected to the first port 121a of the communication device 120a at one end (the upper end of the figure) of the daisy chain connection, and the second connection port 112 of the communication interface 110 is connected to the second port 122d of the communication device 120d at the other end (the lower end of the figure) of the daisy chain connection.

[0027] In addition, in this figure, for convenience of explanation, a case where four communication devices 120a to 120d are daisy-chain connected is shown as an example, but the number of communication devices 120 can be similarly applied to any number of two or more.

[0028] Figure 2 2 is a diagram showing an example of frame processing performed by the communication interface 110 of the present embodiment. In step S210, the communication interface 110 receives a first frame and a second frame from the battery manager 30 via the network 50. Such first frame and second frame may include a command for the battery manager 30 to request monitoring data.

[0029] In the first frame, first information is inserted into the first field, and the first information can identify the first communication device that limits the forwarding of the frame. In the second frame, second information is inserted into the first field, and the second information can identify the second communication device that limits the forwarding of the frame. The first information and the second information can be inserted by the battery manager. Previously, the case where the first communication device is the communication device 120b and the second communication device is the communication device 120c was explained as an example. If the communication devices 120b and 120c configured in the center of the daisy chain connection are used as the first communication device and the second communication device, it is possible to use two-way communication equally, so it is preferred. However, it is not limited to this, and two communication devices 120 configured at a position biased towards one end or the other end of the daisy chain connection can also be used as the first communication device and the second communication device. As such a case, it is particularly effective in the case where the two-way communication speeds are different in the daisy chain connection.

[0030] In the first embodiment, when limiting the forwarding of frames, an identifier assigned to the communication device 120 is used. An identifier that uniquely identifies each communication device 120 is assigned. Such an identifier may be assigned in advance or assigned afterward at the time of initial communication.

[0031] In the first embodiment, the first information shows the first identifier assigned to the first communication device, and the second information shows the second identifier assigned to the second communication device. That is, in the first frame, "120b" as the identifier of the first communication device can be inserted into the first field. Similarly, in the second frame, "120c" as the identifier of the second communication device can be inserted into the first field.

[0032] In step S220, the communication interface 110 sends the first frame to the communication device group via the first connection port 111, and sends the second frame to the communication device group via the second connection port 112. Thus, the communication interface 110 sends the first frame to the first port 121a of the communication device 120a constituting one end of the daisy chain connection, and sends the second frame to the second port 122d of the communication device 120d constituting the other end of the daisy chain connection.

[0033] For example, the communication interface 110 simultaneously sends two frames in which different information is inserted in the first field to both ends of the daisy chain connection in this way. As a result, as the entire communication system 100, a communication speed twice as high as that in the case of using only one direction in the daisy chain connection can be obtained. In addition, at this time, the communication interface 110 can also determine which of the two frames is the first frame and which is the second frame based on the connection relationship of the communication devices 120 in the daisy chain connection. As an example, the communication device 120b is the second device counted from one end of the daisy chain connection and the third device counted from the other end, so it can be forwarded from one end with a smaller number of forwarding times than from the other end. In this case, the communication interface 110 can determine the frame in which "120b" is inserted in the first field as the first frame. Similarly, the communication device 120c is the third device counted from one end of the daisy chain connection and the second device counted from the other end, so it can be forwarded from the other end with a smaller number of forwarding times than from one end. In this case, the communication interface 110 may determine the frame in which "120c" is inserted in the first field as the second frame.

[0034] Figure 3 1 is a diagram showing an example of frame processing performed by the communication device 120 of the first embodiment. In step S310, the communication device 120 receives the first frame or the second frame. In step S320, the communication device 120 determines whether the first field is consistent with its own identifier. If the first field is inconsistent with its own identifier, the communication device 120 advances the processing to step S330 to forward the first frame or the second frame. On the other hand, if the first field is consistent with its own identifier, the communication device 120 does not perform the processing of step S330. That is, the communication device 120 does not forward the first frame or the second frame. The frame forwarding of the first embodiment is described in detail using the drawings.

[0035] Figure 4 1 is a diagram showing an example of frame forwarding according to the first embodiment. When receiving a first frame with the first field set to 120b and a second frame with the first field set to 120c, the communication interface 110 sends the first frame to the first port 121a of the communication device 120a and sends the second frame to the second port 122d of the communication device 120d.

[0036] Accordingly, when the communication device 120a receives the first frame, it determines whether the first field is consistent with its own identifier. Here, since the first field ≠ 120a and the first field is inconsistent with its own identifier, the communication device 120a recognizes that it is not the first communication device. In this case, the communication device 120a forwards the first frame to the communication device 120b via the second port 122a. That is, when the communication device 120a receives the first frame, it forwards the first frame via the second port 122a when it recognizes that it is not the first communication device based on the first information.

[0037] Similarly, when the communication device 120d receives the second frame, it determines whether the first field is consistent with its own identifier. Here, since the first field ≠ 120d and the first field is inconsistent with its own identifier, the communication device 120d recognizes that it is not the second communication device. In this case, the communication device 120d forwards the second frame to the communication device 120c via the first port 121d. That is, when the communication device 120d receives the second frame, it forwards the second frame via the first port 121d if it recognizes that it is not the second communication device based on the second information.

[0038] Next, when the communication device 120b receives the first frame, it determines whether the first field is consistent with its own identifier. Here, since the first field = 120b and the first field is consistent with its own identifier, the communication device 120b recognizes itself as the first communication device. That is, when the first identifier is consistent with its own identifier, the communication device 120b recognizes itself as the first communication device. In this case, the communication device 120b does not forward the first frame. That is, when the communication device 120b receives the first frame, when it recognizes itself as the first communication device based on the first information, it does not forward the first frame.

[0039] Similarly, when the communication device 120c receives the second frame, it determines whether the first field is consistent with its own identifier. Here, since the first field = 120c and the first field is consistent with its own identifier, the communication device 120c identifies itself as the second communication device. That is, when the second identifier is consistent with its own identifier, the communication device 120c identifies itself as the second communication device. In this case, the communication device 120c does not forward the second frame. That is, when the communication device 120c receives the second frame, when it identifies itself as the second communication device based on the second information, it does not forward the second frame.

[0040] In this way, when the communication device 120 recognizes that it is a designated communication device based on a frame having designated information indicating a designated communication device received via either the first port 121 or the second port 122, the communication device 120 does not forward the frame. Therefore, in the communication system 100 of the present embodiment, the forwarding of the first frame from one end of the daisy chain connection is limited to the communication device 120b, and the forwarding of the second frame from the other end of the daisy chain connection is limited to the communication device 120c. Thus, according to the communication system 100 of the present embodiment, even when two frames are forwarded using a bidirectional path in the daisy chain connection, frame collision can be avoided.

[0041] Although the transfer of frames, that is, the request for monitoring data from the battery manager 30 has been described above, the communication system 100 of the present embodiment can provide the battery manager 30 with monitoring data in response to the request.

[0042] Figure 5 1 is a diagram showing an example of data transfer corresponding to frame transfer in this embodiment. When the communication device 120a receives the first frame via the first port 121a, it sends monitoring data Ma showing the state of the battery cell 124a via the first port 121a. As a result, the communication interface 110 receives the monitoring data Ma via the first connection port 111.

[0043] When the communication device 120b receives the first frame via the first port 121b, it sends the monitoring data Mb indicating the state of the battery cell 124b via the first port 121b. Then, when the communication device 120a receives the monitoring data Mb via the second port 122a, it forwards the monitoring data Mb via the first port 121a. Thus, the communication interface 110 receives the monitoring data Mb via the first connection port 111.

[0044] Likewise, when the communication device 120 d receives the second frame via the second port 122 d , it transmits the monitoring data Md indicating the state of the battery cell 124 d via the second port 122 d . Thus, the communication interface 110 receives the monitoring data Md via the second connection port 112 .

[0045] When the communication device 120c receives the second frame via the second port 122c, it transmits the monitoring data Mc indicating the state of the battery cell 124c via the second port 122c. Then, when the communication device 120d receives the monitoring data Mc via the first port 121d, it forwards the monitoring data Mc via the second port 122d. Thus, the communication interface 110 receives the monitoring data Mc via the second connection port 112.

[0046] Then, when the communication interface 110 receives the monitoring data Ma, Mb, Mc, and Md, it provides the monitoring data Ma, Mb, Mc, and Md to the battery manager 30, which is the transmission source of the first frame and the second frame, via the network 50. At this time, the communication interface 110 may provide the monitoring data Ma, Mb, Mc, and Md to the battery manager 30 together, or may provide the monitoring data Ma, Mb, Mc, and Md to the battery manager 30 separately.

[0047] Thus, in the communication system 100 of the present embodiment, in response to the frame forwarding, the monitoring data is provided to the transmission sources of the first frame and the second frame. At this time, according to the communication system 100 of the present embodiment, the communication device 120 that receives the frame via the first port 121 transmits the monitoring data via the first port 121, and on the other hand, the communication device 120 that receives the frame via the second port 122 transmits the monitoring data via the second port 122. Therefore, even when the monitoring data is forwarded using a bidirectional path in the daisy chain connection, the conflict of the monitoring data can be avoided.

[0048] In addition, the above embodiment can also be transformed into various forms or applied to various purposes. For example, in the above description, the case where the forwarding of the frame is restricted by using the identifier assigned to the communication device 120 is shown as an example. However, the forwarding of the frame can also be restricted by limiting the number of forwarding times. This is described in detail.

[0049] Figure 6 1 is a diagram showing an example of frame processing performed by the communication device 120 of the second embodiment. In step S610, the communication device 120 receives the first frame or the second frame. In the second embodiment, in the first frame, a first number is inserted in the first field, and the first number indicates the remaining number of times that the first frame can be forwarded. In the second frame, a second number is inserted in the first field, and the second number indicates the remaining number of times that the second frame can be forwarded. Previously, the case where the first number and the second number are both one was described as an example. If the first number and the second number are set to the number obtained by dividing the number of multiple communication devices 120 constituting the communication device group by 2 and subtracting 1, it is preferred that bidirectional communication can be used equally. However, it is not limited to this. The first number and the second number may also be different numbers within the range where the sum of the first number and the second number becomes the number obtained by subtracting 2 from the number of multiple communication devices 120 constituting the communication device group.

[0050] In step S620, the communication device 120 determines whether the first field is 0. That is, the communication device 120 determines whether the remaining number of times that the frame can be forwarded is 0. If the first field is not 0, the communication device 120 advances the process to step S630 to decrement the value of the first field, and forwards the first frame or the second frame in step S640. On the other hand, if the first field is 0, the communication device 120 does not perform the process of steps S630 to S640. That is, the communication device 120 does not forward the first frame or the second frame. The frame forwarding of the second embodiment is described in detail using the drawings.

[0051] Figure 7 1 is a diagram showing an example of frame forwarding according to the second embodiment. When receiving a first frame with the first field set to 1 and a second frame with the first field set to 1, the communication interface 110 sends the first frame to the first port 121a of the communication device 120a and sends the second frame to the second port 122d of the communication device 120d.

[0052] Accordingly, when the communication device 120a receives the first frame, it determines whether the first field is 0. Here, since the first field is ≠ 0 and the number of times that the frame can be forwarded remains, the communication device 120a recognizes that it is not the first communication device. In this case, the communication device 120a decrements the value of the first field from 1 to 0, and forwards the first frame to the communication device 120b via the second port 122a. That is, when the communication device 120a forwards the first frame, it decrements the first number.

[0053] Similarly, when the communication device 120d receives the second frame, it determines whether the first field is 0. Here, since the first field is ≠ 0 and the number of times that the frame can be transferred remains, the communication device 120d recognizes that it is not the second communication device. In this case, the communication device 120d decrements the value of the first field from 1 to 0, and transfers the second frame to the communication device 120c via the first port 121d. That is, when the communication device 120d transfers the second frame, it decrements the second number.

[0054] Next, when the communication device 120b receives the first frame, it determines whether the first field is 0. Here, since the first field = 0 and there is no remaining number of times that the frame can be forwarded, the communication device 120b recognizes that it is the first communication device. In this case, the communication device 120b does not forward the first frame. That is, when the number of times the first frame is forwarded reaches the limit, the communication device 120b recognizes that it is the first communication device and does not forward the first frame.

[0055] Similarly, when the communication device 120c receives the second frame, it determines whether the first field is 0. Here, since the first field = 0 and there is no remaining number of times that the frame can be forwarded, the communication device 120c recognizes that it is the second communication device. In this case, the communication device 120c does not forward the second frame. That is, when the number of times the second frame is forwarded reaches the limit, the communication device 120c recognizes that it is the second communication device and does not forward the second frame.

[0056] Thus, in the communication system 100 of the second embodiment, the frame transfer is limited by the remaining number of frame transfers. Thus, according to the communication system 100 of the second embodiment, the first information and the second information can be made smaller in amount than when the identifier assigned to the communication device 120 is used.

[0057] In the second embodiment, the case where frame transfer is limited by the remaining number of times that frame transfer is possible is shown as an example. However, frame transfer may be limited by the maximum number of times that frame transfer is possible. This will be described in detail.

[0058] Figure 8 1 is a diagram showing an example of frame processing performed by the communication device 120 of the third embodiment. In step S810, the communication device 120 receives the first frame or the second frame. In the third embodiment, in the first frame, the first number indicating the maximum number of times the first frame can be forwarded is inserted in the first field, and the number of times the first frame is forwarded in the daisy chain connection is inserted in the second field. In the second frame, the second number indicating the maximum number of times the second frame can be forwarded is inserted in the first field, and the number of times the second frame is forwarded in the daisy chain connection is inserted in the second field. Previously, the case where both the first number and the second number are one was described as an example.

[0059] In step S820, the communication device 120 determines whether the first field is consistent with the second field. That is, the communication device 120 determines whether the number of frame forwarding times has reached the maximum number of times. If the first field is inconsistent with the second field, the communication device 120 advances the process to step S830 to increment the value of the second field, and forwards the first frame or the second frame in step S840. On the other hand, if the first field is consistent with the second field, the communication device 120 does not perform the processing of steps S830 to S840. That is, the communication device 120 does not forward the first frame or the second frame. The frame forwarding of the third embodiment is described in detail using the drawings.

[0060] Fig. 91 is a diagram showing an example of frame forwarding according to the third embodiment. When receiving a first frame in which the first field is set to 1 and the second field is set to 0 and a second frame in which the first field is set to 1 and the second field is set to 0, the communication interface 110 sends the first frame to the first port 121a of the communication device 120a and sends the second frame to the second port 122d of the communication device 120d.

[0061] Accordingly, when the communication device 120a receives the first frame, it determines whether the first field is consistent with the second field. Here, since the first field ≠ the second field and the number of frame transfers does not reach the maximum number of times, the communication device 120a recognizes that it is not the first communication device. In this case, the communication device 120a increments the value of the second field from 0 to 1, and transfers the first frame to the communication device 120b via the second port 122a.

[0062] Similarly, when the communication device 120d receives the second frame, it determines whether the first field is consistent with the second field. Here, since the first field ≠ the second field and the number of frame transfers has not reached the maximum number of times, the communication device 120d recognizes that it is not the second communication device. In this case, the communication device 120d increments the value of the second field from 0 to 1, and transfers the second frame to the communication device 120c via the first port 121d.

[0063] Next, when receiving the first frame, the communication device 120b determines whether the first field is consistent with the second field. Here, since the first field = the second field and the number of frame transfers reaches the maximum number, the communication device 120b recognizes itself as the first communication device. In this case, the communication device 120b does not transfer the first frame.

[0064] Similarly, when receiving the second frame, the communication device 120c determines whether the first field is consistent with the second field. Here, since the first field = the second field and the number of frame transfers reaches the maximum number, the communication device 120c recognizes itself as the second communication device. In this case, the communication device 120c does not transfer the second frame.

[0065] In this way, in the communication system 100 of the third embodiment, the forwarding of the frame is limited by the maximum number of times the frame can be forwarded. Therefore, according to the communication system 100 of the third embodiment, the first information and the second information can be made into smaller information amounts compared to the case of using the identifier assigned to the communication device 120. In addition, according to the communication system 100 of the third embodiment, compared to the case of using the remaining number of times the frame can be forwarded, there is no need to rewrite the value of the first field, so the value of the first field can be kept as the information originally inserted.

[0066] The present disclosure also includes the following.

[0067] (Note 1) A communication system, comprising: a communication device group, wherein a plurality of communication devices each having a first port and a second port are daisy-chained in such a manner that the first port and the second port are connected between adjacent devices; and a communication interface, connecting the communication device group to a network, When receiving via the network a first frame into which first information of a first communication device capable of identifying the forwarding of a restricted frame is inserted and a second frame into which second information of a second communication device capable of identifying the forwarding of a restricted frame is inserted, the communication interface sends the first frame to the first port of the communication device constituting one end of the daisy chain connection and sends the second frame to the second port of the communication device constituting the other end of the daisy chain connection, Each of the plurality of communication devices: When receiving the first frame, if the device recognizes that it is not the first communication device based on the first information, the device forwards the first frame via the second port, and if the device recognizes that it is the first communication device, the device does not forward the first frame. When receiving the second frame, if the device recognizes that it is not the second communication device based on the second information, the device transfers the second frame via the first port, and if the device recognizes that it is the second communication device, the device does not transfer the second frame.

[0068] (Note 2) A communication system according to Supplement 1, wherein: The first information indicates a first identifier assigned to the first communication device, The second information indicates a second identifier assigned to the second communication device, Each of the plurality of communication devices recognizes itself as the first communication device when the first identifier matches its own identifier, and recognizes itself as the second communication device when the second identifier matches its own identifier.

[0069] (Note 3) A communication system according to Appendix 1 or 2, wherein: The first information indicates a first number for limiting the number of times the first frame is forwarded. The second information indicates a second number of times for limiting the number of times the second frame is forwarded. Each of the plurality of communication devices recognizes itself as the first communication device when the number of transfers of the first frame reaches a limit, and recognizes itself as the second communication device when the number of transfers of the second frame reaches a limit.

[0070] (Note 4) A communication system according to Appendix 3, wherein: The first number indicates a remaining number of times the first frame can be transferred. The second number indicates the remaining number of times the second frame can be transferred. Each of the plurality of communication devices decrements the first number of times when forwarding the first frame, and decrements the second number of times when forwarding the second frame.

[0071] (Note 5) A communication system according to any one of Notes 1 to 4, wherein: Each of the plurality of communication devices: It also includes a battery cell and a monitoring unit for monitoring the state of the battery cell, When the first frame is received, monitoring data showing a status of the battery cell is sent via the first port, When the second frame is received, sending the monitoring data via the second port, When receiving the monitoring data, the communication interface provides the monitoring data to a transmission source of the first frame and the second frame via the network.

[0072] (Note 6) A communication device constituting a communication device group, wherein a plurality of communication devices each having a first port and a second port are daisy-chained in a manner that the first port and the second port are connected between adjacent devices, wherein: When receiving a first frame into which first information capable of identifying a first communication device that limits forwarding of frames is inserted, if the device recognizes that it is not the first communication device based on the first information, the device forwards the first frame via the second port, and if the device recognizes that it is the first communication device, the device does not forward the first frame. When receiving a second frame inserted with second information of a second communication device capable of identifying the restricted frame forwarding, if the device identifies itself as not the second communication device based on the second information, the second frame is forwarded via the first port; on the other hand, if the device identifies itself as the second communication device, the second frame is not forwarded.

[0073] (Note 7) The communication device according to Supplement 6, wherein: The first information indicates a first identifier assigned to the first communication device, The second information indicates a second identifier assigned to the second communication device, When the first identifier matches the own identifier, the device identifies itself as the first communication device, and when the second identifier matches the own identifier, the device identifies itself as the second communication device.

[0074] (Note 8) The communication device according to Note 6 or 7, wherein: The first information indicates a first number for limiting the number of times the first frame is forwarded. The second information indicates a second number of times for limiting the number of times the second frame is forwarded. When the number of transfers of the first frame reaches a limit, the device identifies itself as the first communication device, and when the number of transfers of the second frame reaches a limit, the device identifies itself as the second communication device.

[0075] (Note 9) The communication device according to Supplement 8, wherein: The first number indicates a remaining number of times the first frame can be transferred. The second number indicates the remaining number of times the second frame can be transferred. When the first frame is transferred, the first number is decremented, and when the second frame is transferred, the second number is decremented.

[0076] (Note 10) A communication device constituting a communication device group, wherein a plurality of communication devices each having a first port and a second port are daisy-chained in a manner that the first port and the second port are connected between adjacent devices, wherein: When the device recognizes that it is the designated communication device based on the frame having the designation information indicating the designated communication device received via either the first port or the second port, the frame is not forwarded.

[0077] (Note 11) A communication interface connects a communication device group to a network, wherein the communication device group connects a plurality of communication devices having a first port and a second port, respectively, in a daisy-chain manner by connecting the first port and the second port between adjacent devices, wherein when a first frame having first information of a first communication device capable of identifying frame forwarding and a second frame having second information of a second communication device capable of identifying frame forwarding are received via the network, the first frame is sent to the first port of a communication device constituting one end of the daisy-chain connection, and the second frame is sent to the second port of a communication device constituting the other end of the daisy-chain connection.

[0078] Description of Reference Numerals 10: Battery Management System 30: Battery Manager 50: Network 100: Communication Systems 110: Communication interface 111: First connection port 112: Second connection port 120: Communication equipment 121: First port 122: Second port 123: Ministry of Communications 124: Battery Cell 125: Surveillance Department.

Claims

1. A communication system, wherein: have: A communication device group, wherein a plurality of communication devices each having a first port and a second port are daisy-chained in a manner that the first port and the second port are connected between adjacent devices; as well as a communication interface, connecting the communication device group to a network, When receiving via the network a first frame into which first information of a first communication device capable of identifying the forwarding of a restricted frame is inserted and a second frame into which second information of a second communication device capable of identifying the forwarding of a restricted frame is inserted, the communication interface sends the first frame to the first port of the communication device constituting one end of the daisy chain connection and sends the second frame to the second port of the communication device constituting the other end of the daisy chain connection, Each of the plurality of communication devices: When receiving the first frame, if the device recognizes that it is not the first communication device based on the first information, the device forwards the first frame via the second port, and if the device recognizes that it is the first communication device, the device does not forward the first frame. When receiving the second frame, if the device recognizes that it is not the second communication device based on the second information, the device transfers the second frame via the first port, and if the device recognizes that it is the second communication device, the device does not transfer the second frame.

2. The communication system according to claim 1, wherein: The first information indicates a first identifier assigned to the first communication device, The second information indicates a second identifier assigned to the second communication device, Each of the plurality of communication devices recognizes itself as the first communication device when the first identifier matches its own identifier, and recognizes itself as the second communication device when the second identifier matches its own identifier.

3. The communication system according to claim 1, wherein: The first information indicates a first number for limiting the number of times the first frame is forwarded. The second information indicates a second number of times for limiting the number of times the second frame is forwarded. Each of the plurality of communication devices recognizes itself as the first communication device when the number of transfers of the first frame reaches a limit, and recognizes itself as the second communication device when the number of transfers of the second frame reaches a limit.

4. The communication system according to claim 3, wherein: The first number indicates a remaining number of times the first frame can be transferred. The second number indicates the remaining number of times the second frame can be transferred. Each of the plurality of communication devices decrements the first number of times when forwarding the first frame, and decrements the second number of times when forwarding the second frame.

5. The communication system according to any one of claims 1 to 4, wherein: Each of the plurality of communication devices: It also includes a battery cell and a monitoring unit for monitoring the state of the battery cell, When the first frame is received, monitoring data showing a status of the battery cell is sent via the first port, When the second frame is received, sending the monitoring data via the second port, When receiving the monitoring data, the communication interface provides the monitoring data to a transmission source of the first frame and the second frame via the network.

6. A communication device constituting a communication device group, wherein a plurality of communication devices each having a first port and a second port are daisy-chained in such a manner that the first port and the second port are connected between adjacent devices, wherein: When receiving a first frame into which first information capable of identifying a first communication device that limits forwarding of frames is inserted, if the device recognizes that it is not the first communication device based on the first information, the device forwards the first frame via the second port, and if the device recognizes that it is the first communication device, the device does not forward the first frame. When receiving a second frame inserted with second information of a second communication device capable of identifying the restricted frame forwarding, if the device identifies itself as not the second communication device based on the second information, the second frame is forwarded via the first port; on the other hand, if the device identifies itself as the second communication device, the second frame is not forwarded.

7. The communication device according to claim 6, wherein: The first information indicates a first identifier assigned to the first communication device, The second information indicates a second identifier assigned to the second communication device, When the first identifier matches the own identifier, the device identifies itself as the first communication device, and when the second identifier matches the own identifier, the device identifies itself as the second communication device.

8. The communication device according to claim 6, wherein: The first information indicates a first number for limiting the number of times the first frame is forwarded. The second information indicates a second number of times for limiting the number of times the second frame is forwarded. When the number of transfers of the first frame reaches a limit, the device identifies itself as the first communication device, and when the number of transfers of the second frame reaches a limit, the device identifies itself as the second communication device.

9. The communication device according to claim 8, wherein: The first number indicates a remaining number of times the first frame can be transferred. The second number indicates the remaining number of times the second frame can be transferred. When the first frame is transferred, the first number is decremented, and when the second frame is transferred, the second number is decremented.

10. A communication device constituting a communication device group, wherein a plurality of communication devices each having a first port and a second port are daisy-chained in such a manner that the first port and the second port are connected between adjacent devices, wherein: When the device recognizes that it is the designated communication device based on the frame having the designation information indicating the designated communication device received via either the first port or the second port, the frame is not forwarded.

11. A communication interface for connecting a communication device group to a network, wherein the communication device group connects a plurality of communication devices having a first port and a second port respectively in a daisy chain manner by connecting the first port and the second port between adjacent devices, wherein: When a first frame in which first information of a first communication device capable of identifying forwarding of a restricted frame is inserted and a second frame in which second information of a second communication device capable of identifying forwarding of a restricted frame is inserted are received via the network, the first frame is sent to the first port of a communication device constituting one end of the daisy chain connection, and the second frame is sent to the second port of a communication device constituting the other end of the daisy chain connection.

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