Communication system, communication device, and communication interface

Abstract

To allow collision of frames to be avoided in communication using bidirectional paths in a daisy chain connection.SOLUTION: Each of a plurality of communication devices, when receiving a first frame, forwards the first frame through a second port if it recognizes that it is not a first communication device based on the first information, but does not forward the first frame if it recognizes that it is the first communication device, and when receiving a second frame, forwards the second frame through a first port if it recognizes that it is not a second communication device based on the second information, but does not forward the second frame if it recognizes that it is the second communication device.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, there is a technique for monitoring the state of a cell using a communication method of daisy-chain connection in which a plurality of cell units are connected in series.

[0003] For example, there is a technique for a daisy-chain communication bus and protocol (see US Pat. No. 6,399,313), in which a communication circuit transmits cell status data in one direction of a bidirectional data path via a first connection node to a circuit on a first side, and in response to an indication that the bidirectional data path is incomplete, transmits the cell status data along the other direction of the bidirectional data path via a second connection node to a circuit on a second side. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-076890 A Summary of the Invention [Problem to be solved by the invention]

[0005] The prior art discloses an example of a battery management system in which multiple communication circuits mounted on battery cells are daisy-chained to enable bidirectional communication and are managed by a battery manager. Normally, the battery manager communicates in one direction, but if an abnormality such as a disconnection occurs between any of the cells, the battery manager communicates in the opposite direction, making it possible to manage the battery cells even when an abnormality occurs.

[0006] In the conventional technology, communication is performed using a path in one direction, and when communication is unavailable, the communication is switched to a path in the other direction. Although the conventional technology can use paths in both directions, no specific communication control is considered when using paths in both directions, and frame collisions may occur.

[0007] Therefore, an object of the technology disclosed herein is to provide a communication system, a communication device, and a communication interface that are capable of avoiding frame collisions in communication using bidirectional paths in a daisy chain connection. [Means for solving the problem]

[0008] A communication system disclosed herein includes a group of communication devices, each of which has a first port and a second port, and which are daisy-chained together such that the first port and the second port are connected between adjacent devices, and a communication interface that connects the group of communication devices to a network, and when the communication interface receives via the network a first frame into which first information capable of recognizing a first communication device that limits frame forwarding is inserted, and a second frame into which second information capable of recognizing a second communication device that limits frame forwarding is inserted, the communication interface transmits the first frame to the first port of a communication device that constitutes one end of the daisy-chain connection. and transmits the second frame to the second port of the communication device constituting the other end of the daisy chain connection, and each of the plurality of communication devices, upon receiving the first frame, forwards the first frame via the second port if it recognizes that it is not the first communication device based on the first information, but does not forward the first frame if it recognizes that it is the first communication device, and upon receiving the second frame, forwards the second frame via the first port if it recognizes that it is not the second communication device based on the second information, but does not forward the second frame if it recognizes that it is the second communication device.

[0009] The communication device disclosed herein is a communication device that constitutes a communication device group in which a plurality of communication devices, each having a first port and a second port, are daisy-chained so that the first port and the second port are connected between adjacent devices, and when it receives a first frame into which first information capable of recognizing a first communication device that restricts frame forwarding is inserted, if it recognizes that it is not the first communication device based on the first information, it forwards the first frame via the second port, but does not forward the first frame if it recognizes that it is the first communication device, and when it receives a second frame into which second information capable of recognizing a second communication device that restricts frame forwarding is inserted, it forwards the second frame via the first port if it recognizes that it is not the second communication device based on the second information, but does not forward the second frame if it recognizes that it is the second communication device.

[0010] The communication device disclosed herein is a communication device that constitutes a communication device group in which a plurality of communication devices, each having a first port and a second port, are daisy-chained so that the first port and the second port are connected between adjacent devices, and when the communication device recognizes itself as a designated communication device based on a frame having designation information indicating the designated communication device received via either the first port or the second port, the communication device does not forward the frame.

[0011] The communication interface disclosed herein is a communication interface that connects a group of communication devices, each of which has a first port and a second port, to a network, in a daisy chain such that the first port and the second port are connected between adjacent devices, and when it receives via the network a first frame into which first information is inserted that can recognize a first communication device that restricts frame forwarding, and a second frame into which second information is inserted that can recognize a second communication device that restricts frame forwarding, it transmits the first frame to the first port of a communication device that constitutes one end of the daisy chain connection, and transmits the second frame to the second port of a communication device that constitutes the other end of the daisy chain connection. Effect of the Invention

[0012] The technique disclosed herein advantageously makes it possible to avoid collisions of frames in communication using bidirectional paths in a daisy chain connection. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a battery management system 10 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of frame processing executed by a communication interface 110 according to the present embodiment. [Diagram 3] FIG. 4 is a diagram illustrating an example of frame processing executed by the communication device 120 according to the first embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of frame transfer according to the first embodiment. [Diagram 5] 11 is a diagram showing an example of data transfer in response to frame transfer according to the embodiment; [Figure 6] FIG. 11 is a diagram illustrating an example of frame processing executed by a communication device 120 according to the second embodiment. [Figure 7] FIG. 11 is a diagram illustrating an example of frame transfer according to the second embodiment. [Figure 8]FIG. 11 is a diagram illustrating an example of frame processing executed by a communication device 120 according to the third embodiment. [Figure 9] FIG. 13 is a diagram illustrating an example of frame transfer according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an example of an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, the same or equivalent components and parts are given the same reference numerals. In addition, the dimensional ratios of the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios.

[0015] Furthermore, although the term "connection" is used hereinafter, this term means an electrical connection and may be broadly interpreted to include not only a direct connection but also an indirect connection (e.g., a connection via a passive component).

[0016] 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 monitor data, and executes various controls based on the monitor data.

[0018] The network 50 connects between 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 communicatively connected to the battery manager 30 via a network 50. The communication system 100 includes a communication interface 110 and a communication device group including 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 devices to the network 50 and transmits communication between the battery manager 30 and the communication devices. Hereinafter, a case where the communication interface 110 is realized by a dedicated circuit will be described as an example, but the present invention is not limited to this. The communication interface 110 may be realized by a computer having a processor. Also, a program may be provided that causes the computer to function as the communication interface 110 by being executed by the processor. Also, a non-transitory recording medium for recording such a program may be provided. The communication interface 110 has a first connection port 111 and a second connection port 112.

[0021] The communication device 120 transmits the monitor data in response to a request from the battery manager 30. Hereinafter, a case where the communication device 120 is realized by an integrated circuit will be described as an example, but the present invention is not limited to this. The communication device 120 may be realized by a computer having a processor. Also, a program may be provided that causes the computer to function as the communication device 120 by being executed by the processor. Also, a non-transitory recording medium for recording such a program may 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 monitor 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 and the second port 122a. The battery cell 124a may be a lithium ion battery cell, for example. However, the present invention is not limited to this, and the battery cell 124a may be a storage cell such as an electric double layer capacitor. The monitor unit 125a monitors various conditions of the battery cell 124a, such as a current, a voltage, or a temperature.

[0023] In such a communication device 120a, monitor data indicating the state of the battery cell 124a is transmitted in response to a request from the battery manager 30. The configurations of the communication devices 120b, 120c, and 120d may be similar to that of the communication device 120a, and therefore detailed description thereof will be omitted here.

[0024] In this manner, a communication device group is formed by daisy-chaining multiple communication devices 120, each having a first port 121 and a second port 122, so that the first ports 121 and second ports 122 are connected between adjacent devices.

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

[0026] The first connection port 111 of the communication interface 110 is connected to the first port 121a of the communication device 120a that constitutes one end of the daisy chain connection (the top end of the figure), and the second connection port 112 of the communication interface 110 is connected to the second port 122d of the communication device 120d that constitutes the other end of the daisy chain connection (the bottom end of the figure).

[0027] In this figure, for convenience of explanation, a case where four communication devices 120a to 120d are daisy-chained is shown as an example, but the number of communication devices 120 can be any number equal to or greater than two.

[0028] 2 is a diagram showing an example of frame processing executed by the communication interface 110 according to 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 and second frames may include a command for the battery manager 30 to request monitor data.

[0029] In the first frame, first information capable of recognizing a first communication device that limits the transfer of the frame is inserted in the first field. In the second frame, second information capable of recognizing a second communication device that limits the transfer of the frame is inserted in the first field. The first information and the second information may be inserted by a battery manager. Hereinafter, an example will be described in which the first communication device is the communication device 120b and the second communication device is the communication device 120c. In this way, it is preferable to set the communication devices 120b and 120c arranged at the center of the daisy chain connection as the first communication device and the second communication device, since bidirectional communication can be used equally. However, this is not limited to this, and two communication devices 120 arranged at positions biased toward one end or the other end of the daisy chain connection may be set as the first communication device and the second communication device. In such a case, it is particularly effective when the communication speeds in both directions are different in the daisy chain connection.

[0030] In the first embodiment, in 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 may be assigned afterwards at the time of initial communication.

[0031] In the first embodiment, the first information indicates a first identifier assigned to the first communication device, and the second information indicates a second identifier assigned to the second communication device. That is, in the first frame, "120b" which is the identifier of the first communication device may be inserted in the first field. Similarly, in the second frame, "120c" which is the identifier of the second communication device may be inserted in the first field.

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

[0033] In this manner, the communication interface 110 simultaneously transmits two frames with different information inserted in the first field to both ends of the daisy chain connection. This allows the communication system 100 as a whole to obtain a communication speed twice as fast as when only one direction is used in the daisy chain connection. 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 that it is possible to transfer from one end with fewer transfers than from the other end. In this case, the communication interface 110 may determine the frame with "120b" 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 that it is possible to transfer from the other end with fewer transfers than from one end. In this case, the communication interface 110 may determine the frame in which "120c" is inserted into the first field as the second frame.

[0034] FIG. 3 is a diagram showing an example of frame processing executed by the communication device 120 according to the first embodiment. In step S310, the communication device 120 receives a first frame or a second frame. In step S320, the communication device 120 determines whether the first field matches its own identifier. If the first field does not match its own identifier, the communication device 120 advances the process to step S330 and transfers the first frame or the second frame. On the other hand, if the first field matches its own identifier, the communication device 120 does not execute the process of step S330. That is, the communication device 120 does not transfer the first frame or the second frame. Such frame transfer according to the first embodiment will be described in detail with reference to the drawings.

[0035] 4 is a diagram showing an example of frame transfer according to the first embodiment. When the communication interface 110 receives 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 transmits the first frame to the first port 121a of the communication device 120a and transmits the second frame to the second port 122d of the communication device 120d.

[0036] In response, when the communication device 120a receives the first frame, it determines whether the first field matches its own identifier. Here, the first field ≠ 120a, and the first field does not match its own identifier, so the communication device 120a recognizes that it is not the first communication device. In this case, the communication device 120a transfers the first frame to the communication device 120b via the second port 122a. That is, when the communication device 120a receives the first frame, if it recognizes that it is not the first communication device based on the first information, it transfers the first frame via the second port 122a.

[0037] Similarly, when communication device 120d receives the second frame, it determines whether the first field matches its own identifier. Here, the first field is not equal to 120d, and the first field does not match its own identifier, so communication device 120d recognizes that it is not the second communication device. In this case, communication device 120d transfers the second frame to communication device 120c via first port 121d. That is, when communication device 120d receives the second frame, if it recognizes that it is not the second communication device based on the second information, it transfers the second frame via first port 121d.

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

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

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

[0041] Up to this point, the transfer of frames, that is, the request for monitor data from the battery manager 30 has been described. The communication system 100 according to this embodiment can provide the monitor data to the battery manager 30 in response to this request.

[0042] 5 is a diagram showing an example of data transfer in response to frame transfer according to the present embodiment. When the communication device 120a receives a first frame via the first port 121a, the communication device 120a transmits monitor data Ma indicating the state of the battery cell 124a via the first port 121a. As a result, the communication interface 110 receives the monitor data Ma via the first connection port 111.

[0043] When the communication device 120b receives the first frame via the first port 121b, it transmits monitor data Mb indicating the state of the battery cell 124b via the first port 121b. Next, when the communication device 120a receives the monitor data Mb via the second port 122a, it transfers the monitor data Mb via the first port 121a. As a result, the communication interface 110 receives the monitor data Mb via the first connection port 111.

[0044] Similarly, when the communication device 120d receives the second frame via the second port 122d, the communication device 120d transmits monitor data Md indicating the state of the battery cell 124d via the second port 122d. As a result, the communication interface 110 receives the monitor 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 monitor data Mc indicating the state of the battery cell 124c via the second port 122c. Next, when the communication device 120d receives the monitor data Mc via the first port 121d, it transfers the monitor data Mc via the second port 122d. As a result, the communication interface 110 receives the monitor data Mc via the second connection port 112.

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

[0047] In this way, in the communication system 100 according to the present embodiment, monitor data is provided to the senders of the first and second frames in response to frame transfer. At this time, according to the communication system 100 according to the present embodiment, the communication device 120 that receives a frame via the first port 121 transmits the monitor data via the first port 121, while the communication device 120 that receives a frame via the second port 122 transmits the monitor data via the second port 122. Therefore, even when monitor data is transferred using bidirectional paths in a daisy chain connection, collision of monitor data can be avoided.

[0048] The above-described embodiment can be modified in various ways or applied to various uses. For example, the above description shows an example in which frame forwarding is restricted by using an identifier assigned to the communication device 120. However, the number of times a frame can be forwarded may be restricted. This will be described in detail.

[0049] FIG. 6 is a diagram showing an example of frame processing executed by the communication device 120 according to 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, the first number indicating the remaining number of times the first frame can be transferred is inserted in the first field. In the second frame, the second number indicating the remaining number of times the second frame can be transferred is inserted in the first field. From this point on, a case where the first number and the second number are both 1 will be described as an example. In this way, if the first number and the second number are the number obtained by dividing the number of the multiple communication devices 120 constituting the communication device group by 2 and subtracting 1, it is preferable because bidirectional communication can be used evenly. However, the present invention is not limited to this, and the first number and the second number may be different numbers within a range in which the sum of the first number and the second number is the number obtained by subtracting 2 from the number of the multiple communication devices 120 constituting the communication device group.

[0050] In step S620, communications device 120 determines whether the first field is 0. That is, communications device 120 determines whether the remaining number of times the frame can be forwarded is 0. If the first field is not 0, communications device 120 proceeds to step S630, decrements 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, communications device 120 does not execute the processes of steps S630 to S640. That is, communications device 120 does not forward the first frame or the second frame. Such frame forwarding according to the second embodiment will be described in detail with reference to the drawings.

[0051] 7 is a diagram showing an example of frame transfer according to the second embodiment. When the communication interface 110 receives 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 transmits the first frame to the first port 121a of the communication device 120a and transmits the second frame to the second port 122d of the communication device 120d.

[0052] In response, when the communication device 120a receives the first frame, it determines whether the first field is 0 or not. Here, since the first field is not 0 and there is still a number of times the frame can be forwarded, 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, the communication device 120a decrements the first number of times when forwarding the first frame.

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

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

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

[0056] In this way, in the communication system 100 according to the second embodiment, the forwarding of a frame is limited based on the remaining number of times the frame can be forwarded. As a result, according to the communication system 100 according to the second embodiment, the amount of the first information and the second information can be reduced compared to the case where an identifier assigned to the communication device 120 is used.

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

[0058] 8 is a diagram showing an example of frame processing executed by the communication device 120 according to the third embodiment. In step S810, the communication device 120 receives a first frame or a second frame. In the third embodiment, in the first frame, a first number indicating the maximum number of times the first frame can be transferred is inserted into a first field, and the number of times the first frame has been transferred in a daisy-chain connection is inserted into a second field. In the second frame, a second number indicating the maximum number of times the second frame can be transferred is inserted into the first field, and the number of times the second frame has been transferred in a daisy-chain connection is inserted into a second field. From here on, a case where the first number and the second number are both 1 will be described as an example.

[0059] In step S820, the communication device 120 determines whether the first field matches the second field. That is, the communication device 120 determines whether the number of times the frame has been forwarded reaches the maximum number of times. If the first field does not match the second field, the communication device 120 advances the process to step S830, increments 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 matches the second field, the communication device 120 does not execute the processes of steps S830 to S840. That is, the communication device 120 does not forward the first frame or the second frame. Such frame forwarding according to the third embodiment will be described in detail with reference to the drawings.

[0060] 9 is a diagram showing an example of frame transfer according to the third embodiment. When the communication interface 110 receives 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 transmits the first frame to the first port 121a of the communication device 120a and transmits the second frame to the second port 122d of the communication device 120d.

[0061] In response, when the communication device 120a receives the first frame, it determines whether the first field matches the second field. Here, the first field is not equal to the second field, and the number of times the frame has been forwarded has not reached the maximum number of times, so 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 forwards 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 matches the second field. Here, the first field is not equal to the second field, and the number of times the frame has been forwarded has not reached the maximum number of times, so 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 forwards the second frame to the communication device 120c via the first port 121d.

[0063] Next, when the communication device 120b receives the first frame, it determines whether the first field matches the second field. Here, the first field=the second field, and the number of times the frame has been forwarded has reached the maximum number, so the communication device 120b recognizes itself as the first communication device. In this case, the communication device 120b does not forward the first frame.

[0064] Similarly, when the communication device 120c receives the second frame, it determines whether the first field matches the second field. Here, the first field=the second field, and the number of times the frame has been forwarded has reached the maximum number, so the communication device 120c recognizes itself as the second communication device. In this case, the communication device 120c does not forward the second frame.

[0065] In this way, in the communication system 100 according to the third embodiment, the forwarding of a frame is limited by the maximum number of times the frame can be forwarded. As a result, the communication system 100 according to the third embodiment can reduce the amount of information for the first information and the second information compared to when an identifier assigned to the communication device 120 is used. Furthermore, in the communication system 100 according to the third embodiment, compared to when the remaining number of times the frame can be forwarded is used, there is no need to rewrite the value of the first field, so the value of the first field can be left as the information at the time of insertion.

[0066] This disclosure also includes the following:

[0067] (Appendix 1) a communication device group in which a plurality of communication devices, each having a first port and a second port, are daisy-chained such that the first port and the second port are connected between adjacent devices; a communication interface for connecting the communication devices to a network; Equipped with The communication interface includes: when receiving, via the network, a first frame into which first information capable of recognizing a first communication device that restricts forwarding of a frame is inserted and a second frame into which second information capable of recognizing a second communication device that restricts forwarding of a frame is inserted, the first frame is transmitted to the first port of a communication device that constitutes one end of the daisy-chain connection, and the second frame is transmitted to the second port of a communication device that constitutes 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, but if the device recognizes that it is the first communication device, the device does not forward the first frame; Upon receiving the second frame, if the device recognizes that it is not the second communication device based on the second information, the device forwards the second frame via the first port, whereas if the device recognizes that it is the second communication device, the device does not forward the second frame. Communication systems.

[0068] (Appendix 2) the first information indicates a first identifier assigned to the first communication device; the second information indicating 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. 2. The communication system of claim 1.

[0069] (Appendix 3) the first information indicates a first number of times for limiting the number of times the first frame is transferred; the second information indicates a second number of times for limiting the number of times the second frame is transferred; each of the plurality of communication devices recognizes itself as the first communication device when the number of times the first frame has been forwarded reaches a limit, and recognizes itself as the second communication device when the number of times the second frame has been forwarded reaches a limit; 3. A communication system according to claim 1 or 2.

[0070] (Appendix 4) the first number of times indicates a remaining number of times the first frame can be transferred; the second number of times indicates a 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; 4. A communication system as described in claim 3.

[0071] (Appendix 5) Each of the plurality of communication devices The battery cell further includes a monitor unit that monitors a state of the battery cell, Upon receiving the first frame, transmit monitor data indicating a state of the battery cell via the first port; upon receiving the second frame, transmitting the monitor data via the second port; The communication interface includes: upon receiving the monitor data, providing the monitor data to a source of the first frame and the second frame via the network; 5. A communication system according to any one of claims 1 to 4.

[0072] (Appendix 6) A communication device constituting a communication device group in which a plurality of communication devices, each having a first port and a second port, are daisy-chained such that the first port and the second port are connected between adjacent devices, when receiving a first frame into which first information capable of recognizing a first communication device that restricts forwarding of a frame is inserted, if the device recognizes that it is not the first communication device based on the first information, it forwards the first frame via the second port, but if the device recognizes that it is the first communication device, it does not forward the first frame; when receiving a second frame into which second information capable of recognizing a second communication device that restricts forwarding of the frame is inserted, if the device recognizes that it is not the second communication device based on the second information, the device forwards the second frame via the first port, but if the device recognizes that it is the second communication device, the device does not forward the second frame; Communication devices.

[0073] (Appendix 7) the first information indicates a first identifier assigned to the first communication device; the second information indicating a second identifier assigned to the second communication device; 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; 7. A communications device as described in claim 6.

[0074] (Appendix 8) the first information indicates a first number of times for limiting the number of times the first frame is transferred; the second information indicates a second number of times for limiting the number of times the second frame is transferred; recognizes itself as the first communication device when the number of times the first frame has been forwarded reaches a limit, and recognizes itself as the second communication device when the number of times the second frame has been forwarded reaches a limit. 8. A communications device according to claim 6 or 7.

[0075] (Appendix 9) the first number of times indicates a remaining number of times the first frame can be transferred, the second number of times indicates a remaining number of times the second frame can be transferred, decrementing the first number of times when the first frame is transferred, and decrementing the second number of times when the second frame is transferred; 9. A communications device as described in claim 8.

[0076] (Appendix 10) A communication device constituting a communication device group in which a plurality of communication devices, each having a first port and a second port, are daisy-chained such that the first port and the second port are connected between adjacent devices, When the device recognizes itself as a designated communication device based on a frame having designation information indicating a designated communication device received via either the first port or the second port, the device does not forward the frame. Communication devices.

[0077] (Appendix 11) A communication interface for connecting a group of communication devices, each of which has a first port and a second port, to a network, the communication devices being daisy-chained such that the first port and the second port are connected between adjacent devices, the communication interface comprising: when receiving, via the network, a first frame into which first information capable of recognizing a first communication device that restricts forwarding of a frame is inserted, and a second frame into which second information capable of recognizing a second communication device that restricts forwarding of a frame is inserted, the first frame is transmitted to the first port of a communication device that constitutes one end of the daisy-chain connection, and the second frame is transmitted to the second port of a communication device that constitutes the other end of the daisy-chain connection; Communication interface. [Explanation of symbols]

[0078] 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 Devices 121 Port 1 122 2nd Port 123 Communications Department 124 Battery Cells 125 Monitor section

Claims

1. a communication device group in which a plurality of communication devices, each having a first port and a second port, are daisy-chained together such that the first port and the second port are connected between adjacent devices; a communication interface for connecting the communication devices to a network; Equipped with The communication interface includes: when receiving, via the network, a first frame into which first information capable of recognizing a first communication device that restricts forwarding of a frame is inserted and a second frame into which second information capable of recognizing a second communication device that restricts forwarding of a frame is inserted, the first frame is transmitted to the first port of a communication device that constitutes one end of the daisy-chain connection, and the second frame is transmitted to the second port of a communication device that constitutes 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, but if the device recognizes that it is the first communication device, the device does not forward the first frame; Upon 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, whereas if the device recognizes that it is the second communication device, the device does not transfer the second frame. Communication systems.

2. the first information indicating a first identifier assigned to the first communication device; the second information indicating 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. The communication system according to claim 1 .

3. the first information indicates a first number of times for limiting the number of times the first frame is transferred; the second information indicates a second number of times for limiting the number of times the second frame is transferred; each of the plurality of communication devices recognizes itself as the first communication device when the number of times the first frame has been forwarded reaches a limit, and recognizes itself as the second communication device when the number of times the second frame has been forwarded reaches a limit; The communication system according to claim 1 .

4. the first number of times indicates a remaining number of times the first frame can be transferred, the second number of times indicates a 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; The communication system according to claim 3.

5. Each of the plurality of communication devices The battery cell further includes a monitor unit that monitors a state of the battery cell, Upon receiving the first frame, transmit monitor data indicating a state of the battery cell via the first port; upon receiving the second frame, transmitting the monitor data via the second port; The communication interface includes: upon receiving the monitor data, providing the monitor data to a source of the first frame and the second frame via the network; A communication system according to any one of claims 1 to 4.

6. A communication device constituting a communication device group in which a plurality of communication devices, each having a first port and a second port, are daisy-chained such that the first port and the second port are connected between adjacent devices, when receiving a first frame into which first information capable of recognizing a first communication device that restricts forwarding of a frame is inserted, if the device recognizes that it is not the first communication device based on the first information, it forwards the first frame via the second port, but if the device recognizes that it is the first communication device, it does not forward the first frame; when receiving a second frame into which second information capable of recognizing a second communication device that restricts forwarding of the frame is inserted, if the device recognizes that it is not the second communication device based on the second information, the device forwards the second frame via the first port, but if the device recognizes that it is the second communication device, the device does not forward the second frame; Communication devices.

7. the first information indicating a first identifier assigned to the first communication device; the second information indicating a second identifier assigned to the second communication device; If the first identifier matches its own identifier, the device recognizes itself as the first communication device, and if the second identifier matches its own identifier, the device recognizes itself as the second communication device.

7. A communication device according to claim 6.

8. the first information indicates a first number of times for limiting the number of times the first frame is transferred; the second information indicates a second number of times for limiting the number of times the second frame is transferred; recognizes itself as the first communication device when the number of times the first frame has been forwarded reaches a limit, and recognizes itself as the second communication device when the number of times the second frame has been forwarded reaches a limit.

7. A communication device according to claim 6.

9. the first number of times indicates a remaining number of times the first frame can be transferred, the second number of times indicates a remaining number of times the second frame can be transferred, decrementing the first number of times when the first frame is transferred, and decrementing the second number of times when the second frame is transferred; 9. A communication device according to claim 8.

10. A communication device constituting a communication device group in which a plurality of communication devices, each having a first port and a second port, are daisy-chained such that the first port and the second port are connected between adjacent devices, when the device recognizes itself as a designated communication device based on a frame having designation information indicating a designated communication device received via either the first port or the second port, the device does not forward the frame; Communication devices.

11. A communication interface for connecting a group of communication devices, each of which has a first port and a second port, to a network, the communication devices being daisy-chained such that the first port and the second port are connected between adjacent devices, the communication interface comprising: when receiving, via the network, a first frame into which first information capable of recognizing a first communication device that restricts forwarding of a frame is inserted, and a second frame into which second information capable of recognizing a second communication device that restricts forwarding of a frame is inserted, the first frame is transmitted to the first port of a communication device that constitutes one end of the daisy-chain connection, and the second frame is transmitted to the second port of a communication device that constitutes the other end of the daisy-chain connection; Communication interface.

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