WO2016104172A1 - Communication system - Google Patents

Communication system Download PDF

Info

Publication number
WO2016104172A1
WO2016104172A1 PCT/JP2015/084737 JP2015084737W WO2016104172A1 WO 2016104172 A1 WO2016104172 A1 WO 2016104172A1 JP 2015084737 W JP2015084737 W JP 2015084737W WO 2016104172 A1 WO2016104172 A1 WO 2016104172A1
Authority
WO
WIPO (PCT)
Prior art keywords
communication
pair
branch line
lines
line
Prior art date
Application number
PCT/JP2015/084737
Other languages
French (fr)
Japanese (ja)
Inventor
坪内　利康
Original Assignee
株式会社オートネットワーク技術研究所
住友電装株式会社
住友電気工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社オートネットワーク技術研究所, 住友電装株式会社, 住友電気工業株式会社 filed Critical 株式会社オートネットワーク技術研究所
Publication of WO2016104172A1 publication Critical patent/WO2016104172A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/50—Systems for transmission between fixed stations via two-conductor transmission lines
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines

Definitions

  • a terminal resistor is interposed between a pair of communication lines on the trunk line, and each of the two first communication devices connected to each end of the trunk line is connected to the pair of communication lines on the trunk line.
  • the present invention relates to a communication system including one or a plurality of second communication devices having a communication unit connected to a branch line having a pair of communication lines.
  • CAN Controller Area Network
  • CAN-FD CAN with Flexible Data Rate
  • a twisted pair cable in which a pair of communication lines is twisted is used. Is intervening.
  • Each electronic device performs communication using a differential signal, and a dominant is detected when a potential difference between a pair of communication lines exceeds a threshold value, and a recessive is detected when the potential difference is equal to or less than the threshold value.
  • a communication system adopting a CAN (or CAN-FD) communication protocol adopts a bus type network topology.
  • each electronic device is connected to a branch line that branches from a main line used for communication in common with other electronic devices. For example, each electronic device performs data transmission / reception with a dominant corresponding to data 0 and a recessive corresponding to data 1.
  • ringing occurs when an electronic device transmits to another electronic device. Ringing is caused by multiple reflection of a signal due to impedance mismatch at a branching portion that branches from a main line to a branch line, impedance mismatch of a communication device connected to the branch line, and the like.
  • the communication system causes a failure in communication because the dominant signal transmitted from one communication device is judged to be recessive on the received communication device side. May fall out of communication.
  • the degree of freedom of twisted-pair cable routing is limited so that the influence of ringing does not increase, and the branch portion between the main line and the branch line is limited. It has been necessary to adopt a method in which a filter such as ferrite is interposed, or a resistor or a filter is interposed in a non-terminal portion. However, if a new part is necessary, there is a problem that the part cost increases.
  • Patent Document 1 discloses a data communication system in which transmission lines connected to individual subscriber terminal stations are connected to one passive network node in a star shape.
  • the transmission line has a frequency dependent attenuating element, for example a ferrite bead.
  • Good characteristic impedance matching of the high-frequency noise signal can be performed by simultaneously and freely selecting system parameters set in a steady data symbol state.
  • a pair of communication lines included in the branch line of the non-termination portion includes a ferrite or a resistor and an inductor so that the influence of ringing does not increase.
  • a method for reducing the cost of components by interposing filters connected in parallel with each other has been studied.
  • the driver communication unit
  • the effect of lowering the impedance on the receiving side is insufficient.
  • the ringing time may not be reduced.
  • the present invention has been made in view of the circumstances as described above, and when a filter is interposed in each communication line of the branch line of the non-terminal portion, the effect of the filter is increased and the cable routing configuration is free.
  • An object of the present invention is to provide a communication system that can reduce the influence of ringing.
  • the present invention also provides a communication system in which the effect of ferrite is increased, the degree of freedom of cable routing is large, and the influence of ringing can be reduced when ferrite is interposed in each communication line of the branch line of the non-terminal portion. The purpose is to provide.
  • the communication system includes a trunk line having a pair of communication lines, a termination resistor, the termination resistor interposed between the pair of communication lines, and connected to each end of the trunk line.
  • One or more first communication devices a branch line having a pair of communication lines connected to the pair of communication lines, and a communication unit connected to the pair of communication lines via a filter, respectively.
  • the second communication device has a resistor interposed between the pair of communication lines of the branch line. It is characterized by being.
  • the trunk line has a pair of communication lines, and two first communication devices connected to each end of the trunk line are provided with a terminating resistor between the pair of trunk lines.
  • the branch line has a pair of communication lines each connected to a pair of trunk communication lines, and one or a plurality of second communication devices are connected to the pair of branch communication lines via a filter, respectively. Each of the first communication device and the second communication device performs communication.
  • a resistor is interposed between a pair of communication lines included in the branch line.
  • the communication system includes a trunk line having a pair of communication lines, a termination resistor, the termination resistor interposed between the pair of communication lines, and connected to each end of the trunk line.
  • a first communication device a branch line having a pair of communication lines connected to the pair of communication lines, and a communication unit in which the pair of communication lines are connected via a ferrite that suppresses electromagnetic noise.
  • One or a plurality of second communication devices wherein the first communication device and the second communication device communicate with each other, and the second communication device is located between the pair of communication lines of the branch line. It is characterized by interposing a resistor.
  • the trunk line has a pair of communication lines, and two first communication devices connected to each end of the trunk line are provided with a terminating resistor between the pair of trunk lines.
  • the branch line has a pair of communication lines respectively connected to a pair of communication lines of the trunk line, and the one or more second communication devices are configured such that the pair of communication lines of the branch line passes through a ferrite that suppresses electromagnetic noise.
  • Each of the first communication device and the second communication device has a communication unit connected to perform communication.
  • a resistor is interposed between a pair of communication lines included in the branch line.
  • the communication system according to the present invention is characterized in that a resistance value of a resistor interposed between the pair of communication lines is lower than an input impedance of the communication unit and higher than an impedance of the branch line.
  • the communication system according to the present invention includes a plurality of the second communication devices, and the longer the branch line connected to each second communication device, the longer the resistance value of the resistor interposed between the pair of communication lines of the branch line. Is characterized by low.
  • the communication unit is connected to the branch line via a connector, and a second resistor is interposed between the pair of communication lines on the branch line side of the connector. It is characterized by.
  • the communication system of the present invention when a filter is interposed in each communication line of the branch line of the non-termination part, the effect of the filter is increased, the degree of freedom of the cable routing form is great, and the influence of ringing is reduced. A communication system that can be reduced can be realized.
  • the communication system of the present invention when ferrite is interposed in each communication line of the branch line of the non-termination part, the effect of the ferrite is increased, the degree of freedom of the cable routing form is great, and the influence of ringing is reduced. A communication system that can be reduced can be realized.
  • FIG. 1 is a circuit diagram showing a schematic configuration of an embodiment of a communication system according to the present invention. It is a block diagram which shows typically the structural example of ECU. It is a block diagram which shows typically the structural example of terminal ECU. It is a block diagram which shows typically the other structural example of ECU.
  • FIG. 1 is a circuit diagram showing a schematic configuration of an embodiment of a communication system according to the present invention.
  • This communication system includes ECUs (Electronic Control Units) 1a, 1b, and 1c mounted on a vehicle, and terminal ECUs 2a and 2b that are also mounted on the vehicle.
  • the terminal ECU 2a is connected to one end of the trunk line 3 having a communication line, and the terminal ECU 2b is connected to the other end of the trunk line 3.
  • the ECU 1a is connected to a branch line 4a branched from a branch point A in the middle of the trunk line 3, the ECU 1b is connected to a branch line 4b branched from a branch point B in the middle of the trunk line 3, and the ECU 1c is connected to a branch point in the middle of the trunk line 3 It is connected to a branch line 4c branched from C.
  • the branch point B is closer to the end ECU 2b than the branch point A
  • the branch point C is closer to the end ECU 2b than the branch point B.
  • the branch lines 4a, 4b, and 4c are configured to have communication lines.
  • ECUs 1a, 1b, and 1c have the same configuration, they are also collectively referred to as ECU1 below. Since the end ECUs 2a and 2b have the same configuration, they are also collectively referred to as the end ECU 2 below. Since the branch lines 4a, 4b, and 4c have the same configuration, they are also collectively referred to as branch lines 4 below.
  • the ECU 1 corresponds to the second communication device of the present invention
  • the terminal ECU 2 corresponds to the first communication device of the present invention.
  • the trunk line 3 and the branch line 4 are twisted pair cables having the characteristic impedance of a CAN (Controller Area Network) bus.
  • communication is performed between the ECU 1 and the terminal ECU 2 using the main line 3 as a common communication line.
  • a signal is output to the branch line 4b by the ECU 1b
  • this signal reaches the ECU 1a from the branch line 4b via the trunk line 3 and the branch line 4a, and the reflected wave reflected by the connection portion etc. where the ECU 1a connects to the branch line 4a Occurs.
  • the reflected wave reaches the ECU 1b through the branch line 4a, the trunk line 3, and the branch line 4b.
  • the reflected wave that has reached the ECU 1b is reflected again at the connecting portion where the ECU 1b connects to the branch line 4a again.
  • ringing occurs in the communication system due to repeated signal reflection. Since the ringing becomes longer and the ringing time becomes longer as the length of the branch line or the trunk line becomes longer, the range of the ringing is limited.
  • a similar reflected wave is also generated in the ECU 1c. Further, the terminal ECU 2 may generate a similar reflected wave depending on the characteristic impedance values of the main line and the branch line.
  • FIG. 2 is a block diagram schematically illustrating a configuration example of the ECU 1.
  • the ECU 1 includes a control unit 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, an input unit 14, an output unit 15, a driver 16, a connection circuit 17, and the like that are connected to each other via a bus. Yes.
  • the control unit 11 is configured by using an arithmetic processing device such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and reads various control programs stored in the ROM 12 to execute various control processes. I do.
  • a CPU Central Processing Unit
  • MPU Micro Processing Unit
  • the ROM 12 is composed of a nonvolatile memory element such as an EEPROM (Electrically Erasable Programmable ROM) or flash memory, for example, a control program executed by the control unit 11, information necessary for processing performed by the control unit 11, and the like Is stored in advance.
  • the RAM 13 is composed of a memory element such as SRAM (Static RAM) or DRAM (Dynamic RAM), for example, information generated by the processing of the control unit 11, information transmitted to and received from other ECUs, etc. Is memorized.
  • the input unit 14 receives, for example, signals from sensors such as a vehicle speed sensor or a temperature sensor of the vehicle, or various switches for operation disposed inside and outside the vehicle, and performs sampling of the input signal or A / D conversion, etc. Information obtained by performing the processing is given to the control unit 11.
  • the output unit 15 is connected to a load such as a motor or a lamp, and outputs a drive signal for driving these loads in response to an instruction from the control unit 11. Note that the ECU 1 does not necessarily need to include both the input unit 14 and the output unit 15, and may be configured to include only one of them.
  • the driver 16 transmits and receives information according to the CAN protocol to and from other ECUs 1 and 2, and is connected to the branch line 4 via the connection circuit 17.
  • the driver 16 converts the transmission information given from the control unit 11 into transmission data (frame) according to the CAN protocol and gives the data to the transmission unit 16a.
  • the transmission unit 16a outputs a signal to the branch line 4 according to the value of each bit of the given transmission data (0 (dominant) or 1 (recessive)).
  • the trunk line 3 and the branch line 4 are twisted pair cables formed by twisting a pair of communication lines.
  • the transmitter 16 a outputs a differential signal to the branch line 4 connected via the connection circuit 17.
  • the transmission unit 16a When transmitting a dominant signal, the transmission unit 16a outputs a differential signal in which the potential difference between the pair of communication lines of the branch line 4 is 2V.
  • the potential difference When transmitting a recessive signal, the potential difference is 0V.
  • a differential signal is output.
  • the driver 16 corresponds to the communication unit of the present invention.
  • the driver 16 detects the signal level of the branch line 4 to determine whether the signal transmitted on the branch line 4 is a signal corresponding to dominant or recessive, and each bit is dominant or recessive. It has the receiving part 16b which receives the data represented.
  • the signal level of the branch line 4 refers to a potential difference between a pair of communication lines included in the branch line 4.
  • the driver 16 gives the data received by the receiving unit 16b to the control unit 11.
  • the driver 16 receives the data transmitted by the transmission unit 16a at the reception unit 16b, and if the transmission data and the reception data do not match (the recessiveness of the transmission data has changed to dominant in the reception data). In other words, it is detected that data is being transmitted by the other ECU 1 or the terminal ECU 2, and arbitration processing is performed.
  • the arbitration process performed by the ECU 1 is the same as that performed by the conventional CAN protocol, and thus detailed description thereof is omitted.
  • connection circuit 17 is interposed in the branch line 4 and is configured to suppress a reflected wave caused by a signal input from the branch line 4 to the driver 16.
  • a filter in which an inductor 17 a and a resistor 17 b are connected in parallel is interposed in a pair of communication lines included in the branch line 4, and a resistor 17 c is connected between each communication line on the main line 3 side of the filter.
  • the resistor 17c has a resistance value lower than the input impedance of the driver 16 and higher than the impedance when the branch line 4 is opened on the driver 16 side.
  • the branch lines 4 inside and outside the connection circuit 17 are connected by a male connector 18a on the connection circuit 17 side and a female connector 18b on the main line 3 side.
  • the resistance value of the resistor 17c interposed between the pair of communication lines of the branch line 4 is lowered as the branch line 4 is longer.
  • the difference between the impedances of the branch lines 4 and the connection circuit 17 is reduced.
  • only the ECU 1 having a long branch line 4 is provided with a resistor 18c between a pair of communication lines in the female connector 18b to reduce the resistance value between the communication lines.
  • FIG. 3 is a block diagram schematically illustrating a configuration example of the terminal ECU 2.
  • the terminal ECU 2 includes a control unit 21, a ROM 22, a RAM 23, an input unit 24, an output unit 25, a driver 26, a connection circuit 27, and the like connected via a bus.
  • the control unit 21, ROM 22, and RAM 23 operate in the same manner as the control unit 11, ROM 12, and RAM 13 in FIG.
  • the input unit 24, the output unit 25, and the driver 26 operate in the same manner as the input unit 14, the output unit 15, and the driver 16 in FIG.
  • the driver 26 of the terminal ECU 2 is connected to the main line 3 via the connection circuit 27.
  • connection circuit 27 a series circuit composed of two resistors 27a is interposed between a pair of communication lines of the main line 3.
  • the connection circuit 27 includes a capacitor 27b. One end of the capacitor 27b is connected to the common connection node of the two resistors 27a, and the other end is grounded.
  • connection circuit 27 having such a configuration is a so-called split termination in the CAN protocol, and matches the input impedance to the driver 26 and the impedance of the trunk line 3.
  • connection circuit 27 may be a termination resistor and may be configured other than split termination.
  • the resistance of the filter in which the inductor 17a and the resistor 17b are connected in parallel is enhanced by interposing the resistor 17c between the communication lines of the branch line 4 in the ECU 1, and a high-frequency ringing component is removed. Therefore, ringing can be suppressed and communication stability can be improved.
  • the effect of the filter is further enhanced by further interposing the resistor 18c between the communication lines of the branch line 4 in the female connector 18b. Further, in this communication system, even if the ringing component cannot be removed, the peak of the ringing component can be reduced, so that the peak does not exceed the signal threshold and the ringing time is shortened.
  • FIG. 4 is a block diagram schematically showing another configuration example of the ECU 1.
  • the ECU 1 includes a connection circuit 19 instead of the connection circuit 17.
  • the connection circuit 19 has two holes through which the pair of communication lines of the branch line 4 is inserted, and a resistor 19b that connects between the ferrite 19a that suppresses electromagnetic noise of the communication line and the communication line on the male connector 18a side of the ferrite 19a. And.
  • a pair of communication lines of the branch line 4 inserted through the two holes of the ferrite 19a are connected to the driver 16, respectively.
  • the filter effect of the ferrite 19 a can be enhanced and the high-frequency ringing component can be removed. Can improve the stability.
  • the effect of the filter is further enhanced by further interposing the resistor 18c between the communication lines of the branch line 4 in the female connector 18b. Even if the ringing component cannot be removed, the peak of the ringing component can be reduced, so that the peak does not exceed the signal threshold and the ringing time is shortened. Since other configurations and operations are the same as the configurations and operations of the ECU 1 (FIG. 2) described above, description thereof will be omitted.
  • the ECUs 1a, 1b, and 1c are described as bus types (FIG. 1) connected to branch lines 4a, 4b, and 4c branched from different branch points A, B, and C, respectively. Even if the ECUs 1a, 1b, and 1c are star types connected to the branch lines 4a, 4b, and 4c branched from one branch point, similar effects can be obtained.
  • the present invention can be used for a communication system or the like in which a large number of electronic devices mounted on a vehicle are connected via a communication line to communicate with each other.
  • ECU second communication device 2a, 2b Terminal ECU (first communication device) 3 Trunk line 4a, 4b, 4c Branch line 16, 26 Driver (communication part) 17, 19, 27 Connection circuit 17a Inductor (filter) 17b Resistance (filter) 17c, 19b Resistance 18a Male connector 18b Female connector 18c Resistance (second resistance) 19a Ferrite 27a Resistance (Terminal resistance)

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Dc Digital Transmission (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

The objective of the invention is to provide a communication system with which, when a filter is interposed in each communication line of a branch line in a non-terminating part, it is possible to increase the effect of the filters, to increase the degree of freedom with which cable routings can be configured, and to reduce the impact of ringing. This communication system is provided with: two first communication devices (which are not shown in the drawings), connected to both end portions of a trunk line, with the interposition of a termination resistor between a pair of communication lines of the trunk line; a branch line 4 comprising a pair of communication lines connected to the pair of communication lines of the trunk line; and one or more second communication devices 1 each having a communication unit 16 connected to the pair of communication lines in the branch line 4 via filters 17a and 17b, wherein the first communication devices and the second communication devices 1 each perform communication. The second communication devices 1 are configured with a resistor 17c interposed between the pair of communication lines of the branch line 4.

Description

通信システムCommunications system
　本発明は、幹線の一対の通信線の間に終端抵抗を介装し、幹線の各端部に接続してある２つの第１通信装置と、幹線の一対の通信線に各接続してある一対の通信線を有する支線に接続してある通信部を有する１又は複数の第２通信装置とを備える通信システムに関するものである。 In the present invention, a terminal resistor is interposed between a pair of communication lines on the trunk line, and each of the two first communication devices connected to each end of the trunk line is connected to the pair of communication lines on the trunk line. The present invention relates to a communication system including one or a plurality of second communication devices having a communication unit connected to a branch line having a pair of communication lines.
　車両では、搭載された多数の電子機器が通信線を介して接続され、相互に通信し協調動作することにより、車両の走行制御及び車室内の環境制御等が実現されている。搭載された電子機器では、通信プロトコルとしてＣＡＮ（Controller Area Network）及びＣＡＮ－ＦＤ（CAN with Flexible Data Rate）が広く採用されている（非特許文献１参照）。 In a vehicle, a large number of mounted electronic devices are connected via a communication line and communicate with each other to perform cooperative operation, thereby realizing vehicle travel control, vehicle interior environmental control, and the like. In mounted electronic devices, CAN (Controller Area Network) and CAN-FD (CAN with Flexible Data Rate) are widely adopted as communication protocols (see Non-Patent Document 1).
　一般的に、ＣＡＮ（又はＣＡＮ－ＦＤ）の通信プロトコルを採用した通信システムでは、一対の通信線が撚り合わされたツイストペアケーブルが用いられ、ツイストペアケーブルの両終端部では、両通信線間に終端抵抗が介装されている。各電子機器は差動信号による通信を行っており、一対の通信線間の電位差が閾値を超えた場合にドミナントが検出され、電位差が閾値以下である場合にレセシブが検出される。 In general, in a communication system that employs a CAN (or CAN-FD) communication protocol, a twisted pair cable in which a pair of communication lines is twisted is used. Is intervening. Each electronic device performs communication using a differential signal, and a dominant is detected when a potential difference between a pair of communication lines exceeds a threshold value, and a recessive is detected when the potential difference is equal to or less than the threshold value.
　また、一般的に、ＣＡＮ（又はＣＡＮ－ＦＤ）の通信プロトコルを採用した通信システムは、バス型のネットワークトポロジーを採用している。バス型のネットワークトポロジーでは、各電子機器は、他の電子機器と共通して通信に用いる幹線から分岐する支線に接続している。各電子機器は、例えば、ドミナントをデータ０に対応させ、レセシブをデータ１に対応させて、データの送受信を行う。 In general, a communication system adopting a CAN (or CAN-FD) communication protocol adopts a bus type network topology. In the bus-type network topology, each electronic device is connected to a branch line that branches from a main line used for communication in common with other electronic devices. For example, each electronic device performs data transmission / reception with a dominant corresponding to data 0 and a recessive corresponding to data 1.
　ＣＡＮ（又はＣＡＮ－ＦＤ）の通信プロトコルを採用した通信システムでは、電子機器が他の電子機器に送信するときに、リンギングが発生する。リンギングは、幹線から支線に分岐する分岐部分におけるインピーダンス不整合、及び支線に接続する通信装置のインピーダンス不整合等により、信号が多重反射することにより発生する。 In a communication system adopting a CAN (or CAN-FD) communication protocol, ringing occurs when an electronic device transmits to another electronic device. Ringing is caused by multiple reflection of a signal due to impedance mismatch at a branching portion that branches from a main line to a branch line, impedance mismatch of a communication device connected to the branch line, and the like.
　通信システムは、リンギングの影響が大きくなると、一の通信装置から送信されたドミナントの信号が、受信した通信装置側でレセシブと判定されること等により、通信に障害が生じ、障害が大きい場合には通信不能に陥る虞がある。
　その為、ＣＡＮ（又はＣＡＮ－ＦＤ）の通信プロトコルを採用した通信システムでは、リンギングの影響が大きくならないように、ツイストペアケーブルの配策形態の自由度が制限され、幹線と支線との分岐部分にフェライト等のフィルタを介装したり、非終端部分に抵抗又はフィルタを介装したりする方法をとる必要があった。しかし、新規部品が必要であれば、部品コストが増大する問題がある。 When the influence of ringing increases, the communication system causes a failure in communication because the dominant signal transmitted from one communication device is judged to be recessive on the received communication device side. May fall out of communication.
For this reason, in a communication system employing the CAN (or CAN-FD) communication protocol, the degree of freedom of twisted-pair cable routing is limited so that the influence of ringing does not increase, and the branch portion between the main line and the branch line is limited. It has been necessary to adopt a method in which a filter such as ferrite is interposed, or a resistor or a filter is interposed in a non-terminal portion. However, if a new part is necessary, there is a problem that the part cost increases.
　特許文献１には、個々の加入者端末ステーションに接続する伝送線路が、星状に１つの受動的なネットワークノードに接続されたデータ通信システムが開示されている。伝送線路は、周波数依存の減衰素子、例えばフェライトビーズを有する。定常的なデータシンボル状態に設定されたシステムパラメータの同時的な自由な選択により、高周波ノイズ信号の良好な特性インピーダンスマッチングを行うことができる。 Patent Document 1 discloses a data communication system in which transmission lines connected to individual subscriber terminal stations are connected to one passive network node in a star shape. The transmission line has a frequency dependent attenuating element, for example a ferrite bead. Good characteristic impedance matching of the high-frequency noise signal can be performed by simultaneously and freely selecting system parameters set in a steady data symbol state.
特表平７－５００４６３号公報JP 7-700463 Gazette
　上述したようなＣＡＮ（又はＣＡＮ－ＦＤ）の通信プロトコルを採用した通信システムでは、リンギングの影響が大きくならないように、非終端部分の支線が有する一対の通信線それぞれに、フェライト、又は抵抗とインダクタとを並列に接続したフィルタを介装させることにより、部品コストを低減する方法が検討されている。
　しかし、上記のように、非終端部分の支線の各通信線にフェライト又はフィルタを介装させた場合でも、入力インピーダンスが高いドライバ（通信部）であれば、受信側のインピーダンスを下げる効果が不足し、リンギング時間が低減できないことがあるという問題がある。 In a communication system that employs the CAN (or CAN-FD) communication protocol as described above, a pair of communication lines included in the branch line of the non-termination portion includes a ferrite or a resistor and an inductor so that the influence of ringing does not increase. A method for reducing the cost of components by interposing filters connected in parallel with each other has been studied.
However, as described above, even when a ferrite or filter is interposed in each communication line of the branch line of the non-termination part, if the driver (communication unit) has a high input impedance, the effect of lowering the impedance on the receiving side is insufficient. There is a problem that the ringing time may not be reduced.
　本発明は、上述したような事情に鑑みてなされたものであり、非終端部分の支線の各通信線にフィルタを介装させた場合に、フィルタの効果が増大し、ケーブルの配策形態の自由度が大きく、リンギングの影響を低減できる通信システムを提供することを目的とする。
　本発明は、また、非終端部分の支線の各通信線にフェライトを介装させた場合に、フェライトの効果が増大し、ケーブルの配策形態の自由度が大きく、リンギングの影響を低減できる通信システムを提供することを目的とする。 The present invention has been made in view of the circumstances as described above, and when a filter is interposed in each communication line of the branch line of the non-terminal portion, the effect of the filter is increased and the cable routing configuration is free. An object of the present invention is to provide a communication system that can reduce the influence of ringing.
The present invention also provides a communication system in which the effect of ferrite is increased, the degree of freedom of cable routing is large, and the influence of ringing can be reduced when ferrite is interposed in each communication line of the branch line of the non-terminal portion. The purpose is to provide.
　本発明に係る通信システムは、一対の通信線を有する幹線と、終端抵抗を有し前記一対の通信線の間に前記終端抵抗を介装し、前記幹線の各端部に接続してある２つの第１通信装置と、前記一対の通信線に各接続してある一対の通信線を有する支線と、該一対の通信線にそれぞれフィルタを介して接続された通信部を有する１又は複数の第２通信装置とを備え、前記第１通信装置及び第２通信装置それぞれが通信を行う通信システムにおいて、前記第２通信装置は、前記支線が有する前記一対の通信線の間に抵抗を介装してあることを特徴とする。 The communication system according to the present invention includes a trunk line having a pair of communication lines, a termination resistor, the termination resistor interposed between the pair of communication lines, and connected to each end of the trunk line. One or more first communication devices, a branch line having a pair of communication lines connected to the pair of communication lines, and a communication unit connected to the pair of communication lines via a filter, respectively. In the communication system in which each of the first communication device and the second communication device communicates, the second communication device has a resistor interposed between the pair of communication lines of the branch line. It is characterized by being.
　この通信システムでは、幹線が一対の通信線を有し、幹線の各端部に接続してある２つの第１通信装置が、幹線の一対の通信線の間に終端抵抗を介装してある。支線が、幹線の一対の通信線に各接続してある一対の通信線を有し、１又は複数の第２通信装置が、支線の一対の通信線にそれぞれフィルタを介して接続された通信部を有し、第１通信装置及び第２通信装置それぞれが通信を行う。第２通信装置は、支線が有する一対の通信線の間に抵抗を介装してある。 In this communication system, the trunk line has a pair of communication lines, and two first communication devices connected to each end of the trunk line are provided with a terminating resistor between the pair of trunk lines. . The branch line has a pair of communication lines each connected to a pair of trunk communication lines, and one or a plurality of second communication devices are connected to the pair of branch communication lines via a filter, respectively. Each of the first communication device and the second communication device performs communication. In the second communication device, a resistor is interposed between a pair of communication lines included in the branch line.
　本発明に係る通信システムは、一対の通信線を有する幹線と、終端抵抗を有し前記一対の通信線の間に前記終端抵抗を介装し、前記幹線の各端部に接続してある２つの第１通信装置と、前記一対の通信線に各接続してある一対の通信線を有する支線と、該一対の通信線が、電磁ノイズを抑制するフェライトを介して接続された通信部を有する１又は複数の第２通信装置とを備え、前記第１通信装置及び第２通信装置それぞれが通信を行う通信システムにおいて、前記第２通信装置は、前記支線が有する前記一対の通信線の間に抵抗を介装してあることを特徴とする。 The communication system according to the present invention includes a trunk line having a pair of communication lines, a termination resistor, the termination resistor interposed between the pair of communication lines, and connected to each end of the trunk line. A first communication device, a branch line having a pair of communication lines connected to the pair of communication lines, and a communication unit in which the pair of communication lines are connected via a ferrite that suppresses electromagnetic noise. One or a plurality of second communication devices, wherein the first communication device and the second communication device communicate with each other, and the second communication device is located between the pair of communication lines of the branch line. It is characterized by interposing a resistor.
　この通信システムでは、幹線が一対の通信線を有し、幹線の各端部に接続してある２つの第１通信装置が、幹線の一対の通信線の間に終端抵抗を介装してある。支線が、幹線の一対の通信線に各接続してある一対の通信線を有し、１又は複数の第２通信装置は、支線の一対の通信線が、電磁ノイズを抑制するフェライトを介して接続された通信部を有し、第１通信装置及び第２通信装置それぞれが通信を行う。第２通信装置は、支線が有する一対の通信線の間に抵抗を介装してある。 In this communication system, the trunk line has a pair of communication lines, and two first communication devices connected to each end of the trunk line are provided with a terminating resistor between the pair of trunk lines. . The branch line has a pair of communication lines respectively connected to a pair of communication lines of the trunk line, and the one or more second communication devices are configured such that the pair of communication lines of the branch line passes through a ferrite that suppresses electromagnetic noise. Each of the first communication device and the second communication device has a communication unit connected to perform communication. In the second communication device, a resistor is interposed between a pair of communication lines included in the branch line.
　本発明に係る通信システムは、前記一対の通信線の間に介装された抵抗の抵抗値は、前記通信部の入力インピーダンスより低く、前記支線のインピーダンスより高いことを特徴とする。 The communication system according to the present invention is characterized in that a resistance value of a resistor interposed between the pair of communication lines is lower than an input impedance of the communication unit and higher than an impedance of the branch line.
　本発明に係る通信システムは、前記第２通信装置を複数備え、各第２通信装置に接続する支線が長い程、該支線が有する前記一対の通信線の間に介装された抵抗の抵抗値が低いことを特徴とする。 The communication system according to the present invention includes a plurality of the second communication devices, and the longer the branch line connected to each second communication device, the longer the resistance value of the resistor interposed between the pair of communication lines of the branch line. Is characterized by low.
　本発明に係る通信システムは、前記通信部は、コネクタを介して前記支線に接続してあり、前記コネクタの支線側の前記一対の通信線の間に、第２抵抗を介装してあることを特徴とする。 In the communication system according to the present invention, the communication unit is connected to the branch line via a connector, and a second resistor is interposed between the pair of communication lines on the branch line side of the connector. It is characterized by.
　本発明に係る通信システムによれば、非終端部分の支線の各通信線にフィルタを介装させた場合に、フィルタの効果が増大し、ケーブルの配策形態の自由度が大きく、リンギングの影響を低減できる通信システムを実現することができる。 According to the communication system of the present invention, when a filter is interposed in each communication line of the branch line of the non-termination part, the effect of the filter is increased, the degree of freedom of the cable routing form is great, and the influence of ringing is reduced. A communication system that can be reduced can be realized.
　本発明に係る通信システムによれば、非終端部分の支線の各通信線にフェライトを介装させた場合に、フェライトの効果が増大し、ケーブルの配策形態の自由度が大きく、リンギングの影響を低減できる通信システムを実現することができる。 According to the communication system of the present invention, when ferrite is interposed in each communication line of the branch line of the non-termination part, the effect of the ferrite is increased, the degree of freedom of the cable routing form is great, and the influence of ringing is reduced. A communication system that can be reduced can be realized.
本発明に係る通信システムの実施の形態の概略構成を示す回路図である。1 is a circuit diagram showing a schematic configuration of an embodiment of a communication system according to the present invention. ＥＣＵの構成例を模式的に示すブロック図である。It is a block diagram which shows typically the structural example of ECU. 終端ＥＣＵの構成例を模式的に示すブロック図である。It is a block diagram which shows typically the structural example of terminal ECU. ＥＣＵの他の構成例を模式的に示すブロック図である。It is a block diagram which shows typically the other structural example of ECU.
　以下に、本発明をその実施例を示す図面に基づいて詳述する。 Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.
　図１は、本発明に係る通信システムの実施例の概略構成を示す回路図である。
　この通信システムは、車両に搭載されるＥＣＵ（Electronic Control Unit）１ａ，１ｂ，１ｃと、同じく車両に搭載される終端ＥＣＵ２ａ，２ｂとを備えている。終端ＥＣＵ２ａは、通信線を有する幹線３の一端部と接続され、終端ＥＣＵ２ｂは幹線３の他端部と接続されている。 FIG. 1 is a circuit diagram showing a schematic configuration of an embodiment of a communication system according to the present invention.
This communication system includes ECUs (Electronic Control Units) 1a, 1b, and 1c mounted on a vehicle, and terminal ECUs 2a and 2b that are also mounted on the vehicle. The terminal ECU 2a is connected to one end of the trunk line 3 having a communication line, and the terminal ECU 2b is connected to the other end of the trunk line 3.
　ＥＣＵ１ａは、幹線３の中途の分岐点Ａから分岐した支線４ａに接続され、ＥＣＵ１ｂは、幹線３の中途の分岐点Ｂから分岐する支線４ｂに接続され、ＥＣＵ１ｃは、幹線３の中途の分岐点Ｃから分岐する支線４ｃに接続されている。分岐点Ｂは、分岐点Ａよりも終端ＥＣＵ２ｂ側にあり、分岐点Ｃは、分岐点Ｂよりも終端ＥＣＵ２ｂ側にある。支線４ａ，４ｂ，４ｃは、通信線を有して構成されている。 The ECU 1a is connected to a branch line 4a branched from a branch point A in the middle of the trunk line 3, the ECU 1b is connected to a branch line 4b branched from a branch point B in the middle of the trunk line 3, and the ECU 1c is connected to a branch point in the middle of the trunk line 3 It is connected to a branch line 4c branched from C. The branch point B is closer to the end ECU 2b than the branch point A, and the branch point C is closer to the end ECU 2b than the branch point B. The branch lines 4a, 4b, and 4c are configured to have communication lines.
　尚、ＥＣＵ１ａ，１ｂ，１ｃは、同様の構成である為、以下では総称してＥＣＵ１とも称する。終端ＥＣＵ２ａ，２ｂについても同様の構成である為、以下では総称して終端ＥＣＵ２とも称する。支線４ａ，４ｂ，４ｃについても同様の構成である為、以下では総称して支線４とも称する。また、ＥＣＵ１は、本発明の第２通信装置に相当し、終端ＥＣＵ２は、本発明の第１通信装置に相当する。
　ここで、幹線３及び支線４は、ＣＡＮ（Controller Area Network）バスが有する特性インピーダンスを有するツイストペアケーブルとする。 Since the ECUs 1a, 1b, and 1c have the same configuration, they are also collectively referred to as ECU1 below. Since the end ECUs 2a and 2b have the same configuration, they are also collectively referred to as the end ECU 2 below. Since the branch lines 4a, 4b, and 4c have the same configuration, they are also collectively referred to as branch lines 4 below. The ECU 1 corresponds to the second communication device of the present invention, and the terminal ECU 2 corresponds to the first communication device of the present invention.
Here, the trunk line 3 and the branch line 4 are twisted pair cables having the characteristic impedance of a CAN (Controller Area Network) bus.
　このような構成の通信システムでは、ＥＣＵ１及び終端ＥＣＵ２それぞれの間で幹線３を共通の通信線として通信が行われる。例えば、ＥＣＵ１ｂにて支線４ｂへ信号が出力された場合、この信号は支線４ｂから幹線３、支線４ａを経てＥＣＵ１ａへ到達し、ＥＣＵ１ａが支線４ａと接続する接続部等にて反射された反射波が発生する。反射波は、支線４ａ、幹線３、及び支線４ｂを経てＥＣＵ１ｂに到達する。 In the communication system having such a configuration, communication is performed between the ECU 1 and the terminal ECU 2 using the main line 3 as a common communication line. For example, when a signal is output to the branch line 4b by the ECU 1b, this signal reaches the ECU 1a from the branch line 4b via the trunk line 3 and the branch line 4a, and the reflected wave reflected by the connection portion etc. where the ECU 1a connects to the branch line 4a Occurs. The reflected wave reaches the ECU 1b through the branch line 4a, the trunk line 3, and the branch line 4b.
　ＥＣＵ１ｂに到達した反射波は、再度ＥＣＵ１ｂが支線４ａと接続する接続部等にて反射される。このように信号の反射が繰り返されることにより、通信システムにおいてリンギングが発生する。リンギングは、支線や幹線の長さが長くなると、周期が長くなりリンギング時間が長くなる為、配索範囲に制限が設けられている。また、図１では、ＥＣＵ１ｃにおいても同様の反射波が発生する。更に、終端ＥＣＵ２においても、幹線及び支線の特性インピーダンスの値によっては、同様の反射波が発生する虞がある。 The reflected wave that has reached the ECU 1b is reflected again at the connecting portion where the ECU 1b connects to the branch line 4a again. In this way, ringing occurs in the communication system due to repeated signal reflection. Since the ringing becomes longer and the ringing time becomes longer as the length of the branch line or the trunk line becomes longer, the range of the ringing is limited. In FIG. 1, a similar reflected wave is also generated in the ECU 1c. Further, the terminal ECU 2 may generate a similar reflected wave depending on the characteristic impedance values of the main line and the branch line.
　図２は、ＥＣＵ１の構成例を模式的に示すブロック図である。
　ＥＣＵ１は、互いにバス接続された制御部１１、ＲＯＭ（Read Only Memory）１２、ＲＡＭ（Random Access Memory）１３、入力部１４、出力部１５、ドライバ１６、及び接続回路１７等を備えて構成されている。制御部１１は、ＣＰＵ（Central Processing Unit）又はＭＰＵ（Micro Processing Unit）等の演算処理装置を用いて構成されており、ＲＯＭ１２に記憶された制御プログラムを読み出して実行することにより，種々の制御処理を行う。 FIG. 2 is a block diagram schematically illustrating a configuration example of the ECU 1.
The ECU 1 includes a control unit 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, an input unit 14, an output unit 15, a driver 16, a connection circuit 17, and the like that are connected to each other via a bus. Yes. The control unit 11 is configured by using an arithmetic processing device such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and reads various control programs stored in the ROM 12 to execute various control processes. I do.
　ＲＯＭ１２は、例えばＥＥＰＲＯＭ（Electrically Erasable Programmable ROM）又はフラッシュメモリ等の不揮発性のメモリ素子で構成されており、制御部１１にて実行される制御プログラム、及び制御部１１が行う処理に必要な情報等が予め記憶されている。ＲＡＭ１３は、例えばＳＲＡＭ（Static RAM）又はＤＲＡＭ（Dynamic RAM）等のメモリ素子で構成されており、制御部１１の処理に伴って生成された情報、及び他のＥＣＵ１との間で送受信する情報等が記憶される。 The ROM 12 is composed of a nonvolatile memory element such as an EEPROM (Electrically Erasable Programmable ROM) or flash memory, for example, a control program executed by the control unit 11, information necessary for processing performed by the control unit 11, and the like Is stored in advance. The RAM 13 is composed of a memory element such as SRAM (Static RAM) or DRAM (Dynamic RAM), for example, information generated by the processing of the control unit 11, information transmitted to and received from other ECUs, etc. Is memorized.
　入力部１４は、例えば車両の車速センサ若しくは温度センサ等のセンサ、又は車両の内外に配置された操作用の種々のスイッチ等からの信号が入力され、入力信号のサンプリング又はＡ／Ｄ変換等の処理を行って得られた情報を制御部１１へ与える。出力部１５は、例えばモータ又はランプ等の負荷が接続され、制御部１１からの指示に応じてこれらの負荷を駆動する駆動信号を出力する。尚、ＥＣＵ１は、必ずしも入力部１４及び出力部１５の両方を備える必要はなく、何れか一方のみを備える構成であってもよい。 The input unit 14 receives, for example, signals from sensors such as a vehicle speed sensor or a temperature sensor of the vehicle, or various switches for operation disposed inside and outside the vehicle, and performs sampling of the input signal or A / D conversion, etc. Information obtained by performing the processing is given to the control unit 11. The output unit 15 is connected to a load such as a motor or a lamp, and outputs a drive signal for driving these loads in response to an instruction from the control unit 11. Note that the ECU 1 does not necessarily need to include both the input unit 14 and the output unit 15, and may be configured to include only one of them.
　ドライバ１６は、他のＥＣＵ１，２との間でＣＡＮプロトコルに従った情報の送受信を行うものであり、接続回路１７を介して支線４と接続している。ドライバ１６は、制御部１１から与えられた送信情報をＣＡＮプロトコルに応じた送信用のデータ（フレーム）に変換して送信部１６ａへ与える。
　送信部１６ａは、与えられた送信データの各ビットの値（０（ドミナント）又は１（レセシブ））に応じて、支線４へ信号を出力する。 The driver 16 transmits and receives information according to the CAN protocol to and from other ECUs 1 and 2, and is connected to the branch line 4 via the connection circuit 17. The driver 16 converts the transmission information given from the control unit 11 into transmission data (frame) according to the CAN protocol and gives the data to the transmission unit 16a.
The transmission unit 16a outputs a signal to the branch line 4 according to the value of each bit of the given transmission data (0 (dominant) or 1 (recessive)).
　ＣＡＮプロトコルにおいては、幹線３及び支線４は、一対の通信線が撚り合わされてなるツイストペアケーブルが用いられる。送信部１６ａは、接続回路１７を介して接続する支線４に差動信号を出力する。送信部１６ａは、ドミナントの信号を送信するときは、支線４が有する一対の通信線間の電位差が２Ｖとなる差動信号を出力し、レセシブの信号を送信するときは、当該電位差が０Ｖとなる差動信号を出力する。尚、ドライバ１６は、本発明の通信部に相当する。 In the CAN protocol, the trunk line 3 and the branch line 4 are twisted pair cables formed by twisting a pair of communication lines. The transmitter 16 a outputs a differential signal to the branch line 4 connected via the connection circuit 17. When transmitting a dominant signal, the transmission unit 16a outputs a differential signal in which the potential difference between the pair of communication lines of the branch line 4 is 2V. When transmitting a recessive signal, the potential difference is 0V. A differential signal is output. The driver 16 corresponds to the communication unit of the present invention.
　また、ドライバ１６は、支線４の信号レベルを検知することにより、支線４上に送信された信号が、ドミナント又はレセシブの何れに対応する信号であるかを判定し、各ビットがドミナント又はレセシブで表されるデータの受信を行う受信部１６ｂを有している。支線４の信号レベルとは、支線４が有する一対の通信線間の電位差のことを指す。ドライバ１６は、受信部１６ｂにて受信したデータを制御部１１へ与える。 Further, the driver 16 detects the signal level of the branch line 4 to determine whether the signal transmitted on the branch line 4 is a signal corresponding to dominant or recessive, and each bit is dominant or recessive. It has the receiving part 16b which receives the data represented. The signal level of the branch line 4 refers to a potential difference between a pair of communication lines included in the branch line 4. The driver 16 gives the data received by the receiving unit 16b to the control unit 11.
　また、ドライバ１６は、送信部１６ａにて自らが送信したデータを受信部１６ｂにて受信し、送信データと受信データとが一致しない場合（送信データのレセシブが受信データにてドミナントに変化していた場合）、他のＥＣＵ１又は終端ＥＣＵ２によりデータが送信されていることを検知し、アービトレーションの処理を行う。尚、ＥＣＵ１が行うアービトレーションの処理は、従来のＣＡＮプロトコルによるものと同じであるので、詳細な説明は省略する。 Further, the driver 16 receives the data transmitted by the transmission unit 16a at the reception unit 16b, and if the transmission data and the reception data do not match (the recessiveness of the transmission data has changed to dominant in the reception data). In other words, it is detected that data is being transmitted by the other ECU 1 or the terminal ECU 2, and arbitration processing is performed. The arbitration process performed by the ECU 1 is the same as that performed by the conventional CAN protocol, and thus detailed description thereof is omitted.
　接続回路１７は、支線４に介装され、支線４からドライバ１６に入力される信号による反射波を抑制するように構成されている。接続回路１７は、インダクタ１７ａ及び抵抗１７ｂが並列に接続されたフィルタが、支線４が有する一対の通信線にそれぞれ介装され、フィルタの幹線３側の各通信線間に抵抗１７ｃが接続されている。 The connection circuit 17 is interposed in the branch line 4 and is configured to suppress a reflected wave caused by a signal input from the branch line 4 to the driver 16. In the connection circuit 17, a filter in which an inductor 17 a and a resistor 17 b are connected in parallel is interposed in a pair of communication lines included in the branch line 4, and a resistor 17 c is connected between each communication line on the main line 3 side of the filter. Yes.
　抵抗１７ｃは、ドライバ１６の入力インピーダンスより低く、かつ支線４のドライバ１６側開放時のインピーダンスより高い抵抗値を有している。
　接続回路１７内外の支線４は、接続回路１７側のオスコネクタ１８ａと幹線３側のメスコネクタ１８ｂにより接続されている。
　ＥＣＵ１ａ，１ｂ，１ｃに接続する支線４の長さが異なる場合、支線４が長い程、その支線４が有する一対の通信線の間に介装された抵抗１７ｃの抵抗値は低くしてあり、各支線４及び接続回路１７によるインピーダンス間の差を小さくする。その際、支線４が長いＥＣＵ１のみ、メスコネクタ１８ｂ内の一対の通信線間に抵抗１８ｃを介装させて、通信線間の抵抗値を低下させる。 The resistor 17c has a resistance value lower than the input impedance of the driver 16 and higher than the impedance when the branch line 4 is opened on the driver 16 side.
The branch lines 4 inside and outside the connection circuit 17 are connected by a male connector 18a on the connection circuit 17 side and a female connector 18b on the main line 3 side.
When the lengths of the branch lines 4 connected to the ECUs 1a, 1b, and 1c are different, the resistance value of the resistor 17c interposed between the pair of communication lines of the branch line 4 is lowered as the branch line 4 is longer. The difference between the impedances of the branch lines 4 and the connection circuit 17 is reduced. At that time, only the ECU 1 having a long branch line 4 is provided with a resistor 18c between a pair of communication lines in the female connector 18b to reduce the resistance value between the communication lines.
　図３は、終端ＥＣＵ２の構成例を模式的に示すブロック図である。
　終端ＥＣＵ２は、バス接続された制御部２１、ＲＯＭ２２、ＲＡＭ２３、入力部２４、出力部２５、ドライバ２６、及び接続回路２７等を備えて構成されている。ここで、制御部２１、ＲＯＭ２２、及びＲＡＭ２３は、図２中の制御部１１、ＲＯＭ１２、及びＲＡＭ１３とそれぞれ同様に作用するので、説明を省略する。また、入力部２４、出力部２５、及びドライバ２６は、図２中の入力部１４、出力部１５、及びドライバ１６とそれぞれ同様に作用するので、説明を省略する。尚、終端ＥＣＵ２のドライバ２６は、接続回路２７を介して幹線３と接続している。 FIG. 3 is a block diagram schematically illustrating a configuration example of the terminal ECU 2.
The terminal ECU 2 includes a control unit 21, a ROM 22, a RAM 23, an input unit 24, an output unit 25, a driver 26, a connection circuit 27, and the like connected via a bus. Here, the control unit 21, ROM 22, and RAM 23 operate in the same manner as the control unit 11, ROM 12, and RAM 13 in FIG. The input unit 24, the output unit 25, and the driver 26 operate in the same manner as the input unit 14, the output unit 15, and the driver 16 in FIG. Note that the driver 26 of the terminal ECU 2 is connected to the main line 3 via the connection circuit 27.
　接続回路２７では、２つの抵抗２７ａからなる直列回路が、幹線３が有する一対の通信線の間に介装されている。また、接続回路２７は、コンデンサ２７ｂを備えており、コンデンサ２７ｂの一端は、２つの抵抗２７ａの共通接続節点に接続され、他端は接地されている。 In the connection circuit 27, a series circuit composed of two resistors 27a is interposed between a pair of communication lines of the main line 3. The connection circuit 27 includes a capacitor 27b. One end of the capacitor 27b is connected to the common connection node of the two resistors 27a, and the other end is grounded.
　このような構成の接続回路２７は、ＣＡＮプロトコルにおける所謂スプリットターミネーションであり、ドライバ２６への入力インピーダンスと、幹線３のインピーダンスとを整合する。尚、接続回路２７は、終端抵抗であればよく、スプリットターミネーション以外で構成されていてもよい。 The connection circuit 27 having such a configuration is a so-called split termination in the CAN protocol, and matches the input impedance to the driver 26 and the impedance of the trunk line 3. Note that the connection circuit 27 may be a termination resistor and may be configured other than split termination.
　以上の構成の通信システムでは、ＥＣＵ１において支線４の通信線間に抵抗１７ｃを介装することにより、インダクタ１７ａ及び抵抗１７ｂが並列に接続されたフィルタの効果が高まり、高周波のリンギング成分を除去することができる為、リンギングを抑制し、通信の安定性を高めることができる。尚、メスコネクタ１８ｂ内の支線４の通信線間に抵抗１８ｃを更に介装することにより、フィルタの効果は更に高まる。
　また、この通信システムでは、リンギング成分を除去できない場合でも、リンギング成分のピークを削減することができる為、ピークが信号の閾値を超えなくなり、リンギング時間は短くなる。 In the communication system having the above-described configuration, the resistance of the filter in which the inductor 17a and the resistor 17b are connected in parallel is enhanced by interposing the resistor 17c between the communication lines of the branch line 4 in the ECU 1, and a high-frequency ringing component is removed. Therefore, ringing can be suppressed and communication stability can be improved. The effect of the filter is further enhanced by further interposing the resistor 18c between the communication lines of the branch line 4 in the female connector 18b.
Further, in this communication system, even if the ringing component cannot be removed, the peak of the ringing component can be reduced, so that the peak does not exceed the signal threshold and the ringing time is shortened.
　図４は、ＥＣＵ１の他の構成例を模式的に示すブロック図である。
　このＥＣＵ１では、接続回路１７に代えて、接続回路１９を備えている。接続回路１９は、支線４の一対の通信線が挿通する２つの孔を有し、通信線の電磁ノイズを抑制するフェライト１９ａと、フェライト１９ａのオスコネクタ１８ａ側の通信線間を接続する抵抗１９ｂとを備えている。
　フェライト１９ａの２つの孔をそれぞれ挿通した支線４の一対の通信線は、ドライバ１６にそれぞれ接続されている。 FIG. 4 is a block diagram schematically showing another configuration example of the ECU 1.
The ECU 1 includes a connection circuit 19 instead of the connection circuit 17. The connection circuit 19 has two holes through which the pair of communication lines of the branch line 4 is inserted, and a resistor 19b that connects between the ferrite 19a that suppresses electromagnetic noise of the communication line and the communication line on the male connector 18a side of the ferrite 19a. And.
A pair of communication lines of the branch line 4 inserted through the two holes of the ferrite 19a are connected to the driver 16, respectively.
　以上のように、ＥＣＵ１において、支線４の通信線間に抵抗１９ｂを介装することにより、フェライト１９ａのフィルタ効果が高まり、高周波のリンギング成分を除去することができる為、リンギングを抑制し、通信の安定性を高めることができる。尚、メスコネクタ１８ｂ内の支線４の通信線間に抵抗１８ｃを更に介装することにより、フィルタの効果は更に高まる。また、リンギング成分を除去できない場合でも、リンギング成分のピークを削減することができる為、ピークが信号の閾値を超えなくなり、リンギング時間は短くなる。その他の構成及び動作は、上述したＥＣＵ１（図２）の構成及び動作と同様であるので、説明を省略する。 As described above, in the ECU 1, by interposing the resistor 19 b between the communication lines of the branch line 4, the filter effect of the ferrite 19 a can be enhanced and the high-frequency ringing component can be removed. Can improve the stability. The effect of the filter is further enhanced by further interposing the resistor 18c between the communication lines of the branch line 4 in the female connector 18b. Even if the ringing component cannot be removed, the peak of the ringing component can be reduced, so that the peak does not exceed the signal threshold and the ringing time is shortened. Since other configurations and operations are the same as the configurations and operations of the ECU 1 (FIG. 2) described above, description thereof will be omitted.
　尚、本実施の形態の通信システムでは、ＥＣＵ１ａ，１ｂ，１ｃが、異なる分岐点Ａ，Ｂ，Ｃからそれぞれ分岐した支線４ａ，４ｂ，４ｃに接続されたバス型（図１）により説明したが、ＥＣＵ１ａ，１ｂ，１ｃが、１つの分岐点から分岐した支線４ａ，４ｂ，４ｃにそれぞれ接続されたスター型であっても、同様の効果を奏することができる。 In the communication system of the present embodiment, the ECUs 1a, 1b, and 1c are described as bus types (FIG. 1) connected to branch lines 4a, 4b, and 4c branched from different branch points A, B, and C, respectively. Even if the ECUs 1a, 1b, and 1c are star types connected to the branch lines 4a, 4b, and 4c branched from one branch point, similar effects can be obtained.
　今回開示された実施の形態は全ての点で例示であって、制限的なものではないと考えられるべきである。本発明の範囲は、上記した意味ではなく、特許請求の範囲によって示され、特許請求の範囲と均等の意味及び範囲内での全ての変更が含まれることが意図される。 The embodiment disclosed herein is illustrative in all respects and should not be considered as restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of claims for patent, and is intended to include all modifications within the scope and meaning equivalent to the scope of claims for patent.
　本発明は、車両に搭載された多数の電子機器間を通信線を介して接続し相互に通信する通信システム等に利用することができる。 The present invention can be used for a communication system or the like in which a large number of electronic devices mounted on a vehicle are connected via a communication line to communicate with each other.
　１ａ，１ｂ，１ｃ　ＥＣＵ（第２通信装置）
　２ａ，２ｂ　終端ＥＣＵ（第１通信装置）
　３　幹線
　４ａ，４ｂ，４ｃ　支線
　１６，２６　ドライバ（通信部）
　１７，１９，２７　接続回路
　１７ａ　インダクタ（フィルタ）
　１７ｂ　抵抗（フィルタ）
　１７ｃ，１９ｂ　抵抗
　１８ａ　オスコネクタ
　１８ｂ　メスコネクタ
　１８ｃ　抵抗（第２抵抗）
　１９ａ　フェライト
　２７ａ　抵抗（終端抵抗）
 
 
 
 
 
 
 
 
 
  1a, 1b, 1c ECU (second communication device)
2a, 2b Terminal ECU (first communication device)
3 Trunk line 4a, 4b, 4c Branch line 16, 26 Driver (communication part)
17, 19, 27 Connection circuit 17a Inductor (filter)
17b Resistance (filter)
17c, 19b Resistance 18a Male connector 18b Female connector 18c Resistance (second resistance)
19a Ferrite 27a Resistance (Terminal resistance)









Claims (5)

  1. 　一対の通信線を有する幹線と、終端抵抗を有し前記一対の通信線の間に前記終端抵抗を介装し、前記幹線の各端部に接続してある２つの第１通信装置と、前記一対の通信線に各接続してある一対の通信線を有する支線と、該一対の通信線にそれぞれフィルタを介して接続された通信部を有する１又は複数の第２通信装置とを備え、前記第１通信装置及び第２通信装置それぞれが通信を行う通信システムにおいて、
    　前記第２通信装置は、前記支線が有する前記一対の通信線の間に抵抗を介装してあることを特徴とする通信システム。     A trunk line having a pair of communication lines, two first communication devices having a termination resistor, the termination resistance being interposed between the pair of communication lines, and being connected to each end of the trunk line, A branch line having a pair of communication lines each connected to a pair of communication lines, and one or a plurality of second communication devices each having a communication unit connected to the pair of communication lines via a filter, In the communication system in which each of the first communication device and the second communication device performs communication,
    In the communication system, the second communication device includes a resistor interposed between the pair of communication lines of the branch line.
  2. 　一対の通信線を有する幹線と、終端抵抗を有し前記一対の通信線の間に前記終端抵抗を介装し、前記幹線の各端部に接続してある２つの第１通信装置と、前記一対の通信線に各接続してある一対の通信線を有する支線と、該一対の通信線が、電磁ノイズを抑制するフェライトを介して接続された通信部を有する１又は複数の第２通信装置とを備え、前記第１通信装置及び第２通信装置それぞれが通信を行う通信システムにおいて、
    　前記第２通信装置は、前記支線が有する前記一対の通信線の間に抵抗を介装してあることを特徴とする通信システム。     A trunk line having a pair of communication lines, two first communication devices having a termination resistor, the termination resistance being interposed between the pair of communication lines, and being connected to each end of the trunk line, One or more second communication devices each having a branch line having a pair of communication lines each connected to a pair of communication lines, and a communication unit in which the pair of communication lines are connected via a ferrite that suppresses electromagnetic noise In the communication system in which each of the first communication device and the second communication device communicates,
    In the communication system, the second communication device includes a resistor interposed between the pair of communication lines of the branch line.
  3. 　前記一対の通信線の間に介装された抵抗の抵抗値は、前記通信部の入力インピーダンスより低く、前記支線のインピーダンスより高い請求項１又は２に記載の通信システム。 The communication system according to claim 1 or 2, wherein a resistance value of a resistor interposed between the pair of communication lines is lower than an input impedance of the communication unit and higher than an impedance of the branch line.
  4. 　前記第２通信装置を複数備え、各第２通信装置に接続する支線が長い程、該支線が有する前記一対の通信線の間に介装された抵抗の抵抗値が低い請求項１乃至３の何れか１項に記載の通信システム。 The resistance value of the resistance interposed between the pair of communication lines of the branch line is lower as the branch line connected to each second communication apparatus is longer. The communication system according to any one of the above.
  5. 　前記通信部は、コネクタを介して前記支線に接続してあり、前記コネクタの支線側の前記一対の通信線の間に、第２抵抗を介装してある請求項１乃至４の何れか１項に記載の通信システム。
          5. The communication unit according to claim 1, wherein the communication unit is connected to the branch line via a connector, and a second resistor is interposed between the pair of communication lines on the branch line side of the connector. The communication system according to item.
PCT/JP2015/084737 2014-12-22 2015-12-11 Communication system WO2016104172A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2014-258477 2014-12-22
JP2014258477A JP2016119582A (en) 2014-12-22 2014-12-22 Communication system

Publications (1)

Publication Number Publication Date
WO2016104172A1 true WO2016104172A1 (en) 2016-06-30

Family

ID=56150202

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2015/084737 WO2016104172A1 (en) 2014-12-22 2015-12-11 Communication system

Country Status (2)

Country Link
JP (1) JP2016119582A (en)
WO (1) WO2016104172A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07500463A (en) * 1991-10-26 1995-01-12 ダイムラークライスラー　アクチエンゲゼルシャフト data communication system
JP2007201697A (en) * 2006-01-25 2007-08-09 Auto Network Gijutsu Kenkyusho:Kk Branching connector
JP2012235336A (en) * 2011-05-02 2012-11-29 Auto Network Gijutsu Kenkyusho:Kk Communication system
JP2015053633A (en) * 2013-09-09 2015-03-19 株式会社オートネットワーク技術研究所 Communication system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07500463A (en) * 1991-10-26 1995-01-12 ダイムラークライスラー　アクチエンゲゼルシャフト data communication system
JP2007201697A (en) * 2006-01-25 2007-08-09 Auto Network Gijutsu Kenkyusho:Kk Branching connector
JP2012235336A (en) * 2011-05-02 2012-11-29 Auto Network Gijutsu Kenkyusho:Kk Communication system
JP2015053633A (en) * 2013-09-09 2015-03-19 株式会社オートネットワーク技術研究所 Communication system

Also Published As

Publication number Publication date
JP2016119582A (en) 2016-06-30

Similar Documents

Publication Publication Date Title
CN105409175B (en) Subscriber station for a bus system and method for improving the error robustness of a subscriber station of a bus system
US10020841B2 (en) Feedforward ringing suppression circuit
US10530606B2 (en) Method for transmitting data via a serial communication bus, bus interface, and computer program
US11176070B2 (en) Push pull ringing suppression circuit
US7855573B1 (en) Controller area network active bus terminator
JP5445667B2 (en) Communication connector, communication harness and communication system
JP6299692B2 (en) Communications system
US8681881B2 (en) Communication signal generating device and communication apparatus for use in communication system
CN105991382B (en) Subscriber station for a bus system and method for data transmission in a bus system
JP2012235427A (en) Connection method for bus controller, and communication system
CN108353016B (en) Relay device, electronic control device, and in-vehicle network system
CN105981319B (en) Subscriber station of a bus system and method for increasing the data rate of a bus system
JP2015053633A (en) Communication system
US10397057B2 (en) Transmitting digital data in two-wire communication networks
JP5532910B2 (en) Optical communication device, communication harness, and communication system
WO2016084647A1 (en) Communication system
WO2016104172A1 (en) Communication system
JP2016123054A (en) Communication system, communication device and communication method
JP2015088919A (en) Communication system and communication device
JP5626240B2 (en) Driver circuit
CN106464560B (en) Bus system
JP2016184791A (en) Communication controller and communication system
JP2013133073A (en) Local area network
JP2015204164A (en) Harness and communication system
JP2009290409A (en) Address setting device, communication unit, communication system and address setting method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15872741

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15872741

Country of ref document: EP

Kind code of ref document: A1