Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L12/40006—Architecture of a communication node
  • H04L12/40026—Details regarding a bus guardian
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L12/40006—Architecture of a communication node
  • H04L12/40032—Details regarding a bus interface enhancer
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L2012/40208—Bus networks characterized by the use of a particular bus standard
  • H04L2012/40215—Controller Area Network CAN
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L2012/40267—Bus for use in transportation systems
  • H04L2012/40273—Bus for use in transportation systems the transportation system being a vehicle
• • 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
  • H04L25/0264—Arrangements for coupling to transmission lines

Definitions

• the invention relates to CAN HS communication networks ("Controller Area Network High Speed” - ISO 11898).
• communication networks of the aforementioned type include a bus which are connected in parallel, via two electrical wires, called CANJH and CAN_L, communicating equipment (or bodies (such as for example computers). ). Note that the bus does not include a specific clock wire. The data exchange between communicating equipment (or organs) is via the bus, using multiplexed digital data frames.
• Such networks are used in many fields, and in particular in the field of vehicles
• the bus can be placed in either a recessive state or a so-called dominant state. These states correspond to particular voltage combinations on the CANJH and CAN_L wires. More precisely :
• the CANJH wire must be placed at a voltage between 2.0 V and 3.0 V
• the CAN_L wire must be placed at a voltage between 2.0 V and 3.0 V
• the voltage difference between the CANJH wire and the CAN_L wire must be between -500 mV and +50 mV
• the CANJH wire must be placed at a voltage between 2.75 V and 4.5 V
• the CAN_L wire must be placed at a voltage between 0.5 V and 2.25 V
• the voltage difference between the CANJH wire and the CAN_L wire must be between 1.5 V and 3 V.
• the voltages on the CANJH and CAN_L wires of the bus can be imposed by internal resistances to the organs (for example computers), called “pulling at most” and “pulling to the ground", or by equivalent devices, and two so-called “termination” resistors which are connected to both ends of the bus between the wires CANJH and CAN_L and which have identical values (for example between 100 ⁇ and 130 ⁇ ).
• control modules which comprise the network members, impose voltages intended to allow the input voltages of the other components to satisfy the aforementioned conditions as well if a single device imposes a state dominant (by emission of a dominant bit), only if several organs impose in parallel a dominant state (by emission of a dominant bit).
• the members comprise a logic module (or circuit) arbitration which continuously determines the state of the network. If several organs emit at the same time, as soon as one of them wishes to emit a recessive bit while at least one other of them is transmitting a dominant bit, the state of the bus is dominant and the arbitrary logic module (or circuit) for arbitration of the organ that wished to transmit the recessive bit prevents the latter organ from continuing to transmit, so that it does not disturb the other organs.
• a logic module (or circuit) arbitration which continuously determines the state of the network. If several organs emit at the same time, as soon as one of them wishes to emit a recessive bit while at least one other of them is transmitting a dominant bit, the state of the bus is dominant and the arbitrary logic module (or circuit) for arbitration of the organ that wished to transmit the recessive bit prevents the latter organ from continuing to transmit, so that it does not disturb the other organs.
• the purpose of the invention is therefore to improve the situation in the case of a partial disconnection of an organ, by means of a hardware solution that acts both in the absence of parry at the protocol level or software application, that 'in case of malfunction of a parry at the protocol level or software application.
• a protection device for an organ of a communication network CAN HS type and having a bus comprising a first wire called CANJH and a second wire called CAN_L can be placed under different combinations of voltages corresponding to so-called recessive and dominant states, this member comprising an interface module provided with first and second connected inputs / outputs respectively to said first and second son of the bus and being prohibited to issue a recessive bit when the network is in its dominant state.
• This protection device is characterized in that it comprises protection means arranged to prevent as much as possible (and if possible prohibit) the device from transmitting a bit on the bus when one of the first and second inputs / outputs of its interface module is disconnected functionally from the first or second wire of the bus.
• the protective device according to the invention may comprise other characteristics that can be taken separately or in combination, and in particular:
• its protection means may be arranged to cause (force) the first and second inputs / outputs of the interface module to be placed under input voltages which together correspond to a dominant state of the bus when the one its first and second inputs / outputs is functionally disconnected from the first or second bus wire;
• first resistive means comprising a first terminal capable of being connected to the first input / output of the interface module and a second terminal adapted to be connected to an auxiliary terminal which is placed under a chosen voltage
• second resistive means comprising a first terminal adapted to be connected to the second input / output of the interface module and a second terminal adapted to be connected to a mass or another selected voltage of the communication network
• the first and second resistive means may each provide a resistance which is between about 1 k ⁇ and about 100 k ⁇ ;
• the first resistive means and the second resistive means may be substantially identical;
• the second terminal of the first resistive means may be suitable for being connected to an auxiliary terminal which is placed under a fixed voltage of between about 3 volts and about 7 volts.
• the invention also proposes a member, on the one hand, intended to be part of a communication network, of CAN HS type and having a bus comprising a first wire called CANJH and a second wire called CAN_L which can be placed under different combinations of voltages corresponding to states of the recessive and dominant network, and secondly, comprising an interface module, provided with first and second inputs / outputs respectively connected to the first and second wires of the bus and being prohibited from transmit a recessive bit when the bus is in its dominant state, and a protection device, of the type shown above and connected to the first and second inputs / outputs of the interface module.
• the invention is well adapted, although not limited to vehicles, possibly of the automotive type.
• the attached drawing may not only serve to complete the invention, but also contribute to its definition, if any.
• the object of the invention is to provide a protection device D intended to be coupled to a communicating equipment (or device) Ci connected to a bus BU of a CAN HS RC type communication network.
• the RC communication network is part of a motor vehicle. But, the invention is not limited to this type of application. It concerns indeed any type of system or equipment or device that can host at least one communication network CAN HS type, including land vehicles, boats and aircraft.
• the number of members of a CAN HS network that can be coupled to protection devices D depends essentially on the voltage margin that exists at said CAN HS network. In general, at least one of the members (or communicating equipment) of a CAN HS network may be coupled to a protection device D.
• device coupled to a protective device is understood to mean both the fact that the component Ci is internally equipped with a protection device D, that the fact that the component Ci be connected to a protection device D.
• the number of organs (or communicating equipment) of a CAN HS RC network is not limited to four. This network must in fact comprise at least two organs (or communicating equipment).
• the device D slightly modifies the electrical characteristics of the physical layer of the RC network, it is advisable to select the organs that must be coupled to a device D at the time of the definition of the architecture of the RC network. For example, it may be wise to select the organs whose absence (or disconnection) leads to a degraded mode of operation that is of interest. Conversely, it may be wise not to select the organs that have a resistor called "termination" RT1, RT2 (described later), because the RC network can not be operated without them.
• the power steering computer of a vehicle may be coupled to a device D if it does not contain a terminating resistor and if it is on a "transverse" network branch (such as is the case of two members C1 and C2 of the figure).
• organs Ci and Oj are calculators. But, this is not mandatory. Indeed, an organ can be in any form since it constitutes a communicating equipment suitable for exchanging frames of digital data with other organs via the bus BU.
• each element Ci, Oj comprises at least one interface module M1, a control module (or stages) MP and an arbitration logic module (or circuit) MA.
• the interface module (or stage) Ml of a component Ci, Oj, also called line transceiver (or ERL), is responsible for ensuring the physical interface of its computer Ci, Oj with the network RC (and more precisely with its bus BU). It comprises a first input / output ES1 electrically connected to the first electrical wire (or CANJH wire) CH of the bus BU and a second input / output ES2 electrically connected to the second electrical wire (or wire CAN_L) CL bus BU. Moreover, it is connected, on the one hand, to a terminal BA 'placed under a chosen voltage, for example equal to + 12 V, and on the other hand, to an electric ground G of the network RC. This terminal BA 'is for example connected to the vehicle battery.
• the interface module (or stage) Ml of a body Ci, Oj is responsible for imposing on the CANJH CH and CAN_L CL wires voltages which are intended to allow the input voltages of the other components to satisfy the conditions which define dominant and recessive states (presented in the introductory section).
• the control module (or stage) MP of a body Ci, Oj is responsible for supplying the interface module (or stage) M1 with a logic state indicating to it at all times whether to impose on the CANJH CH and CAN_L wires.
• CL voltages that are intended to allow the input voltages of other organs to satisfy the conditions that define the dominant or recessive states (presented in the introductory part).
• the arbitrary logic module (or circuit) MA of an organ Ci, Oj is responsible for permanently determining the state of the network RC (and more specifically of its bus BU). He is especially charged, when his organ Ci, Oj wishes to emit a recessive bit but that another organ has emitted a dominant bit (and therefore the state of the bus BU is dominant), to prevent its organ Ci, Oj from continuing to transmit for a certain time so not to disturb the other organs of the RC network.
• the two terminating resistors RT1 and RT2 are respectively housed in the two members 01 and 02 between the first ES1 and second ES2 inputs / outputs of the interface module M1, which are connected respectively to the CANJH CH and CAN_L CL wires of the BU bus.
• this is not mandatory. Indeed, they could be located at the two main ends of the bus BU, between CANJH CH son and CAN_L CL, for example near the organs Oj.
• a (protection) device D mainly comprises protection means RP1 and RP2 which are arranged in such a way as to prevent as much as possible (and if possible forbid) their component Ci from emitting a bit on the bus BU when one of the first ES1 and second ES2 inputs / outputs of its interface module M1 is disconnected functionally from the CANJH CH wire or CAN_L CL bus BU wire.
• the invention proposes blocking the transmission of bits in the bus BU by the member Ci whose interface module M1 is partially disconnected functionally from said bus BU, and therefore when this member Ci is not more able to communicate properly with the other organs Ci ', Oj of the RC network.
• the organ Ci (partially disconnected) is thus somehow "Removed" from the RC network, and the probability that it disrupts the RC network is (very) greatly reduced.
• the device D is not intended to deal with the case where its member Ci is totally disconnected from the bus BU (that is to say that neither the CANJH CH wire nor the CAN_L CL wire are connected to the bus BU). Indeed, in this case, the fully disconnected member Ci can no longer electrically disturb the other organs Ci 'and Oj of the RC network. In this case, the device D is designed to avoid further degrade the overall functional situation.
• the protection means RP 1 and RP2 may for example be arranged to force the first ES1 and second ES2 inputs / outputs of the interface module M1 to be placed at input voltages that together correspond to a dominant state of the bus.
• BU when one of these first and second inputs / outputs is functionally disconnected from the CANJH CH wire or CAN_L CL wire of the BU bus.
• the arbitrary logic module (or circuit) MA of the element Ci believes that the bus BU is in its dominant state, so that it prevents this element Ci from transmitting bits. (in particular recessive) in order not to disturb the other organs of the RC network by its input / output still connected.
• the protection means RP1 and RP2 comprise first resistive means RP1 and second resistive means RP2 which are responsible for biasing the first ES1 and second ES2 inputs / outputs of the interface module. ml.
• the first resistive means RP1 comprise, on the one hand, a first terminal which is to be connected to the first input / output ES1 of the interface module M1, and secondly, a second terminal which is connected to an auxiliary terminal BA which is placed under a chosen voltage, and
• the second resistive means RP2 comprise, on the one hand, a first terminal which is connected to the second input / output ES2 of the interface module M1 and a second terminal which is connected to the ground G of the network RC. Note that in a variant not shown, the second terminal of the second resistive means RP2 can be connected to a terminal other than the ground G), which is placed at another selected voltage.
• the auxiliary terminal BA is for example part of the body Ci. It can, as illustrated, be an internal power supply terminal of the body Ci responsible for supplying a fixed voltage chosen to the interface module M1.
• this selected fixed voltage may be between about 3 volts and about 7 volts. For example it is chosen equal to 5 volts (usual power supply voltage of an interface module type ERL).
• the first resistive means RP1 may for example comprise at least one resistor.
• the second resistive means RP2 may for example comprise at least one resistor.
• the first resistive average RP1 and second RP2 may for example each provide a resistor which is between about 1 k ⁇ and about 100 k ⁇ .
• the values of the resistive means can be chosen so that the divider bridges, which they respectively constitute with the resistors "pulling at most” and “pull to the ground” of the interface modules of type ERL, generate corresponding voltages to a dominant state when one of the first and second inputs / outputs is functionally disconnected from the CANJH CH wire or CAN_L CL wire of the bus BU, regardless of the state of the bus BU, dominant or recessive.
• first resistive means RP1 and the second resistive means RP2 may be identical (in particular in order to simplify the calculations). By way of example, they may for example both have a resistance of approximately 10 k ⁇ . But, other values can be used.
• protection means RP1 and RP2 are located as close as possible to the interface module M1, so as to treat as many functional disconnection cases as possible (for example on the electronic card of the organ Ci concerned) and chopped wires.
• a device D (of the type illustrated in the single figure) to a member Ci is described below, when the auxiliary terminal BA is placed under a voltage of 5 V and the means of protection include a first resistor RP1 of 10 k ⁇ and a second resistor RP2 of 10 k ⁇ .
• the voltage values are here given for illustration and may vary according to the versions of the standard in question and / or according to the applications.
• the effect of the coupling of the device D is as follows:
• the second input / output ES2 of the interface module M1 of the component Ci is typically polarized at 2.5 V
• the effect of the coupling of the device D is as follows:
• the second input / output ES2 of the interface module M1 of the component Ci is typically biased at 1.5 V
• the first input / output ES1 of the interface module M1 of the component Ci is typically polarized at 2.5 V
• the first input / output ES1 of the interface module M1 of the component Ci is typically biased to 3.5 V
• the invention offers several advantages, among which:

Landscapes

• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Dc Digital Transmission (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=41327601

Family Applications (1)

Country Status (3)

Family Cites Families (2)

• 2009
  • 2009-07-03 FR FR0954570A patent/FR2947685B1/fr active Active
• 2010
  • 2010-06-24 EP EP10745310A patent/EP2449729A1/de not_active Withdrawn
  • 2010-06-24 WO PCT/FR2010/051287 patent/WO2011001071A1/fr not_active Ceased

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events