FR2944661A1 - NON-INTRUSTIVE DEVICE FOR DIAGNOSING FAULT (S) OF OPERATION IN AT LEAST ONE COMMUNICATION NETWORK - Google Patents

Abstract

A device (D) is dedicated to fault diagnosis (s) of operation in at least one communication network (RC) having a bus (BU). This device (D) comprises i) connection means (MC1) adapted to be connected in shunt on the bus (BU) to access the voltages (V1, V2) present, ii) detection means (MD) arranged to analyze these voltages (V1, V2) in order to deliver a first signal (S1) representative of the state of presence of data in the network (RC) and a second signal (S2) representative of the operating state of the network (RC) iii) processing means (MT1) arranged to deliver from the first (S1) and / or second (S2) signals and / or third signals (S3 -S3), each representative of a comparison result between one of the voltages (V1, V2) and at least one reference voltage, at least one fourth signal (S4 -S4) representative of a fault or absence of a fault, and v) display means (MA1 ) arranged to signal each defect or absence of malfunction represented by a fourth signal (S4 -S4) delivered ed.

Description

The invention relates to devices for performing diagnostics in communication networks equipped with a bus on which voltages can be measured in such a way that they are able to perform diagnostics in communication networks equipped with a bus on which voltages can be measured in such a way that not intrusive. As known to those skilled in the art, certain communication networks of the aforementioned type include a bus to which are connected in parallel, via Zo a limited number of electrical son, communicating equipment. The data exchanges between communicating equipment are then done via the bus, by means of multiplexed frames. This is for example the case of CAN LS (Controller Area Network Low Speed), CAN HS (Controller Area Network High Speed), VAN (Vehicle Area Network) 15 or LIN (Local Interconnect Network) networks. Such networks are used in many fields, and in particular in the field of vehicles (possibly of the automotive type). Many malfunctions (or failures) can occur in such networks, such as a short circuit between an electrical wire carrying data and a ground, a short circuit between an electrical wire carrying data and a voltage d a power network (for example of a vehicle), a short circuit between two electrical wires carrying data and the breaking of an electrical wire carrying data. It will be appreciated that the larger the network, the more difficult it is to diagnose the cause of a malfunction. As a result, it has been proposed to use diagnostic devices (or tools) to facilitate fault detection. Such devices are in particular described in the documents US Pat. No. 5,491,418, US Pat. No. 4,975,847, US Pat. No. 4,796,206, FR 2666418 and EP 0231607. These diagnostic devices have a certain number of disadvantages, such as the need to establish with the network a bidirectional communication in accordance with a predefined and therefore intrusive protocol, and / or the need to use calculators and / or the need to perform complex programming and / or congestion and / or the need to be used by previously trained technicians. The invention therefore aims to provide a non-intrusive alternative solution, delivering a diagnosis instantly, and moreover (very) little space and / or reduced cost and / or particularly simple to use. It proposes more specifically for this purpose a device, dedicated to fault diagnosis (s) of operation in at least one communication network having a bus, and comprising: - connection means suitable for being connected bypass on the bus for accessing the voltages present, detection means arranged to analyze the voltages present in order to deliver a first signal representative of the state of presence of data in the network and a second signal representative of the operating state of the network; processing means arranged to deliver, from the first and / or second signals and / or third signals, each representative of a comparison result between one of the voltages present and at least one reference voltage, at least one fourth signal representative of a defect or absence of defect, and - display means arranged to signal each defect or absence of defect d e operation represented by a fourth signal delivered. The term "faulty operation" is understood to mean both the absence of data on the bus and the detection of abnormal operation of the network or of a problem or malfunction of a particular type. Furthermore, the term "absence of malfunction" is understood here to mean the presence of data on the bus as well as the detection of normal operation of the network or the absence of a problem or malfunction of a particular type.

The diagnostic device according to the invention can comprise other characteristics that can be taken separately or in combination, and in particular: its processing means can comprise i) comparison means arranged to compare at least one of the voltages present on the bus at a reference voltage to provide at least a third signal representative of the result of a comparison, and ii) analysis means arranged to deliver from said first and / or second and / or third (s) signals at least a fourth signal representative of a defect or absence of defect; the comparison means may comprise at least one differential amplifier with high input impedance comprising at least one input able to receive a voltage and at least one output able to deliver a third signal; the analysis means may comprise at least one set of electronic component (s) defining a logic gate able to receive said first and / or second signals and / or at least one of the third signals, and to deliver a fourth signal; its detection means can be arranged in the form of an integrated circuit comprising a first state machine arranged to analyze the voltages present in order to deliver the first signal, and a second state machine arranged to analyze the voltages present so as to to deliver the second signal; in a variant, its detection means may be arranged in the form of an integrated circuit comprising a state machine arranged to analyze the voltages present in order to deliver the first and second signals; its display means may comprise at least one indicator light associated with a fourth signal and arranged to be placed in an on state or an off state according to the value of the fourth associated signal; it may comprise amplification means mounted upstream of the display means and arranged to generate currents suitable for placing each indicator light in its on or off state according to the value taken by the fourth associated signal; • the amplification means may comprise at least one transistor amplifier having an input adapted to receive a fourth signal and an output connected to a light indicator for the power supply; it may comprise delay means interposed between the processing means and the display means and arranged to maintain each fourth signal at its initial value for a selected time delay, so that each fault or absence of malfunction is signaled for at least this delay time; the delay means may comprise at least one monostable recloser circuit with capacitor (s); it may comprise complementary connection means adapted to be connected in shunt to a voltage supply source for supplying the sampled voltage; it may comprise regulating means suitable for being connected to the complementary connection means so as to regulate the withdrawn supply voltage in order to deliver a regulated voltage. The invention is well adapted, although not limited to, communication networks of the type said fault tolerant. Furthermore, the invention is well adapted, although not limited to vehicles, possibly of automotive type. Other features and advantages of the invention will appear on examining the detailed description below, and the accompanying drawings, in which: FIG. 1 diagrammatically and functionally illustrates an embodiment of a diagnostic device according to FIG. invention, connected to a CAN LS type communication network and to an external battery, - Figure 2 schematically and functionally illustrates an embodiment of processing means, delay means, amplification means and display means; a diagnostic device according to the invention, and - Figure 3 schematically illustrates an example of arrangement of LEDs display means of a diagnostic device according to the invention. The attached drawings 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 diagnostic device (D) intended to be connected to at least one communication network (RC) equipped with a bus (BU), to which are connected in parallel, via a limited number of electric wires, communicating equipment, and on which voltages can be measured in a non-intrusive manner.

In the following, we consider, by way of non-limiting example, that the communication network (RC) is a CAN LS type network (Controller Area Network Low Speed). However, the invention is not limited to this type of communication network. It concerns indeed any type of communication network equipped with a bus allowing non-intrusive voltages measurements, and in particular the CAN HS (Controller Area Network High Speed), Vehicle Area Network (VAN) and LIN (Local Interconnect) networks. Network). The invention particularly relates to land vehicles, boats and airplanes. It is recalled here that a CAN LS type network (ISO 11898 standard) is a fault tolerant network, that is to say that can ensure a complete multiplexed data frame transmission and in a predefined time, including in the presence of malfunctions in their physical layer (according to the OSI model of protocol layers). The bus (BU) of such a network (RC) comprises first and second electrical son dedicated to the transport of data frames and respectively called CANL and CAN H. Furthermore, it is considered in the following, by way of non-limiting example, that the network (RC) is part of a vehicle, possibly of automotive type (such as a car). But, the invention is not limited to this application. In addition, it is considered in the following, by way of non-limiting example, that the diagnostic device (D) is intended to perform diagnostics for only one type of network. But, this is not mandatory. It could indeed be arranged to perform diagnostics for at least two different types of network. FIG. 1 shows schematically a network (communication) RC equipped with a bus BU which is connected in parallel with an exemplary embodiment of a diagnostic device D according to the invention. The network here being of the CAN LS type, its bus BU comprises a first electrical wire CL, dedicated to the transport of data frames and usually called CAN_L, and a second electrical wire CH, also dedicated to the transport of data frames and usually called CAN_H . As illustrated, such a diagnostic device D comprises at least connection means MC1, detection means MD, processing means MT1 and MAY display means which cooperate with each other. The connection means MC1 are arranged so as to allow the branch connection of their (diagnostic) device D to the bus BU, in order to access the voltages Vi which are present on the bus BU. Here, the index i takes the values 1 and 2, associated respectively with the electric wires CH and CL, because the bus BU comprises two electric data transport wires.

These connection means MC1 comprise, for example, two electrical connection cables, each provided, at one of their two opposite ends, with a connector, for example of the crocodile clip type or contact tip (insertable into a cell of BU bus connector).

It will be noted that, as shown in a nonlimiting manner, the device D can also and possibly also include complementary connection means MC3 intended to be connected in shunt to a voltage supply source BA for supplying the elements which constitute the device D to the sampled voltage. In the case of a car, the voltage supply source BA is for example the 12-volt battery on board. These complementary connection means MC3 comprise, for example, two electrical connection cables, each provided, at one of their two opposite ends, with a connector, for example of the crocodile clip type or the touch point, which is just connect to the plus (+) terminal of the BA battery or to a vehicle ground screw. It is important to note that in one variant the device D could include an internal power source, for example a rechargeable battery, provided that it keeps a wire connected to a ground screw of the vehicle. Note also that when the device D does not include an internal power source, it is advantageous, as illustrated without limitation, that it comprises regulating means MR connected to the ends of the electrical connection cables (complementary connection means MC3), which are opposite to those provided with connectors. These regulation means MR are arranged so as to regulate the supply voltage which is taken by the complementary connection means MC3 on the external power supply source BA, in order to supply regulated voltage to the elements which constitute the device D. The detection means MD are arranged to analyze the voltages Vi which are taken by the connection means MC1. To do this, they may for example be connected to the ends of the electrical connection cables (connection means MC1), which are opposite to those provided with the connectors. These detection means MD are arranged to deliver, on the one hand, a first signal S1 (or RX) which is representative of the state of presence of data in the network RC (and more specifically on its bus BU), and of on the other hand, a second signal S2 (or ERR (for error)) which is representative of the operating state of the network RC.

The first signal S1 (or RX) is more precisely representative of the instantaneous binary state of the network RC as regards the presence or absence of data frames on its bus BU. It is preferably an analog signal (such as a voltage) that can take two different values.

The second signal S2 (or error signal (ERR)) is more precisely representative of the instantaneous operating state of the RC network (network apparently operating normally or not operating normally (in error)). It is preferably an analog signal (such as a voltage) that can take two different values. As illustrated without limitation in FIG. 1, the detection means MD may for example be arranged in the form of an integrated circuit. For example, the latter may comprise, on the one hand, a first state machine ME1 arranged to analyze the voltages sampled Vi (here V1 and V2) in order to deliver a first signal S1, and on the other hand, a second machine state ME2 arranged to analyze the voltages taken Vi (here V1 and V2) in order to deliver the second signal S2. Such an integrated circuit MD may for example be what the skilled person sometimes calls a golden component. These state machines ME1 and ME2 are configured (possibly programmed) according to each type of RC network that its device D must diagnose. In other words, state machines ME1 and ME2 are configured according to selected (preferably standardized) definitions of data presence states (or data receiving states) and operating states or malfunctions (errors). of the considered RC network. Note that in an alternative embodiment, the integrated circuit may comprise only one state machine having two inputs for receiving the present voltages Vi and two outputs for delivering the first S1 and second S2 signals. The processing means MT1 are arranged to deliver at least a fourth signal S4j which is representative of a fault or absence of a fault within the network RC, from the first S1 and / or second S2 signals and / or third signals S3; k which are generated internally. Each of these (S3; k) is more precisely representative of the result of a comparison made internally (by MT1) between one of the sampled voltages Vi and a reference voltage Vrik. Here, by default, the absence of data on the bus BU as well as the detection of abnormal operation of the RC network or of a problem or malfunction of a particular type are understood as meaningless. Furthermore, the term "absence of malfunction" is understood here to mean the presence of data on the bus BU as well as the detection of normal operation of the RC network or the absence of a problem or malfunction of a particular type. For example, the processing means MT1 compare: the first sampled voltage V1 to a first reference voltage Vol which is an intermediate value voltage, in order to deliver a first third signal S311, the first sampled voltage V1 to a second voltage reference Vr12 which is a maximum voltage, in order to deliver a second third signal S312, - the first sampled voltage V1 to a third reference voltage Vr13 which is a minimum voltage, in order to deliver a third third signal S313, - the second voltage taken V2 at a fourth reference voltage Vr24 which is an intermediate value voltage, in order to deliver a fourth third signal S321, - the second sampled voltage V2 to a fifth reference voltage Vr25 which is a maximum voltage, in order to deliver a fifth third signal S322, the second voltage sampled V2 at a sixth reference voltage Vr26 q ui is a maximum voltage, in order to deliver a sixth third signal S323. The number of third signals S3; k determined internally by the processing means MT1 is not necessarily equal to 6. It depends in fact on the number of voltages taken Vi and the number of voltage thresholds (or reference voltages ) for defining the operating faults that can be detected by the device D. As is illustrated in Figures 1 and 2, the processing means MT1 may comprise comparison means MC1 responsible for performing the different comparisons (and therefore to determine the third signals S3; k) and analysis means MA2 responsible for delivering at least a fourth signal S4i from the first S1 and / or second S2 signals delivered by the detection means MD and / or one or more third signals S3; k.

As illustrated in FIG. 2, the comparison means MC1 can be arranged in the form of parallel sub-modules, each responsible for performing one of the comparisons. Each sub-module may, for example, comprise a differential amplifier with a high input impedance comprising at least one input able to receive a sampled voltage Vi and at least one output able to deliver a third signal S3; k. The high input impedance makes it possible not to disturb the RC network. In the case of a CAN LS type network, the device D can for example diagnose six operating defects among those listed below: - abnormal operation of the RC network, - the absence of frames of data on the bus BU, - a short circuit between the electric wire CL and a ground, - a short circuit between the electric wire CH and a ground, - a short circuit between the electric wire CL and a voltage of the power network of the vehicle - a short circuit between the electric wire CH and a voltage of the power network of the vehicle, - a short circuit between the two electrical wires CL and CH, - the cutting of the electric wire CL, - the breaking of the electric wire CH . In the nonlimiting example illustrated, the analysis means MA2 are for example arranged to deliver: a first fourth signal S41 representative of a normal or abnormal operation of the network, from the signal S2 and no third signal S3; k, - a second fourth signal S42 representative of the presence or absence of data frames, from the first S1 and second S2 signals and no third signal S3; k, - a third fourth signal S43; representative of the presence or absence of a short-circuit fault between the electric wire CL and a voltage of the power network, from the first S1 and second S2 signals and a first third signal S311, a result of the comparison of the voltage on the wire CL with a reference voltage Vol can discriminate the logic states on the wire CL, and so that the analysis module MA2 can check the consistency of these states with those of the signal S1 in the ca s where the latter corresponds, in normal operation, to a voltage on the wire CL less than said reference voltage Vol, - a fourth fourth signal S44 representative of the presence or absence of a short-circuit fault between the electrical wire CH and a voltage of the power network, from the first S1 and second S2 signals and a second third signal S321, resulting from the comparison of the voltage on the wire CH with a reference voltage Vr21 which can discriminate the states logic on the CH wire, and so that the analysis module MA2 can check the consistency of these states with those of the signal S1 in the case where the latter corresponds, in normal operation, to a voltage on the wire CH less than said voltage reference Vr21, a fifth fourth signal S45 representative of the presence or absence of a short-circuit fault between the electric wire CL and a mass, from the first S1 and second S2 signals and a third third signal S312, resulting from the comparison of the voltage on the wire CL with a reference voltage Vol which can discriminate the logic states on the wire CL, and so that the analysis module MA2 can verify the coherence of these states with those of the signal S1 in the case where the latter corresponds, in normal operation, to a voltage on the wire CL greater than said reference voltage Vol, - a sixth fourth signal S46 representative of the presence or the absence of a short-circuit fault between the electric wire CH and a ground, from the first S1 and second S2 signals and a fourth third signal S322, result of the comparison of the voltage on the wire CH with a voltage reference Vr21 can discriminate the logic states on the wire CH, and the module MA2 checks the consistency of these states with those of the signal S1 in the case where the latter corresponds, in normal operation, to a e voltage on the CH wire greater than said reference voltage Vr21.

Note that it is possible for a fourth signal S4i to be determined as a function of the first S1 and / or second S2 signals and at least two third signals S3; k. As illustrated in FIG. 2, the analysis means MA2 may be arranged in the form of parallel sub-modules, each responsible for performing a signal analysis S1 and / or S2 and / or S3; k. At least one of these submodules may for example comprise a set of at least one electronic component which defines a logic gate adapted to receive the first S1 and / or second S2 signals and / or at least one of the third S3; k signals, and to deliver a fourth signal S4i. A logic gate can thus comprise an input and an output, or two inputs and an output, or three inputs and one output, or four inputs and one output. The MAY display means are arranged to signal to the users each fault or absence of malfunction represented by a fourth signal S4i delivered. These display means MAI may for example be located in a front of a box BO of the device D, in which are housed the detection means MD, the processing means MT1, the possible control means MR, and possible timing means MT2 and possible MA3 amplification means to which we will return later. As shown in FIGS. 2 and 3, the display means M1 may, for example, comprise at least one indicator light VLj associated with a fourth signal S4i, and therefore with a malfunction (as well as with its complement (FIG. absence of malfunction)). Each LED VLi can for example be arranged in the form of a light emitting diode (or LED) can be placed in a lit state or an off state according to the value of the fourth signal S4i associated. Each indicator light VLj can protrude on the side of an external face (visible) of the front of the BO box in order to be easily observed by its user.

In the nonlimiting example illustrated in FIGS. 2 and 3, the display means MAI comprise six LEDs VL1-VL6 (j = 1 to 6) associated respectively with the six fourth signals S41-S46. As indicated above, the number of indicator lights VLj depends mainly on the number of fourth signals S4i that are delivered by the processing means MT1. For example: - the VL1 LED indicates normal operation of the RC network when it is switched on and abnormal operation of the RC network when it is off, - the VL2 LED indicates the presence of data frames in the BU bus when it is switched on and the absence of data frames in the bus BU when it is off, - the signal light VL3 signals a short circuit between the electric wire CL and a voltage of the vehicle power network when it is switched on and the absence of a short circuit between the electric wire CL and a voltage of the vehicle power network when it is switched off, - the warning light VL4 signals a short circuit between the electric wire CH and a voltage of the power supply network. the power of the vehicle when it is switched on and the absence of a short-circuit between the electric wire CH and a voltage of the vehicle power network when it is switched off, - the warning light VL5 signals a short circuit between the electric wire CL and a ground when it is on and the absence of a short circuit between the electric wire CL and a ground when it is off, - the indicator light VL6 signals a short circuit between the electric wire CH and a mass when it is on and the absence of short circuit between the electric wire CH and a mass when it is off. The device D may optionally include at least one additional indicator light, to signal at least one additional function, such as for example the fact that it is connected (or in operation, and therefore usable) or disconnected (or out of operation, and therefore unusable). It is important to note that the display means MAY may be in other forms than that presented above (VLj lights). Indeed, they may for example comprise a display screen (for example LCD (or LCD)) for displaying messages for signaling each operating fault associated with a fourth signal S4i. In this case, the display means M1 must also comprise conversion means responsible for converting each fourth signal value S4i into a displayed message. Note that a displayed message may optionally be accompanied by an equivalent or identical synthetic sound message. It will also be noted that the device D may optionally comprise timing means MT2 interposed between its processing means MT1 and its display means MA1 and arranged so as to maintain each fourth signal S4i at its initial value for a duration of selected delay. More specifically, these delay means MT2 are loaded when they receive a fourth signal S4i of a given value of delivering on their output (s) the same value given during the delay time. Thus, each fault or absence of malfunction can be signaled during at least the delay time. This timeout time may be chosen to be greater than the duration of the average retinal persistence of the human eye. This option is intended to allow a user to visualize the switching on or off of a light indicator VLj including when the processing means MT1 generate the fourth signal S4i associated for a very short time due to a defect of intermittent operation (e.g. related to false contact or transient vibration). This delay may possibly only concern the display of the presence of a fault. For example, we can choose a delay time at least equal to about 40 ms. These delay means MT2 may for example comprise at least one monostable recloser circuit with capacitor (s) associated with at least one fourth signal S4i. This type of circuit rapidly charges a capacitor at the beginning of the delay and slowly discharges this capacitor, the difference in speed between the charge and the discharge being obtained by means of a diode which is conducting during charging. It will also be noted that the device D may optionally comprise amplification means MA3 mounted upstream of the display means MA1, and preferably between the possible delay means MT2 and the display means MA1, and arranged in such a way as to generating currents which are adapted to (or capable of) placing each LED VLj in its on or off state according to the value taken by the associated fourth signal S4i. These amplification means MA3 may for example comprise at least one transistor amplifier ATj having an input capable of receiving a fourth signal S4i via the possible delay means MT2 and an output connected to a light indicator VLj for powering it ( and therefore control its operation). In the foregoing, functional blocks comprising comparison means (or module) MC2, possible timer means (or module) MT2 and any means (or module) for amplification MT2, coupled to each other, have been presented. . But, these functional blocks can be subdivided into parallel modules distributed in different cells (possibly arranged in the form of integrated components). One can indeed consider making cells operating in parallel and each associated with a malfunction. In this case, each cell may for example comprise a submodule of the comparison means MC2, a submodule of the possible timing means MT2 and a submodule of the possible amplification means MT2. However, at least one of the sub-modules of the comparison means MC2 may possibly be used by several sub-modules of the analysis means MA2 in order to simplify the internal design of the device D. It will also be noted that the device D may possibly include one or more electrical protection blocks to prevent damage in the event of an error of use (for example a polarity inversion) or in case of electrical disturbances induced by voltages taken (Vi) abnormally important . Note also that the device D is not only non-intrusive, but also passive type insofar as it does not transmit data to the RC network and only observes the voltages Vi that are present on its bus BU . The use of the device D is particularly simple. Once the user has connected in branch on the network RC (and more precisely on its bus BU) with its means of connection MC1, as well as possibly to the external battery BA with its complementary connecting means MC3, it delivers immediately results via its MAY display means.

If a malfunction is indicated by the display means MAY, then the user can disconnect from the network RC an organ to determine if it is at the origin of this malfunction. Each malfunction can correspond in a predetermined manner (for example in a correspondence table) at least one suspect organ. If this is the case and the device D not only does not report any other malfunction but now signals normal operation, the diagnosis is completed and the suspect organ is to be examined. If the disconnected device is not the cause of the malfunction, the user reconnects it to the RC network and disconnects from the latter (RC) another organ, until it determines the one (or those ) which is (are) the cause of the reported operating fault (s). Note that if one (or) defect (s) is (s) at the son of the network RC (pinched or cut son), the same method can be applied.

It should also be noted that these connection / disconnection operations are generally called load shedding. In the presence of multiple malfunctions, the device D signals normal operation once all the organs causing a malfunction have been disconnected. As long as a member causing one of the malfunctions remains connected, the device D continues to signal a malfunction. The invention is not limited to the embodiments of diagnostic device described above, only by way of example, but it encompasses all the variants that may be considered by those skilled in the art within the scope of the claims below. after.

Claims (15)

REVENDICATIONS1. Device (D) for diagnosing malfunction (s) in at least one communication network (RC) having a bus (BU), characterized in that it comprises i) connection means (MC1) adapted to be connected in shunt on said bus (BU) to access the voltages (Vi) present, ii) detection means (MD) arranged to analyze said voltages (Vi) in order to deliver a first signal (Si) representative of the state of presence of data in said network (RC) and a second signal (S2) representative of the operating state of said network (RC), iii) processing means (MT1) arranged to deliver from said first (Si) and / or second (S2) signals and / or third signals (S3ik), each representative of a comparison result between one of said voltages (Vi) and at least one reference voltage (Vrik), at least one fourth signal (S4i) representative of a defect or absence of defect, and iv) means of display (MAI) arranged to signal each fault or absence of malfunction represented by a fourth signal (S4i) issued. 2. Device according to claim 1, characterized in that said processing means (MT1) comprise i) comparison means (MC2) arranged to compare at least one of the voltages (Vi) present on said bus (B) to a reference voltage (Vrik) for delivering at least one third signal (S3ik) representative of the result of a comparison, and ii) analysis means (MA2) arranged to output from said first (Si) and / or second (S2) and / or third (S3ik) signals at least one fourth signal (S4i) representative of a fault or absence of a fault. 3. Device according to claim 2, characterized in that said comparison means (MC2) comprise at least one differential amplifier with high input impedance comprising at least one input adapted to receive a voltage (Vi) and at least one output of its own. delivering a third signal (S3ik). 4. Device according to one of claims 2 and 3, characterized in that said analysis means (MA2) comprise at least one electronic decomposant assembly (s) defining a logic gate adapted to receive said first (Si) and / or second (S2) signals and / or one of said third signals (S3ik), and outputting a fourth signal (S4i). 5. Device according to one of claims 1 to 4, characterized in that said detection means (MD) are arranged in the form of an integrated circuit comprising a first state machine (ME1) arranged to analyze said voltages ( Vi) to output said first signal (Si), and a second state machine (ME2) arranged to analyze said voltages (Vi) to output said second signal (S2). 6. Device according to one of claims 1 to 4, characterized in that said detection means (MD) are arranged in the form of an integrated circuit comprising a state machine arranged to analyze said voltages (Vi) in order to delivering said first signal (Si) and said second signal (S2). 7. Device according to one of claims 1 to 6, characterized in that said display means (MAI) comprise at least one indicator light (VLj) associated with a fourth signal (S4i) and arranged to be placed in a state on or off depending on the value of said associated fourth signal (S4i). 8. Device according to claim 7, characterized in that it further comprises amplification means (MA3) mounted upstream of said display means (MAI) and arranged to generate clean currents to place each indicator light (VLj ) in its on or off state according to the value taken by the associated fourth signal (S4i). 9. Device according to claim 8, characterized in that said amplification means (MA3) comprise at least one transistor amplifier having an input adapted to receive a fourth signal (S4i) and an output connected to a warning light (VLj). to power it. 10. Device according to one of claims 1 to 9, characterized in that it further comprises timing means (MT2) interposed between said processing means (MT1) and said display means (MAI) and arranged for maintain each fourth signal (S4i) at its initial value for a selected time delay so that each fault or absence of malfunction is signaled for at least said time delay. 11. Device according to claim 10, characterized in that said timing means (MT2) comprise at least one monostable recloser circuit capacitor (s). 12. Device according to one of claims 1 to 11, characterized in that it further comprises complementary connection means (MC3) adapted to be connected in shunt on a voltage supply source (BA) for supplying said device (D) in tension taken. 13. Device according to claim 12, characterized in that it further comprises regulating means (MR) adapted to be connected to said complementary connection means (MC3) so as to regulate the supply voltage taken to deliver a voltage regulated. 14. Use of the diagnostic device (D) according to one of claims 1 to 13 for a communication network of the type said fault tolerant. 15. Use according to claim 14 in a motor vehicle.