JP3050961B2 - Network system fault diagnosis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a failure diagnosis method for a network system which can easily detect a failure such as a disconnection of a network mounted on an automobile or the like or a disconnection of a connector of a control device connected to the network. .

[0002]

2. Description of the Related Art Hitherto, as one form of a bus applied to an on-vehicle network system, a multi-drop ring in which both ends of a multi-drop bus are short-circuited has been developed by the present applicant.

FIG. 5 is a diagram showing a schematic configuration example of a vehicle-mounted network system to which this kind of multi-drop ring is applied. In the figure, reference numeral 1 denotes a multi-drop ring composed of a two-wire bus such as a pair wire or a twisted pair wire. U1 to Un are multiplex units. The multiplex units U1 to Un exchange messages with each other by digital multiplex transmission via the multidrop ring 1, and control various auxiliary machines. Here, the various auxiliary devices are, for example, various electrical components provided in the vehicle, such as an engine control unit, a lighting device, or a wiper. Each of the multiplex units U1 to Un includes a control unit that controls various auxiliary devices (not shown) and a communication unit that performs message communication with another multiplex unit.

An output connector 2 is inserted into the bus line of the multidrop ring 1 and opens the line.
Reference numeral 3 denotes a short-circuit connector that is connected to the output connector 2 and short-circuits the bus line of the ring 1. The output connector 2 and the short-circuit connector 3 are usually combined as shown to form a multi-drop ring 1.

[0005] In a vehicle network system having such a configuration, for example, when a stop lamp switch is connected to the multiplex unit U1 and a stop lamp is connected to the multiplex unit U4, the multiplex unit U1 is stopped in response to brake pedal operation. Generates a message to instruct the lamp to light, and sends this message to Multi Drop Ring 1
To the multiplexing unit U4. On the other hand, the multiplex unit U4 controls lighting of the stop lamp according to this message. Note that the message sent from such a multiplex unit is
The ring 1 is transmitted clockwise as well as counterclockwise.

In the above-described on-vehicle network system, when a failure such as disconnection of the bus line of the multidrop ring 1 or disconnection of a connector connecting the bus line and the multiplex unit occurs, which part has a failure. It is necessary to check whether there is. In such a case, a failure diagnosis is performed using the failure diagnosis unit 7 shown in FIG. 6, and the failure location is detected.

As shown in FIG. 6, the failure diagnosis unit 7 includes communication units 7a and 7b and a control unit 7c for controlling the communication units 7a and 7b. Communication unit 7a,
7b transmits and receives messages to and from the multiplex units U1 to Un, respectively, and its input / output terminals are connected to the connector 8 as shown. This connector 8
It can be connected to the aforementioned output connector 2 (see FIG. 5). The control unit 7c includes a CPU (not shown) and an RO
M, a RAM, and an input / output interface, generate a failure diagnosis message, and supply it to the communication units 7a and 7b.

[0008] In order to inspect the fault location of the in-vehicle network system using the fault diagnosis unit 7 having the above configuration, first, the short-circuit connector 3 is detached from the output connector 2 and the connector 8 is replaced with the faulty connector. The diagnostic unit 7 is connected to a network. By doing so, this in-vehicle network has the connection form shown in FIG.

In such a connection state, the failure diagnosis unit 7 sends a failure diagnosis message to the multi-drop ring 1 counterclockwise and clockwise. That is,
In the connection form of FIG. 7, a message designating each multiplex unit is sequentially transmitted from the communication units 7a and 7b connected to the left end and the right end of the network. Then, based on the response results of the multiplex units U1 to Un obtained in response to these messages, a failure such as disconnection of the multidrop ring 1 or disconnection of a connector connecting the ring 1 and the multiplex unit is detected. It has become possible.

Note that such a failure diagnosis unit 7 is also called an off-board failure diagnosis device because it is not mounted on a vehicle. On the other hand, there is also a mode in which a failure diagnosis unit 7 having the same function as the multiplex units U1 to Un is connected to the multidrop ring 1. In this case, the unit 7
Are called on-board fault diagnostics.

[0011]

By the way, in the above-mentioned conventional failure diagnosis method, the disconnection on the multi-drop ring 1 constituting the on-vehicle network or the ring 1
Disconnection of a branch line connected to the multidrop ring 1 can be detected, but when the multi-drop ring 1 is formed of a two-wire bus such as a twisted pair line, it is not possible to distinguish which bus line is disconnected. There is.

Further, in order to distinguish a broken bus line by the conventional failure diagnosis method, a special transmission protocol is added to the network, for example, a communication protocol for failure diagnosis is newly defined. Would. Therefore, a simpler and less expensive diagnostic method than in the past is required in view of the easiness of network design and cost. The present invention has been made in view of the above circumstances, and has as its object to provide a simple and inexpensive failure diagnosis method for a network system, which can distinguish a disconnected bus line.

[0013]

According to the present invention, there is provided an annular bus formed by a first bus line and a second bus line, and a plurality of units connected to each line of the annular bus. In a network system comprising a multiplexing unit that multiplexes and transmits messages to each other via a ring bus, predetermined portions of the first and second bus lines are respectively opened, and each of the first and second bus lines is opened. A first step of applying a current from the open end to determine the connection state of the first and second bus lines; and in the first step, one of the first and second bus lines is in a disconnected state. Is determined, a message addressed to each of the multiplexing units is sequentially transmitted from the open end of the first bus line, and the multiplexing unit corresponding to the message is transmitted. A second step of receiving a response at the open end of the second bus line, a third step of specifying a broken line location on the bus line according to a response result from each of the multiplexing units, and In the process of the first and second
If it is determined that both bus lines are connected,
A message addressed to each of the multiplex units is sequentially transmitted from the open end of the first bus line, and a response from the multiplex unit in response to the message is sent to the open end of the second bus line. Receiving the first
And a fourth step of determining a connection state between the second bus line and each of the multiplex units.

[0014]

According to the failure diagnosis method of the present invention, the connection state of the bus line is determined by checking the energization. Here, when it is determined that the disconnection state has occurred, a message addressed to each of the multiplex units is sequentially transmitted from the open end of the first bus line, and a response from each of the multiplex units according to the message is sent. Is received at the open end of the second bus line. Then, a disconnection point on the bus line is specified according to a response result from each multiplex unit. On the other hand, when the connection state is determined, the connection state between the first and second bus lines and each of the multiplex units is determined according to the response result from each of the multiplex units.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of a vehicle-mounted network system according to an embodiment of the present invention. In this figure, parts corresponding to the respective parts shown in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 10 denotes a four-pole connector inserted into a two-wire multidrop ring 1 formed by a bus line A and a bus line B. This four-pole connector 10 typically has the configuration shown in FIGS.
The short connector 11 is connected as shown in FIG. That is, the short connector 11 provided with the short terminals 11a and 11b for shorting the bus line A and the bus line B is connected to the four-pole connector 10, thereby forming the multi-drop ring 1.

In the multi-drop ring 1 having the above configuration, when performing a network failure diagnosis, FIG.
As shown in (1), the short connector 11 is detached, and the diagnostic device 13 is connected via the connector 12 which is connected instead. The diagnostic device 13 includes a not-shown transmitting / receiving unit 13a, a control unit 13b, and a power supply unit 13c.

The transmitting and receiving unit 13a includes multiplex units U1 to U connected to the bus line A and the bus line B, respectively.
n and a message are exchanged. That is, when a message is exchanged via the bus line A,
A message is sent from the terminal Ta of the diagnostic device 13. On the other hand, when a message is exchanged via the bus line B, the message is transmitted from the terminal Tb of the diagnostic device 13.

Here, the message transmitted from the transceiver 13a includes data indicating the destination of the message. That is, in general digital multiplex transmission, a transmission signal carrying a message includes a data area for specifying a destination, and based on this, it is possible to specify multiplex units U1 to U4. on the other hand,
The multiplex units U1 to U4 that have received the message transmitted in this way transmit a response message on both the bus lines A and B. As a result, the diagnostic device 13 and each multiplex unit exchange messages via the following route. When a message is transmitted from the terminal Ta; the route goes from the terminal Ta → the bus line A → the multiplex unit → the bus line B → the terminal Tb. Hereinafter, this is defined as a first route. When transmitting a message from the terminal Tb; terminal Tb → bus line B → multiplex unit → bus line A →
It becomes the route of the terminal Ta. Hereinafter, this is defined as a second route.

The control unit 13b includes a CPU, a ROM and an R
A message to be transmitted is generated in accordance with the operation of a predetermined diagnostic program, and a network failure is determined from a response message received by the transmission / reception unit 13a. Also, the control unit 13b
Controls the energizing unit 13c, which will be described later, checks the energization of the bus line A and the bus line B, and determines whether or not these lines are disconnected. The energization unit 13c checks the energization of the bus line A by energizing the loop between the terminals Sa and Ta, and checks the energization of the bus line B by energizing the loop between the terminals Sb and Tb.

Next, a failure diagnosis method using the diagnostic device 13 having the above configuration will be described in the order of the diagnosis procedure. In this diagnostic method, first, the disconnection of the bus lines A and B serving as the trunk of the network is checked, and then the disconnection of the branch line connected to the bus lines A and B is checked. Hereinafter, these procedures will be sequentially described.

(A) Check for disconnection of the bus lines A and B In this case, the conduction of the bus lines A and B is checked by the conduction section 13c of the diagnostic device 13.
Here, if both the bus lines A and B are in the connected state, a branch wire disconnection check described later is performed. On the other hand, when the bus line is in the disconnected state, the following disconnection point determination is performed to identify the disconnection point.

Determination of Disconnection Location of Bus Line A When the bus line A is disconnected, the disconnection location is determined according to the determination pattern shown in FIG. In the determination pattern shown in the figure, the diagnosis A is the first route described above, that is, a message is transmitted from the terminal Ta of the diagnostic device 13 to the specified multiplex unit, and a message that is a response to the message is transmitted to the terminal. It refers to the case of receiving at Tb. On the other hand, the diagnosis B refers to a case where a message is transmitted from the terminal Tb of the diagnostic device 13 to the designated multiplex unit and a message corresponding to the message is received at the terminal Ta.

Then, a disconnection point is specified from a determination pattern that matches the result of message exchange between the diagnostic device 13 and each of the multiplex units U1 to U4 based on the diagnoses A and B. For example, when there is no response from the multiplex units U1 to U4, that is, when the determination patterns are all “x”
In this case, the disconnection point is determined to be "S1". here,
The disconnection point “S1” is connected to the diagnostic device 13 and the multiplex unit U1.
And between. On the other hand, when there are all responses from the multiplex units U1 to U4, that is, when the determination patterns are all
In this case, the disconnection point is determined to be “S5”. here,
The disconnection point “S5” means that the multiplex unit U4 and the diagnostic device 1
Between 3. Note that the disconnection point "S2" is between the multiplex units U1 and U2, and "S3" is the multiplex units U2 and U3.
, “S4” is between the multiplex units U3 and U4.

As described above, in the diagnosis method according to this embodiment, it is possible to specify which part of the bus line A has a disconnection from the determination pattern that matches the message exchange result based on the above-described diagnosis A and B. Become. Here, in order to increase the certainty of the diagnosis, the above-described diagnosis A,
Although both of B and B are performed, the disconnection can be determined by performing only one of the diagnosis A and the diagnosis B.

In this case, the determination of the disconnection location of the bus line A is performed in the same manner as the determination of the disconnection location of the bus line A. The determination pattern at this time is the same as that shown in FIG. "○" and "X" are opposite. That is, when the disconnection point is “S1”, there is a response from all of the designated multiplex units, and all the determination patterns become “○”. On the other hand, when the disconnection point is "S
At the time of "5", there is no response from the designated multiplex unit at all, and the judgment patterns are all "x".

(B) Disconnection Check of Branch Line Connected to Bus Lines A and B The disconnection check of the branch line is performed as follows. In other words, the disconnection check of the branch line connected to the bus line A is performed by sending a message from the terminal Ta of the diagnostic device 13 to the specified multiplex unit, and receiving a message corresponding to the message at the same terminal Ta. Is made. On the other hand, the disconnection check of the branch line connected to the bus line B
Diagnosis B 'is performed in which a message is transmitted from the terminal Tb of the diagnostic device 13 to the specified multiplex unit, and a message corresponding to the message is received at the same terminal Tb. In such a disconnection check, for example, if only a branch line connecting the multiplex unit U1 and the bus line A is disconnected, a response of the multiplex unit U1 cannot be obtained only in the diagnosis A '.

The diagnosis procedure described above is performed by the control unit 1
The diagnostic program is stored in the ROM 3b as a diagnostic program, and is read and executed by the CPU, thereby enabling automatic diagnosis. Further, in the in-vehicle network according to the above-described embodiment, when a reception response confirmation data area for a unit number is defined in the multiplex transmission signal itself, a response message can be stored in this data area. When such a multiplex transmission signal is used, there is no need to transmit a message specifying each multiplex unit, and the above-described diagnosis can be performed by one transmission / reception operation.

[0028]

As described above, according to the present invention, the connection state of the bus line is determined by the energization check, and when the disconnection state is determined, each of the multiplex units is opened from the open end of the first bus line. Are sequentially transmitted, and a response from each of the multiplex units corresponding to the message is received at the open end of the second bus line. Then, a disconnection point on the bus line is specified according to a response result from each multiplex unit. On the other hand, when the connection state is determined, the connection state between the first and second bus lines and each of the multiplex units is determined according to the response result from each of the multiplex units. As a result, a failure diagnosis method that can distinguish a disconnected bus line even with a simple and inexpensive configuration is provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment according to the present invention.

FIG. 2 is a view for explaining a connection state between a four-pole connector 10 and a short connector 11 in the embodiment.

FIG. 3 is a perspective view showing the structure of a four-pole connector 10 and a short connector 11 in the embodiment.

FIG. 4 is an exemplary view for explaining a determination pattern of the failure diagnosis method according to the embodiment.

FIG. 5 is a diagram for explaining a conventional example.

FIG. 6 is a diagram for explaining a conventional example.

FIG. 7 is a diagram for explaining a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Multi-drop ring, 10 ... 4-pole connector, 13 ... Diagnostic device, A, B ... Bus line, U1-U4 ... Multiple unit.

Claims (1)

(57) [Claims] 1. A circular bus formed by a first bus line and a second bus line, and a plurality of units connected to each line of the circular bus, wherein messages are transmitted to each other via the circular bus. And a multiplexing unit for multiplexing transmission, wherein predetermined portions of the first and second bus lines are respectively opened, and power is supplied from each open end of the first and second bus lines. A first step of determining a connection state between the first and second bus lines; and, if it is determined in the first step that any of the first and second bus lines is in a disconnected state, A message addressed to each of the multiplex units is sequentially transmitted from the open end of the first bus line, and a response from the multiplex unit corresponding to the message is transmitted to the second bus line. A second step of receiving the signal at the open end of the connection unit, a third step of specifying a disconnection point on the bus line according to a response result from each of the multiplex units, and a step of the first and second steps in the first step. When it is determined that both of the bus lines are in the connected state, a message addressed to each of the multiplex units is sequentially transmitted from the open end of the first bus line, and the respective buses corresponding to the messages are transmitted. Receiving a response from a multiplex unit at an open end of the second bus line and determining a connection state between the first and second bus lines and each of the multiplex units. Characteristic fault diagnosis method for network system.