JP3310021B2 - Multiplex transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex transmission apparatus, and more particularly, to a multiplex transmission apparatus in which a plurality of control units are connected to a common multiplex transmission line to transmit and receive signals between the control units via the multiplex transmission line. About.

[0002]

2. Description of the Related Art In recent automobiles, various controls have been digitized in accordance with the rapid progress of electronics technology, and new electronic components have been increased in order to increase user requirements and added value. It tends to be mounted.
In this case, control signals are transmitted to each device using a wire harness in which a large number of electrical wirings are bundled. However, as electronics become more advanced, the wire harness becomes bloated, and the installation space is secured. And the layout tended to be difficult.

In order to solve the above-mentioned problems, a multiplex transmission system has been developed in which multiplex communication technology is applied to an automobile, as disclosed in, for example, Japanese Patent Application Laid-Open No. 64-143533. In this type of system, a plurality of control units to which various electric loads and sensors are connected are connected by a common multiplex transmission line, and signals are exchanged between the control units via the multiplex transmission line. Based on this, the operation of the electric load or the like is controlled. According to this, a plurality of control units are connected by a common multiplex transmission line, so that a larger number of signal lines are omitted as compared with the related art, and the enlargement of the wire harness that bundles these is suppressed. As a result, the wiring harness is simplified, a space for disposing the wiring harness can be secured, and the wiring harness can be appropriately laid out.

[0004]

By the way, in the above-described multiplex transmission apparatus for a vehicle, for example, after all the control units have been started, a plurality of electric loads are simultaneously operated so that the power supply voltage is temporarily reduced. If a particular control unit of the plurality of control units is once shut down due to the voltage drop, the unit is reset to erase its own data. . In this case, when the drop of the power supply voltage is resolved and the specific control unit that has once shut down the system is restarted, a return signal indicating its own return is transmitted from the specific control unit to all other control units. And, from each control unit that has received the return signal, a return confirmation signal is transmitted to the restarted specific control unit, and immediately after the restart of the specific control unit, A signal for confirming the return is exchanged between the unit and all other control units. For this reason, the communication amount between the control units immediately after the restart of the specific control unit once the system has been down for some reason, that is, the traffic amount temporarily increases, and the transmission and reception of the signal is reliably performed. Therefore, a reception error may occur in some control units.

Usually, when a reception error occurs in a certain control unit, the source control unit repeatedly transmits data to the control unit at a predetermined cycle. In this case, a signal for eliminating a reception error is repeatedly transmitted, and the traffic volume is further increased, which may hinder transmission and reception of other data signals.

Accordingly, the present invention relates to a multiplex transmission apparatus in which a plurality of control units are connected to a common multiplex transmission path and exchange signals between the control units via the multiplex transmission path. By suppressing the increase in the traffic volume, particularly when the specific control unit of the plurality of control units is restarted after the system down, the reception error caused by the traffic volume increase can be reduced. An object of the present invention is to prevent signals from being transmitted and received between control units.

[0007]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized in that it is configured as follows.

First, the invention according to claim 1 of the present application (hereinafter referred to as “the invention”)
The present invention provides a multiplex transmission apparatus in which a plurality of control units are connected to a common multiplex transmission line and signals are exchanged between the control units via the multiplex transmission line. A specific control unit that has once gone down is provided with return signal transmitting means for transmitting a return signal at the time of restart, while a predetermined control unit of the other control units except the specific control unit is provided with:
A receiving unit for receiving the return signal; and a transmitting unit for transmitting a return confirmation signal for confirming the return to a specific control unit that has been once shut down and restarted when the return signal is received by the receiving unit. At the same time, the restarted specific control unit receives a return confirmation signal from the predetermined control unit and determines whether or not it returns to its normal state.
After judging the return to normal,
Other than the own unit.
Transmit to the control unit and exchange data with the other control unit.
Data restoration signal transmission / reception means for receiving data restoration signal
Characterized in that a and.

[0009]

[0010]

According to the present invention, in a specific control unit that has once gone down the system among a plurality of control units,
Transmits a return signal at restart, while keep <br/> a predetermined control unit of the control units other than said specific control unit, upon receipt of the return signal, once After the system down A return confirmation signal is transmitted to the restarted specific control unit. Then, the restarted specific control unit determines its own normal recovery by receiving the reception confirmation signal.

As described above, when a specific control unit of the plurality of control units is restarted after the system goes down, the communication between the specific control unit and one of the control units other than the specific control unit is started. A signal for confirming the return is transmitted and received, and one of the control units confirms the return of a specific control unit on behalf of all the other control units.
As in the prior art, when a specific control unit that has once gone down is restarted, a signal for confirming the return is not sent and received between the specific control unit and all other control units. Accordingly, an increase in the traffic volume immediately after the restart of the specific control unit is suppressed, a reception error is prevented, and signals are reliably transmitted and received between the control units.

When a specific control unit that has been system-down has been restarted, a signal for data restoration accompanying the system-down is exchanged between the specific control unit and another control unit. As a result, the traffic volume may temporarily increase and a reception error may occur. However, according to the present invention, the transmission and reception of the signal for data restoration damaged by the system down is performed in the case where the restart is performed. Between the control unit and a predetermined control unit of the plurality of control units, that is, only between the control unit and the predetermined control unit that needs to transmit and receive signals to and from the specific control unit. Therefore, an increase in the traffic volume immediately after the restart of the specific control unit is further suppressed, so that a reception error is prevented, and So that the transfer of signals between the units is carried out more reliably.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, a case where the multiplex transmission apparatus according to the present invention is applied to an automobile will be described.

FIG. 1 is a schematic diagram showing the overall configuration of a multiplex transmission apparatus according to the present embodiment. This multiplex transmission apparatus 1 includes a multiplex consisting of one or two twisted pair lines or the like formed in a loop. A plurality of control units, for example, first to sixth control units 3 to 8 are respectively connected to a transmission line (multiplex communication line) 2, and signals are exchanged between the control units 3 to 8. It is.

The first control unit 3 controls the operation of the engine such as controlling the fuel injection amount, fuel injection timing, intake air amount, and the like. The second control unit 4 includes: The third control unit 5 is a control unit for performing anti-skid control for improving braking performance, and the traction control for improving traction stability and riding comfort. Furthermore,
The fourth control unit 6 is a control unit for controlling the operation of a lamp system and an alarm device provided on the right front of the vehicle body, and the fifth control unit 7 is a lamp system provided on the left front of the vehicle body. The sixth control unit 8 is a control unit for controlling various switches and indicators provided around the steering column.

The first control unit 3 is connected to sensors such as an air flow meter, an engine rotation sensor, and a water temperature sensor, and serves as an actuator for controlling a fuel injection amount, a fuel injection timing, an intake air amount, and the like. Various electric loads are connected, and the second control unit 4
Is connected to an acceleration for detecting deceleration at the time of vehicle braking, and an electric load as various actuators including a hydraulic control valve provided in a hydraulic circuit for brake for performing anti-skid control. Is connected. The third control unit 5 is connected to a vehicle height sensor and the like for detecting a vehicle height, and includes a control valve and the like for controlling supply and discharge of fluid pressure to a damper of a suspension device for performing traction control. The first control unit 6 is connected to a front turn signal lamp, a fog lamp, a small lamp, and a switch for lighting or blinking them, which are provided on the front right side of the vehicle body. The fifth control unit 7 is connected to a front turn signal lamp, a fog lamp, a small lamp, and switches for lighting or blinking them, which are provided on the front left side of the vehicle body. Further, the sixth control unit 8 is connected to various indicators indicating the lighting state of each lamp, the engine water temperature, and the like.

The first to sixth control units 3 to
8 is supplied with the power supply voltage from the battery directly or when the accessory switch or the ignition switch is turned on, so that each control unit is activated.

In this embodiment, the first to sixth control units 3 to 8 are connected to the multiplex transmission line 2, but the number of control units connected to the multiplex transmission line 2 is as follows. Not limited to six, the first to sixth
In addition to the control units 3 to 8, for example, a control unit or the like for performing four-wheel steering control for improving steering stability can be connected as necessary.

Here, a specific configuration of the first to sixth control units 3 to 8 will be described with reference to FIG. Although FIG. 2 shows a specific configuration of the first control unit 3, the other control units 4 to 8 have the same configuration as the first control unit 3. The configuration will be described in detail, and the description of the specific configuration of the other control units 4 to 8 will be omitted.

As shown in FIG. 2, the first control unit 3
Is connected to the multiplex transmission line 2 via a connector 10, and an information signal transmitted from the other control units 4 to 8 via the multiplex transmission line 2 is transmitted to a reception control unit 11a which is a multiplex interface module. The signal received and converted by the reception control unit 11a is input to the controller 12 and subjected to logical operation processing. At the same time, the signal output from the controller 12 to the transmission control unit 11b composed of a multiplex interface module is converted. The data is transmitted to the other control units 4 to 8 via the multiplex transmission line 2. Further, various switches and sensors 14 and various electric loads 15 are connected to the controller 12 through an input / output interface 13, and signals from the various switches and sensors 14 are input to the controller 12. The controller 12 outputs signals for controlling various electric loads 15.

By the way, in the present embodiment, the first
As information signals transmitted from the sixth to sixth control units 3 to 8, various types of information are transmitted for each frame F having a configuration as shown in FIG. This frame F
Are SOM code, priority / destination address code, ID code, VALID / INVALID code,
The frame has a data area, an EOD code, an ACK area, and an EOM code.

The SOM code is a code indicating the start of the frame F, and each of the control units 3 to 8
By receiving the M code, the start of the frame F is recognized. In the priority / destination address code, the priority is a priority which indicates which signal is to be processed with priority when signals are transmitted simultaneously from a plurality of control units 3 to 8 and collision occurs. It shows. On the other hand, the destination address indicates a control unit of a transmission destination to which a signal is to be transmitted. Further, the ID code is a code indicating the contents of the data of the frame F, and the control units 3 to 8 can know the contents of the data area of the frame F from the ID code. Also, VALID / INVA
The LID code is a code indicating whether data to be transmitted is valid or invalid. In the data area, the number of various types of data, the contents of each data, and the like are indicated.
This code indicates the end of data. Further, the ACK area is an area for determining whether or not the transmission and reception of signals between the control units 3 to 8 has been correctly performed. The EOM code is a code indicating the end of the frame F.

The ACK area is composed of a plurality of bits, for example, 16 bits.
A predetermined bit area is allocated to each unit in correspondence with the above, and each of the control units 3 to 8 confirms normal reception based on each bit. That is, the source control unit sets only the bit at the position corresponding to its own unit in the 16-bit ACK area to “0”,
All other bits are set to “1” and one “0” and 15
"1" bits are transmitted. On the other hand, the control unit on the receiving side checks whether there is any error in the content of the received frame F, and if there is no error, a unique bit region at a preset position for its own unit is assigned to each control unit. The ACK signal (hereinafter referred to as an ACK signal) is returned to the transmission source control unit as "0". Therefore, the control unit in which the bit area in the ACK area is “0”
Indicates that the frame F has been received normally.

If no ACK signal is returned from the control unit on the receiving side, it is determined that a reception error has occurred, and the control unit at the transmission source retransmits frame F repeatedly at a predetermined cycle. If the ACK signal is not returned even after repeated transmissions more than three times, for example, three times or more, the control unit is removed from the multiplex transmission path 2 as a system down for some reason.

Next, the first to sixth control units 3
The control operation at the time of startup of Nos. To 8 will be described with reference to the flowchart of FIG.

As shown in FIG. 4, a specific control unit of the first to sixth units 3 to 8, for example, the controller 12 of the first control unit 3 first performs an initial check in step S1, In step S2, it is determined whether the engine rotation is in an idle state.
When YES is determined, that is, when the engine rotation is in the idle state and the operating state of the generator is stabilized, in step S3, the other control units 4 to 8 are activated to activate those units. Transmit the activation frame as a signal. Next, in step S4, the timer is cleared, and in step S5, it is determined whether an ACK signal has been returned from the other control units 4 to 8. In the case of YES, that is, each of the control units 4 to
If the ACK signal from step 8 is received, step S6
Confirms the activation of each of the control units 4 to 8, and proceeds to step S7.
In, it is determined whether or not a predetermined time set in advance has elapsed. If the predetermined time has elapsed, the process proceeds to step S8. Note that came with the result of determination is NO in step S5, i.e., if any of the control unit does not send back an ACK signal,
Steps S5 to S7 until a predetermined time has elapsed.
Is repeatedly executed, and if the ACK signal is not returned from the specific control unit even after the lapse of a predetermined time, it is determined that the specific control unit is in a system down state and the control unit in the activated state in step S6. Check.

Then, in step S8, the control unit that has completed the activation and is in a state capable of multiplex communication is determined, and an activation completion frame indicating that the activation has been completed is transmitted in step S9.

That is, as shown in FIG. 8, in response to the transmission (ON state) of the activation frame F from the first control unit 3, each of the second to sixth control units 4 to 8 transmits the frame F (ACK). When the first control unit 3 confirms that the activation of all the control units 3 to 8 has been completed (ON state), the first control unit 3 transmits the activation completion frame Fa (ON state). Later, as shown by the dotted line a, the multiplex communication state is entered.

Next, when a specific control unit among the first to sixth control units 3 to 8 which is a characteristic part of the present embodiment is once restarted after the system is shut down, a series of control of each control unit is performed. The operation is shown in FIGS.
This will be described based on the flowchart shown in FIG.

As shown in FIG. 5, each of the control units 3
First, in step S10, the controller in any one of the control units 1 to 8 receives a frame from another control unit (an ACK signal returned from the control unit on the receiving side) along with the frame transmission from its own unit. It is determined whether or not the frame has been received (if YES), the ACK of the frame received in step S11
It is determined whether the bit assigned to the control unit on the receiving side in the area is “1”. If it is “1” (in the case of YES), in step S12, the specific control unit whose bit is “1”, for example, the sixth control unit
If the bit of the control unit 8 is "1", it is determined that the sixth control unit 8 is in the system down state, and the frame indicating the system down of the sixth control unit 8 is replaced by another control unit in step S13. Send to Thereby, as shown in FIG. 8, the sixth control unit 8
It is recognized that the system is down due to some cause such as a temporary voltage drop.

On the other hand, when the sixth control unit 8 that has once gone down is restarted, as shown in FIG. 8, a return frame Fx indicating that the sixth control unit 8 has restarted is transmitted. However, the return frame Fx is received by one of the other control units 3 to 7 except the sixth control unit 8, for example, the first control unit 3, and the first control unit 3 receives the return frame Fx. 8 as a representative of the restart, and transmits a return confirmation frame Fy.

That is, as shown in FIG. 6, the controller 12 of the first control unit 3 first checks whether or not the return frame Fx from the sixth control unit 8 that has been restarted after the system has been shut down once in step S20. If it is determined and received (in the case of YES), in step S21, it is determined whether the bit assigned to the sixth control unit 8 in the ACK area of the received frame Fx is already “0”. I do. If it is determined that the bit corresponding to the sixth control unit 8 is still "1" (NO), the bit corresponding to the sixth control unit 8 is rewritten to "0" in step S22. After that, a return confirmation frame Fy is transmitted to the sixth control unit 8 restarted in step S23.

On the other hand, as shown in FIG. 7, the controller of the sixth control unit 8 which has been restarted after the system has been shut down first, when the cause of the system down such as a temporary voltage drop has been resolved in step S30. In step S31, when it is determined that the first control unit 3 has been restarted (YES), the first control unit 3
, A return frame Fx is transmitted, and then the timer is cleared in step S32. Then, step S33
And the return confirmation frame Fy from the first control unit 3
Is determined, and if received (in the case of YES)
In step S34, the latest data of the self and the frame requesting the data necessary for the self are transmitted to a predetermined control unit, for example, the fourth control unit 6. As a result, as shown in FIG. 8, after transmission of the return confirmation signal Fy from the first control unit 3, transmission and reception of the frame F between the restarted sixth control unit 8 and the fourth control unit 6 are performed. As a result, data damaged by the system down will be repaired.

If the determination in step S33 is NO, that is, if the return confirmation frame Fy from the first control unit 3 has not been received, the process proceeds to step S35.
Is performed to determine whether a predetermined time T has elapsed. If the predetermined time T has elapsed (in the case of YES), the count N is incremented by one in step S36, and the count N is increased by a predetermined value (step S37). For example, it is determined whether or not 5) is reached. If the count is equal to or smaller than a predetermined value (in the case of NO), steps S33, S35, and S36 are repeatedly performed until the count N exceeds the predetermined value, and the count N is set to the predetermined value. If the return confirmation frame Fy cannot be received even if the value exceeds the value, the system goes down on the assumption that there is some failure in its own unit.

As described above, according to this embodiment, a specific control unit among the first to sixth control units 3 to 8
For example, when the sixth control unit 8 goes down due to some cause, the sixth control unit 8 transmits a return frame Fx to restart. Then, a predetermined control unit of the control units 3 to 8 other than the sixth control unit 8, for example, the first control unit 3 is connected to the return frame Fx.
Is received and the return confirmation frame Fy is transmitted to the restarted sixth control unit 8. The restarted sixth control unit 8 receives the reception confirmation frame Fy from the first control unit 3 and thereby receives itself. Is determined to return to normal.

Therefore, when a specific control unit (the sixth control unit 8 in this embodiment) of the plurality of control units 3 to 8 is restarted after a system down, the specific control unit and the specific control unit A frame (signal) for confirming the return is exchanged with one of the control units other than the specific control unit (the first control unit 3 in this embodiment), and one of the control units is controlled. Since the unit confirms the return of the specific control unit on behalf of all the other control units, when the specific control unit is restarted once the system goes down, the specific control No signal is sent and received between the unit and all other control units for confirming the return, so that immediately after the specific control unit is restarted, Traffic increase is suppressed, so that the reception error can be prevented, it is possible to surely transmit and receive signals between each control unit.

Further, transmission and reception of a signal for data restoration damaged by the system down is performed between the restarted specific control unit and a predetermined control unit among the plurality of control units, that is, the specific control unit. It is performed only with a predetermined control unit (in this embodiment, the fourth control unit 6, but not limited to only the unit 6) which needs to exchange signals with the unit. Therefore, an increase in the traffic volume immediately after the restart of the specific control unit is further suppressed, a reception error is prevented, and the transmission and reception of signals between the control units becomes more difficult. It will be done reliably.

In this embodiment, the case where the multiplex transmission apparatus according to the present invention is applied to an automobile has been described, but the object to which the multiplex transmission apparatus is applied is not necessarily limited to an automobile.

[0040]

As described above, according to the present invention, when a specific control unit of a plurality of control units is restarted after the system goes down, the specific control unit and the specific control unit are restarted. A signal for confirming the return is exchanged with one of the other control units, and the one control unit confirms the return of the specific control unit on behalf of all the other control units. As in the past, when a specific control unit that has once gone down is restarted, a signal for confirming the return between the specific control unit and all other control units is transmitted and received. Therefore, the increase in the traffic volume immediately after the restart of the specific control unit is suppressed, and the reception error is prevented. Transmission and reception of signals is to be ensured between units.

In particular, according to the present invention, the transmission / reception of a signal for data restoration damaged by the system down is performed between the restarted specific control unit and a predetermined control unit among the plurality of control units. That is, since the communication is performed only with the predetermined control unit which needs to exchange signals with the specific control unit, an increase in the traffic amount immediately after the restart of the specific control unit is further increased. As a result, the reception error is prevented, and transmission and reception of signals between the control units can be performed more reliably.

[Brief description of the drawings]

FIG. 1 is an overall schematic system diagram of a multiplex transmission device.

FIG. 2 is a system diagram showing a specific structure of each control unit constituting the multiplex transmission device.

FIG. 3 is an explanatory diagram illustrating an example of a specific configuration of a signal frame.

FIG. 4 is a flowchart showing a control operation of a first control unit at the time of activation.

FIG. 5 is a flowchart illustrating a determination operation for determining a system down of a specific control unit.

FIG. 6 is a flowchart showing a confirmation operation for confirming restart of a specific control unit.

FIG. 7 is a flowchart illustrating a control operation after restart of a specific control unit.

FIG. 8 is a time chart showing a transmission state of each control unit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 multiplex transmission device 2 multiplex transmission line 3 to 8 first to sixth control unit 11 a reception control unit 11 b transmission control unit 12 controller 14 switch, sensor 15 electric load

────────────────────────────────────────────────── ─── Continued on the front page (72) Koji Terayama, Inventor 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References JP-A-4-329048 (JP, A) Japanese Utility Model 2 -70203 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28 100 H04L 12/40 H04Q 9/00 311 H04Q 9/00 321

Claims (1)

(57) [Claims] 1. A multiplex transmission apparatus in which a plurality of control units are connected to a common multiplex transmission line and signals are exchanged between the control units via the multiplex transmission line. Among them, a specific control unit that has once gone down is provided with return signal transmitting means for transmitting a return signal at the time of restart, while a predetermined control unit of the other control units except the specific control unit is provided with:
Receiving means for receiving the return signal, and transmitting means for transmitting a return confirmation signal for confirming the return to a specific control unit that has been once shut down and then restarted when the return signal is received by the receiving means are provided. The specific control unit that has been restarted has a normal return determining unit that determines its own normal recovery by receiving a return confirmation signal from the predetermined control unit, and its own normal return determining unit has After judging normal return ,
Own unit a signal for data required to Kutomo self
To other control units except for the other control unit
Multiplex transmission apparatus characterized by a data recovery signal <br/> transmission receiving means for receiving data repair signals are provided to and from.