JPH08275270A - Multiplex transmitter - Google Patents

Abstract

PURPOSE: To surely detect a fault of a transmission reception function of a communication node by monitoring a reception function of its own communication node and other communication node mutually by an ACK signal and monitoring its own communication node with a transmission end signal. CONSTITUTION: An ACK control circuit 1255 executes the control to send an ACK bit when no error is in existence in a frame received by a control circuit 1256. Furthermore, a transmission control circuit 1250 outputs a transmission end signal of a frame F to a CPU 100 via an input output port control circuit 1252. When the CPU 100 receives a transmission end signal from the transmission control circuit 1250 within a prescribed time, the CPU 100 discriminates it that the transmission function of its own node is normal. Moreover, when the CPU 100 does not send an ACK bit to other node, the CPU 100 discriminates it that the reception function of its own node is faulty and when the ACK signal is not returned from the other node on the contrary, the CPU 100 discriminates it that the reception function of the other node is faulty.

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 capable of monitoring the communication status of each communication node in a plurality of multiplex communication nodes connected to a common multiplex transmission path.

[0002]

2. Description of the Related Art In recent years, in order to eliminate the enlargement and complication of wiring (wire harness) that connects the electric component units with the increase in the number of electronic parts (electric component units) of automobiles, it has been provided in a plurality of electric component units. Attention has been paid to multiplex communication in which a communication node is connected to a common multiplex communication line, and signal transmission between each electrical unit is performed by the communication node.

In the multiplex communication system constructed by connecting a plurality of communication nodes for sending or receiving digital information or for sending and receiving digital information, each communication node sends the communication information to a communication line. The digital information captured by the communication node designated in advance forms a data frame of a certain length, for example, in order to facilitate its handling. This data frame is called a communication frame and is a group of code data having a predetermined number of bits and a total data length according to a preset data format.

FIG. 1 shows a format of a communication frame adopted in a conventional vehicle multiplex transmission system.
In FIG. 1, frame F is SD (Start Delimiter).
) A frame structure having a code, a priority code, a frame ID code, a data length, data 1 to data N, and a check code.

First, the "SD code" is a specific code indicating the start of the frame F, and the receiving multiplex node uses this S code.
When the D code code is received, the start of the frame F is recognized. The “priority code” is a code indicating a priority order that indicates which signal should be preferentially processed when a plurality of multiple nodes simultaneously transmit data and the signals collide. In this embodiment, the lower the bit value, the higher the priority is assigned. This is because the low level is WIRED-OR on the bus. If signals are sent from multiple nodes at the same time, the “priority code” of the node with the higher priority remains on the bus, and the lower priority node changes its own “priority code” to another code. Therefore, the data collision is detected. And
By delaying the retransmission of its own failed frame, the retransmission from the node with a high priority is prioritized.

The "frame ID code" is a code indicating the transmission destination of the frame, and if N types of communication nodes are provided, areas from ID0 to IDN are set. The transmission source node writes the transmission destination ID in the frame and transmits the frame. Further, the receiving node stores the ID of the frame to be received by the node as a memory map, and only when the ID code of the received frame matches the ID registered in the own node, the reception frame capturing process is performed. To execute.

In the "data length", the number of data that follows is written, and if there are N data, N is sent as the data length. The multi-node which receives this frame reads the data of the data length. The field following the data is a CRC check code (error detection code), and by confirming this, it can be known that the end of the frame.

The ACK field is where ACK signals from other nodes (N nodes are planned for the entire system) are inserted. This ACK signal is not returned to the source node if the receiving node does not receive the data correctly, and the multiple node on the transmission side determines whether the returned frame includes the ACK signal. By determining whether or not the frame transmission to the transmission destination has failed, if the frame transmission fails, the same frame is retransmitted.

FIG. 2 is a diagram showing a general configuration of a communication node used in an automobile network. Each node is connected to the transmission line 10 via the communication LSI 101. Reference numeral 100 denotes a CPU for controlling, RAM /
It operates according to the program stored in the ROM 102. The CSMA / CD system physical layer level protocol control is performed by the LSI 101. This communication node is connected to the electrical equipment unit 104. This unit is, for example, an EGI controller for engine control or a node of meters.

The CPU 100 controls the LSI 101,
In addition, control is performed to process data from the LSI 101 and pass the data to the electrical unit 104, or to pass data from the electrical unit 104 to the LSI 101. That is, the frame data on the bus is converted into a format usable by the electrical component unit 104, and
Converts data from 4 to frame format. Another important role of the CPU 100 is management of ACK data. That is, as described above, in this communication method,
When all nodes (communication LSI 101) receive the frame data from other nodes without error, the ACK bit is returned to the node that sent the frame data. Therefore, by checking the contents of this ACK field, it is possible to know which node could not receive the frame transmitted by itself. This check work is C
PU100 is entrusted. This is the communication LSI 101
Is limited to communication control, and high-level data processing is performed by the CPU 10.
This is because 0 is trying to do it.

In the multiplex transmission system including the communication nodes described above, the reception function of another communication node is checked by determining whether or not the transmission-side multiplex node includes the ACK signal in the frame returned from the other node. There has been proposed (JP-A-3-283842).

[0012]

However, in the conventional example disclosed in Japanese Patent Application Laid-Open No. 3-283842, when an abnormality occurs in the receiving function of its own communication node or another communication node, the node transmits from the node at the time of frame transmission. Although it can be judged that an error has occurred in the reception function because the frame containing the ACK signal is not returned, when checking that an error has occurred in the transmission function of its own communication node, the frame is sent without the ACK signal. Since the operation itself is possible, it cannot be determined that an abnormality has occurred in the transmission function even in the own communication node.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to monitor the receiving functions of its own communication node and other communication nodes by ACK signals, and An object of the present invention is to provide a multiplex transmission device capable of reliably detecting an abnormality in the transmission / reception function of a communication node by monitoring the transmission function of the communication node with a transmission completion signal output from a circuit that performs transmission / reception processing.

[0014]

[Means for Solving the Problems] and

In order to solve the above problems and achieve the object, the multiplex transmission apparatus of the present invention has the following configuration. That is, in a multiplex transmission apparatus in which a plurality of communication nodes are connected via a common multiplex transmission path, and each of the communication nodes controls an electrical equipment unit of a vehicle connected to the other, the multiplex transmission apparatus is at least another A transmission / reception processing circuit for receiving data transmitted from a communication node via the multiplex transmission path and transmitting data from the communication node to be transmitted via the multiplex transmission path, and the reception processing circuit A communication node having an arithmetic processing circuit that takes in data, controls the electrical unit based on the data, generates data to be transmitted from its own communication node, and causes the transmission / reception processing circuit to perform transmission processing. The transmission / reception processing circuit includes means for transmitting a first signal indicating that the data transmitted from another communication node has been normally received and processed. Means for outputting to the arithmetic processing circuit a second signal indicating that the data to be transmitted from its own node has been normally transmitted, and the arithmetic processing circuit comprises the first and second signals. And a determination unit that determines whether the communication state of the communication node is normal or abnormal.

As described above, in the multiplex transmission apparatus of the present invention, according to the invention described in claim 1, the transmission / reception processing circuit indicates that the data to be transmitted from its own node is normally transmitted. Since the signal No. 2 is output to the arithmetic processing circuit and the arithmetic processing circuit determines whether the communication state of the communication node is normal or abnormal based on the second signal, the abnormality of the transmission function of the communication node can be reliably detected.

According to the second aspect of the invention, since the arithmetic processing circuit determines the communication state of the communication node of its own, it is possible to reliably detect an abnormality in the transmission function of the communication node of its own. Further, according to the invention described in claim 3, since the arithmetic processing circuit determines the communication state of the other communication node, it is possible to reliably detect the abnormality of the transmission function of the other communication node.

Further, according to the invention described in claim 4, when it is determined that the communication state of the communication node is abnormal, the transmission / reception processing circuit of the communication node is initialized and the transmission is performed from its own node. Since the data that should be sent is sent again, it can be easily dealt with if there is a prospect of recovery. Further, according to the invention described in claim 5, since the predetermined data for determining the communication state of the own communication node is transmitted to the other communication node, the abnormality detection accuracy can be improved.

According to the sixth aspect of the invention, when the second signal is not received within the predetermined time, it is determined that the communication state of its own communication node is abnormal. The detection cycle of the signal No. 2 can be set, and the reliability of the system can be improved without deteriorating the original performance of the node. Further, according to the invention described in claim 7, when the abnormality of the communication state of the own communication node is repeatedly judged a predetermined number of times or more, the data transmission / reception by the own communication node is stopped, and thus the malfunction of the electrical unit Can reduce the risk due to

Further, according to the invention described in claim 8, when the abnormality of the communication state of the other communication node is repeatedly determined a predetermined number of times or more, it is determined that the electrical unit based on the data transmitted from the other communication node. Since the control is prohibited, the risk of malfunction of the electrical component unit can be reduced. Further, according to the invention of claim 9, when the abnormality of the communication state of the other communication node is repeatedly determined a predetermined number of times or more, the data to be transmitted from the own communication node is transmitted to the other communication node. Is prohibited, the amount of traffic on the bus can be effectively reduced.

[0020]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 3 shows the configuration of this embodiment. In the figure, 10 and 20 are transmission lines, and twisted pair lines are used. The communication speed was 20 kbps. A plurality of nodes are connected to each of these transmission lines, and each forms a network. That is,
Nodes 1 to 5 are connected to the network 10, and nodes 21 to 28 are connected to the network 20.

The networks 10 and 20 are networks provided in the vehicle. Networks 10, 20 are
Gateway node 4 via transmission lines 52 and 50, respectively.
0 are connected to each other, and the networks 10, 2
0 forms an integrated network in the vehicle. The function of the gateway node will be described. There can be no more than one frame on each network. In other words, there can be one frame on each network at the same time. Gateway 4 allows this
The function is 0 (also serves as an ABS node). That is, the respective networks are connected by the gateway 40, and the frame switching function of the gateway 40 as required allows the frames to be simultaneously transmitted on the respective networks at the same time. This point will be described in more detail later in connection with functional addressing.

The nodes of each network in FIG. 3 will be briefly described. The network 10 includes a node 1 for an airbag control unit (indicated by C / U in the figure), a node 2 for the above-mentioned controller EGI / C / U for controlling the engine, and an automatic node. Node 3 for the transmission controller, node 4 for the rear wheel steering control controller (4WS C / U), node 40 for the anti-lock braking system (ABS C / U) controller (gateway And the node 5 for the traction controller TRC C / U. That is, nodes for the controller are mainly connected to the network 10.

The network 20 includes a node 21 for a combination switch, a node 22 for various meters such as a vehicle speed meter, a node 23 for a steering switch, and a node 2 for various switches on the passenger door.
4, a node 25 for an air conditioner power amplifier, a node 26 for various operation switches for audio, a node 27 for an air conditioner switch, and a node 28 for various switches on the driver's door. That is, the nodes connected to the network 20 are switches, sensors, and actuators related to the vehicle body.

By thus consolidating only the controller system nodes in the network 10, efficient "cooperative control" is possible in the network 10, and by consolidating only the body system nodes in the network 20, the network 10 is integrated. It is possible to prevent the runaway of the controller system node from reaching the network 20 by disconnecting the controller system.

In the multiplex transmission system for automobiles of this embodiment,
Vehicle driving information is transmitted for each frame F having the configuration described in FIG. FIG. 4 shows an internal configuration of the communication LSI of FIG. Transmission control circuit 1250, reception control circuit 12
56 executes the CSMA / CD control procedure. The ACK control circuit 1255 executes control for transmitting an ACK bit if the frame received by the control circuit 1256 has no error. Further, the transmission control circuit 1250 outputs a transmission completion signal of the frame F to the CPU 100 via the input / output port control circuit 1252. When the CPU 100 receives the transmission completion signal from the transmission control circuit 1250 within a predetermined time, it determines that the transmission function of its own node (hereinafter referred to as its own node) is normal. Further, when the ACK bit is not sent to the other node, the CPU 100 determines that the receiving function of the own node is abnormal, and when the ACK signal is not returned from the other node, the receiving function of the other node is abnormal. Judge that there is.

[Communication Function Judgment] Next, a procedure for judging the normality / abnormality of the communication function of the above-mentioned communication node will be described with reference to FIGS. By the way, before explaining this operation procedure, a general initial operation after power-on or reset of the communication node will be briefly described. After power-on or reset, each communication node of this system is in a transmission / reception ready state in which each communication node can send a frame to the communication line or capture a frame from the communication line after a predetermined rise time. Become. Then, the communication node in the transmission / reception enabled state first sequentially transmits a plurality of transmission request data frames describing the content for requesting the transmission of a predetermined frame to another communication node, and then the transmission request data is transmitted. The other communication node that fetched the frame returns the specified data in response to the content of the transmission request data frame, and the own node sets its own initial operation state based on the returned data frame. , And then shifts to the normal operation state.

<Determination of Transmission Function Abnormality at Initial Operation> FIG.
6 is a flowchart of a main routine showing a procedure for determining an abnormality in the transmission function of the own node at the time of initial operation. In FIG. 5, when the process is started, the system is powered on in step S2, and in step S4, each node initializes an application such as an input / output auxiliary device to be controlled. Next, in step S6, the previous value and the counter value of the control data stored in each node are cleared and the communication system is initialized. After that, in step S8, the communication node in the transmission / reception enabled state first sequentially transmits to the other communication nodes a plurality of transmission request data frames in which the contents requesting the transmission of the frame designated in advance are described ( Initial transmission). In step S10, every time one or more frames are sent to the transmission path in the initial transmission state, the CPU 100 of the own node sends the transmission control circuit 125.
It is determined whether or not the transmission completion signal is received from 0. When the transmission completion signal is received in step S10 (YES in step S10), the process proceeds to step S12, and when the transmission completion signal is not received (NO in step S10), the process proceeds to step S16. In step S12, it is determined whether or not all the frames to be transmitted at the time of initial transmission have been transmitted. If all frames have been transmitted in step S12 (YES in step S12), step S1
4, the process returns to step S18 if all the frames have not been transmitted (NO in step S12).

In step S16, the CPU is a communication LSI.
It is determined whether or not a state in which the transmission completion signal is not received has passed a predetermined time. When the predetermined time has elapsed in step S16 (YES in step S16), the process proceeds to step S18, and when the predetermined time has not elapsed (N in step S16)
O), the process returns to step S10 to enter the waiting state for receiving the transmission completion signal.

In step S18, the number of times N1 at which the transmission completion signal is not received after the predetermined time has elapsed is counted. In step S20, it is determined whether the number N1 of non-receptions is equal to or greater than the predetermined number P, and if the number N1 is greater than or equal to the predetermined number P, the process proceeds to step S22, and it is determined that the transmission function of the own node is abnormal. On the other hand, if the number N1 is not equal to or more than the predetermined number P in step S20, the process returns to step S6,
The communication LSI is initialized again and the initial transmission is executed again.

<Determination of Transmission Function Abnormality During Normal Operation> Steps S30 to S44 in FIG. 6 are a flowchart of a main routine showing a procedure for determining an abnormality of the transmission function of the own node during normal operation. In FIG. 6, after the processing of step S14 or step S22 of FIG.
At 30, a normal control of an application such as an input / output auxiliary device by the own node is executed. Next, in step S32, a frame transmission operation is performed to another node. After that, in step S34, every time the CPU of the own node outputs a frame transmission command to the communication LSI, it is determined whether the CPU 100 of the own node has received the transmission completion signal from the transmission control circuit 1250. Step S34
When the transmission completion signal is received (Y in step S34)
ES), the process proceeds to step S36, and the transmission function of the own node is determined to be normal. On the other hand, if the transmission completion signal is not received (NO in step S34), the process proceeds to step S38.

In step S38, it is determined whether the CPU has not received the transmission completion signal from the communication LSI for each frame transmission command for a predetermined time. Step S3
When a predetermined time has elapsed in step 8 (YES in step S38)
S), the process proceeds to step S40, and if the predetermined time has not elapsed (NO in step S38), the process returns to step S34 and waits for reception of the transmission completion signal.

In step S40, the number N2 of times when the transmission completion signal is not received after the predetermined time has elapsed is counted. In step S42, it is determined whether or not the number N2 of non-receptions is equal to or greater than the predetermined number Q, and when the number N2 is equal to or greater than the predetermined number Q, the process proceeds to step S44, and it is determined that the transmission function of the own node is abnormal. On the other hand, if the number N2 is not equal to or more than the predetermined number Q in step S42, the process returns to step S30 and the frame transmission is performed again.

<Determination of Reception Function Abnormality During Normal Operation> Steps S50 to S66 of FIG. 6 are a flowchart of a main routine showing a procedure for determining an abnormality of the reception function of the own node and another node during normal operation. 6, after the process of step S36 of FIG. 5, step S50
Receives the frame sent from another node. Next, in step S52, the CPU of the own node
Determines whether the communication LSI is replying ACK data to the frame received from another node. When ACK data is not returned in step S52 (YES in step S52), the process proceeds to step S54, it is determined that the receiving function of the own node is normal, and the process proceeds to step S56. On the other hand, if the ACK data is returned in step S52 (NO in step S52), the process proceeds to step S66, it is determined that the receiving function of the own node is abnormal, and the process returns to step S34.

<Determination of Reception Function Abnormality of Other Node During Normal Operation> Steps S56 to S64 of FIG. 6 are flowcharts of the main routine showing a procedure for determining an abnormality of the reception function of the own node and other nodes during normal operation. is there. In FIG. 6, after the processing of step S54, step S5
At 6, the CPU of the own node determines whether or not ACK data has been returned from another node in response to the frame sent by the own node. If the ACK data is returned in step S56 (YES in step S56), the process proceeds to step S58, it is determined that the receiving function of the other node to which the ACK data is returned is normal, and the process returns to step S30. On the other hand, if the ACK data is not returned in step S56 (NO in step S56), the process proceeds to step S60. In step S60, each time the node retransmits a frame, the number N3 of times when ACK data is not returned from another node is counted. In step S62, it is determined whether or not the number N3 of non-reply is equal to or more than the predetermined number R, and when the number N3 is not less than the predetermined number R, the process proceeds to step S64 and
It is determined that the transmission function of the node to which K data is returned is abnormal. On the other hand, if the number N3 is not equal to or greater than the predetermined number R in step S62, the process returns to step S30 and the frame transmission is performed again.

<Subroutine for Abnormality Judgment> Next, with reference to the flow charts shown in FIGS. 5 and 6, a subroutine control procedure for judging an abnormality in the transmission / reception function of the own node or another node will be described. FIG. 7 is a flow chart illustrating a control procedure of a subroutine at the time of abnormality determination of the transmission / reception function of the own node or another node shown in FIGS. Figure 7
In step S70, when the process is started,
It is determined whether or not the own node has performed the abnormality determination of the other node A, and in step S72, the determination count X1 is counted every time the abnormality determination of the other node A is performed. Next, in steps S74 and S76, it is determined whether or not the own node has made an abnormality determination of the other node B, and the other node B
Each time the abnormality determination is performed, the number of determinations X2 is counted. Thereafter, the same procedure is followed to count the abnormality determination for each of the connected nodes. Then, step S
At 78, it is determined whether or not the number of determinations X1 of the other node A exceeds a predetermined number of times S. In step S78, when the determination count X1 of the other node A is less than or equal to the predetermined count S (YES in step S78), the auxiliary device control of the own node by the transmission data of the node A is executed. On the other hand, when the determination count X1 of the other node A exceeds the predetermined count S (N in step S78).
O), the process proceeds to step S86, it is determined that the transmission data of the node A may be destroyed, and the auxiliary device control of the own node by the transmission data of the node A is not performed. Perform predetermined control. This predetermined control is
For example, the output auxiliary device such as a headlight that cannot be controlled by the transmission data of the node A is controlled to be in a constantly lit state to avoid the risk of a node abnormality during traveling. Therefore, the control procedure varies depending on the auxiliary device to be controlled.

Continuing with the description, in step S82, it is determined whether the number of determinations X2 of the other node B has exceeded a predetermined number T. In step S82, when the number of determinations X2 of the other node B is less than or equal to the predetermined number of times T (Y in step S82).
ES), the auxiliary device control of the own node is executed by the transmission data of the node B. On the other hand, when the determination count X2 of the other node B exceeds the predetermined count T (NO in step S82), the process proceeds to step S90, it is determined that the transmission data of the node B may be destroyed, and the node B In step S92, the auxiliary device control of the own node is not performed by the transmission data of
Predetermine control of auxiliary devices. Thereafter, in the same procedure, the abnormality determination is counted for each of the connected nodes and the auxiliary device control is executed.

As described above, according to the procedure shown in FIGS. 5 to 7, the abnormality of the transmission / reception function of the own node and the reception function of the other node is surely detected, and the data transmitted from the node determined to be abnormal is detected. Since the auxiliary device control based on it is not executed,
The reliability of the entire system can be improved. <Determination of Transmission Function Abnormality by Receiving Node During Initial Operation of Transmitting Node> Next, referring to FIGS. 8 and 9, when the transmitting node is in initial operation, the receiving node has a transmitting function of the transmitting node. A procedure for determining an abnormality will be described. FIG. 8 is a flowchart showing a procedure for determining a transmission function abnormality by the receiving side node. As described above, the communication node of the present system, after power-on or reset, sequentially transmits a plurality of transmission request data frames in which the contents requesting the transmission of a frame designated in advance are described to other communication nodes. Here, in the present embodiment, after transmitting these initial transmission frames, the reception side node transmits a predetermined check frame for checking whether the data of the reception frame is true or false. At the receiving side node, it is determined whether the data written in the data area of the check frame and common to both the receiving side and the transmitting side match, and if they match, the received frame data is true. judge.

The control procedure of the receiving side node will be described below with reference to the flowchart of FIG. In FIG. 8, when the process is started, steps S100 to S104 are performed.
In, the receiving side node receives the frames Aa to Az from the certain transmitting side node A which were initially transmitted. When all the initial transmission frames of the transmission side node are received in steps S100 to S104, step S10
In step 6, the check frame D is finally received. Then, in step S108, the receiving side node determines whether the data described in the data area of the check frame D matches the data stored in the receiving side node. When it is determined that they match in step S108 (YES in step S108), steps S110 to S1.
12, the transmission function of node A is normal, and node A
It is determined that the data of the initial transmission frame received from is true, and the auxiliary device control of the own node by the transmission data of the node A is executed. On the other hand, if they do not match (step S108)
NO), it is determined that the transmission function of the node A is abnormal and the transmission data of the node A may be destroyed in steps S114 to S116.
The auxiliary device of the own node is not controlled by the transmission data of 1., but the auxiliary device is controlled in a predetermined manner in step S118. As shown in FIG. 9, in the data described in the data area of the check frame, information indicating that the data is a check frame transmitted from a predetermined transmitting node is entered in the frame ID area, and In the data 1 area described above, the address of the transmitting node, inversion information of data 1 in the data 2 area,
Predetermined information negotiated between the receiving side node and the transmitting side node is written in the data 3 area, and inversion information of the data 3 is written in the data 4 area. In this way, by setting all of the check frame data 1 to data 4 as the abnormality determination information, the receiving node can receive the data 3 data even if the data 1 is destroyed and a frame with a different address is received. Since the information is different, it is possible to determine the mismatch of check frames. Further, by using the data of the check frame as the composite data of the data 1 and the data 3 and the respective inversion data, it is possible to further improve the abnormality determination accuracy. Further, since information indicating that the frame is a check frame is entered in the frame ID area, even if an interrupt is received in a frame of another node, the receiving node can easily determine which transmitting node the check frame is. it can. It should be noted that the abnormality detection of the transmitting side node by the check frame can be applied not only during the initial operation but also during the normal operation.

The present invention can be variously modified without departing from the spirit thereof. For example, the number and types of nodes are not limited to the above embodiment.

[0040]

As described above, in the multiplex transmission apparatus of the present invention, according to the invention described in claim 1, it is possible that the transmission / reception processing circuit normally transmits the data to be transmitted from its own node. The arithmetic processing circuit outputs the second signal indicating to the arithmetic processing circuit, and the arithmetic processing circuit determines whether the communication state of the communication node is normal or abnormal based on the second signal, so that the abnormality of the transmission function of the communication node is reliably detected. it can.

According to the second aspect of the present invention, the arithmetic processing circuit determines the communication state of its own communication node, so that an abnormality in the transmission function of its own communication node can be reliably detected. Further, according to the invention described in claim 3, since the arithmetic processing circuit determines the communication state of the other communication node, it is possible to reliably detect the abnormality of the transmission function of the other communication node.

According to the invention described in claim 4, when it is determined that the communication state of the communication node is abnormal, the transmission / reception processing circuit of the communication node is initialized and the transmission is performed from the own node. Since the data that should be sent is sent again, it can be easily dealt with if there is a prospect of recovery. Further, according to the invention described in claim 5, since the predetermined data for determining the communication state of the own communication node is transmitted to the other communication node, the abnormality detection accuracy can be improved.

Further, according to the invention described in claim 6, when the second signal is not received within the predetermined time, it is determined that the communication state of the communication node of its own is abnormal, and therefore the communication node of The detection cycle of the signal No. 2 can be set, and the reliability of the system can be improved without deteriorating the original performance of the node. Further, according to the invention described in claim 7, when the abnormality of the communication state of the own communication node is repeatedly judged a predetermined number of times or more, the data transmission / reception by the own communication node is stopped, and thus the malfunction of the electrical unit Can reduce the risk due to

According to the invention described in claim 8, when the abnormality of the communication state of the other communication node is repeatedly determined a predetermined number of times or more, it is determined that the electrical equipment unit based on the data transmitted from the other communication node. Since the control is prohibited, the risk of malfunction of the electrical component unit can be reduced. Further, according to the invention of claim 9, when the abnormality of the communication state of the other communication node is repeatedly determined a predetermined number of times or more, the data to be transmitted from the own communication node is transmitted to the other communication node. Is prohibited, the amount of traffic on the bus can be effectively reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a format of a communication frame adopted in a conventional multiplex transmission system for a vehicle.

FIG. 2 is a diagram showing a general configuration of a communication node used in a vehicle network.

FIG. 3 is a diagram showing a network configuration of this embodiment.

FIG. 4 is a block diagram showing a hardware configuration of a node used in this embodiment.

FIG. 5 is a flowchart illustrating a procedure for determining normality / abnormality of the communication function of the communication node according to the present embodiment.

FIG. 6 is a flowchart illustrating a procedure for determining normality / abnormality of the communication function of the communication node according to the present embodiment.

FIG. 7 is a flowchart illustrating a procedure for determining normality / abnormality of the communication function of the communication node according to the present embodiment.

FIG. 8 is a flowchart showing a procedure for determining a transmission function abnormality by a receiving node.

FIG. 9 is a diagram showing data described in a frame ID area and a data area of a check frame.

[Explanation of symbols]

 1 ... Airbag C / U node, 2 ... EGIC / U node, 3 ... EATC / U node, 4 ... 4WSC / U node, 5 ... TRCC / U node, 10, 20 ... Network, 50, 52 ... Transmission line, 21 ... Combination switch node, 22 ... Meter node, 23 ... Steering switch node, 24 ... Front passenger door module node, 25 ... Air conditioner amplifier node, 26 ... Audio node, 27 ... Air conditioner switch node, 28 ... Driver door module node, 40 ... Gateway node

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location H04Q 9/14 H04L 11/00 321 (72) Inventor Toshifumi Ikeda 3-1, Shinchi Fuchu-cho, Aki-gun, Hiroshima Mazda Incorporated (72) Inventor Hiroaki Sakamoto 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation

Claims (9)

[Claims] 1. A multiplex transmission apparatus in which a plurality of communication nodes are connected via a common multiplex transmission path, and each of the communication nodes controls an electrical equipment unit of a vehicle connected to each of them, wherein the multiplex transmission apparatus comprises: A transmission / reception processing circuit for receiving and processing data transmitted from at least another communication node via the multiplex transmission path, and transmitting and processing data to be transmitted from its own communication node via the multiplex transmission path, and this reception And an arithmetic processing circuit that takes in the processed data, controls the electrical unit based on the data, generates data to be transmitted from its own communication node, and causes the transmission / reception processing circuit to perform transmission processing. A communication node, wherein the transmission / reception processing circuit transmits a first signal indicating that the data transmitted from another communication node has been normally received and processed. And a means for outputting to the arithmetic processing circuit a second signal indicating that the data to be transmitted from its own node has been normally transmitted, the arithmetic processing circuit comprising: A multiplex transmission device comprising: a determination unit that determines whether the communication state of the communication node is normal or abnormal based on the signal of 2. 2. The arithmetic processing circuit determines whether the communication state of its own communication node is normal or abnormal based on the first and second signals sent from the transmission / reception processing circuit of its own communication node. The multiplex transmission device according to claim 1, wherein: 3. The arithmetic processing circuit determines whether the communication state of the other communication node is normal or abnormal based on the first signal sent by the other communication node.
The multiplex transmission device as set forth in. 4. The arithmetic processing circuit initializes the transmission / reception processing circuit of the communication node and transmits from its own node when the communication state of the communication node is judged to be abnormal by the judging means. The multiplex transmission device according to claim 1, wherein the power data is retransmitted. 5. The arithmetic processing circuit determines the communication state of its own communication node in another communication node when causing the transmission / reception processing circuit to transmit data to be transmitted from its own communication node. 2. The multiplex transmission device according to claim 1, wherein the predetermined data is transmitted. 6. The arithmetic processing circuit, when not receiving the second signal from the transmission / reception processing circuit within a predetermined time, determines that the communication state of the communication node of its own is abnormal. The multiplex transmission device according to claim 1. 7. The arithmetic processing circuit stops transmission / reception of data by the own communication node when the abnormality in the communication state of the own communication node is repeatedly determined a predetermined number of times or more. 2. The multiplex transmission device according to item 2. 8. The arithmetic processing circuit prohibits control of the electrical component unit based on data transmitted from the other communication node when the arithmetic processing circuit repeatedly determines that the communication state of the other communication node is abnormal for a predetermined number of times or more. The multiplex transmission device according to claim 3, wherein 9. The arithmetic processing circuit, when the abnormality of the communication state of the other communication node is repeatedly judged a predetermined number of times or more, sends the data to be transmitted from the own communication node to the other communication node. 9. The multiplex transmission device according to claim 8, which is prohibited.