JPH04356841A - Multiple transmitter - Google Patents

Abstract

PURPOSE:To prevent another normal node from being affected by a node fault at a multiple transmission network. CONSTITUTION:General nodes 11 and 12 are added to a loop-shaped transmission line 1, and a TMS (monitor) node 13 is connected for detecting the faults of these nodes. The respective nodes 11 and 12 are equipped with relay switches 21a, 21b, 22a and 22b for disconnecting its own nodes from the transmission line 1 in the case of receiving a fault detection signal transmitted from the TMS node 13 to its own nodes. These relay switches are also equipped with fault node disconnecting functions and feeding functions to an alarm lamp for alarming the fault.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention prevents the influence of node failure from affecting other healthy nodes by disconnecting the failed node from the transmission path when a failure occurs in any node in a multiplex transmission network. The present invention relates to a multiplex transmission device.

0002

[Background Art] Recently, in the field of automobiles, the number of electrical components such as switches, sensors, actuators, etc. has increased due to electronicization, and as a result, the wire harnesses that connect electrical components have become larger and more complex. It has become a problem. Therefore, a multiplex transmission system in which one transmission path is shared by a large number of electrical components is attracting attention. in particular,
The nodes of the various electrical components and engine control (EGI), four-wheel steering control (4WS), and anti-lock brake control (A
Control nodes for BS), etc. are connected to the transmission paths, thereby forming a time-division multiplex transmission network. Each node sends and receives communication data to and from other nodes through a transmission path.

Now, in Japanese Patent Application Laid-Open No. 2-184210,
An example of constructing a multiplex transmission network in a car is disclosed. In this example, communication lines made of twisted pair wires are arranged in a loop to form a transmission path, and a plurality of nodes are connected to this loop-shaped transmission path.

0004

[Problems to be Solved by the Invention] In the above-mentioned conventional multiplex transmission device, the form of the transmission path is simply a loop, so if some kind of failure occurs in a component at any node, the operation of the failed node is guaranteed. Not only will this fail, but if a faulty node sends erroneous communication data, there is a risk that other healthy nodes may malfunction. Furthermore, if a failed node transmits a large amount of invalid communication data, the amount of traffic on the transmission path increases and the operations of other healthy nodes are inhibited.

[0005] An object of the present invention is to prevent the node failure from affecting other healthy nodes by disconnecting the failed node from the transmission path when a failure occurs in one of the nodes. It is in.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the solving means of the present invention not only makes the form of the transmission path loop-like, but also includes node failure detection means for detecting node failure, and node failure detection means for detecting node failure. A node disconnection means is provided for disconnecting a failed node from a transmission line in conjunction with a failure detection means. To be more specific, the invention of claim 1 connects a plurality of nodes to a loop-shaped transmission line, and detects a failure when a failure occurs in any one of the plurality of nodes. The node failure detecting means transmits a failure detection signal when the failure detection signal is received, and the node disconnecting means disconnects the node in which the failure has occurred from the transmission path when the failure detection signal is received. Further, the invention of claim 2 further includes an alarm lamp for notifying the failure, and
The node disconnection means is constituted by a relay switch that disconnects a node in which a failure has occurred from the transmission path and simultaneously supplies power to an alarm lamp.

[0007]

According to the first aspect of the invention, when a node failure occurs, the node failure detection means and the node disconnection means work together to disconnect the failed node from the transmission path. However, since the transmission path is loop-shaped, even if a faulty node is disconnected from the transmission path, communication data can be sent and received among all remaining healthy nodes. Moreover, since the faulty node is separated from the transmission path, the faulty node will not send erroneous communication data to the transmission path, and malfunctions of other healthy nodes can be prevented. Furthermore, since the failed node does not send a large amount of invalid communication data to the transmission path, an increase in the amount of traffic on the transmission path can be prevented, and the operation of other healthy nodes will not be inhibited.

According to the invention of claim 2, when a node failure occurs, power is supplied to the alarm lamp by the relay switch at the same time as the failure node is disconnected by the relay switch, and a failure notification is issued at the same time as the failure node is disconnected. It will be done.

[0009]

Embodiments Hereinafter, embodiments in which the present invention is applied to an automobile will be explained based on the drawings.

FIG. 1 is a block diagram showing an embodiment of a multiplex transmission apparatus according to the present invention. In the multiplex transmission apparatus shown in the figure, a large number of nodes are connected to a loop-shaped transmission line 1 made up of, for example, twisted pair wires to form a time-division multiplex transmission network. Among these nodes, A,
Two nodes 11, 12 of B are illustrated. The transmission path 1 further includes a monitoring node (hereinafter referred to as a TMS node) that detects a failure when a failure occurs in any node and sends a failure detection signal to the transmission path 1 to the failed node. 13 are connected. Node A11 is TM
It has relay switches 21a and 21b for disconnecting itself from the transmission path 1 when it receives a failure detection signal addressed to itself transmitted from the S node 13 through the transmission path 1. Similarly, the node B 12 connects the TMS node 13 to the transmission line 1.
It has relay switches 22a and 22b for disconnecting itself from the transmission line 1 when it receives a failure detection signal addressed to itself transmitted through the transmission line 1. Other nodes (not shown) also have relay switches for disconnecting themselves from the transmission path 1 in the event of a failure. These relay switches 21a, 21b; 22a, 22b, etc. are inserted in series on the transmission line 1.

[0011] The nodes A11, B12, etc. each send and receive communication data to and from nodes other than themselves through the transmission path 1. However, the transmitting node transmits, as communication data, a frame to which a frame ID code indicating that the transmitting node is the transmitter is attached. Each of the other nodes knows whether the frame is addressed to itself based on the frame ID code, and if the frame is addressed to itself, receives the frame. The TMS node 13 can detect failures in nodes such as A11 and B12 through frame information on the transmission path 1.

For example, when some kind of failure occurs in a component in the node A11, the TMS node 13 detects the node failure and transmits a failure detection signal addressed to the node A11 to the transmission line 1. The node A11 that has received the failure detection signal addressed to itself operates the relay switches 21a and 21b to disconnect itself from the transmission path 1. On this occasion,
Since transmission line 1 is in a loop, even if node A11 is disconnected from transmission line 1 and transmission line 1 is partially cut off, communication data will not be transmitted between all remaining healthy nodes. Can be sent and received. When node A11, which is a failed node, is disconnected from transmission path 1, it is possible to prevent a healthy node from malfunctioning, which may occur if node A11 sends erroneous communication data to transmission path 1. Further, since it is possible to prevent an increase in the amount of traffic on the transmission line 1 due to the failed node A11 transmitting a large amount of invalid communication data to the transmission line 1, the operation of a healthy node is not inhibited.

As described above, the TMS node 13 constitutes the node failure detection means, and the relay switches 21a,
21b constitutes the node separation means described above. Note that the operation when a failure occurs in a node other than the node A11, for example, the node B12, is the same, so a description thereof will be omitted.

Now, FIG. 2 shows the node A1 shown in FIG.
1 and two relay switches 21a and 21b for disconnecting the node A11 from the transmission path 1. FIG. In the figure, the loop-shaped transmission line 1 is composed of a set of twisted pair wires consisting of two buses, a first bus 1a and a second bus 1b. 2 is a warning lamp for notifying a failure, one end of which is connected to the power supply;
1b has one end connected to the other end of the alarm lamp 2, and both buses 1a
, 1b.

To explain the internal configuration of the node A11, 3
0 is an input interface (input I/F) to which sensors etc. are connected, 31 is a CPU, and 32 is a multiplexer connected to the first bus 1a and the second bus 1b between the two relay switches 21a and 21b, respectively. Multiplex I for communication
C, 33 is an output interface (output I/F) for operating the two relay switches 21a, 21b.

To explain the internal configuration of the relay switch 21a, 40 is a coil excited by the output of the output I/F 33, 41 is a normally closed contact inserted in series with the first bus 1a,
42 is a normally closed contact inserted in series into the second bus 1b;
3 is a normally open contact inserted in series with the alarm lamp line 1c, and 44 is a normally open contact for grounding the alarm lamp line 1c between both relay switches 21a and 21b. The internal configuration of the relay switch 21b is also the same as the relay switch 2.
1a, 50 is a coil excited by the output of the output I/F 33, 51 is a normally closed contact inserted in series with the first bus 1a, and 52 is inserted in series with the second bus 1b. 53 is a normally open contact inserted in series with the alarm lamp line 1c, 54 is both relay switches 21a, 21
This is a normally open contact for grounding the alarm lamp line 1c between the lines 1c and 1c.

To explain the operation of this circuit, node A1
1 is healthy, the coils 40 and 50 are not excited by the output of the output I/F 33, so the four normally closed contacts 41 and 4
2, 51, 52 are closed, and the four normally open contacts 43, 4
4, 53, and 54 are open. Therefore, CPU31
can communicate through the multiplex IC 32 with other nodes connected to the transmission path consisting of the first bus 1a and the second bus 1b. Further, the alarm lamp 2 is off because one end is connected to the power source but the other end is open.

Now, a failure occurs in the node A11, and the CP
When the U31 receives a failure detection signal addressed to itself from the TMS node 13 through the multiplex IC 32, the CPU 3
1 connects two coils 40 and 50 via the output I/F 33.
Excite. When both coils 40, 50 are excited, the four normally closed contacts 41, 42, 51, 52 open and the four normally open contacts 43, 44, 53, 54 close. Therefore, the node A11 is electrically disconnected from both the first bus 1a and the second bus 1b. Moreover, at the same time, the alarm lamp 2 is grounded through the alarm lamp line 1c and lights up upon receiving power from the power supply, so that failure notification of the node A11 is performed at the same time as the disconnection of the node.

Note that a configuration may be adopted in which the TMS node 13 directly operates the relay switches 21a and 21b without involving the CPU 31. It may also be configured such that the nodes adjacent on both sides of the faulty node each receive a fault detection signal from the TMS node 13 and actuate a relay switch near the faulty node, thereby disconnecting the faulty node from the transmission path.

[0020] Furthermore, when a transmission path failure such as a short circuit between the two buses 1a and 1b occurs and the location of the failure can be identified, two relays sandwiching the failure location are activated by a command from the TMS node 13. A configuration may be adopted in which each normally closed contact of the switch is opened to isolate the faulty portion of the transmission line.

[0021]

Effects of the Invention As explained above, according to the invention of claim 1, the form of the transmission line is not only looped, but also
Since the configuration includes a node failure detection means for detecting a node failure and a node disconnection means for disconnecting the failed node from the transmission path in conjunction with the node failure detection means, it is possible to prevent the failure node from being disconnected from the transmission path. Not only can communication data be sent and received between the remaining healthy nodes even if the transmission line is partially cut off, but also other errors may occur due to a faulty node sending incorrect communication data to the transmission line. Malfunctions of healthy nodes can be prevented. Further, since it is possible to prevent an increase in the amount of traffic on the transmission path due to a faulty node transmitting a large amount of invalid communication data to the transmission path, the operation of a healthy node is not inhibited. In other words, it is possible to prevent the adverse effects of node failure on healthy nodes.

Further, according to the invention of claim 2, since a configuration is adopted in which a relay switch is provided which has both the function of disconnecting the failed node and the function of supplying power to the alarm lamp for notifying the failure, it is possible to disconnect the failed node and It is possible to reduce the number of component parts while simultaneously realizing failure notification.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a multiplex transmission device of the present invention.

FIG. 2 is a circuit diagram showing a detailed configuration example of a node A in FIG. 1 and two relay switches for disconnecting the node A from a transmission path.

[Explanation of symbols]

1...Transmission line 2...Alarm lamp 11...Node A 12...Node B 13...TMS node (node failure detection means) 21a, 2
1b, 22a, 22b... Relay switch (node disconnection means) 41, 42, 51, 52... Normally closed contact 43, 44, 53, 54... Normally open contact

Claims (2)

[Claims] Claim 1: In a multiplex transmission device in which a plurality of nodes are connected to a loop-shaped transmission path, a failure is detected by detecting a failure when a failure occurs in any one of the plurality of nodes. A multiplex transmission device comprising: node failure detection means for transmitting a signal; and node separation means for disconnecting a node in which the failure has occurred from the transmission path when receiving the failure detection signal. 2. The multiplex transmission device according to claim 1, further comprising an alarm lamp for notifying a failure, and the node disconnecting means disconnects the node in which the failure has occurred from the transmission path, and at the same time disconnects the node in which the failure has occurred from the transmission path. A multiplex transmission device characterized by having a relay switch that supplies power to the.