JP2003114835A - Electronic system having multiple nodes connected to network by optical waveguide, and method and computer program for diagnosing the electronic system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an electronic device and method for self-testing an optical waveguide network, and a program for executing the method. SOLUTION: In this electronic system having multiple nodes connected to a network by optical waveguides, each node comprises a means for transmitting a message to each adjacent node with a reduced transmitting output; a means for receiving the confirmation of receipt of this message from the related adjacent node; and a means for outputting an error message to a bus management node when receiving no confirmation. This electronic system is diagnosed by use of these means, and the diagnosis is executed by a computer program.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic system having a plurality of nodes connected to a network by an optical waveguide, a method for self-testing such an electronic system, and a computer program program.

[0002]

Various methods and systems for checking optical waveguides are known from the prior art.

EP-A-823621 describes an optical waveguide transmission section, in which a number of diffraction gratings are provided along the optical waveguide to identify the location of the fault. Reflective elements that reflect different wavelengths can be distributed in the lightwave transmission section, whereby the location of the fault can be identified with high accuracy.

A further development of this system is known from DE 69 400 438 T2, in which the position of a possible fault in one optical element is determined.
This position determination is done by sending a signal to this optical element, measuring the signal reflected by the event of the reflection and comparing the measured reflected signal with the expected signal, where The expected signal is the signal of the optical element without failure.

A method for determining a fault position in an optical transmission system is known from DE 6951990T2. A fault-locating device based on the backscatter measurement technique is used here, which device is used to evaluate the data stream transmitted in the downstream direction and reflected by statistical characteristics.

Optical transmission systems are also used in automobiles, and more specifically, for example, MOST standard and IEEE.
It is used in bus systems that comply with the E1394 standard. Using the IEEE 1394 standard, a serial bus system can be realized, where the individual network nodes are connected to each other by optical waveguides. The premise of this standard is that the network can be configured by itself. That is, after continuity or reset, every node sends some information about itself to the network. This information is received by all nodes. Here we are implementing one node,
It is possible to allow this node to perform additional management functions to the so-called bus management of the network.

To this end, the node in question collects all the information of another node, processes it and stores it internally appropriately. A competition system is provided for the case where a plurality of nodes having a bus management function are provided in the network. In this system, one of these nodes becomes the "winner" and performs bus management. is there. Here, the bus management node determines, for example, the power supply, activity and bus occupancy of the individual nodes and also provides information about the network topology and the transmission speed.

IEEE 1394a and IEEE 139
The 4b standard is an IE for applications especially in the automotive field.
It is an extension of the EE1394 standard. These standards are
Institute of Electrical and Electronics Engineers,
Inc., 345 East 47th Street, New York, NY 10017-
Available from 2394, USA.

In particular for applications in the automotive field,
It is extremely important that the network functions are always available, in particular for engine control, various applications in the area of so-called body electronics, and for information and multimedia technology applications. .

[0010]

SUMMARY OF THE INVENTION It is an object of the invention to improve an electronic device, a method and a program implementing the method for self-testing an optical waveguide network.

[0011]

SUMMARY OF THE INVENTION According to the present invention, the above object is to provide an electronic system having a plurality of nodes connected to a network by optical waveguides, wherein each node has a reduced transmission power and each adjacent node. To send a message to and confirm receipt of this message,
Characterized in that it comprises means for receiving from the associated neighbor node and means for outputting an error message to the bus management node if this confirmation is not received,
Solved by configuring an electronic system having a plurality of nodes connected to a network by an optical waveguide, and by diagnosing the electronic system by utilizing this means, and further executing this diagnosis by a computer program. To be done.

[0012]

Advantageous embodiments of the invention are described in the respective dependent claims.

The knowledge underlying the present invention is that optical waveguides generally do not fail suddenly, but their optical properties can deteriorate over time, where such optical The manner of deterioration of the transmission characteristics may also depend on the frequency.

The invention makes it possible to prevent network failures, since this is done by the fact that the degraded transmission properties of the optical waveguide link can already be diagnosed by self-test before a failure or a malfunction. is there.

In an advantageous embodiment of the invention, such a self-test is carried out, in which a given node of the network sends a message with a transmission power which is reduced compared to the normal transmission power. It is done by. For example, the transmission power reduction is 3 dB or 6 d
It can have a value of B. The reception of the message with the reduced transmission power is sometimes responded by confirmation of reception by the receiving node. Confirmation of this reception is also returned via the optical waveguide.

This confirmation is then preferably transmitted at the normal transmission power. However, this confirmation can likewise be transmitted with reduced transmit power to test the reverse link.

In a further advantageous embodiment, a new message with a reduced transmission power is transmitted if the receipt of the message is not confirmed within a predetermined time. Repeated transmission of the message can be done by increasing the power in steps, which makes it possible to see at which transmission power the transmission of the message still works.

If the node that sent the message cannot receive an acknowledgment of receipt of the message or receives it only after gradually increasing the reduced transmission power, the corresponding node outputs an error message. The error message can also include, as a parameter, the size of the reduced transmission power that is gradually increased.

In an advantageous embodiment of the invention, the above error message can be stored by the bus management node. In this case, a maintenance plan can be automatically generated based on these error messages. At the next inspection, for example, the corresponding light guides with limited light transmission properties can be replaced proactively, without the user of this vehicle being aware of any malfunction or malfunction.

In another advantageous embodiment of the invention, a self test is introduced when the network is under light load. Advantageously, the self-test is introduced when ignition is off. For example, such a self-test can be performed cyclically at predetermined time intervals while the ignition is off.

Another advantageous embodiment of the invention introduces a self-test, in which the bus management node sends a self-test command to all the nodes of the network, so that these nodes are put into a corresponding mode. To Alternatively, the bus management node sends the self-test message only to its immediate neighbors. This self-test message causes only the node immediately next to the bus management node to enter the self-test mode. However, immediately next to the bus management mode, this node forwards this self-test message to another neighboring node so that this neighboring node also goes into self-test mode. This self-test message is thus distributed throughout the network.

In another advantageous embodiment of the invention, the transmission power at the node which caused the error message is increased above the normal transmission power. This makes it possible, for example, to temporarily eliminate the attenuation caused by the corresponding light guide, until this light guide is replaced at the next service.

[0023]

The preferred embodiments of the present invention will now be described in detail with reference to the drawings.

In FIG. 1, nodes 100, 200, 300,
A network 1 having 400, 500 and 600 is shown. Here, these nodes can be totally different kinds of network elements and devices in the electronics of automobiles, and different kinds of network elements and devices applied to information, entertainment and multimedia. In the embodiment of FIG. 1, network 1 complies with the IEEE 1394 standard for serial bus systems. This standard allows individual nodes of the network to be connected via, for example, 4 to 6 types of cables or optical waveguides.

In the embodiment of FIG. 1, nodes 100-600 are connected together by optical waveguides 2-6. Here, the optical waveguide can be a pair of optical waveguides for forward and return transmissions, or it can be a separate single optical waveguide that uses different transmission frequencies for forward and return transmissions.

Each individual node 100-600 has one microprocessor with various ports for connecting optical waveguides. Where each port is 1
It has one input side and one output side. A photodiode is preferably used for the transmission. This is because this is particularly cost-effective. For example, glass fibers or plastic fibers can be used to realize the optical waveguide.

The network 1 can itself be configured according to the method specified in the IEEE 1394 standard. That is, node 100-
Network 1 by one of the nodes 600
The function of the bus management node is executed during the initialization phase of. In the example of FIG. 1, this is node 10
0, this node functions as a bus management node. That is, the node 100 is in charge of network management.

The bus management node 100 is a storage device for the network topology of the network 1,
That is, it has a storage device for information indicating individual nodes of this network and how to connect them. In addition to network management functions, this bus management node can perform self-test activation and evaluation functions.

In order to introduce such a self test,
The bus management node commands the node using predetermined commands or self-test messages transmitted network-wide or exclusively so that the optical transmission power is reduced for a limited time.
After receiving this command to reduce the transmit power, the individual nodes transmit their own data packets to all the ports to which the device is connected. If this packet is successfully received, the confirmation is again done by a unique data packet. If no confirmation is made, it is particularly advantageous to send a new packet for inspection. If the confirmation does not arrive even after repeating once or a plurality of times, the device that has started up sends an error message to the bus management node.

Such an error message contains information about which optical waveguide caused this error message. It is particularly advantageous if at least the error message is transmitted at the normal transmission power, but also the confirmation is transmitted at the normal transmission power. That is, by the node, only data packets dedicated for checking are sent with reduced power.

When the bus management node receives an error message, the transmission characteristics generally inevitably deteriorate gradually due to the inherent characteristics of the optical waveguide link.
An image of the failure can be stored in a timely manner, and it can be pointed out to the service technician or the user at the next maintenance that the transmission characteristic has deteriorated and the failure may occur in the future. It is also possible to increase the transmission power as desired for further compensation.

In FIG. 2, nodes 100, 200 and 30 are shown.
The corresponding state diagram for 0 (see network 1 in FIG. 1) is shown. The other nodes in FIG. 1 are not shown in the state diagram of FIG. 2 for clarity.

In order to introduce the self test, the bus management node 100 uses the self test command "Link
Introduce self-test by sending _Check_Mode to all nodes in the network. This can be done at any time. However, it is especially advantageous to introduce a self-test procedure when the network is lightly loaded or is cut off. In automotive applications, this is the case, for example, when ignition is switched off.

The self-test command includes a numerical value as a parameter, and the transmission output at each node is reduced by this numerical value. In the example under consideration, the relevant parameter has a value of 3 dB.

After receiving this self-test command,
All nodes of the network send messages, for example unique data packets, with reduced power and test the corresponding connecting cables. This message is sent by each node in the network to all nodes immediately next to it. The receipt of this message is then responded to by each receiving node, which is done by means of a confirmation sent at normal output. This guarantees that each connecting link is reliably checked in both directions.

If no confirmation is received within the predetermined time,
A new message is sent. This is preferably done by increasing the transmission power in steps. If the repeated message is also not confirmed, the invoking device sends an error message to the bus manager indicating which link is not fully functional.

This is shown in the state diagram of FIG.
That is, the bus management node 00 transmits the message “Link_Test” to the node 200 immediately adjacent to the bus management node 100. Similarly, the same message "Link_
Similarly, "Test" is sent to the node 600 (see FIG. 1) immediately adjacent to the bus management node 100, but this is not shown in FIG. 2 for the sake of clarity.

The node 200 receives the message "Link_Tes
Although "t" is transmitted to the immediately adjacent nodes 100, 300 and 400, only the message "Link_Test" to the node 300 is shown in FIG. Node 300
Sends the message "Link_Test" to the next node 200
And 500, but in FIG.
Only 00 is shown.

The node 200 responds to the reception of "Link_Test" from the bus management node 100 by confirmation, that is, by the so-called response "Link_Test_ACK". In order to realize such confirmation, I
The mechanism for response provided in the EEE1394 standard can be used.

Here, the bus management node 100
Sends the message "Link_Test" from the normal transmission output 3
The transmission output was reduced by only dB. The message "Link_Test" is correctly received by the node 200 despite the reduced transmission power. This message "Link_Test" has been correctly received.
00, where this is the normal send output, and the message “Link_Tes” with confirmation “Link_Test”
The response to "t" is done.

The message "Link_Test_" of the node 200
“ACK” is recorded in the bus management node 100. From this, it can be concluded for the bus management node 100 that the bus management node 1
The connection between 00 and node 200 is that there is no obstruction or significant degradation in the direction from bus management node 100 to node 200.

Accordingly, the node 200 also confirms the message “Link_Test_AC” in the message “Link_Test” of the node 300.
Reply with "K". This is because the node 200 sends the message "Link sent by the node 300 for confirmation of correct reception, ie with a transmission power reduced by 3 dB.
Node 300 with normal transmission output to confirm “_Test”
Is to be sent to. What is checked by this is that the connection between nodes 300 and 200 is fully functional, in particular from node 300 to node 200.

Correspondingly, the bus management node 100
Responds to node 200's message "Link_Test" with a confirmation "Link_Test_ACK", so that the test on the optical waveguide link between nodes 200 and 100 also goes from node 200 to node 100. Well, this has been successful. In response to the message “Link_Test” of the node 200 to the node 300, the node 200 initially does not receive a response from the node 300.

The timer is started with the transmission of the message "Link_Test". If the message "Link_Test_ACK" is not received from the corresponding node that has transmitted the message "Link_Test" before this timer expires, the message "Link_Test" is newly transmitted to the corresponding node.

In the embodiment of FIG. 2 under consideration, this means that the first message “Link_Test” from node 200 to node 300 will result in a confirmation “Link_Test_ACK” within the time defined by the timer. The message “Link_Test” is newly transmitted by the node 200 because it was not received from the node 300. This new transmission of the message "Link_Test" resets the timer.

If the node 200 does not receive a confirmation in the form of "Link_Test_ACK" again in the time defined by this timer, the node 200 informs the bus management node 100 of the error message "Link_Test_Faile".
Send "d". This error message has as parameters the data of the corresponding node and the direction of the optical waveguide link between the nodes that caused this error message, that is, the optical waveguide link in the direction from node 200 to node 300 in this case. The directions of and are included. The corresponding parameter of the error message "Link_Test_Failed" is "Port_200_to_300".

After the timer first expires, the node 200
The transmission power can be increased for repeated transmission of the message "Link_Test" from the node to the node 300,
Thereby, it is checked whether a link with the node 300 can be formed from the node 200 with a transmission power which is greater than the reduced transmission power mentioned above, but which is always below the normal transmission power. When such a link can be formed, the message “Link_Test_Failed” is transmitted, but in this case, the transmission output increased stepwise as another parameter can be transmitted together to the bus management node.

A corresponding flow chart is shown in FIG.
In step 30, the bus management node sends a command for the self-test to all the nodes of the network with a normal transmission output (see the self-test command "Link_Test_Check" in FIG. 2). Upon receipt of this self-test command, all nodes of the network enter test mode.

In step 31, each node K _i of the network sends a test message to the node immediately next to it in the network topology, referred to as the node of the set M _i , which is more than the transmission power during normal operation. Is also done with reduced transmit power. The amount of transmission output that is reduced as compared with the normal operation can be included as a parameter in the self-test command in step 30, or can be fixedly set.

The transmission of the test message in step 31 takes place from the node K _i to its adjacent nodes of the set M _i with reduced transmission power, which can be done serially or in parallel. That is, the node K _i sends a test message to the individual nodes of the set M _i sequentially, or the node K _i sends a plurality of test messages to all the nodes of the set M _i substantially simultaneously. . This step 31 is performed by all nodes K ₀ , ..., K _i , ..., K _n of the network.

In step 32, node K _i checks that all nodes of set M _i
It is whether or not the confirmation of the reception of the test message 1 has been performed. If this is done, this means that the corresponding optical waveguide link is operating normally and no further action is taken in step 33.

If the opposite of the above occurs for one or more nodes of the set M _{i as} a result of the check in step 32, this can already be construed as a failure, and the node K _i is considered appropriate. Error message to the bus management node. However, in the embodiment of FIG. 3, the node K _i first checks in step 34 whether the test message should be repeated.

It is also possible, for example, to pre-configure in this network so that the transmission of the test message has to be repeated once or several times before diagnosing the faulty line link. For example, a test message is already set M in advance.
_i are sent to the appropriate node from the node K _i of,
If this node K _i has not received confirmation at that time,
It is also possible to perform a check in step 34 so that no further repetition of the test message is necessary. In this case, the node K _i notifies the bus management node in step 36 of the corresponding error.

If the check in step 34 leads to the opposite, a test message with a reduced transmission power is newly transmitted from node K _i to the corresponding node of set M _i and received by repeating the test message. It is checked whether or not the confirmation has been made (see step 32). However, in the embodiment under consideration here, first in step 35, the reduced transmission power is increased by a preset value, which is always below the normal transmission power. This test message is then newly transmitted in step 31 from the node K _i to one or more corresponding nodes of the set M _i with increased transmission power,
A new check is made in step 32 whether a confirmation can be received.

FIG. 4 shows an alternative embodiment of the method according to the invention. In step 40, the bus management node sends a test message to the node immediately next to it in the network, yet with reduced transmit power. The node immediately next to the bus management node is the node of set M _B.

In step 41, the nodes of the set M _B that have received the test message from the bus management node, despite the reduced transmission power, send a confirmation to the bus management node. This is done with normal transmit power.

In step 42, the nodes of the set M _B send the test message received from the bus management node to each adjacent node. That is, each individual node of the set M _B forwards the test message to its immediate neighbor in the network.
In step 43, the node adjacent to the node of set M _B acknowledges receipt of a test message, possibly after which this test message is forwarded to another node adjacent to this node. This is likewise continued below.

In this way, test messages are distributed throughout the network. Acknowledgments for receipt of test messages sent by individual nodes of the network are recorded by the bus management node,
This is compared in step 44 with the network topology.

If all the expected confirmations could be recorded by the bus management node, this means that none of the optical waveguide links have failed. In the opposite case, the bus management node forms a corresponding error message in step 45 and stores it in the storage of the bus management node, whereby a service plan, for example, is automatically generated.

The storage device with the error message or service plan can be read out at the time of maintenance, whereby the corresponding light guide is replaced as a precaution.
Further, in step 45, the bus management node can send a command to a node that does not confirm the test command. At the node concerned, the transmission power is thereby increased above the normal transmission power, which compensates for the relatively large attenuation of the optical waveguide link, for example.

FIG. 5 shows another alternative embodiment of the method of FIG. Step 50 is step 40 of FIG.
Corresponds to. In step 51, the nodes of the set M _B also send confirmations with reduced transmission power. That is, upon receipt of the confirmation at the bus management node, the optical waveguide link is simultaneously examined in the direction from the bus management node to the adjacent node and vice versa.

Correspondingly, the nodes of the set M _B are found in step 5
In step 2, the test message is transferred to the adjacent node, but unlike step 42 in FIG. 4, the test message is not transferred to the node that is the transmission source of the received test message. That is, in this case, it is not transferred to the bus management node.

In step 54, the test message is also sequentially distributed to the entire network in the same manner as in step 43 of FIG. 4, and the node that has received the test message is excluded except the node that is the source of the test message that the corresponding node has received. A test message is sent to all nodes adjacent to.

Steps 54 and 55 are performed similarly to steps 44 and 45 of FIG.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an advantageous embodiment of an electronic system according to the invention.

FIG. 2 is a diagram showing an embodiment of a self-test method according to the present invention.

FIG. 3 is a flow chart of an embodiment of a method according to the invention in which a self-test is activated by a self-test command of a bus management node.

FIG. 4 shows an embodiment of a method according to the invention in which a self-test is activated by a test message of a bus management node.

5 shows an alternative embodiment of the method of FIG.

[Explanation of symbols]

Set of neighbor nodes of 1 network 2-6 optical waveguide 100,200,300,400,500,600 node _{K i} node _{M i} node _{K i}

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Wolfgang Biar             Germany Remshalden Ina             -Seidel-Strasse 9 F term (reference) 5B083 AA08 BB06 BB08 DD12 EF15                 5K033 BA06 BA08 DB22

Claims (28)

[Claims] 1. A plurality of nodes (100, 200, 300, 400, 500, 600) connected to a network (1) by optical waveguides (2, 3, 4, 5, 6).
An electronic system comprising: each of the nodes sending a message to each neighbor with reduced transmission power; means for receiving confirmation of receipt of the message from an associated neighbor; An electronic system having a plurality of nodes connected to the network by optical waveguides, characterized in that it comprises means for outputting an error message to the bus management node (100) if not received. 2. The electronic system according to claim 1, wherein the network is configured according to a serial bus system, preferably according to the IEEE 1384, IEEE 1394a or IEEE 1394b standard. 3. The electronic system according to claim 1, wherein the electronic system is applied to a vehicle, for example, applied to automobile electronics. 4. The electronic system according to claim 1, wherein the network has a tree structure. 5. The bus management node has means for transmitting a self-test command to a node of the network, and means for transmitting the self-test command of the node upon receipt of the self-test command. Is activated, the electronic system according to claim 1. 6. The bus management node has means for transmitting a self-test message to each adjacent node, and each adjacent node has means for transferring the self-test message. The electronic system according to any one of 1 to 5. 7. The electronic system according to claim 1, wherein each node has means for transmitting an acknowledgment that a message has been received from a neighboring node. 8. The electronic system of claim 7, wherein the means for transmitting the confirmation is configured to transmit the confirmation with reduced transmission power. 9. The means for transmitting the message in each node repeatedly transmits the message after the preset time if the reception of the message is not confirmed within the preset time. The electronic system according to claim 1, wherein the electronic system is configured as described above. 10. The electronic system of claim 9, wherein the means for transmitting is configured to incrementally increase the transmission power as the message transmission is repeated. 11. The electronic system of claim 10, wherein the means for sending an error message is configured such that the error message includes data indicating a magnitude of the reduced transmit power. 12. The means for sending the message at each node includes a message, if there is an error message about the node and / or the link between the node and another node of the network topology, Electronic system according to any one of the preceding claims, configured to transmit with an increased transmit power. 13. The bus management node has a storage device for storing a network topology, and the bus management node has means for assigning an error message to a node and / or a track link in the network topology. The electronic system according to any one of claims 1 to 12. 14. The bus management node has means for increasing a transmission output of a means for transmitting a message in one of the plurality of nodes, wherein the node is provided to the node. There is a corresponding error message, and the means for increasing the transmission power are advantageously constituted by means for transmitting a corresponding command to the corresponding node. . 15. The electronic system according to claim 1, wherein the bus management node has a storage device for storing an error message. 16. The electronic system according to claim 1, further comprising means for generating a maintenance plan based on the one or more error messages. 17. The electronic device according to claim 1, further comprising means for automatically activating a self-test when the electronic system is in a light load state or a cutoff state. system. 18. The electronic system of claim 17, wherein the means for automatically introducing the self-test is configured to perform the self-test when the vehicle ignition is shut off. 19. A method of self-testing an electronic system having a plurality of nodes connected to a network by optical waveguides, wherein a message is transmitted from each node to a node adjacent to the node with reduced transmit power, If a message is received, a confirmation of the receipt of the message is sent from the adjacent node in question to each node that sent it with the reduced transmit power, and if no confirmation is received, an error message is sent. Is output to the bus management node from the node that has previously transmitted with the reduced transmission output, a method for self-testing an electronic system. 20. The method of claim 19, wherein the self test is introduced by a bus management node self test command to all nodes of the network. 21. The self-test is introduced by a self-test message of a bus management node to an adjacent node, and the self-test message is transferred to another adjacent node by each adjacent node. the method of. 22. The method according to claim 19, wherein the transmission of the confirmation that the message has been received is carried out with a reduced transmission power. 23. The method according to any one of claims 19 to 22, wherein if the confirmation is not performed within a predetermined time, the message with the reduced transmission power is repeatedly transmitted from the corresponding node. . 24. The method according to claim 23, wherein the reduced transmission power is increased in steps upon repeated output of a message. 25. The method according to any one of claims 19 to 24, wherein the transmission power of the node which caused the error message is increased above the normal transmission power. 26. The method according to any one of claims 19 to 25, wherein the reduced transmission power upon which the confirmation is received is part of an error message. 27. A self-test is automatically introduced when the network is under light load, preferably when the ignition of the vehicle concerned is switched off. The method described in. 28. A computer program product, means for carrying out the method according to any one of claims 19 to 27 when the computer program is executed in an electronic system, preferably an electronic vehicle system. A computer program product, comprising: