JP4746251B2 - Electronic system having a plurality of nodes connected to a network by optical waveguides, and method and computer program for diagnosing the electronic system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic system having a plurality of nodes connected to a network by optical waveguides, a method for self-testing such an electronic system, and a computer program program.
[0002]
[Prior art]
Various methods and systems are known from the prior art for checking optical waveguides.
[0003]
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 a failure. Reflective elements that reflect different wavelengths can be distributed in the lightwave transmission section, thereby identifying the location of the failure with high accuracy.
[0004]
From DE 69800438T2, a further development of the system is known, in which the position of a fault that can occur in one optical element is determined. This positioning is done by sending a signal to the optical element, measuring the signal reflected by the event of reflection, and comparing the measured reflected signal with the expected signal, where The expected signal is that of an optical element without failure.
[0005]
From DE 695199990 T2, a fault location determination method in an optical transmission system is known. In this case, a fault location apparatus using backscattering measurement technology is used, and this apparatus is used to evaluate a data string transmitted and reflected in the downstream direction by statistical characteristics.
[0006]
The optical transmission system is also used in automobiles. Specifically, for example, it is used in a bus system compliant with the MOST standard and the IEEE 1394 standard. Using the IEEE 1394 standard, a serial bus system can be realized, in which individual network nodes are connected to each other by optical waveguides. This standard assumes that the network can be configured by itself. That is, after conduction or reset, all nodes send some information about the selected themselves to the network. This information is received by all nodes. It is possible here to implement one node and to perform an additional management function for the so-called bus management of the network.
[0007]
For this purpose, the relevant node collects all the information of another node, processes it and stores it appropriately internally. There is a competition method for cases where multiple nodes with bus management functions are provided in the network. In this method, 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 provides information about the network topology and transmission speed.
[0008]
The IEEE 1394a and IEEE 1394b standards are extensions of the IEEE 1394 standard, especially for applications in the automotive field. These standards are available from The Institute of Electrical and Electronics Engineers, Inc., 345 East 47th Street, New York, NY 10017-2394, USA.
[0009]
Especially for applications in the automotive field, it is very important that the network functions are always available, in particular, various applications in the area of engine control, so-called body electronics, and information and multimedia technologies. It is very important that it is available for application.
[0010]
[Problems to be solved by the invention]
It is an object of the present invention to improve an electronic device and method for self-testing an optical waveguide network and a program for implementing this method.
[0011]
[Means for Solving the Problems]
According to the present invention, in the electronic system having a plurality of nodes connected to the network by the optical waveguide, the optical characteristics of the optical waveguide that deteriorate with time are diagnosed by self-test. Means for sending a message to each neighboring node with reduced transmission power; If this message is received, means for sending confirmation of receipt of the message to each node that was previously transmitted with reduced transmission power; Confirm receipt of this message Applicable An electron having a plurality of nodes connected to the network by an optical waveguide, characterized in that it comprises means for receiving from an adjacent node and means for outputting an error message to the bus management node if this confirmation is not received This problem can be solved by configuring the system, diagnosing the electronic system using this means, and further causing the electronic system to execute this diagnosis by a computer program.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Advantageous embodiments of the invention are described in the dependent claims.
[0013]
The knowledge underlying the present invention is that optical waveguides generally do not fail suddenly, and their optical properties can degrade over time, where such optical transmission characteristics are The way of degradation can also depend on the frequency.
[0014]
Network failures can be prevented with the present invention, where the degraded transmission characteristics of the optical waveguide link are already diagnosed by self-test before failure or functional failure.
[0015]
In an advantageous embodiment of the invention, such a self-test is performed, where this is done by a message being transmitted by a given node of the network with a transmission power reduced from the normal transmission power. It is. For example, the transmission power reduction can have a value of 3 dB or 6 dB. The reception of a message with a reduced transmission output is responded by confirmation of reception by a receiving node in some cases. This confirmation of reception is also returned via the optical waveguide.
[0016]
Here, this confirmation is preferably transmitted with a normal transmission power. However, this confirmation can also be transmitted with a reduced transmit power to test the reverse link.
[0017]
In another 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 messages can be done by increasing the output in stages, so that at which transmission output the transmission of the message still works.
[0018]
If the node that sent the message fails to receive the message acknowledgment or receives it only after increasing the reduced transmission power step by step, the corresponding node outputs an error message. This error message can also include as a parameter the magnitude of the reduced transmit power in steps.
[0019]
In an advantageous embodiment of the invention, the above error message can be stored by a bus management node. In this case, a maintenance plan can be automatically generated based on these error messages. For example, at the next inspection, the relevant optical waveguide with limited optical transmission characteristics can be replaced as a precaution, in which case the user of this vehicle is not aware of a malfunction or failure.
[0020]
In another advantageous embodiment of the invention, a self-test is introduced when the network is under light load. A self-test is preferably introduced when the ignition is switched off. For example, such a self-test can be performed cyclically at predetermined time intervals while the ignition is shut off.
[0021]
Another advantageous embodiment of the invention introduces a self-test, in which a bus management node sends a self-test command to all nodes of the network, so that these nodes are put into the corresponding mode. Alternatively, the bus management node sends a self-test message only to the immediately adjacent node. Due to this self-test message, only the node immediately adjacent to the bus management node shifts to the self-test mode. However, this node immediately next to the bus management mode forwards this self-test message to another adjacent node so that this adjacent node is also moved to the self-test mode. This self-test message is thus distributed throughout the network.
[0022]
In another advantageous embodiment of the invention, the transmission power at the node that 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 optical waveguide, until this optical waveguide is replaced at the next maintenance.
[0023]
【Example】
In the following, preferred embodiments of the invention will be described in detail with reference to the drawings.
[0024]
FIG. 1 shows a network 1 having nodes 100, 200, 300, 400, 500 and 600. Here, these nodes can be entirely different types of network elements and devices in automotive electronics, as well as completely different types of network elements and devices applied to information, entertainment and multimedia. In the embodiment of FIG. 1, the network 1 conforms to the IEEE 1394 standard for a serial bus system. According to this standard, individual nodes of the network can be connected via, for example, 4 to 6 types of cables or optical waveguides.
[0025]
In the embodiment of FIG. 1, nodes 100-600 are connected to each other by optical waveguides 2-6. Here, the optical waveguide can be a pair of optical waveguides for forward and return transmissions, or can be an individual optical waveguide that uses a different transmission frequency for each forward and return transmission.
[0026]
Each of the individual nodes 100 to 600 has one microprocessor having various ports for connecting optical waveguides. Here, each port has one input side and one output side. A photodiode is preferably used for transmission. This is because this is particularly cost-effective. In order to realize the optical waveguide, for example, glass fiber or plastic fiber can be used.
[0027]
The network 1 can be configured by itself according to the method specified in the IEEE 1394 standard. That is, the function of the bus management node is executed by one of the nodes 100 to 600 during the initialization phase of the network 1. In the example of FIG. 1, this is a node 100, which serves as a bus management node. That is, the node 100 is in charge of network management.
[0028]
The bus management node 100 has a storage device for the network topology of the network 1, that is, a storage device for information indicating individual nodes of the network and how to connect them. In addition to the network management function, the bus management node can perform self-test activation and evaluation functions.
[0029]
In order to introduce such a self-test, the bus management node commands the node using a predetermined command or a self-test message sent network-wide or exclusively, and for a limited time optical The transmission power is reduced. After receiving this command to reduce the transmit power, each node transmits a unique data packet to every port to which the device is connected. If this packet is successfully received, it is again confirmed by a unique data packet. If confirmation is not performed, it is particularly advantageous to send a new packet for inspection. If confirmation does not come even after one or more repetitions, the activated device transmits an error message to the bus management node.
[0030]
Such an error message includes information about which optical waveguide caused the error message. It is particularly advantageous if at least the error message is transmitted with normal transmission power, but also the confirmation is transmitted with normal transmission power. That is, the node only transmits a dedicated data packet for checking with reduced output.
[0031]
When a bus management node receives an error message, it is possible to memorize an image of the failure in a timely manner because of the inherent characteristics of the optical waveguide link, which generally inevitably degrades transmission characteristics. It can be pointed out to the service technician or user during maintenance that the transmission characteristics have deteriorated and may fail in the future. It is also possible to increase the transmission power as desired for further compensation.
[0032]
FIG. 2 shows a corresponding state diagram for nodes 100, 200 and 300 (see network 1 in FIG. 1). The other nodes in FIG. 1 are not shown for clarity in the state diagram of FIG.
[0033]
In order to introduce the self test, the bus management node 100 introduces the self test by transmitting a self test command “Link_Check_Mode” to all the nodes of the network. This can be done at any time. However, it is particularly advantageous to introduce a self-test procedure when the network load is low or when it is interrupted. When applied to an automobile, this is the case, for example, when the ignition is cut off.
[0034]
The self-test command includes a numerical value as a parameter, and the transmission output is reduced at each node by this numerical value. In the embodiment under consideration, the relevant parameter has a value of 3 dB.
[0035]
After receiving this self-test command, all nodes of the network send messages, for example unique data packets, with reduced power to test the corresponding connection cables. This message is sent from each node in the network to all nodes immediately adjacent to this node. The reception of this message is then responded by each receiving node, where this is done by a confirmation sent at normal output. This ensures that each connection link is checked in both directions.
[0036]
If no confirmation is received within a predetermined time, a new message is sent. This is preferably done by increasing the transmission power in stages. If the message sent repeatedly is not confirmed, the initiating device sends an error message to the bus manager indicating which link is not fully functional.
[0037]
This is illustrated in the state diagram of FIG. That is, the bus management node 00 transmits a message “Link_Test” to the node 200 immediately adjacent to the bus management node 100. Similarly, to this bus management node, the same message “Link_Test” is also sent to the node 600 (see FIG. 1) immediately adjacent to the bus management node 100, which is shown in FIG. Not shown.
[0038]
The node 200 transmits the message “Link_Test” to the adjacent nodes 100, 300 and 400, and only the message “Link_Test” to the node 300 is shown in FIG. The node 300 transmits the message “Link_Test” to the adjacent nodes 200 and 500, of which only the node 200 is shown in FIG.
[0039]
The node 200 responds to the reception of “Link_Test” from the bus management node 100 by confirmation, ie, a so-called response “Link_Test_ACK”. In order to realize such confirmation, a response mechanism provided in the IEEE 1394 standard can be used.
[0040]
Here, the bus management node 100 transmits the message “Link_Test” with a transmission output reduced by 3 dB from the normal transmission output. Despite the reduced transmission power, the message “Link_Test” is correctly received by the node 200. The correct reception of this message “Link_Test” is confirmed by the node 200, where it is a normal transmission output and is made by a response to the message “Link_Test” with the confirmation “Link_Test”.
[0041]
The message “Link_Test_ACK” of the node 200 is recorded by the bus management node 100. From this, it can be concluded for the bus management node 100 that the connection between the bus management node 100 and the node 200 is free of faults or significant degradation in the direction from the bus management node 100 to the node 200. .
[0042]
Correspondingly, the node 200 responds to the message “Link_Test” of the node 300 with a confirmation “Link_Test_ACK”. This is what the node 200 sends to the node 300 with normal transmission power for confirmation of correct reception, ie for confirmation of the message “Link_Test” sent from the node 300 with transmission power reduced by 3 dB. It is. This checks that the connection between the nodes 300 and 200 is fully functional, specifically in the direction from the node 300 to the node 200.
[0043]
Correspondingly, the bus management node 100 responds to the message “Link_Test” of the node 200 with a confirmation “Link_Test_ACK”, whereby a test for the optical waveguide link between the nodes 200 and 100 is received from the node 200. This is also done in the direction of node 100 and this is successful. In response to the message “Link_Test” of the node 200 to the node 300, the node 200 does not receive a response from the node 300 at first.
[0044]
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 the timer expires, the message “Link_Test” is newly transmitted to the corresponding node.
[0045]
In the embodiment of FIG. 2 under consideration, this means that, depending on the first message “Link_Test” from node 200 to node 300, a confirmation “Link_Test_ACK” is received from node 300 within the time determined by the timer. The message “Link_Test” is newly transmitted by the node 200 because it has not been received. This new transmission of the message “Link_Test” resets the timer.
[0046]
If the node 200 does not receive the confirmation in the form of “Link_Test_ACK” again at the time determined by this timer, the node 200 transmits an error message “Link_Test_Failed” to the bus management node 100. In this error message, as parameters, the data of the corresponding node and the direction of the optical waveguide link between the nodes causing the error message, that is, in this case, the optical waveguide link in the direction from the node 200 to the node 300 And directions are included. The corresponding parameter of the error message “Link_Test_Failed” is “Port_200_to_300”.
[0047]
After the timer expires for the first time, the transmission power can be increased for repeated transmission of the message “Link_Test” from the node 200 to the node 300, which is greater than the reduced transmission power described above. Whether or not a link with the node 300 can be formed from the node 200 is always checked based on a transmission output that is always equal to or lower than the normal transmission output. When such a link can be formed, the message “Link_Test_Failed” is transmitted. At this time, the transmission output increased stepwise as another parameter can be transmitted to the bus management node together.
[0048]
A corresponding flow diagram is shown in FIG. In step 30, the bus management node sends a command for self-test to all nodes of the network with a normal transmission output (see the self-test command “Link_Test_Check” in FIG. 2). By receiving this self-test command, all the nodes of the network shift to the test mode.
[0049]
In step 31, each node K of the network _i Is the set M _i A test message is sent to a node immediately adjacent in the network topology, referred to as a node of the network topology, where this is done with a reduced transmission power compared to the transmission power during normal operation. The amount of transmission power that is reduced compared to normal operation can be included as a parameter in the self-test command of step 30 or can be fixedly set.
[0050]
In step 31, the test message is transmitted by the node K. _i To the adjoining set M _i At a reduced transmit power, where this can be done serially or in parallel. Node K _i Sends a test message to the set M _i Sequentially to each individual node or node K _i Sets a plurality of test messages at substantially the same time M _i To all nodes.
This step 31 is for all nodes K of the network. ₀ , ..., K _i , ..., K _n Executed by.
[0051]
Node K in step 32 _i Checks the set M _i Whether or not the confirmation of reception of the test message in step 31 is performed by all the nodes. If this is done, this means that the corresponding optical waveguide link is operating normally, so that no further action is taken in step 33.
[0052]
Due to the examination in step 32, the set M _i If the opposite situation occurs for one or more of the nodes, this can already be interpreted as a failure situation and the node K _i Outputs a corresponding error message to the bus management node. However, in the embodiment of FIG. _i In step 34, it is checked whether the test message should be repeated.
[0053]
For example, it is possible to make a setting in this network in advance so that the transmission of the test message must be repeated once or several times before diagnosing that the line link is broken. For example, the test message has already been set M _i Node K to the corresponding node _i At this time, this node K _i If no confirmation has been received, a check may be made at step 34 to prevent further repetition of the test message. In this case, node K _i In step 36, a corresponding error is notified to the bus management node.
[0054]
If the test in step 34 causes the opposite, a test message with a reduced transmission power is newly added to node K. _i To set M _i It is transmitted to the corresponding node of (1) and it is checked whether or not reception confirmation has been performed by repeating the test message (see step 32). However, in the embodiment under consideration, first in step 35 the reduced transmission power is increased by a preset value, where this is always done below the normal transmission power. This test message is then sent to node K in step 31. _i To set M _i A new check is made in step 32 whether or not the confirmation can be received and transmitted to the one or more corresponding nodes of the first.
[0055]
FIG. 4 shows an alternative embodiment of the method of the invention. In step 40, the bus management node sends a test message to the immediately adjacent node in the network and with a reduced transmission power. The node right next to the bus management node is a set M _B Node.
[0056]
In step 41, the set M that has received the test message from the bus management node in spite of the reduced transmission power. _B Sends a confirmation to the bus management node. This is done with normal transmission power.
[0057]
In step 42, the set M _B The node sends a test message received from the bus management node to each adjacent node. That is, the set M _B Each individual node forwards a test message to the immediately adjacent node in the network. In step 43, the set M _B The node adjacent to this node may confirm receipt of the test message in some cases, after which this test message is forwarded to another node adjacent to this node. This continues in the same manner.
[0058]
In this way, test messages are distributed throughout the network. Acknowledgments for receipt of test messages sent from individual nodes of the network are recorded by the bus management node, which is compared in step 44 to the network topology.
[0059]
If all the confirmations to be expected 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 device of the bus management node, so that, for example, a service plan is automatically generated.
[0060]
The storage device with the error message or service plan can be read out at the time of maintenance, whereby the corresponding optical waveguide is replaced for prevention. Further, in step 45, the command can be transmitted from the bus management node to a node that does not confirm the test command. Based on this at the relevant node, the transmission power is increased above the normal transmission power, so that, for example, a relatively large attenuation of the optical waveguide link is compensated.
[0061]
FIG. 5 shows another alternative embodiment of the method of FIG. Step 50 corresponds to step 40 of FIG. In step 51, the set M _B The node also sends a confirmation with a reduced transmission power. That is, upon receipt of confirmation at the bus management node, the optical waveguide link is simultaneously inspected in the direction from the bus management node to the adjacent node and vice versa.
[0062]
Correspondingly set M _B In step 52, the node forwards the test message to the adjacent node, but here, unlike step 42 in FIG. That is, in this case, it is not transferred to the bus management node.
[0063]
In step 54, the test message is also distributed to the entire network sequentially in the same manner as in step 43 of FIG. 4, and is adjacent to the node that received the test message except for the node from which the test message was received by the corresponding node. A test message is sent to all nodes.
[0064]
Steps 54 and 55 are executed in the same manner as steps 44 and 45 in FIG.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of an advantageous embodiment of an electronic system according to the present invention.
FIG. 2 shows an embodiment of a self-test method according to the invention.
FIG. 3 is a flow diagram of an embodiment of a method according to the present invention in which a self test is initiated by a self test command of a bus management node.
FIG. 4 shows an embodiment of the method according to the invention in which a self-test is activated by a test message of the bus management node.
FIG. 5 shows an alternative embodiment of the method of FIG.
[Explanation of symbols]
1 network
2-6 Optical waveguide
100, 200, 300, 400, 500, 600 nodes
K _i node
M _i Node K _i Set of adjacent nodes

Claims (28)

In an electronic system having a plurality of nodes (100, 200, 300, 400, 500, 600) connected to a network (1) by optical waveguides (2, 3, 4, 5, 6),
In order to diagnose the optical properties of the optical waveguide (2, 3, 4, 5, 6), which deteriorate with time, by self-test,
Means for transmitting a message to each adjacent node with a reduced transmission power via the optical waveguide (2, 3, 4, 5, 6), and when the message is received, the message is reduced first. Means for sending confirmation of receipt of the message to each node that has sent with the sent output,
Means for receiving confirmation of reception of the message from the corresponding adjacent node;
Means for outputting an error message to the bus management node (100) when the confirmation is not received,
An electronic system having a plurality of nodes connected to a network by optical waveguides. The network is configured in accordance with a serial bus system, preferably according to the IEEE 1384, IEEE 1394a or IEEE 1394b standard;
The electronic system according to claim 1. Applied to vehicles, for example applied to automotive electronics,
The electronic system according to claim 1 or 2. The network has a tree structure;
The electronic system according to any one of claims 1 to 3. The bus management node has means for transmitting a self-test command to the nodes of the network;
Upon receipt of the self-test command, the means for transmitting of the node is activated.
The electronic system according to any one of claims 1 to 4. The bus management node has means for transmitting a self-test message to each adjacent node,
Each adjacent node has means for transferring the self-test message,
The electronic system according to any one of claims 1 to 5. Each node has means for sending confirmation that it has received a message from an adjacent node,
The electronic system according to any one of claims 1 to 6. The means for transmitting the confirmation is configured to transmit the confirmation with reduced transmission power;
The electronic system according to claim 7. The means for transmitting the message in each node is configured to repeatedly transmit the message after a preset time if the receipt of the message is not confirmed within a preset time. Yes,
The electronic system according to any one of claims 1 to 8. The means for transmitting is configured to increase the transmission output step by step when repeating the transmission of the message,
The electronic system according to claim 9. The means for sending the error message is configured such that the error message includes data indicating a magnitude of the transmission power to be reduced;
The electronic system according to claim 10. The means for transmitting the message at each node may include an increased transmission power message if there is an error message about the node and / or a link between the node and another node in the network topology. The electronic system according to any one of claims 1 to 11, wherein the electronic system is configured to transmit with the electronic system. The bus management node has a storage device for storing a network topology,
The bus management node comprises means for assigning error messages to nodes and / or line links in a network topology;
The electronic system according to any one of claims 1 to 12. The bus management node has means for increasing the transmission power of the means for transmitting a message in one of the plurality of nodes, wherein the corresponding error message There is
Said means for increasing the transmission power is preferably constituted by means for transmitting a corresponding command to the corresponding node,
The electronic system according to claim 13. The bus management node has a storage device for storing an error message.
The electronic system according to any one of claims 1 to 14. Means for generating a maintenance plan based on the one or more error messages;
The electronic system according to any one of claims 1 to 15. Means for automatically initiating a self-test when the electronic system is in a light load state or shut off state;
The electronic system according to any one of claims 1 to 16. The means for automatically introducing the self-test is configured such that the self-test is performed when the ignition of the automobile is cut off.
The electronic system according to claim 17. In a method for self-testing an electronic system having a plurality of nodes connected to a network by optical waveguides,
In order to diagnose the optical properties of the optical waveguide (2, 3, 4, 5, 6) that deteriorate over time by self-test,
When a message is transmitted from each node to the adjacent node of the node with a reduced transmission power via the optical waveguide (2, 3, 4, 5, 6) , and the message is received , Send confirmation of receipt of the message from the corresponding adjacent node to each node that sent it earlier with reduced transmission power,
When the confirmation is not received, an error message is output to the bus management node from the node that has been transmitted with the previously reduced transmission output.
How to self-test electronic systems. Introducing the self-test by a self-test command of the bus management node to all nodes of the network,
The method of claim 19. The self-test is introduced by the self-test message of the bus management node to the adjacent node,
Forwarding each self-test message by each neighboring node to another neighboring node;
21. A method according to claim 19 or 20. Sending confirmation that the message has been received, with reduced transmission power,
The method according to any one of claims 19-21. If the confirmation is not performed within a predetermined time, the message is repeatedly transmitted from the corresponding node with a reduced transmission output.
23. A method according to any one of claims 19-22. Increasing the reduced transmission power step by step upon repeated output of the message;
24. The method of claim 23. Increase the transmit power of the node that caused the error message to exceed the normal transmit power,
25. A method according to any one of claims 19 to 24. The reduced transmission power at which confirmation was received is part of the error message,
26. A method according to any one of claims 19-25. If the network is under light load, it is advantageous to automatically introduce a self-test if the ignition of the relevant car is cut off,
27. A method according to any one of claims 19 to 26. Let an electronic system with multiple nodes connected to the network by an optical waveguide perform the following steps to determine the optical properties of the optical waveguide (2, 3, 4, 5, 6) that degrade over time: In a computer program that diagnoses by self-test,
Transmitting a message from each node to the adjacent node of the node with reduced transmission power via the optical waveguide (2, 3, 4, 5, 6) ;
If the message is received, sending confirmation of message reception from the corresponding adjacent node to each node that has been transmitted with the previously reduced transmission power;
A computer program that, when the confirmation is not received, executes a step of outputting an error message to a bus management node from a node that has been transmitted with a reduced transmission power.

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