DE102019104918A1 - Method for recognizing a faulty bus node address assignment in data bus systems with auto-addressing by means of an addressing stream - Google Patents

Abstract

The invention relates to a method for identifying a faulty bus node address assignment in, for example, linear data bus systems with auto-addressing by means of an addressing stream, such as LIN data bus systems with auto-addressing. The method comprises the steps of carrying out the auto-addressing of the n bus nodes, initiating the supply of an addressing current by a bus node - the supply bus node - whereby the initiating is carried out by the bus master, recording the data bus current by the bus nodes and determining a bus node-specific bus current measured value Decision as to whether an addressing stream flows through the respective bus node and determination of a bus node-specific addressing current presence value, whereby the decision can be made in the bus node and / or in the bus master, the transmission of the bus node-specific bus current measurement value and / or the bus node-specific addressing current presence value from the bus node to the bus master, the formation of a feed bus node-specific result vector from the received bus node-specific addressing current values and the comparison of the feed bus node-specific result vector with a Infeed bus node specific expectation vector.

Description

Generic term

The invention is directed to a method for detecting an incorrect bus node address assignment in data bus systems with auto-addressing by means of an addressing stream and an associated device.

General introduction

• EP 1490 772 B1 , EP 1 603 282 B1 , DE 10 2017 122 365 B3 und DE 10 2010 026 431 B4 .

Auto-addressing methods have been known for a long time. To understand the following disclosure, knowledge of the following scriptures is strongly recommended:

• EP 1490 772 B1 , EP 1 603 282 B1 , DE 10 2017 122 365 B3 and DE 10 2010 026 431 B4 .

The auto-addressing technology described in these documents is used primarily in the automotive industry for the auto-addressing of bus nodes in a sequential LIN data bus with a bus master for controlling these bus nodes. The method presented here assumes that the bus nodes are inserted into the data bus so that they form a linear chain along the data bus, with the bus master located at one of the two ends, which is referred to below as the start of the bus.

Further unpublished applications of the applicant are pending for the auto-addressing of such linear chains of bus nodes along a data bus: DE 10 2017 128 489.3 , DE 10 2017 128 923.2 , DE 10 2018 104 488.7 , DE 10 2018 104 489.5 , DE 10 2018 124 279.4 , DE 10 2018 124 281.6 .

Furthermore, the registration DE 10 2017 012 179.6 on this subject still pending.

The combination of the technology presented here with the technical content of all of these above-mentioned documents is part of this disclosure.

An essential feature of the auto-addressing methodology proposed in these documents is that each bus node that has not yet been addressed feeds an auto-addressing stream in the direction of the bus master in an addressing cycle initiated by the bus master. All bus nodes feeding in the addressing stream and the bus master can then recognize that they are not the bus nodes furthest away from the bus master. Only the bus node, which on the first does not have a valid bus node address and on the second does not detect an addressing stream of a subsequent bus node that is further away from the bus master, accepts the bus node address offered by the bus master in response to a command from the bus master. We understand a valid bus node address to be an address that was correctly assigned to the bus node in the course of the address allocation process. It is conceivable to assign a provisional bus node address to the bus node in a different way before the addressing process, for example by means of a random number method, which is not related to the physical position in the data bus. By accepting the bus node address to be assigned offered by the bus master, this bus node then immediately has a valid bus node address in the sense of this document and then no longer takes part in subsequent addressing cycles until the bus node address becomes invalid, for example at the command of the bus master. In particular, it no longer feeds an addressing stream in the direction of the bus master in the subsequent addressing cycles, which means that the bus node closest to it that has not yet been addressed can then recognize itself as the last bus node in the next addressing cycle and can take over the further bus node address then offered from the bus master. In the context of this document, a “not yet addressed bus node” is understood to mean a bus node that has not yet received a new bus node address that is valid in the sense of this document in the course of the addressing process described here. This process is then continued until all bus nodes have received a bus node address and the bus is thus fully addressed.

However, it cannot be ruled out that this addressing will lead to errors.

In the event of an unsuccessful address assignment, be it due to duplicate assignment or swapping of a bus node address for whatever reasons that ultimately play no role here, it cannot be decided at which physical position a bus node with an incorrect bus node address is actually located. Therefore, the position of the detection is checked in a complex end-of-line test at the car manufacturer. These costs should be avoided.

So far, increased security of the addressing cycle has been carried out by a redundant second addressing cycle for test purposes (Assign ID and Check ID). In the case of static errors, which are reproduced for whatever reason, an incorrect position is always assigned the same or, with a high degree of probability, incorrectly. In the prior art, the error can therefore only be reliably detected for intermittent errors with a high change rate.

Object of the invention

The invention is therefore based on the object of creating a solution that does not have the above disadvantages of the prior art and also allows static errors to be recognized. The method also has other advantages.

This object is achieved by a method according to claim 1 and a device according to claim 8.

The further refinements of the method are the subject of the dependent claims.

Solution of the problem according to the invention

In a data bus system with auto-addressing by means of an addressing stream of the type described at the beginning, the object is achieved according to the invention in that the bus master causes an addressing stream to be fed in by a bus node - the feed bus node, the bus nodes then detect the respective data bus flow through this bus node at their respective bus node position and a Determine bus node-specific bus current measured value. A decision is then made as to whether an addressing current flows through the respective bus node and a bus node-specific addressing current value is determined, the decision being able to be made in the bus node and / or in the bus master. The method also includes the transmission of the bus node-specific bus current measured value and / or the bus node-specific addressing current presence value from the bus node to the bus master. The bus node-specific addressing current presence value can also only be determined in the bus master. The method also includes the formation of a feed-in bus node-specific result vector from the received bus-node-specific addressing current presence values and the comparison of a feed-in bus node-specific result vector with a feed-in bus node-specific expectation vector. The concrete further treatment of the comparison results is the subject of the further development of this procedure.

A method for checking the correct position of auto-addressed bus users is therefore proposed, which is provided and suitable for recognizing incorrect address allocation even after the modules have been installed and addressed. Such an incorrect address assignment can also result from the failure of the addressing logic in a bus node with the same effect.

A further advantage of the method presented here is therefore that it can also be carried out after the vehicle has been delivered in operation or when the vehicle is idle.

After an auto-addressing method has been carried out on the basis of an addressing stream, in particular after one or more of the steps listed above, an independent test sequence follows as proposed, from which the position of the sensors can be clearly identified. This is the essence of the invention.

The bus master preferably requests each bus node in turn to feed its addressing stream into the data bus in the direction of the bus master. The bus master carries out a test cycle for each bus node, in which each bus node feeds its addressing stream for test purposes. The bus master requests all bus nodes to measure the bus current at their bus node position and to determine a bus current measurement value. The bus nodes transmit their respective bus current measured value to the bus master in such a way that the bus master can assign a bus node address to each of the transmitted bus current measured values. Bus node ID4 Bus node ID3 Bus node ID2 Bus node ID1 Cycle 1 Measure current, Measure current, Measure current, Switch on the current and measure Result: current detected Result: current detected Result: current detected Result A: NO current detected Result B: Current detected Cycle 2 Measure current, Measure current, Switch on the current and measure Measure current, Result: current detected Result: current detected Result: NO power detected Result A: NO current detected Result B: Current detected Cycle 3 Measure current, Switch on the current and measure Measure current, Measure current, Result: current detected Result: NO power detected Result: NO power detected Result A: NO current detected Result B: Current detected Cycle 4 Switch on the current and measure Measure current, Measure current, Measure current, Result: NO power detected Result: NO power detected Result: No power detected Result A: NO current detected Result B: Current detected

• • Ergebnis A: Sofern eine Methodik zur Autoadressierung, bei der Adressierstrom eines Busknotens nicht durch den ihm zugeordneten Bus-Shunt-Widerstand fließt, verwendet wird, muss das Ergebnis sein, das der Busknoten seinen eigenen Adressierungsstrom nicht misst. [z.B. EP 1490 772 B1 ]
• • Ergebnis B: Sofern eine Methodik zur Autoadressierung, bei der Adressierstrom eines Busknotens jedoch durch den ihm zugeordneten Bus-Shunt-Widerstand fließt, verwendet wird, muss das Ergebnis sein, das der Busknoten seinen eigenen Adressierungsstrom misst. [z.B. DE 10 2017 122 365 B3 ]

For a better understanding of the table above, here is an important note:

• • Result A: If a method for auto addressing is used in which the addressing current of a bus node does not flow through the bus shunt resistor assigned to it, the result must be that the bus node does not measure its own addressing current. [e.g. EP 1490 772 B1 ]
• • Result B: If a method for auto-addressing is used in which the addressing current of a bus node flows through the bus shunt resistor assigned to it, the result must be that the bus node measures its own addressing current. [e.g. DE 10 2017 122 365 B3 ]

Example for 4 bus nodes on the data bus with correct addressing.

Since the correct sequence of the bus nodes is usually known structurally, this structurally specifiable information can be made available to the bus master during production times, which is typically done by programming.

• Zum Ersten kann der Busmaster feststellen, ob ausschließlich die Busknoten, die zwischen dem einspeisenden Busknoten und ihm selbst angeordnet sind, wie erwartet einen Adressierungsstrom messen.

The bus master can now carry out the following four tests:

• First of all, the bus master can determine whether only the bus nodes that are arranged between the feeding bus node and itself are measuring an addressing stream as expected.

Second, the bus master can determine whether all the bus nodes that are arranged between the feeding bus node and itself measure an addressing current as expected.

Thirdly, the bus master can determine whether only those bus nodes that are NOT arranged between itself and the feeding bus node and itself do NOT measure an addressing stream, as expected.

FOURTH, the bus master can determine whether all the bus nodes that are NOT arranged between the feeding bus node and itself, as expected, do NOT measure an addressing stream.

If one of these questions does not correspond to the expected value, an error has occurred. This error can be signaled by the bus master to a higher-level in-vehicle system or an external system, for example a test system or a vehicle user, depending on the application and safety requirements and usage situation.

In production and / or during maintenance work, however, it makes sense to be able to determine precisely which of the bus nodes has an error. In addition, full fault coverage is usually required.

• -abcd
• A0111
• B0011
• C0001
• D0000

To do this, the bus master repeats the test cycle for each of the bus nodes. In this way, the bus master determines a response vector for each of the bus nodes. In a bus system with n bus nodes, the response vector has n dimensions. The bus master thus determines an nxn response matrix, with an entry in a response matrix being a 1 or a 0. The diagonal relates to the feeding bus nodes themselves and is assigned 1 or 0, depending on the programmer's perspective. A 1 can mean, for example, that an addressing current was measured during the test. A 0 must then mean that no addressing current was measured. An exemplary matrix for a system with four bus nodes with correct assignment looks like this:

• -abcd
• A0111
• B0011
• C0001
• D0000

The bus nodes are numbered consecutively with the letters a, b, c, d.

In measuring cycle A, bus node a feeds an addressing current. Since the bus node a is located furthest away from the bus master, the bus nodes b, c, d determine an addressing stream. Therefore the corresponding values of the matrix are set to 1.

In measurement cycle B, bus node b fed in an addressing stream. Since bus node a follows bus node b as seen from the bus master, it did not detect any addressing stream in the data bus. Therefore its value is set to 0. Since bus nodes c and d precede bus node b as seen by the bus master, they each determined an addressing stream in the data bus. Therefore their values are set to 1.

In measurement cycle C, bus node c feeds an addressing stream. Since bus nodes a and b follow bus node c as seen from the bus master, they did not detect any addressing stream in the data bus. Therefore their values are set to 0. Since bus node d precedes bus node c from the bus master's point of view, it detected an addressing stream in the data bus. Therefore, its value is set to 1.

In measurement cycle D, bus node d feeds an addressing current. Since bus nodes a, b and c follow bus node d as seen from the bus master, they did not detect any addressing stream in the data bus. Therefore their values are set to 0.

The matrix is characteristically deformed when certain defects are present.

• Ausfall der Adressierungsstromquelle Knoten B zum Testzeitpunkt (Adressierung möglicherweise korrekt.):
  • -abcd
  • A0111
  • B0000
  • C0001
  • D0000

A few examples are listed below:

• Failure of the addressing power source node B at the time of the test (addressing possibly correct.):
  • -abcd
  • A0111
  • B0000
  • C0001
  • D0000

• -abcd
• A0110
• B0000
• C0000
• D0000

Da der Busknoten c in Folge des fehlenden Adressierungsstroms des Busknotens b der Auffassung war, der letzte Knoten zu sein, haben sowohl der Busknoten c als auch der Busknoten b die gleiche Busknotenadresse übernommen, da sie während des Adressierungsvorgangs zum gleichen Zeitpunkt sich als letzte Busknoten wähnten. Die Busknotenadresse für den Busknoten d wurde daher von keinem Busknoten übernommen.Failure of the addressing power source node B at the time of the test and at the time of addressing:

• -abcd
• A0110
• B0000
• C0000
• D0000

Since bus node c was of the opinion that it was the last node as a result of the lack of addressing flow of bus node b, both bus node c and bus node b have adopted the same bus node address, since they believed they were the last bus node at the same time during the addressing process . The bus node address for bus node d was therefore not adopted by any bus node.

After the master has received the results from all cycles (current detected / no current detected), it can be clearly evaluated whether the bus nodes have been correctly addressed one after the other on the data bus.

• • Durchführen der Autoadressierung der n Busknoten;
• • Veranlassung der Einspeisung eines Adressierungsstromes durch einen Busknoten - dem Einspeisebusknoten - , wobei die Veranlassung durch den Busmaster erfolgt;
• • Erfassen des Datenbusstromes durch die Busknoten und Ermittlung eines Busknoten spezifischen Busstrommesswerts;
• • Entscheidung, ob ein Adressierungsstrom den jeweiligen Busknoten durchströmt und Ermittlung eines Busknoten spezifischen Adressierungsstromvorhandenseinswerts, wobei die Entscheidung im Busknoten und/oder im Busmaster erfolgen kann;
• • Übermittlung des Busknoten spezifischen Busstrommesswerts und /oder des Busknoten spezifischen Adressierungsstromvorhandenseinswerts vom Busknoten an den Busmaster
• • Bildung eines Einspeisebusknoten spezifischen Ergebnisvektors aus den erhaltenen Busknoten spezifischen Adressierungsstromvorhandenseinswerten;
• • Vergleich eines Einspeisebusknoten spezifischen Ergebnisvektors mit einem Einspeisebusknoten spezifischen Erwartungsvektor.

A method is therefore proposed for identifying an incorrect bus node address assignment in data bus systems with auto-addressing by means of an addressing stream. The data bus system has a data bus, a bus master and n bus nodes. Each bus node is inserted into the data bus and is therefore flowed through by an electric current in the direction of the bus master, which is fed in by a subsequent bus node. The procedure can therefore not be used in a star configuration. The bus master is therefore at one end of the data bus. The bus node which, as seen from the bus master, is closer to the bus master in the order of the bus nodes along the data bus than another bus node is referred to below as the preceding bus node and the other bus node as the following bus node. Each bus node can feed an addressing stream in the direction of the bus master into the data bus. Each bus node is thus flowed through by the addressing stream of subsequent bus nodes in the event of such a feed by subsequent bus nodes. Each of the bus nodes preferably has a measuring device which is provided to be able to detect the addressing stream of subsequent bus nodes. The proposed method has the following steps:

• • Carrying out the auto-addressing of the n bus nodes;
• • Initiation of the supply of an addressing stream by a bus node - the supply bus node -, the initiation being carried out by the bus master;
• • Acquisition of the data bus current by the bus nodes and determination of a bus node-specific bus current measured value;
• • Decision as to whether an addressing stream flows through the respective bus node and determination of a bus node-specific addressing current value, whereby the decision can be made in the bus node and / or the bus master;
• • Transmission of the bus node-specific bus current measured value and / or the bus node-specific addressing current presence value from the bus node to the bus master
• • Formation of a feed bus node-specific result vector from the received bus node-specific addressing current values;
• • Comparison of a feed-in bus node-specific result vector with a feed-in bus node-specific expectation vector.

The method steps described above are preferably carried out for all bus nodes as feed bus nodes. In this case, of course, the step of performing the auto-addressing of the n bus nodes for all other bus nodes as feed-in bus nodes does not take place again.

A comparison of the determined infeed bus node-specific result vectors with infeed bus node-specific expectation vectors for a correct assignment and a conclusion on a correct assignment then takes place if the determined infeed bus node-specific result vectors match the infeed bus node-specific expectation vectors for a correct assignment.

The comparison of the determined feed-bus node-specific result vectors with feed-bus node-specific expectation vectors for a correct assignment and the conclusion that the feed-bus node-specific result vectors do not match the feed-bus node-specific expectation vectors for a correct assignment is also preferably carried out.

In addition, specific errors can be calculated in advance using the resulting patterns. This can be used to identify the type of error.

A comparison of the determined feed-bus node-specific result vectors with feed-bus node-specific expectation vectors for a non-correct assignment and the inference of a predetermined specific error therefore takes place if the determined feed-bus node-specific result vectors match the feed-bus node-specific expectation vectors for a NOT correct assignment.

Depending on the detected error, error-specific signaling can then take place to a user, to a test device and / or to a higher-level system.

Advantage of the invention

• • Eine erhöhte Sicherheit bei der Auto-Adressierung durch die Trennung in zwei verschiedene Mechanismen zur Adressierung und Prüfung ob die Adressierung korrekt war.
• • Eine Erkennung fehlerhafter Adresszuweisungen.
• • Eine Erhöhung der Testabdeckung und Vereinfachung des Produktionsendtests beim Autohersteller.
• • Die Ermöglichung von Mechanismen der funktionalen Sicherheit. Insbesondere wird hierdurch ein sogenanntes „Safety Measure“ also ein Sicherheitsmesswert für eine erfolgreiche Auto-Adressierung durch das vorgeschlagene Verfahren möglich.
• • Der Test kann im Ruhezustand und Betrieb eines Fahrzeugs durchgeführt werden.

Such a method for detecting a faulty bus node address assignment in data bus systems with auto-addressing by means of an addressing stream enables at least in some implementations:

• • Increased security with auto-addressing through the separation into two different mechanisms for addressing and checking whether the addressing was correct.
• • Detection of incorrect address assignments.
• • An increase in test coverage and simplification of the final production test at the car manufacturer.
• • Enabling mechanisms of functional safety. In particular, a so-called “safety measure”, that is, a safety measured value for successful auto-addressing, is made possible by the proposed method.
• • The test can be carried out when the vehicle is idle and in operation.

The advantages are not limited to this.

List of scriptures cited

• EP 1490 772 B1 ,
• EP 1603 282 B1 ,
• DE 10 2017 122 365 B3 ,
• DE 10 2010 026 431 B4 .

List of applications cited

• DE 10 2017 128 489.3 ,
• DE 10 2017 128 923.2 ,
• DE 10 2018 104 488.7 ,
• DE 10 2018 104 489.5 ,
• DE 10 2018 124 279.4 ,
• DE 10 2018 124 281.6 .
• DE 10 2017 012 179.6 .

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 1490772 B1 [0002, 0019, 0046]
• EP 1603282 B1 [0002, 0046]
• DE 102017122365 B3 [0002, 0019, 0046]
• DE 102010026431 B4 [0002, 0046]
• DE 102017128489 [0004, 0046]
• DE 102017128923 [0004, 0046]
• DE 102018104488 [0004, 0046]
• DE 102018104489 [0004, 0046]
• DE 102018124279 [0004, 0046]
• DE 102018124281 [0004, 0046]
• DE 102017012179 [0005, 0046]

Claims (8)

Method for recognizing a faulty bus node address assignment in data bus systems with auto-addressing by means of an addressing stream - The data bus system having a data bus, a bus master and n bus nodes and - Each bus node is inserted into the data bus and - The bus master is at one end of the data bus and - Whereby a bus node that is closer to the bus master in the order of the bus nodes along the data bus than another bus node is referred to below as the preceding bus node and the other bus node as the following bus node - Each bus node can feed an addressing stream in the direction of the bus master into the data bus and - With each bus node being flowed through by the addressing stream of subsequent bus nodes in the case of such a feed through subsequent bus nodes and - each of the bus nodes being able to detect such an addressing stream flowing through it, with the steps - Carrying out the auto-addressing of the n bus nodes; - Initiation of the feed of an addressing stream by a bus node - the feed bus node -, the initiation being carried out by the bus master; - Acquisition of the data bus current by the bus nodes and determination of a bus node-specific bus current measured value; - Decision as to whether an addressing stream flows through the respective bus node and determination of a bus node-specific addressing current presence value, whereby the decision can be made in the bus node and / or in the bus master; - Transmission of the bus node-specific bus current measured value and / or the bus node-specific addressing current presence value from the bus node to the bus master - Formation of a feed-in bus node-specific result vector from the received bus node-specific addressing current values; - Comparison of the infeed bus node-specific result vector with a infeed bus node-specific expectation vector. Method according to Claim 1 - carrying out the steps of Claim 1 except for the step "Carrying out the auto-addressing of the n bus nodes" for all other bus nodes as feed-in bus nodes. Procedure according to Claim 1 or 2 • Comparison of the determined infeed bus node-specific result vectors with infeed bus node-specific expectation vectors for a correct assignment; and • Inferring a correct assignment if the determined infeed bus node-specific result vectors match the infeed bus node-specific expectation vectors for a proper assignment. Procedure according to Claim 1 or 2 • Comparison of the determined infeed bus node-specific result vectors with infeed bus node-specific expectation vectors for a correct assignment and • Conclusion of a NOT correct allocation if the determined infeed bus node-specific result vectors do NOT match the infeed bus node-specific expectation vectors for a correct assignment. Procedure according to Claim 1 or 2 or 3 or 4th • Comparison of the determined infeed bus node-specific result vectors with infeed bus node-specific expectation vectors for a NOT proper assignment and • Inferring a predetermined specific error if the determined infeed bus node-specific result vectors match the infeed bus node-specific expectation vectors for a NOT proper assignment. Method according to one or more of the Claims 1 to 5 - The method being carried out when a vehicle is at rest. Method according to one or more of the Claims 1 to 5 - wherein the method is carried out while a vehicle is in operation. Device which is set up and / or provided for, one or more of the methods according to the Claims 1 to 7th perform.