Communication equipment, vehicles, communication methods, and communication programs

Abstract

To provide a communication device that can prevent situations where data that should be prioritized is not prioritized. [Solution] The communication device 10 exchanges data containing identifiers. The identifier indicates priority, and there are two formats: a first format and a second format. When transmitted data collide, the communication device 10 performs arbitration by comparing the identifier contained in the data it transmits with the identifier contained in the data of the other party that it collided with. When the communication device 10 transmits data containing an identifier in the second format, and that data collides with other data, it performs arbitration while simultaneously performing correction processing to correct the identifier so that the data it transmits has a lower priority than the other party's data. When the communication device 10 transmits data containing an identifier in the first format, and that data collides with other data, it performs arbitration without performing correction processing.

Description

[Technical Field]

[0001] The present disclosure relates to a communication device, a vehicle, a communication method, and a communication program. [Background Art]

[0002] Patent Document 1 describes a communication network system compliant with the CAN protocol. CAN is an abbreviation for Controller Area Network. In this communication network system, a message including an arbitration unit is transmitted. The arbitration unit is a part for performing an arbitration process that determines which piece of data is to continue transmission when pieces of data collide with each other in the communication network system among constituent elements of data.

[0003] The arbitration unit includes an identifier indicating the priority of the transmitted data. In this communication network system, there are two types of identifiers included in data to be transmitted: an identifier with a bit length of 11 bits and an identifier with a bit length of 29 bits. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent No. 6281917 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] In the arbitration process, for example, data assigned with a smaller value as an identifier is prioritized. When there are a plurality of types of identifiers included in data to be transmitted in a communication network system, data including an identifier that should inherently be prioritized may not be properly prioritized in the arbitration process. [Means for Solving the Problem]

[0006] The communication device that solves the above problem is a communication device in a communication network system. The communication network system comprises a plurality of the communication devices, and data including identifiers is exchanged between the plurality of communication devices through communication compliant with the CAN protocol. In the communication network system, the identifier indicates the priority of the data, and there are a first format and a second format different from the first format. The communication network system is configured such that when transmitted data collide, the communication device transmitting the data compares the identifier contained in the data it transmits with the identifier contained in the data of the other party that it collided with, and continues transmitting the data if the data it transmits has a higher priority, and stops transmitting the data if the data it transmits has a lower priority. This communication device includes a processing circuit. When the processing circuit transmits data containing the identifier formed in the second format, and the data collides with data transmitted by another communication device, it performs a correction process to correct the identifier contained in the data it transmits so that the data it transmits has a lower priority than the data of the other party that it collided with, while performing the arbitration process. When the processing circuit transmits data including the identifier formed in the first format, if the data conflicts with data transmitted by another communication device, it performs the arbitration process without performing the correction process.

[0007] A vehicle that solves the above problem is equipped with a communication device. The communication device is a communication device in a communication network system. The communication network system comprises a plurality of the communication devices, and data including an identifier is exchanged between the plurality of communication devices through communication compliant with the CAN protocol. In the communication network system, the identifier indicates the priority of the data, and there are a first format and a second format different from the first format. The communication network system is configured such that when transmitted data collide, the communication device transmitting the data compares the identifier contained in the data it transmits with the identifier contained in the data of the other party that it collided with, and continues transmitting the data if the data it transmits has a higher priority, and stops transmitting the data if the data it transmits has a lower priority. This communication device is equipped with a processing circuit. When the processing circuit transmits data containing the identifier formed in the second format, and the data collides with data transmitted by another communication device, it performs the arbitration process while performing a correction process to correct the identifier contained in the data it transmits so that the data it transmits has a lower priority than the data of the other party that it collided with. When the processing circuit transmits data including the identifier formed in the first format, if the data conflicts with data transmitted by another communication device, it performs the arbitration process without performing the correction process.

[0008] The communication method that solves the above problem is a communication method in a communication network system. The communication network system is composed of a plurality of communication devices, and data containing identifiers is exchanged between the plurality of communication devices through communication compliant with the CAN protocol. The identifier indicates the priority of the data, and has a first format and a second format different from the first format. The communication network system is configured such that when transmitted data collide, the communication device transmitting the data compares the identifier contained in the data it transmits with the identifier contained in the data of the other party that it collided with, and continues transmitting the data if the data it transmits has a higher priority, and stops transmitting the data if the data it transmits has a lower priority. This communication method includes the step that, when transmitting data containing the identifier formed in the second format, the data collided with data transmitted by another communication device, the communication device performs the arbitration process while performing a correction process to correct the identifier contained in the data it transmits so that the data it transmits has a lower priority than the data of the other party that it collided with. This communication method includes the step of performing the arbitration process without performing the correction process if, when data including the identifier formed in the first format is transmitted, the data conflicts with data transmitted by another communication device.

[0009] The communication program that solves the above problem is a communication program executed by the processing circuit of a communication device in a communication network system. The communication network system is composed of a plurality of communication devices, and data containing identifiers is exchanged between the plurality of communication devices through communication compliant with the CAN protocol. The identifier indicates the priority of the data, and has a first format and a second format different from the first format. The communication network system is configured such that when transmitted data collide, the communication device transmitting the data compares the identifier contained in the data it transmits with the identifier contained in the data of the other party that it collided with, and continues transmitting the data if the data it transmits has a higher priority, and stops transmitting the data if the data it transmits has a lower priority. When this communication program transmits data containing the identifier formed in the second format, and the data collides with data transmitted by another communication device, it causes the processing circuit to execute the arbitration process while performing a correction process to correct the identifier contained in the data it transmits so that the data it transmits has a lower priority than the data of the other party that it collided with. When this communication program transmits data containing the identifier formed in the first format, if the data conflicts with data transmitted by another communication device, it causes the processing circuit to execute the arbitration process without performing the correction process. [Effects of the Invention]

[0010] The above-mentioned communication device, vehicle, communication method, and communication program can suppress situations in which data that should be prioritized is not prioritized. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a vehicle equipped with a communication device according to one embodiment. [Figure 2]Figure 2 shows the data format transmitted by the communication device shown in Figure 1. [Figure 3] Figure 3 shows the standard arbitration section included in the data transmitted by the communication device shown in Figure 1. [Figure 4] Figure 4 shows the extended arbitration unit included in the data transmitted by the communication device shown in Figure 1. [Figure 5] Figure 5 shows (a) the signals that make up data A and (b) the signals that make up data B. [Figure 6] Figure 6 shows (a) the signals that make up data C and (b) the signals that make up data D. [Figure 7] Figure 7 is a table showing the types of identifiers in the first format transmitted by the communication device shown in Figure 1. [Figure 8] Figure 8 is a table showing the types of identifiers in the second format transmitted by the communication device shown in Figure 1. [Figure 9] Figure 9 shows (a) the signal that constitutes the control frame, which represents "636" in hexadecimal, (b) the signal that constitutes the physical address frame, (c) the signal that constitutes the function address frame, and (d) the signal that constitutes the control frame, which represents "637" in hexadecimal. [Figure 10] Figure 10 is a flowchart showing a series of processes performed by a communication device when transmitting data having an identifier in a first format. [Figure 11] Figure 11 is a flowchart showing the series of processes performed by a communication device when transmitting data having an identifier in a second format. [Figure 12] Figure 12 shows (a) the signals that make up the data before correction and (b) the signals that make up the data after correction. [Modes for carrying out the invention]

[0012] An embodiment of the communication device will be described below with reference to Figures 1 to 12. <Composition of 50 vehicles> As shown in FIG. 1, the vehicle 50 includes a communication network system 40. The communication network system 40 includes a plurality of communication devices 10. The communication devices 10 are electronic control units included in the vehicle 50. Each communication device 10 implements a specific function in the vehicle 50 by communicating with other communication devices 10 in the communication network system 40.

[0013] As the communication devices 10, the communication network system 40 includes a first device 11, a second device 12, a third device 13, a fourth device 14, a fifth device 15, and a relay device 20. Among the communication devices 10, the first device 11, the second device 12, the third device 13, the fourth device 14, and the fifth device 15 each include a processing circuit 16 and a storage device 17. The storage device 17 stores programs. The processing circuit 16 executes various processes by running the programs stored in the storage device 17. The processing circuit 16 includes a processor.

[0014] As shown in FIG. 1, the storage device 17 stores a communication program PC. The communication program PC causes the processing circuit 16 to execute processing related to communication with other communication devices 10 in the communication network system 40.

[0015] Among the communication devices 10, the relay device 20 includes a processing circuit 21 and a storage device 22. The storage device 22 stores programs. The processing circuit 21 executes various processes by running the programs stored in the storage device 22. The processing circuit 21 includes a processor.

[0016] As shown in FIG. 1, the storage device 22 stores a communication program PC. The communication program PC causes the processing circuit 21 to execute processing related to communication with other communication devices 10 in the communication network system 40.

[0017] The communication network system 40 exchanges data between multiple communication devices 10 through communication compliant with the CAN protocol. CAN stands for Controller Area Network.

[0018] The communication network system 40 includes a first communication network 46 and a second communication network 47 as a communication network 45. The communication network 45 is a group of communication devices 10 connected on the same communication bus 30. The communication network system 40 includes a first bus 31 and a second bus 32 as a communication bus 30.

[0019] As shown in Figure 1, the first bus 31 is connected to the first device 11, the second device 12, and the relay device 20. The first device 11 and the second device 12 exchange data with other communication devices 10 via the first bus 31. The first device 11 and the second device 12 constitute the first communication network 46.

[0020] As shown in Figure 1, the second bus 32 is connected to the third device 13, the fourth device 14, the fifth device 15, and the relay device 20. The third device 13, the fourth device 14, and the fifth device 15 exchange data with other communication devices 10 via the second bus 32. The third device 13, the fourth device 14, and the fifth device 15 constitute the second communication network 47.

[0021] The relay device 20 is connected to both the first bus 31 and the second bus 32. In other words, the relay device 20 is connected to both the first communication network 46 and the second communication network 47. The relay device 20 relays data exchanged between multiple communication networks 45.

[0022] The relay device 20 receives data transmitted in the first communication network 46 via the first bus 31 and transmits the data to the second bus 32, thereby transmitting the data to the second communication network 47. The relay device 20 receives data transmitted in the second communication network 47 via the second bus 32 and transmits the data to the first bus 31, thereby transmitting the data to the first communication network 46. The relay device 20 can simultaneously and concurrently relay data in the direction from the first communication network 46 to the second communication network 47 and relay data in the direction from the second communication network 47 to the first communication network 46.

[0023] <Data exchanged by communication device 10> Figure 2 shows the format of the data exchanged by the communication device 10. As shown in Figure 2, the data consists of SOF61, arbitration unit62, and data unit63. In Figure 2, the data components are transmitted on the communication bus 30 in the order shown from left to right.

[0024] SOF61 is the first part of the data that is transmitted. SOF stands for Start Of Frame. SOF61 indicates the starting position in the data. SOF61 is a 1-bit dominant. In other words, SOF61 is a signal that indicates zero.

[0025] The arbitration unit 62 is the part of the data that is transmitted after SOF 61. As will be described later, when the communication device 10's transmitted data collides with other data on the communication bus 30, it performs arbitration processing to determine which of the colliding data should continue to be transmitted. The arbitration unit 62 is the part that is referenced to determine which data takes priority when a data collision occurs. Prioritized data is the data that continues to be transmitted when there is a data collision.

[0026] The data section 63 is the part of the data that is transmitted after the arbitration section 62. The data section 63 is the part that stores the message that the communication device 10 transmits to other communication devices 10. <Modes by which the communication device 10 transmits data> When the communication device 10 transmits data, it first checks whether other communication devices 10 are transmitting data on the communication bus 30. When the first device 11, the second device 12, and the relay device 20 transmit data toward the first bus 31, they check whether other communication devices 10 connected to the first bus 31 are transmitting data through the first bus 31. When the third device 13, the fourth device 14, the fifth device 15, and the relay device 20 transmit data toward the second bus 32, they check whether other communication devices 10 connected to the second bus 32 are transmitting data through the second bus 32.

[0027] Communication device 10 transmits data if it confirms that no other communication device 10 is transmitting data on the communication bus 30. If communication device 10 confirms that another communication device 10 is transmitting data on the communication bus 30, it waits until the transmission of the data being transmitted is complete. After that, communication device 10 checks again whether or not another communication device 10 is transmitting data on the communication bus 30, and transmits data when it confirms that no other communication device 10 is transmitting data.

[0028] When multiple communication devices 10 transmit data simultaneously, data collisions occur. When a data collision occurs, the communication device 10 that was transmitting the data performs arbitration. The arbitration process will be described below with reference to Figures 3 to 6.

[0029] <62 types of mediation departments> There are two types of arbitration units 62: a standard arbitration unit 62a and an extended arbitration unit 62b. The communication device 10 inserts either the standard arbitration unit 62a or the extended arbitration unit 62b into the arbitration unit 62 portion of the data shown in Figure 2.

[0030] Figure 3 shows the configuration of the standard arbitration unit 62a. As shown in Figure 3, the standard arbitration unit 62a consists of ID 71 and RTR 72. In Figure 3, the components of the standard arbitration unit 62a are transmitted on the communication bus 30 in the order shown from left to right.

[0031] ID71 is the first part transmitted in the standard arbitration unit 62a. ID71 is an identifier used to identify the content of the data and the communication device 10 that is transmitting the data. RTR72 is the portion transmitted after ID71 in the standard arbitration unit 62a. RTR stands for Remote Transmission Request. RTR72 is a 1-bit dominant signal. In other words, RTR72 is a signal indicating zero.

[0032] Figure 4 shows the configuration of the extended arbitration unit 62b. As shown in Figure 4, the extended arbitration unit 62b consists of a base ID 71a, an SRR 73, an IDE 74, an extended ID 71b, and an RTR 72. In Figure 4, the components of the extended arbitration unit 62b are transmitted on the communication bus 30 in the order shown from left to right.

[0033] The basic ID 71a is the first part transmitted by the extended arbitration unit 62b. The extended arbitration unit 62b includes an identifier for identifying the content of the data and the communication device 10 transmitting the data. The basic ID 71a is the first part of the identifier provided by the extended arbitration unit 62b.

[0034] SRR73 is the portion transmitted after the base ID71a in the extended arbitration unit 62b. SRR stands for Substitute Remote Request bit. SRR73 is a 1-bit recessive signal. In other words, SRR73 is a signal indicating 1.

[0035] IDE74 is the part transmitted after SRR73 in the extended arbitration unit 62b. IDE stands for Identifier Extension bit. IDE74 is a 1-bit recessive signal. In other words, IDE74 is a signal indicating 1.

[0036] The extended ID 71b is the part transmitted after the IDE 74 in the extended arbitration unit 62b. The extended ID 71b is the latter part of the identifier provided by the extended arbitration unit 62b. RTR72 is the portion transmitted after the extended ID71b in the extended arbitration unit 62b. The RTR72 of the extended arbitration unit 62b is a 1-bit dominant, similar to the case of the standard arbitration unit 62a.

[0037] As shown and explained in Figure 3, the standard arbitration unit 62a has an identifier ID71. The identifier of the standard arbitration unit 62a is formed by the first format. As shown in Figure 3, the bit length of the identifier ID70 in the first format is 11 bits.

[0038] As shown and explained in Figure 4, the identifier of the extended arbitration unit 62b is composed of a base ID 71a and an extended ID 71b. The identifier of the extended arbitration unit 62b is formed by a second format. As shown in Figure 4, the bit length of the base ID 71a is 11 bits. As shown in Figure 4, the bit length of the extended ID 71b is 18 bits. The bit length of the identifier in the second format is 29 bits, which is the sum of the bit lengths of the base ID 71a and the extended ID 71b.

[0039] Thus, the standard arbitration unit 62a and the extended arbitration unit 62b differ in the length of the identifier bits they possess. Identifiers indicate the priority of data during the mediation process. In mediation, data with lower identifier values ​​has higher priority than data with higher identifier values.

[0040] <Method of mediation> In arbitration processing, the communication device 10 determines the priority of data by comparing identifiers held by the arbitration unit 62.

[0041] Figures 5 and 6 show two sets of signals that make up the data. The following explanation will describe how arbitration processing is performed when two data sets collide, using Figures 5 and 6 as references. <When data containing standard arbitration unit 62a conflict> In the following section, with reference to Figure 5, we will explain how the communication device 10 performs arbitration processing when data having a standard arbitration unit 62a collide.

[0042] Figure 5(a) shows the signals that make up data A. Data A has a standard arbitration unit 62a as the arbitration unit 62. In Figure 5(a), the portion from ID10 to ID0 is the signals that make up ID71.

[0043] Figure 5(b) shows the signals that make up data B. Data B has a standard arbitration unit 62a as the arbitration unit 62. In Figure 5(b), the portion from ID10 to ID0 is the signal that makes up ID71.

[0044] In ID71, ID10 is the most significant digit and ID0 is the least significant digit. The signals shown in Figures 5(a) and 5(b) are transmitted on the communication bus 30 in order from left to right. In other words, when the communication device 10 transmits data having a standard arbitration unit 62a, it transmits SOF61 first, and then transmits ID71 on the communication bus 30 in order from the most significant digit.

[0045] As shown in Figure 5(a), the ID71 of data A is "01101100011" in binary. As shown in Figure 5(b), the ID71 of data B is "01110111001" in binary. Therefore, in Figure 5, the identifier of data A has a smaller value than the identifier of data B.

[0046] In Figure 5, data A and data B are transmitted simultaneously and collide on the communication bus 30. The communication device 10 can detect when it is transmitting data that it is transmitting has collided with other data.

[0047] The timing at which the communication device 10 detects a data collision depends on the capabilities of the communication device 10. In other words, the communication device 10 may detect a data collision when transmitting the higher-order digits of the identifier, or it may detect it when transmitting the lower-order digits of the identifier.

[0048] In the following, we will describe a scenario in which, in the example shown in Figure 5, when a data collision is detected at the same time that communication device 10 transmitting data A and communication device 10 transmitting data B are both transmitting ID 10, both devices perform arbitration processing.

[0049] The communication device 10 monitors the signals that make up the data transmitted on the communication bus 30 on a bit-by-bit basis. If there is only one communication device 10 that transmits data on the communication bus 30, and the signal transmitted by that communication device 10 is dominant, then a dominant signal flows on the communication bus 30. If there is only one communication device 10 that transmits data on the communication bus 30, and the signal transmitted by that communication device 10 is recessive, then a recessive signal flows on the communication bus 30.

[0050] If multiple communication devices 10 transmit data simultaneously on the communication bus 30, and all communication devices 10 that transmit data transmit a recessive signal, then a recessive signal flows on the communication bus 30. On the other hand, if multiple communication devices 10 transmit data simultaneously on the communication bus 30, and even one of the communication devices 10 that transmits data transmits a dominant signal, then a dominant signal flows on the communication bus 30.

[0051] In Figure 5, after the communication device 10 that sent data A and the communication device 10 that sent data B detect a data collision, they perform arbitration. In the arbitration process, the communication device 10 compares the signal it sent with the signal flowing on the communication bus 30. It then determines that it has lost the arbitration if a dominant signal is flowing on the communication bus 30 when it has sent a recessive signal. Losing the arbitration means that the data it is sending has a lower priority than the data of the other party involved in the collision.

[0052] In Figure 5, the communication device 10 that transmitted data B detects a collision with other data when it transmits the signal for ID 10. It then compares the signal for data B that it transmits with the signals flowing on the communication bus 30.

[0053] In Figure 5, data A and data B have the same signals from ID10 to ID8. In Figure 5, the ID7 signal of data A is dominant, and the ID7 signal of data B is recessive. Therefore, in Figure 5, when the communication device 10 that transmitted data B transmits the ID7 signal, a dominant signal flows on the communication bus 30.

[0054] When the communication device 10 that transmitted data B transmits the ID 7 signal, it determines that it has lost the arbitration. As shown in Figure 5(b), the communication device 10, having determined that it has lost the arbitration, stops transmitting data thereafter.

[0055] On the other hand, in Figure 5, the communication device 10 that transmitted data A detects a collision with other data when it transmits the signal for ID 10. Subsequently, it compares the signal for data B that it transmits with the signals flowing on the communication bus 30.

[0056] For communication device 10 that sent data A, at the point when it is transmitting signals ID 10 to ID 7, the signals it has transmitted match the signals flowing on the communication bus 30. Then, because communication device 10 that sent data B stops transmitting the data from ID 6 onwards, communication device 10 that sent data A can transmit the data from ID 6 onwards without colliding with other data.

[0057] In Figure 5, communication device 10, which transmitted data A, wins the mediation. Winning the mediation means that the data being transmitted has a higher priority than the data of the other party involved in the conflict.

[0058] In this way, during arbitration, the communication device 10 compares the identifiers of the conflicting data, starting from the most significant digit. When comparing the identifiers, if the signal representing one identifier is zero and the signal representing the other identifier is one, the communication device 10 that sent the signal of one stops transmitting the data. This allows the communication device 10 transmitting the data with the lower-value identifier to continue transmitting the data. In this way, the communication device 10 can prioritize the transmission of data with a higher priority on the communication bus 30.

[0059] Furthermore, in the mediation process, the communication device 10 that lost the mediation will wait for the communication device 10 that won the mediation to complete its data transmission, and then, after confirming that no data has been transmitted on the communication bus 30, it will transmit data again.

[0060] Figure 5 illustrates the arbitration process when data having a standard arbitration unit 62a collide. Even when data having an extended arbitration unit 62b collide, the communication device 10 can prioritize the transmission of data with a smaller identifier value by performing arbitration in the same manner as in Figure 5.

[0061] <If data with identifiers in different formats collide> As shown and explained in Figure 5, in arbitration processing, data with an identifier that has a lower value is normally given priority. On the other hand, when data with a standard arbitration unit 62a and data with an extended arbitration unit 62b collide, if arbitration processing is performed in the same manner as in Figure 5, the magnitude of the identifier values ​​cannot be properly compared due to the need to compare the signals in order from the most significant digit of the identifier.

[0062] In the following section, with reference to Figure 6, we will explain, as a comparative example, the case in which arbitration processing is performed in the same manner as in Figure 5 when data having a standard arbitration unit 62a and data having an extended arbitration unit 62b conflict. In the explanation of the comparative example, the device that performs the arbitration processing will be simply referred to as "device".

[0063] Figure 6(a) shows the signals that make up data C. Data C has a standard arbitration unit 62a as the arbitration unit 62. In Figure 6(a), the portion from ID10 to ID0 is the signals that make up ID71.

[0064] Figure 6(b) shows the signals that make up data D. Data D has an extended arbitration unit 62b as the arbitration unit 62. In Figure 6(b), the portion from ID28 to ID18 is the signal that makes up the basic ID71a.

[0065] In the basic ID 71a, ID 28 is the most significant digit and ID 18 is the least significant digit. The signals shown in Figures 6(a) and 6(b) are transmitted on the communication bus 30 in order from left to right. In other words, when the communication device 10 transmits data with an extended arbitration unit 62b, it transmits SOF 61 and then transmits the basic ID 71a on the communication bus 30 in order from the most significant digit.

[0066] If data C and data D collide, the device will perform arbitration in the same manner as in Figure 5, comparing the ID 71 of data C and the base ID 71a of data D sequentially from the most significant digit. As shown in Figure 6(a), the ID 71 of data C is "01111100011" in binary. As shown in Figure 6(b), the base ID 71a of data D is "01100111001" in binary. In other words, when comparing the ID 71 of data C and the base ID 71a of data D, the value of the base ID 71a of data D is smaller.

[0067] In Figure 6, when the device that sent data C transmits the signal ID7 and the device that sent data D transmits the signal ID25, the device that sent data C determines that it has lost the arbitration. The device that sent data C then refrains from transmitting ID6 and beyond in data C. Thus, in the comparative example shown in Figure 6, the device that sent data D wins the arbitration.

[0068] Thus, when data having a standard arbitration unit 62a and data having an extended arbitration unit 62b conflict, if arbitration processing is performed in the manner shown in Figure 5, ID 71 and basic ID 71a are compared. Then, the transmission of data containing the smaller value between ID 71 and basic ID 71a is prioritized.

[0069] Furthermore, if the values ​​indicated by ID71 and base ID71a are the same, the RTR72 transmitted after ID71 is dominant, and the SRR73 transmitted after base ID71a is recessive, so the data having the standard arbitration unit 62a takes precedence.

[0070] The identifier in the first format is intended to indicate priority within the identifiers of the first format. Similarly, the identifier in the second format is intended to indicate priority within the identifiers of the second format. In other words, conventionally, it was not anticipated that identifiers of the first format and identifiers of the second format would be transmitted together. Therefore, when identifiers of the first format and the second format are transmitted together, if arbitration processing is performed in the manner shown in Figure 6, the magnitude of the identifier values ​​cannot be properly compared. As a result, the arbitration result may be unpredictable.

[0071] <Types of identifiers transmitted by communication device 10> Figures 7 and 8 show identifiers included in the data transmitted by the communication device 10. The types of identifiers transmitted by the communication device 10 are described below.

[0072] <Identifier in the first format> Figure 7 shows the content of ID71, which is an identifier included in the standard arbitration unit 62a among the identifiers transmitted by the communication device 10. In other words, Figure 7 shows the content of the identifier in the first format among the identifiers transmitted by the communication device 10.

[0073] The various processes that the communication device 10 performs when transmitting data are executed by the communication program PC, which instructs the processing circuits 16 and 21 to perform. As shown in Figure 7, the processing circuits 16 and 21 form a control frame, a management frame, and a diagnostic frame in a first format.

[0074] The control frame is an identifier that indicates that the data is being transmitted for the control of the vehicle 50. The communication device 10, for example, includes the control frame as an identifier in the data it transmits for the control of the engine of the vehicle 50.

[0075] As shown in Figure 7, the control frame is represented by a hexadecimal number in the range of "00F" to "650". The management frame is an identifier that indicates that the data is transmitted to manage the communication status on the communication bus 30. The communication device 10, for example, in the communication network system 40, includes the management frame as an identifier in the data indicating that it is in a state where it can communicate.

[0076] As shown in Figure 7, the management frame is represented by a hexadecimal number in the range of "651" to "6FF". The diagnostic frame is an identifier that indicates that the data is being transmitted for fault diagnosis in the vehicle 50. The communication device 10 transmits the diagnostic frame as an identifier along with data indicating a communication error log, for example, when a dealer uses a diagnostic tool for inspection.

[0077] As shown in Figure 7, the diagnostic frame is represented by a hexadecimal number in the range of "710" or higher. As mentioned earlier, identifiers have higher priority the smaller their value. In the first format, the priority of identifiers is set so that control frames, management frames, and diagnostic frames are prioritized in that order from highest to lowest.

[0078] Figure 7 shows the binary representation of each identifier. In the binary representation shown in Figure 7, the first three digits correspond to the first digit of the hexadecimal representation. In the binary representation shown in Figure 7, the fourth to seventh digits correspond to the second digit of the hexadecimal representation. In the binary representation shown in Figure 7, the eighth to eleventh digits correspond to the third digit of the hexadecimal representation.

[0079] As shown in Figure 7, the control frame is represented in binary by a number within the range of "00000001111" to "11001010000". As shown in Figure 7, the management frame is represented in binary by a number within the range of "11001010001" to "11011111111".

[0080] As shown in Figure 7, the diagnostic frame is represented in binary by a number in the range of "11100010000" and above. The binary number shown in Figure 7 has 11 digits. The communication device 10 uses 11 bits of signal in the first format to transmit information representing the binary number shown in Figure 7 onto the communication bus 30.

[0081] <Identifier in second format> Figure 8 shows the contents of the identifiers included in the extended arbitration unit 62b among the identifiers transmitted by the communication device 10. In other words, Figure 8 shows the contents of the identifiers in the second format among the identifiers transmitted by the communication device 10.

[0082] The identifiers shown in Figure 8 all represent diagnostic frames. Processing circuits 16 and 21 of the communication device 10 form diagnostic frames in the first format, as shown in Figure 7. In addition, processing circuits 16 and 21 of the communication device 10 may also form diagnostic frames in the second format.

[0083] As shown in Figure 8, there are two types of diagnostic frames formed by the second format: physical address frames and functional address frames. A physical address frame is an identifier attached to data transmitted to a single communication device 10 in the communication network system 40, among the diagnostic frames formed by the second format. A functional address frame is an identifier attached to data transmitted to multiple communication devices 10 in the communication network system 40, among the diagnostic frames formed by the second format.

[0084] Figure 8 shows the information input to the basic ID 71a and the extended ID 71b in the diagnostic frame formed by the second format. The communication device 10 uses the 29 bits of signal in the second format to transmit the information shown in Figure 8 in binary on the communication bus 30.

[0085] In Figure 8, ID28 to ID24 represent the top five digits of the identifier in the second format. The communication device 10 inputs information indicating "18" in hexadecimal as binary into ID28 to ID24 in the physical address frame and functional address frame.

[0086] In Figure 8, IDs 23 to 16 represent the 6th to 13th digits from the top of the identifier in the second format. The communication device 10 inputs information indicating "DA" in hexadecimal as binary numbers into IDs 23 to 16 in the physical address frame. The communication device 10 inputs information indicating "DB" in hexadecimal as binary numbers into IDs 23 to 16 in the functional address frame.

[0087] In Figure 8, IDs 15 to 21 represent the 14th to 21st digits of the identifier in the second format. The communication device 10 inputs destination information in binary to IDs 15 to 8 in the physical address frame and functional address frame. Destination information indicates the destination of the transmitted data.

[0088] In Figure 8, ID7 to ID0 represent the 22nd to 29th digits from the top of the identifier in the second format. The communication device 10 inputs source information in binary to ID7 to ID0 in the physical address frame and functional address frame. Source information indicates the source of the transmitted data.

[0089] Thus, the information entered in the range of ID28 to ID16 in the physical address frame and functional address frame is fixed. On the other hand, the information entered in the range of ID15 to ID0 in the physical address frame and functional address frame varies depending on the data.

[0090] In the second format, signals ID28 to ID18 are input to basic ID71a. Then, in the second format, signals ID17 to ID0 are input to extended ID71b.

[0091] <Identifier priority> As mentioned above, when data with a standard arbitration unit 62a and data with an extended arbitration unit 62b collide, if arbitration processing is performed in the same manner as in Figure 5, the magnitude of the identifier values ​​cannot be properly compared.

[0092] Figure 9 shows the signals that make up the data. In Figure 9, a total of four signals are arranged: two signals representing identifiers formed by the first format and two signals representing identifiers formed by the second format.

[0093] Figure 9(a) shows a control frame representing the hexadecimal number "636", which is a signal indicating an identifier formed by the first format, represented in binary. Figure 9(b) shows the portion of the physical address frame from ID28 to ID16, which is a signal indicating an identifier formed by the second format, represented in binary. Figure 9(c) shows the portion of the functional address frame from ID28 to ID16, which is a signal indicating an identifier formed by the second format, represented in binary. Figure 9(d) shows a control frame representing the hexadecimal number "637", which is a signal indicating an identifier formed by the first format, represented in binary.

[0094] Comparing Figure 9(a) and Figure 9(b), the signals in the ID10-ID0 portion of Figure 9(a) and the ID28-ID18 portion of Figure 9(b) are identical. In other words, the value of ID71 in the control frame, which indicates "636" in hexadecimal, and the value of base ID71a in the physical address frame are the same. As mentioned earlier, when the values ​​indicated by ID71 and base ID71a are the same, the RTR72 transmitted after ID71 is dominant, and the SRR73 transmitted after base ID71a is recessive, so the data having the standard arbitration unit 62a takes precedence. In other words, if data containing a control frame indicating "636" in hexadecimal and data containing a physical address frame collide, and arbitration processing is performed in the same manner as in Figure 5, the communication device 10 that transmitted the former data will win the arbitration.

[0095] Comparing Figure 9(b) and Figure 9(c), the signals in the ID28-ID17 portion of Figure 9(b) and the ID28-ID17 portion of Figure 9(c) are identical. In Figure 9(b), ID16 is dominant, while in Figure 9(c), ID16 is recessive. Therefore, if data containing a physical address frame and data containing a functional address frame collide, and arbitration is performed in the same manner as in Figure 5, the communication device 10 that transmitted the former data will win the arbitration.

[0096] Comparing Figure 9(c) and Figure 9(d), the signals in the ID28-ID19 portion of Figure 9(c) and the ID10-ID1 portion of Figure 9(d) are identical. In Figure 9(c), ID18 is dominant, while in Figure 9(d), ID0 is recessive. Therefore, if data containing a functional address frame and data containing a control frame indicating "637" in hexadecimal collide, and arbitration is performed in the same manner as in Figure 5, the communication device 10 that transmitted the former data will win the arbitration.

[0097] Thus, when the communication device 10 transmits data containing an identifier in the second format, and it collides with data containing a control frame represented by a hexadecimal number within the range of "00F" to "636", if arbitration is performed in the same manner as in Figure 5, the arbitration will be unsuccessful.

[0098] On the other hand, when the communication device 10 transmits data containing an identifier in the second format, and it conflicts with data containing an identifier in the first format represented by a hexadecimal number in the range of "637" or later, arbitration processing will be performed in the same manner as in Figure 5, resulting in a arbitration victory. The identifier represented by a hexadecimal number in the range of "637" or later includes a control frame represented by a hexadecimal number in the range of "637" to "650", the entire management frame, and the entire diagnostic frame formed by the first format.

[0099] When data containing an identifier formed by the first format and data containing an identifier formed by the second format collide, the communication device 10 performs processing such that the data containing the identifier formed by the second format is not given priority.

[0100] <Processing to be performed when sending data containing an identifier in the first format> Figure 10 shows the sequence of processes that the communication device 10 executes when it detects a data collision while transmitting data containing an identifier formed in the first format. When the communication device 10 detects a data collision while transmitting data containing the identifier shown in Figure 7, it executes the sequence of processes shown in Figure 10. Hereinafter, S means step.

[0101] When the first devices 11 to the fifth devices 15 detect a data collision while transmitting data containing an identifier formed according to the first format, they execute a series of processes shown in Figure 10. When the relay device 20 receives data containing an identifier formed according to the first format from one communication network 45 and is relaying the data to the other communication network 45, it executes a series of processes shown in Figure 10 if it detects a data collision.

[0102] The series of processes shown in Figure 10 are executed by the communication program PC when it detects a data collision while transmitting data containing an identifier formed in the first format, causing processing circuits 16 and 21 to perform the process.

[0103] Processing circuits 16 and 21 determine whether the data they are transmitting has collided with other data on the communication bus 30 while they are transmitting data. As illustrated in Figure 5, the communication device 10 can detect when it is transmitting data that has collided with other data.

[0104] When the series of processes shown in Figure 10 is started, in process S11, processing circuits 16 and 21 perform arbitration processing. At this time, processing circuits 16 and 21 perform arbitration processing in the manner shown in Figure 5.

[0105] Subsequently, processing circuits 16 and 21 proceed to S12. In the process of S12, processing circuits 16 and 21 determine whether they won the mediation process.

[0106] Processing circuits 16 and 21 determine that they have won the arbitration process in S11 when they have completed transmitting data without interrupting their own data transmission. If processing circuits 16 and 21 determine that they have won the arbitration process in S12 (S12: YES), they terminate the series of processes shown in Figure 10.

[0107] Processing circuits 16 and 21 determine in the arbitration process of S11 that they lost the arbitration and, when they stop transmitting data, they determine that they did not win the arbitration. If processing circuits 16 and 21 determine in the process of S12 that they did not win the arbitration (S12: NO), they proceed to process S13.

[0108] In the process of S13, processing circuits 16 and 21 determine whether or not there is data being transmitted on the communication bus 30. If processing circuits 16 and 21 determine that there is data being transmitted on the communication bus 30 (S13: YES), they execute the process in S13 again. In other words, processing circuits 16 and 21 execute the process in S13 until they determine that there is no data being transmitted on the communication bus 30.

[0109] If processing circuits 16 and 21 determine that there is no data being transmitted on the communication bus 30 (S13: NO), they proceed to S14. In the process of S14, processing circuits 16 and 21 retransmit the data that could not be transmitted in S11 due to a failed arbitration. After that, processing circuits 16 and 21 terminate this series of processes.

[0110] <Processing to be performed when sending data containing identifiers in the second format> Figure 11 shows the sequence of processes that the communication device 10 executes when it detects a data collision while transmitting data containing an identifier formed in the second format. When the communication device 10 detects a data collision while transmitting data containing the identifier shown in Figure 8, it executes the sequence of processes shown in Figure 11. Hereinafter, S means step.

[0111] When the first to fifth devices 11 to 15 detect a data collision while transmitting data containing an identifier formed in the second format, they execute the series of processes shown in Figure 11. When the relay device 20 receives data containing an identifier formed in the second format from one communication network 45 and is relaying the data to the other communication network 45, it executes the series of processes shown in Figure 11 when it detects a data collision.

[0112] The series of processes shown in Figure 11 are executed by the communication program PC when it detects a data collision while transmitting data containing an identifier formed in the second format. The PC then instructs processing circuits 16 and 21 to perform these processes.

[0113] When the series of processes shown in Figure 11 is initiated, in S21, processing circuits 16 and 21 perform a correction process. The correction process corrects the identifier of the data being transmitted so that the data being transmitted does not take precedence over the data of the other party with which it has collided.

[0114] Figure 12 shows the mode in which the communication device 10 performs correction processing. The signal shown in Figure 12(a) is an example of the signal in the original data before correction, which would have been transmitted if processing circuit 16 or processing circuit 21 had not performed the correction process. In Figure 12(a), processing circuit 16 or processing circuit 21 transmits an identifier indicating "11000110110" as the basic ID 71a in the original data.

[0115] As mentioned earlier, the timing at which the communication device 10 detects a data collision depends on the capabilities of the communication device 10. In Figure 12, processing circuit 16 or processing circuit 21 determines that the data it is transmitting has collided on the communication bus 30 when it is transmitting the signal for ID 25 in the basic ID 71a.

[0116] The signal shown in Figure 12(b) is the corrected data output by processing circuit 16 or processing circuit 21 after performing the correction process. After detecting a data collision, processing circuits 16 and 21 correct the signal from the next signal onward.

[0117] As shown in Figure 12(b), in the corrected data, all signals from ID 24 onwards in the base ID 71a are recessive. After detecting a data collision, processing circuit 16 or processing circuit 21 uniformly changes all subsequent signals to recessive, regardless of whether the original signals were dominant or recessive. Alternatively, after detecting a data collision, processing circuit 16 or processing circuit 21 may search for dominant signals in subsequent signals and make only those signals recessive.

[0118] In the correction process, processing circuits 16 and 21 correct the basic ID 71a in the identifier, but do not correct the extended ID 71b. In this way, by performing correction processing, processing circuits 16 and 21 ensure that all signals transmitted after a collision is detected in the base ID 71a are recessive signals.

[0119] Subsequently, processing circuits 16 and 21 execute the process of S22. At this time, processing circuits 16 and 21 execute arbitration processing in the manner shown in Figure 5. If an identifier formed by the first format conflicts with a corrected portion of an identifier formed by the second format, the communication device 10 that transmitted the latter will lose the arbitration.

[0120] Unless all conflicting parts in the identifier of the first format are recessive, the communication device 10 transmitting the identifier of the second format will determine that it has lost the arbitration at the time it transmits the basic ID 71a and will stop transmitting the data.

[0121] If all collision points in the identifier of the first format are recessive, the identifier of the second format will collide with RTR72 in the identifier of the first format at the time the SRR73 signal is transmitted. Therefore, even in this case, the communication device 10 that transmitted the identifier of the second format will determine that it has lost the arbitration and will stop transmitting the data.

[0122] Furthermore, if data having identifiers in the second format collide, the communication device 10 performs arbitration by comparing the extended IDs 71b. Subsequently, processing circuits 16 and 21 proceed to S23. In the process of S23, processing circuits 16 and 21 determine whether they won the mediation process.

[0123] In Figure 11, processing circuits 16 and 21 may win the arbitration process if data having identifiers in the second format collide. Processing circuits 16 and 21 determine that they have won the arbitration process in S22 when the transmission of data is completed without them stopping the transmission of data. If processing circuits 16 and 21 determine that they have won the arbitration process in S23 (S23: YES), they terminate the series of processes shown in Figure 11.

[0124] Processing circuits 16 and 21 determine in the arbitration process of S22 that they lost the arbitration and, when they stop transmitting data, they determine that they did not win the arbitration. If processing circuits 16 and 21 determine in the process of S23 that they did not win the arbitration (S23: NO), they proceed to process S24.

[0125] In the processing of S24, processing circuits 16 and 21 determine whether or not there is data being transmitted on the communication bus 30. If processing circuits 16 and 21 determine that there is data being transmitted on the communication bus 30 (S24: YES), they execute the process in S24 again. In other words, processing circuits 16 and 21 execute the process in S24 until they determine that there is no data being transmitted on the communication bus 30.

[0126] If processing circuits 16 and 21 determine that there is no data being transmitted on the communication bus 30 (S24: NO), they proceed to S25. In the process of S25, processing circuits 16 and 21 retransmit the data that could not be transmitted in S22 due to a failed arbitration. After that, processing circuits 16 and 21 terminate this series of processes.

[0127] Thus, when a communication device 10 that transmits data containing an identifier formed by the second format detects a data collision, it corrects the data it transmits so that its own data has a lower priority than the data of the other party that it is colliding with. Furthermore, when a data collision occurs, the communication device 10 performs a correction process and then executes a mediation process to prevent its own data from being prioritized. Therefore, if data containing an identifier formed by the first format and data containing an identifier formed by the second format collide, the communication device 10 that transmitted the former can continue transmission during the mediation process.

[0128] <Operation of this embodiment> When the communication device 10 transmits data containing an identifier formed by the second format, if the transmitted data conflicts with other data, it corrects the identifier so that the data it transmitted does not take precedence in arbitration processing. As a result, in the communication network system 40 configured by the communication device 10, data containing an identifier formed by the first format takes precedence over data containing an identifier formed by the second format.

[0129] <Effects of this embodiment> (1) Even if there are multiple types of identifiers included in the data transmitted in the communication network system 40, the arbitration result will be in a predetermined order according to the type of identifier. Therefore, the above communication device 10 can suppress the occurrence of situations in which data that should be prioritized is not prioritized.

[0130] (2) The bit length of the identifier in the first format is shorter than the bit length of the identifier in the second format. (3) The bit length of the identifier in the first format is 11 bits. The bit length of the identifier in the second format is 29 bits.

[0131] When the communication device 10 transmits data containing an identifier formed in a 29-bit format, if the transmitted data conflicts with other data, it performs a correction process. This prevents the communication device 10 from determining in arbitration that data containing a 29-bit identifier has higher priority than data containing an 11-bit identifier.

[0132] (4) The communication device 10 is mounted on the vehicle 50. Processing circuits 16 and 21 form a control frame in a first format, which is an identifier indicating that the data is transmitted for the control of the vehicle 50. Processing circuits 16 and 21 form a diagnostic frame in a second format, which is an identifier indicating that the data is transmitted for fault diagnosis of the vehicle 50.

[0133] The types of identifiers included in the data transmitted by the communication device 10 include control frames and diagnostic frames. When data containing diagnostic frames that it has transmitted conflicts with other data in the communication network system 40, the communication device 10 performs a correction process. This allows the communication device 10 to prioritize the transmission of data containing control frames over data containing diagnostic frames in the communication network system 40.

[0134] (5) Processing circuits 16 and 21 form a management frame in a first format, which is an identifier indicating that the data is transmitted to manage the communication status in the communication network system 40.

[0135] The types of identifiers included in the data transmitted by the communication device 10 include control frames, diagnostic frames, and management frames. When data containing diagnostic frames that it has transmitted conflicts with other data in the communication network system 40, the communication device 10 performs a correction process. This allows the communication device 10 to prioritize the transmission of data containing management frames over data containing diagnostic frames in the communication network system 40.

[0136] (6) Multiple communication devices 10 constitute a communication network 45. The communication network system 40 comprises multiple communication networks 45. The communication network system 40 is a relay device 20 that relays data exchanged between multiple communication networks 45.

[0137] Among the communication devices 10, the relay device 20, which transmits data sent in one communication network 45 to another communication network 45, tends to transmit data more frequently than the other communication devices 10. Furthermore, because the relay device 20 relays data sent from multiple communication devices 10, it is highly likely to transmit data containing various types of identifiers. Therefore, when the relay device 20 relays data exchanged between communication networks 45, situations where data that should be prioritized is not prioritized are likely to occur.

[0138] Of the communication devices 10, the relay device 20 corrects the identifier when it transmits data containing an identifier formed by the second format, so that if the transmitted data conflicts with other data, the transmission of that data is not given priority in the arbitration process. As a result, in the communication network system 40, which is composed of multiple communication networks 45, data containing an identifier formed by the first format takes precedence over data containing an identifier formed by the second format.

[0139] As a result, even if there are multiple types of identifiers included in the data transmitted in the communication network system 40, which is composed of multiple communication networks 45, the arbitration result will be in accordance with a predetermined order corresponding to the type of identifier. Therefore, the communication device 10 can suppress the occurrence of situations in which data that should be prioritized is not prioritized.

[0140] (7) In the vehicle 50, when the communication device 10 transmits data containing an identifier formed in the second format, if the transmitted data conflicts with other data, it corrects the identifier so that the data it transmitted does not take precedence in arbitration processing. As a result, in the communication network system 40 provided in the vehicle 50, data containing an identifier formed in the first format takes precedence over data containing an identifier formed in the second format.

[0141] As a result, even if there are multiple types of identifiers included in the data transmitted in the communication network system 40, the arbitration result will be in accordance with a predetermined order corresponding to the type of identifier. Therefore, the vehicle 50 can prevent situations in which data that should be prioritized is not prioritized.

[0142] (8) The vehicle 50 is equipped with a communication device 10. In the communication device 10, the bit length of the identifier in the first format is shorter than the bit length of the identifier in the second format. (9) The vehicle 50 is equipped with a communication device 10. In the communication device 10, the bit length of the identifier in the first format is 11 bits. In the communication device 10, the bit length of the identifier in the second format is 29 bits.

[0143] In vehicle 50, when communication device 10 transmits data containing an identifier formed in a 29-bit format, if the transmitted data conflicts with other data, it performs a correction process. This prevents a situation in arbitration where data containing a 29-bit identifier is judged to have higher priority than data containing an 11-bit identifier.

[0144] (10) The communication method is a communication method in the communication network system 40. The communication network system 40 is composed of multiple communication devices 10, and data containing identifiers is exchanged between the multiple communication devices 10 through communication compliant with the CAN protocol. In the communication network system 40, the identifier indicates the priority of the data, and there are two formats: a first format and a second format which is different from the first format. In the communication network system 40, when transmitted data collide, the communication device 10 transmitting the data is configured to perform arbitration processing. In the arbitration processing, the communication device 10 transmitting the data compares the identifier contained in the data it transmits with the identifier contained in the data of the other party with which it collided. In the arbitration processing, if the data it transmits has a higher priority, the communication device 10 continues to transmit the data, and if the data it transmits has a lower priority, it stops transmitting the data. The communication method includes, when transmitting data containing an identifier formed in the second format, the communication device 10 performs the arbitration process (S21, S22) while correcting the identifier included in the data it transmits so that the data it transmits has a lower priority than the data of the other party that it collided with. The communication method also includes, when transmitting data containing an identifier formed in the first format, the communication device 10 performs the arbitration process (S11) without performing the correction process if the data collided with data transmitted by another communication device.

[0145] The communication method corrects the identifier when transmitting data containing an identifier formed by the second format, so that if the transmitted data conflicts with other data, the transmitted data does not take precedence in arbitration processing. As a result, in a communication network system 40 configured with communication devices 10 to which the above communication method is applied, data containing identifiers formed by the first format takes precedence over data containing identifiers formed by the second format.

[0146] As a result, even if there are multiple types of identifiers included in the data transmitted in the communication network system 40, the arbitration result will be in accordance with a predetermined order corresponding to the type of identifier. Therefore, the above communication method can suppress situations in which data that should be prioritized is not prioritized.

[0147] (11) When the communication program PC transmits data containing an identifier formed by the second format, if the transmitted data conflicts with other data, the PC corrects the identifier so that the data it transmitted does not take precedence in arbitration processing. As a result, in the communication network system 40, which is composed of communication devices 10 that store the communication program PC, data containing an identifier formed by the first format takes precedence over data containing an identifier formed by the second format.

[0148] As a result, even if there are multiple types of identifiers included in the data transmitted in the communication network system 40, the arbitration result will be in accordance with a predetermined order corresponding to the type of identifier. Therefore, the communication program PC can prevent situations in which data that should be prioritized is not prioritized.

[0149] In the above embodiment, the communication program PC is stored in storage device 17 and storage device 22. The communication program PC may also be provided already recorded on a recording medium. Examples of recording media on which the communication program PC is recorded include memory such as USB memory, SSD, and SD card, as well as CD-ROMs and optical discs.

[0150] <Example of changes> The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0151] The bit length of the identifier in the first format may be the same as the bit length of the identifier in the second format. The bit length of the identifier in the first format may be longer than the bit length of the identifier in the second format.

[0152] The bit length of the identifier in the first format does not have to be 11 bits. The bit length of the identifier in the second format does not have to be 29 bits. The communication device 10 does not necessarily have to be mounted on the vehicle 50.

[0153] The types of identifiers are not limited to those shown in Figures 7 and 8. The communication device 10 does not have to form control frames in the first format. The communication device 10 does not have to form management frames in the first format. The communication device 10 does not have to form diagnostic frames in the first format. The communication device 10 does not have to form diagnostic frames in the second format.

[0154] The communication network system 40 does not necessarily have to include multiple communication networks 45. In this case, the communication network system 40 does not necessarily have to include a relay device 20 as a communication device 10.

[0155] [Note] The technical concepts that can be understood from the above embodiments and modified examples are described below. [Note 1] The system is configured to have multiple communication devices, which exchange data containing identifiers through communication compliant with the CAN protocol, where the identifier indicates the priority of the data, and has a first format and a second format different from the first format, and when transmitted data collide, the communication device transmitting the data compares the identifier contained in its own transmitted data with the identifier contained in the data of the other party that collided with it, and performs arbitration processing to continue transmitting the data if its own transmitted data has a higher priority, and to stop transmitting the data if its own transmitted data has a lower priority. A communication device in a communication network system, comprising a processing circuit, wherein the processing circuit performs the following: when transmitting data containing the identifier formed in the second format, if the data conflicts with data transmitted by another communication device, it performs the arbitration process while correcting the identifier contained in the data it transmits so that the data it transmits has a lower priority than the data of the other party; and when transmitting data containing the identifier formed in the first format, if the data conflicts with data transmitted by another communication device, it performs the arbitration process without performing the correction process.

[0156] [Note 2] The communication device according to Note 1, wherein the bit length of the identifier in the first format is shorter than the bit length of the identifier in the second format. [Note 3] The communication device according to Note 2, wherein the bit length of the identifier in the first format is 11 bits, and the bit length of the identifier in the second format is 29 bits.

[0157] [Note 4] An electronic control device mounted on a vehicle, wherein the processing circuit performs the following actions: forming a control frame, which is an identifier indicating that the data is transmitted for the control of the vehicle, in the first format; and forming a diagnostic frame, which is an identifier indicating that the data is transmitted for fault diagnosis of the vehicle, in the second format; as described in any one of Notes 1 to 3.

[0158] [Note 5] The communication device according to Note 4, wherein the processing circuit performs the operation of forming a management frame, which is an identifier indicating that it is data to be transmitted for managing the state of communication in the communication network system, in the first format.

[0159] [Note 6] The communication device described in any one of Notes 1 to 5, wherein the plurality of communication devices constitute a communication network, and the communication network system comprises the plurality of communication networks and is a relay device that relays data exchanged between the plurality of communication networks.

[0160] [Note 7] A vehicle equipped with a communication device as described in any one of Notes 1 to 6. [Explanation of symbols]

[0161] 10…Communication device 11...First device 12…Second device 13…Third device 14…Fourth device 15...Fifth device 16…Processing circuit 17...Storage device 20…Relay device 21…Processing circuit 22…Storage device 30... Communications bus 31... Bus No. 1 32... Bus No. 2 40…Communication network systems 45…Communication Networks 46…First Telecommunications Network 47…Second Communications Network 50... Vehicles 61…SOF 62...Mediation Department 62a…Standard Mediation Department 62b... Extended Mediation Section 63...Data Section 71…ID 71a…Basic ID 71b... Extended ID 72…RTR 73…SRR 74…IDE PC...communication program

Claims

1. The system is equipped with multiple communication devices, and these multiple communication devices exchange data containing identifiers through communication compliant with the CAN protocol. The aforementioned identifier indicates the priority of the data, and the format includes a first format and a second format that is different from the first format. In a communication network system, the communication device is configured such that when transmitted data collide, the communication device transmitting the data compares the identifier contained in its own transmitted data with the identifier contained in the data of the other party that it collided with, and performs arbitration processing to continue transmitting the data if its own transmitted data has a higher priority, and to stop transmitting the data if its own transmitted data has a lower priority. Equipped with a processing circuit, The aforementioned processing circuit is When data containing the identifier formed by the second format is transmitted, if such data conflicts with data transmitted by another communication device, the arbitration process is performed while correcting the identifier contained in the data transmitted by the device itself so that the data transmitted by the device itself has a lower priority than the data of the other party that caused the conflict. When data containing the identifier formed in the first format is transmitted, if such data conflicts with data transmitted by another communication device, the arbitration process is executed without performing the correction process. Execute Communication device.

2. The bit length of the identifier in the first format is shorter than the bit length of the identifier in the second format. The communication device according to claim 1.

3. The bit length of the identifier in the first format is 11 bits, and the bit length of the identifier in the second format is 29 bits. The communication device according to claim 2.

4. It is an electronic control device installed in a vehicle. The aforementioned processing circuit is A control frame, which is the identifier indicating that the data is transmitted for the control of the vehicle, is formed in the first format, The diagnostic frame, which is the identifier indicating that the data is transmitted for fault diagnosis of the vehicle, is formed in the second format, Execute A communication device according to any one of claims 1 to 3.

5. The processing circuit performs the operation of forming a management frame, which is an identifier indicating that the data is transmitted to manage the communication status in the communication network system, in the first format. The communication device according to claim 4.

6. Multiple of the aforementioned communication devices constitute a communication network. The aforementioned communication network system comprises a plurality of such communication networks, This is a relay device that relays data exchanged between multiple aforementioned communication networks. A communication device according to any one of claims 1 to 3.

7. A vehicle equipped with a communication device according to any one of claims 1 to 3.

8. It consists of multiple communication devices, and these multiple communication devices exchange data including identifiers through communication compliant with the CAN protocol. The aforementioned identifier indicates the priority of the data, and the format includes a first format and a second format that is different from the first format. A communication method in a communication network system configured such that, when transmitted data collide, the communication device transmitting the data compares the identifier contained in its own transmitted data with the identifier contained in the data of the colliding party, and performs arbitration processing to continue transmitting the data if its own transmitted data has a higher priority, and to stop transmitting the data if its own transmitted data has a lower priority. When data containing the identifier formed in the second format is transmitted, if such data conflicts with data transmitted by another communication device, the communication device performs a correction process to correct the identifier contained in the data it transmits so that the data it transmits has a lower priority than the data of the other party that it conflicted with, while simultaneously performing the arbitration process. When data containing the identifier formed in the first format is transmitted, if such data conflicts with data transmitted by another communication device, the communication device performs the arbitration process without performing the correction process. including Communication method.

9. It consists of multiple communication devices, and these multiple communication devices exchange data including identifiers through communication compliant with the CAN protocol. The aforementioned identifier indicates the priority of the data, and the format includes a first format and a second format that is different from the first format. In a communication network system configured such that when transmitted data collide, the communication device transmitting the data compares the identifier contained in its own transmitted data with the identifier contained in the data of the colliding party, and performs arbitration processing to continue transmitting the data if its own transmitted data has a higher priority, and to stop transmitting the data if its own transmitted data has a lower priority, the communication program is executed by the processing circuit of the communication device. When data containing the identifier formed by the second format is transmitted, if such data conflicts with data transmitted by another communication device, the arbitration process is performed while correcting the identifier contained in the data transmitted by the device itself so that the data transmitted by the device itself has a lower priority than the data of the other party that caused the conflict. When data containing the identifier formed in the first format is transmitted, if such data conflicts with data transmitted by another communication device, the arbitration process is executed without performing the correction process. The processing circuit is made to execute the above. Communication program.

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