A Node Online Scanning Configuration Method and System Applied to CAN Bus Communication

Abstract

The present invention provides a method and system for online scanning and configuration of nodes applied to CAN bus communication, including the following steps: S1: The master controller sends a downstream CAN broadcast scan message based on the CAN bus; S2: In a single scan cycle, the preceding first node device receives the downstream CAN broadcast scan message based on the forward unidirectional serial line and sets its own position number to n; S3: The first node device transmits the downstream CAN broadcast scan message and its own position number information to the second node device adjacent to the rear of the first node device through the backward unidirectional serial line, and the second node device sets its own position number to n + 1; S4: Each node device repeats step S3 until all node devices have completed setting their own position numbers. All node devices respectively send upstream CAN heartbeat messages based on the CAN bus, and the master controller obtains the configuration data corresponding to the position numbers and device IDs of all node devices based on the upstream CAN heartbeat messages.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial communication, and particularly relates to a method and system for online scanning and configuration of nodes applied to CAN bus communication. Background Art

[0002] The CAN bus (Controller Area Network) is a serial communication protocol widely used in the fields of automotive and industrial control. It aims to solve the problem of efficient and reliable communication between an increasing number of complex electronic control units (ECUs) in modern automobiles. The CAN bus allows various electronic systems or components to exchange data through a pair of twisted-pair wires, thereby reducing wiring costs and weight and improving the reliability of the system. It has the advantages of high reliability, real-time performance, flexibility, low cost, and multi-master structure, and thus has become one of the important technologies for communication between distributed control systems.

[0003] However, in the prior art, when the master controller uses the CAN bus to connect multiple CAN node devices, if the device ID information corresponding to the independent CAN node is not known in advance, it is impossible to perform point-to-point communication with the target node relying on the COBID field in the CAN message. Moreover, it is difficult to perform node remote positioning, ID scanning, and configuration functions relying solely on the CAN protocol. In addition, when there is an ID conflict, it is impossible to quickly and accurately locate the specific conflicting node. Summary of the Invention

[0004] The present invention aims to provide a method and system for online scanning and configuration of nodes applied to CAN bus communication to solve the technical problem that in the prior art, a conventional CAN bus communication system cannot achieve remote positioning, ID scanning, and configuration of node devices.

[0005] To solve the above problems, the technical solution of the present invention is as follows: A method for online scanning and configuration of nodes applied to CAN bus communication includes the following steps:

[0006] S1: The master controller sends a downstream CAN broadcast scan message based on the CAN bus;

[0007] S2: In a single scan cycle, the frontmost first node device receives the downstream CAN broadcast scan message based on the forward unidirectional serial port line and sets its own position number to n;

[0008] S3: The first node device transmits the downstream CAN broadcast scan message and its own position number information to the second node device adjacent to the rear of the first node device through the backward unidirectional serial port line, and the second node device sets its own position number to n + 1;

[0009] S4: Each node device repeats step S3 until all node devices have completed setting their own position numbers. All node devices respectively send upstream CAN heartbeat messages based on the CAN bus, and the master controller obtains the configuration data corresponding to the position numbers and device IDs of all node devices based on the upstream CAN heartbeat messages.

[0010] Preferably, in S2, within a single scan process, the first node device receives the downstream CAN broadcast scan message, which specifically includes the following steps:

[0011] S21: During a single scan cycle, all powered-on node devices respectively perform self-check actions. During the self-check waiting time, if there is a node device that cannot receive the downstream CAN broadcast scan message from the forward unidirectional serial port line, the current node device is set as the first node device. The first node device selects to receive the downstream CAN broadcast scan message from the CAN bus and sets its own position number to 1.

[0012] Preferably, it further includes the following steps:

[0013] S5: After the master controller receives the upstream CAN heartbeat message, it sends a downstream CAN control message including the corresponding position number and device ID to the target node device to be controlled based on the CAN bus;

[0014] The target node device receives the downstream CAN control message based on the CAN bus, and after performing the control action, it sends an upstream CAN feedback message including its own position number and device ID to the master controller based on the CAN bus.

[0015] Preferably, when the master controller sends the downstream CAN control message to the target node device in S5, it further includes the following steps:

[0016] S51: During a single control cycle, if all the device IDs in the downstream CAN control messages already sent by the master controller do not completely cover all the device IDs in the upstream CAN heartbeat messages sent by all node devices, the master controller continues to send the downstream CAN control messages for the un-controlled node devices until all node devices receive the corresponding downstream CAN control messages, and the single control cycle ends.

[0017] Preferably, the scan cycle is repeatedly executed at a specific time interval, and the specific time interval at least includes the total time taken for the master controller to send the downstream CAN control messages to all target node devices and for all target node devices to send the upstream CAN feedback messages to the master controller.

[0018] Preferably, in S4, each node device repeats the S3 step until all node devices have completed their own position number settings, which further includes the following steps:

[0019] S41: When the device IDs recorded in the uplink CAN heartbeat messages respectively sent by all node devices match the device IDs of all node devices recorded locally in sequence, the master controller pauses the repeated scanning action for the node devices until any node device has a power-off action, and then the master controller restarts the scanning action for the node devices.

[0020] Preferably, in S4, the master controller obtains the data corresponding to the position numbers and device IDs of all node devices, which further includes the following steps:

[0021] S42: During a single scanning cycle, if there are two identical sets of device IDs among the data corresponding to the position numbers and device IDs of all node devices received by the master controller, the master controller outputs a node device ID conflict alarm.

[0022] Preferably, after the master controller outputs a node device ID conflict alarm in S42, it further includes the following steps:

[0023] S43: The master controller obtains the data corresponding to the position numbers and device IDs of the conflict node devices with device ID conflicts. The master controller sends a downlink CAN configuration message including the position number and a new device ID to the conflict node devices respectively based on the CAN bus. The conflict node devices receive the downlink CAN configuration message based on the CAN bus and automatically configure the new device ID;

[0024] The conflict node devices resend an uplink CAN heartbeat message including the correct position number and device ID based on the CAN bus.

[0025] Based on the same concept, the present invention also provides a node online scanning and configuration system applied to CAN bus communication for executing the node online scanning and configuration method applied to CAN bus communication as described in any one of the above, including a master controller and several node devices;

[0026] The master controller is electrically connected to the CAN bus, and the master controller is used to implement the online scanning configuration and control functions of several said node devices;

[0027] Several said node devices are respectively electrically connected to the CAN bus, and adjacent said node devices are electrically connected in sequence. The node devices are used to execute operation tasks according to the control instructions of the master controller.

[0028] Preferably, each of the node devices is provided with a data conversion module, which includes a front-end single-wire serial communication interface and a rear-end single-wire serial communication interface. The node devices are electrically connected to another adjacent front-end node device through a forward single-way serial port line, and are electrically connected to another adjacent rear-end node device through a backward single-way serial port line.

[0029] Due to the above technical solutions, the present invention has the following advantages and positive effects compared with the prior art:

[0030] The present invention provides a node online scanning and configuration method and system applied to CAN bus communication. By utilizing the unidirectional characteristic of data transmission between the front-end node device and the rear-end node device, the functions of automatic position numbering and dynamic adjustment of the numbering of each node device are realized. Furthermore, through the characteristic that the device ID corresponds to the position number, the functions of quickly locating the node device and achieving point-to-point precise control can be satisfied, and the time for configuring the device ID can be significantly reduced. In addition, the node device with a device ID conflict can be detected, which is convenient for fault troubleshooting and device maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The first process schematic diagram of a node online scanning and configuration method applied to CAN bus communication provided by the present invention;

[0032] Figure 2 The second process schematic diagram of a node online scanning and configuration method applied to CAN bus communication provided by the present invention;

[0033] Figure 3 The structural schematic diagram of a node online scanning and configuration system applied to CAN bus communication provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The following further details the node online scanning and configuration method and system applied to CAN bus communication proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will be clearer according to the following description and the claims.

[0035] The First Embodiment

[0036] Refer to Figures 1 to 3 , this embodiment provides a node online scanning and configuration method applied to CAN bus communication, which is used to realize the function of automatically setting the position numbers of node devices in sequence, and specifically includes the following steps:

[0037] S1: The main controller sends a downstream CAN broadcast scanning message based on the CAN bus;

[0038] S2: In a single scan cycle, the preceding first node device receives a downstream CAN broadcast scan message based on the forward unidirectional serial port line, and sets its own position number to n;

[0039] S3: The first node device transmits the downstream CAN broadcast scan message and its own position number information to the second node device adjacent to and behind the first node device through the backward unidirectional serial port line, and the second node device sets its own position number to n + 1;

[0040] S4: Each node device sequentially repeats step S3 until all node devices have completed setting their own position numbers. All node devices respectively send upstream CAN heartbeat messages based on the CAN bus, and the main controller obtains the configuration data corresponding to the position numbers and device IDs of all node devices based on the upstream CAN heartbeat messages.

[0041] Specifically, in this embodiment, the main controller is electrically connected to the CAN bus. In addition to being respectively and individually electrically connected to the CAN bus, each node device is also connected in a daisy chain with the other node devices adjacent to it in the front and back. After receiving the downstream CAN broadcast scan message within a single scan cycle, the preceding first node device can set its own position number to n, and pack the downstream CAN broadcast scan message and its own position number n to form a new downstream CAN broadcast scan message. After receiving the downstream CAN broadcast scan message output by the first node device, the second node device behind the first node device can set its own position number to n + 1, and pack the downstream CAN broadcast scan message and its own position number n + 1 again to form a new downstream CAN broadcast scan message, and transmit it to the third node device behind the second node device... and so on, until all node devices have completed setting their own position numbers. That is, in this embodiment, the position number of the node device that first receives the downstream CAN broadcast scan message is automatically set to 1, and the position numbers of the subsequent node devices are automatically set to 2, 3, 4... based on the sorting position (the receiving order of the downstream CAN broadcast scan messages).

[0042] It can be seen from this that in this embodiment, the main controller can obtain the configuration data corresponding to the position numbers and device IDs of all node devices based on the upstream CAN heartbeat messages respectively output by each node device. The main controller can determine the specific device ID of the node device through the position number of the node device, thereby realizing the online scan of the node device and the subsequent point-to-point precise control function for the node device with a specific device ID.

[0043] It should be noted that the first node device, the second node device, etc. mentioned above do not refer to the specific positions of the node devices in the CAN bus, but are only used to indicate that the first node device is the adjacent preceding node device of the second node device.

[0044] Next, the specific implementation steps and functions of a node online scanning configuration method applied to CAN bus communication provided in this embodiment will be further described in detail:

[0045] Preferably, in this embodiment, in S2, within a single scan process, the first node device receives a downlink CAN broadcast scan message, which specifically includes the following steps:

[0046] S21: During a single scan cycle, all powered-on node devices respectively perform self-check actions. During the self-check waiting time, if there is a node device that cannot receive the downlink CAN broadcast scan message from the forward unidirectional serial port line, the current node device is set as the first node device. The first node device selects to receive the downlink CAN broadcast scan message from the CAN bus and sets its own position number to 1.

[0047] That is, in this embodiment, only the first node device receives the downlink CAN broadcast scan message through the CAN bus, and any subsequent node device respectively receives the downlink CAN broadcast scan message through its forward unidirectional serial port line. Based on the time sequence in which the downlink CAN broadcast scan message arrives at each node device in turn, the position numbers of each node device are determined.

[0048] It should be noted that in this embodiment, there are differences in the power-on times of different node devices. Therefore, within a single scan cycle, only the position numbers of the powered-on node devices within the single scan cycle can be automatically set. In the next scan cycle, the position numbers of the powered-on node devices will be automatically adjusted based on the power-on and power-off conditions of each node device.

[0049] Preferably, in this embodiment, the following steps are further included:

[0050] S5: After the main controller receives the uplink CAN heartbeat message, it sends a downlink CAN control message including the corresponding position number and device ID to the target node device to be controlled based on the CAN bus;

[0051] Among them, the downlink CAN control message is a broadcast message, that is, any node device can respectively receive this downlink CAN control message based on the CAN bus. According to the position number and device ID recorded in the downlink CAN control message, only the target node device corresponding to this position number and device ID finally obtains the control instruction recorded correspondingly in the downlink CAN control message.

[0052] The target node device receives the downlink CAN control message based on the CAN bus, and after performing relevant control actions, it sends an uplink CAN feedback message including its own position number and device ID to the main controller based on the CAN bus to implement the data feedback function.

[0053] Further, in this embodiment, when the master controller sends a downlink CAN control message to the target node device in S5, the following steps are further included:

[0054] S51: In a single control cycle, if all the device IDs in the downlink CAN control messages already sent by the master controller do not completely cover all the device IDs in the uplink CAN heartbeat messages sent by all the node devices, the master controller continues to send downlink CAN control messages for the un-controlled node devices until all the node devices receive the corresponding downlink CAN control messages, and the single control cycle ends.

[0055] In this embodiment, the master controller does not send multiple downlink CAN control messages to each node device simultaneously. Therefore, the master control module can also record all the device IDs in the sent downlink CAN control messages and compare these device IDs with all the device IDs in the uplink CAN heartbeat messages sent by all the node devices until the downlink CAN control messages for all the device IDs are sent, which proves that the instruction control of all the node devices has been completed.

[0056] Preferably, in this embodiment, due to the difference in the power-on time of different node devices, the scanning cycle is repeatedly executed at a specific time interval, and the specific time interval at least includes the total time taken for the master controller to send downlink CAN control messages to all the target node devices and for all the target node devices to send uplink CAN feedback messages to the master controller. That is, in this embodiment, the scanning cycle and the control cycle alternate, and any scanning cycle and the adjacent control cycle following it share the configuration data corresponding to the same position number and device ID.

[0057] Preferably, in this embodiment, when each node device repeatedly executes step S3 until all the node devices have completed their own position number settings in S4, the following steps are further included:

[0058] S41: When the device IDs recorded in the uplink CAN heartbeat messages respectively sent by all the node devices match the device IDs of all the node devices recorded locally in sequence, the master controller pauses the repeated scanning action for the node devices until any node device has a power-off action, and then the master controller restarts the scanning action for the node devices.

[0059] In this embodiment, the device IDs of all node devices can be pre-stored locally in advance. When the device IDs recorded in the uplink CAN heartbeat messages sent by all node devices respectively completely cover the device IDs of all node devices recorded locally, it proves that all node devices have been powered on and are communicatively connected to the master controller. At this time, if there is no situation where a node device is powered off, the number of node devices communicatively connected to the master controller remains unchanged, and the position numbers of each node device remain unchanged. Therefore, at this time, the master controller suspends the repeated scanning operation for the node devices, reduces the communication volume added to the CAN bus by continuous broadcast scanning, optimizes the system performance and resource utilization, and improves the response speed of the system.

[0060] Preferably, in this embodiment, in S4, the master controller obtains the data corresponding to the position numbers and device IDs of all node devices, which further includes the following steps:

[0061] S42: During a single scanning cycle, if there are two or more groups of the same device IDs in the data corresponding to the position numbers and device IDs of all node devices received by the master controller, the master controller outputs a node device ID conflict alarm.

[0062] In this embodiment, the repetition of device IDs may be caused by reasons such as manual configuration errors of node device IDs, failure of node device initialization, or loss of configuration. When two or more node devices share the same device ID, a message sent to one of these node devices may be received by another node device with the same device ID, resulting in information misalignment or loss. Therefore, in this embodiment, when the existence of the same device ID is detected during the scanning cycle, the master controller suspends the subsequent control actions and outputs a node device ID conflict alarm.

[0063] Further, after the master controller outputs a node device ID conflict alarm in S42, the following steps are further included:

[0064] S43: The master controller obtains the data corresponding to the position numbers and device IDs of the conflicting node devices with device ID conflicts. The master controller sends downlink CAN configuration messages including the position numbers and new device IDs to the conflicting node devices respectively based on the CAN bus. The conflicting node devices receive the downlink CAN configuration messages based on the CAN bus and automatically configure the new device IDs;

[0065] The conflicting node devices re-send uplink CAN heartbeat messages including the correct position numbers and device IDs to the master controller based on the CAN bus.

[0066] In this embodiment, since the position number is unique and generated sequentially according to the order of the node devices, when there is a situation where the device IDs are the same, the conflicting node devices with device ID conflicts can still be determined through the position numbers. Subsequently, new device IDs are re-allocated to the conflicting node devices with device ID conflicts to solve the device ID conflict problem.

[0067] In summary, this embodiment provides a node online scanning and configuration method applied to CAN bus communication. By utilizing the unidirectional characteristic of data transmission between the pre-node device and the post-node device, the automatic position numbering and dynamic adjustment of the position numbers of each node device are realized. Furthermore, through the characteristic of the corresponding binding of the device ID and the position number, the functions of quickly positioning the node device and achieving point-to-point precise control can be satisfied, and the time for configuring the device ID can be significantly reduced. In addition, the node devices with device ID conflicts can be detected, which is convenient for troubleshooting and device maintenance.

[0068] Second Embodiment

[0069] Refer to Figure 3 , based on the same concept, this embodiment provides a node online scanning and configuration system applied to CAN bus communication, which is used to execute the node online scanning and configuration method applied to CAN bus communication described in any one of the first embodiments, and includes a main controller and several node devices.

[0070] Among them, the main controller includes a PLC or a CPU module. The main controller is electrically connected to the CAN bus, and the main controller is used to realize the online scanning, configuration and control functions of several node devices through the CAN bus.

[0071] Several node devices are respectively electrically connected to the CAN bus, and adjacent node devices are electrically connected in sequence. The node devices are used to execute operation tasks according to the control instructions output by the main controller.

[0072] Among them, any one of the node devices is provided with a data conversion module. The data conversion module includes a CAN bus interface, a front single-wire serial communication interface and a rear single-wire serial communication interface. The node device is electrically connected to the CAN bus through the CAN bus interface. At the same time, the node device is respectively electrically connected to another adjacent pre-node device through a forward unidirectional serial port line, and electrically connected to another adjacent post-node device through a backward unidirectional serial port line.

[0073] In this embodiment, the master controller can send a downlink CAN broadcast scan message through the CAN bus. The first node device at the forefront in the CAN network receives the downlink CAN broadcast scan message through the CAN bus, and sets its position number to 1. Subsequently, the first node device reorganizes the downlink CAN broadcast scan message with its own position number 1 to form a new downlink CAN broadcast scan message, and sends it to another node device adjacent to the first node device at the back through a one-way serial line. The latter node device sets its position number to 2 based on the position number 1 of the first node device, and reorganizes the downlink CAN broadcast scan message with its own position number 2 to form a new downlink CAN broadcast scan message... and so on, to achieve automatic sequential setting of the position numbers of all node devices.

[0074] By using the online scanning and automatic numbering mechanism, the position numbers of the node devices can be quickly determined. And based on the corresponding binding relationship between the position numbers of the node devices and the device IDs, the master controller can subsequently precisely control each node device in a point-to-point manner without interfering with other node devices, with relatively high precision and security. At the same time, when any node device fails, the operator can quickly and accurately locate the specific faulty node device based on the position number, improving the maintenance efficiency. Also, as new node devices are added or existing node devices are removed, the system can dynamically adjust and update the position numbers of the node devices, that is, it supports flexible expansion of the system.

[0075] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, provided that these changes fall within the scope of the claims of the present invention and their equivalent technologies, they still fall within the protection scope of the present invention.

Claims

1. A method for online scanning and configuration of nodes applied to CAN bus communication, characterized in that, It includes the following steps: S1: The main controller sends a downstream CAN broadcast scan message based on the CAN bus; S2: In a single scan cycle, the first node device in front receives the downstream CAN broadcast scan message based on the forward unidirectional serial line, and sets its own position number to n; S3: The first node device transmits the downstream CAN broadcast scan message and its own position number information to the second node device adjacent and behind it through the backward unidirectional serial line, and the second node device sets its own position number to n + 1; S4: Each node device repeats step S3 until all node devices have completed setting their own position numbers. All node devices respectively send upstream CAN heartbeat messages based on the CAN bus, and the main controller obtains the configuration data corresponding to the position numbers and device IDs of all node devices based on the upstream CAN heartbeat messages.

2. The on-line scanning configuration method for nodes applied to CAN bus communication according to claim 1, characterized in that, In S2, when the first node device receives the downstream CAN broadcast scan message within a single scan process, it specifically includes the following steps: S21: In a single scan cycle, all powered-on node devices respectively perform self-check actions. During the self-check waiting time, if there is a node device that cannot receive the downstream CAN broadcast scan message from the forward unidirectional serial line, the current node device is set as the first node device. The first node device chooses to receive the downstream CAN broadcast scan message from the CAN bus and sets its own position number to 1.

3. The on-line scanning configuration method for a node applied to CAN bus communication according to claim 1, characterized in that, It also includes the following steps: S5: After receiving the upstream CAN heartbeat message, the main controller sends a downstream CAN control message including the corresponding position number and device ID to the target node device to be controlled based on the CAN bus; The target node device receives the downstream CAN control message based on the CAN bus, and after executing the control action, sends an upstream CAN feedback message including its own position number and device ID to the main controller based on the CAN bus.

4. The method for online scanning and configuration of nodes applied to CAN bus communication according to claim 3, wherein, In S5, when the main controller sends the downstream CAN control message to the target node device, it further includes the following steps: S51: In a single control cycle, if all the device IDs in the downstream CAN control messages already sent by the main controller do not completely cover all the device IDs in the upstream CAN heartbeat messages sent by all node devices, the main controller continues to send the downstream CAN control messages for the un-controlled node devices until all node devices receive the corresponding downstream CAN control messages, and the single control cycle ends.

5. The on-line scanning configuration method for nodes applied to CAN bus communication according to claim 4, characterized in that, The scan cycle is repeatedly executed at a specific time interval, and the specific time interval at least includes the total time taken for the main controller to send the downstream CAN control messages to all target node devices and for all target node devices to send the upstream CAN feedback messages to the main controller.

6. The on-line scanning configuration method for nodes applied to CAN bus communication according to claim 3, characterized in that, In S4, when each node device repeats step S3 until all node devices have completed setting their own position numbers, it further includes the following steps: S41: When the device IDs recorded in the uplink CAN heartbeat messages respectively sent by all node devices match the device IDs of all node devices recorded locally in sequence, the master controller suspends the repeated scanning action for the node devices until any node device has a power-off action, and then the master controller restarts the scanning action for the node devices.

7. The on-line scanning and configuration method for nodes applied to CAN bus communication according to claim 1, characterized in that, In S4, the step that the master controller obtains the data corresponding to the position numbers and device IDs of all node devices further includes the following steps: S42: During a single scanning cycle, if there are two identical sets of device IDs among the data corresponding to the position numbers and device IDs of all node devices received by the master controller, the master controller outputs a node device ID conflict alarm.

8. The method for online scanning and configuration of nodes applied to CAN bus communication according to claim 7, wherein, After the master controller outputs a node device ID conflict alarm in S42, it further includes the following steps: S43: The master controller obtains the data corresponding to the position numbers and device IDs of the conflict node devices with device ID conflicts. The master controller sends a downlink CAN configuration message including the position number and a new device ID to the conflict node devices respectively based on the CAN bus. The conflict node devices receive the downlink CAN configuration message based on the CAN bus and automatically configure the new device ID; The conflict node devices re-send an uplink CAN heartbeat message including the correct position number and device ID based on the CAN bus.

9. A node online scanning and configuration system applied to CAN bus communication, characterized in that, A node online scanning and configuration method applied to CAN bus communication according to any one of claims 1-8, including a master controller and a plurality of node devices; The master controller is electrically connected to the CAN bus, and the master controller is used to implement the online scanning configuration and control functions of the plurality of node devices; The plurality of node devices are respectively electrically connected to the CAN bus, and adjacent node devices are electrically connected in sequence. The node devices are used to execute operation tasks according to the control instructions of the master controller.

10. The on-line scanning and configuration system for nodes applied to CAN bus communication as described in claim 9, characterized in that, Any one of the node devices is respectively provided with a data conversion module. The data conversion module includes a front single-wire serial communication interface and a rear single-wire serial communication interface. The node devices are respectively electrically connected to another adjacent front node device through a forward single-way serial port line, and are electrically connected to another adjacent rear node device through a backward single-way serial port line.

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