Node online scanning configuration method and system applied to CAN bus communication

Abstract

The invention provides a node online scanning configuration method and system applied to CAN bus communication. The node online scanning configuration method comprises the following steps that S1, a main controller sends a downlink CAN broadcast scanning message based on a CAN bus; s2, in a single scanning period, a front first node device receives a downlink CAN broadcast scanning message based on a forward one-way serial port line, and sets the position number of the front first node device as n; s3, the first node device transmits the downlink CAN broadcast scanning message and the position number information of the first node device to a second node device adjacent to and behind the first node device through a backward one-way serial port line, and the second node device sets the position number of the second node device to be n + 1; and S4, all the node devices repeat the step S3 until all the node devices complete setting of the position numbers of the node devices, all the node devices send uplink CAN heartbeat messages based on the CAN bus, and the main controller obtains the position numbers of all the node devices and configuration data corresponding to the device IDs based on the uplink CAN heartbeat messages.

Description

Technical Field

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

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

[0003] However, under the existing technology, when the main 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 rely on the COBID field in the CAN message for point-to-point communication of the target node. It is difficult to perform node remote positioning, ID scanning and configuration functions relying solely on the CAN protocol, and 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 node online scanning configuration method and system applied to CAN bus communication, so as to solve the technical problem that conventional CAN bus communication system cannot realize remote positioning, ID scanning and configuration of node equipment under the prior art.

[0005] To solve the above problems, the technical solution of the present invention is: a node online scanning configuration method applied to CAN bus communication, comprising the following steps: S1: The main controller sends a downlink CAN broadcast scan message based on the CAN bus; S2: In a single scanning cycle, the front first node device receives the downlink CAN broadcast scanning message based on the forward unidirectional serial port line, and sets its own position number to n; S3: The first node device transmits the downlink CAN broadcast scan message and its own position number information to a second node device located adjacent to and behind the first node device through a backward unidirectional serial port 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 their own position number setting, and all node devices send uplink CAN heartbeat messages based on the CAN bus respectively. The main controller obtains the configuration data corresponding to the position numbers and device IDs of all node devices based on the uplink CAN heartbeat messages.

[0006] Preferably, in S2, the first node device receives the downlink CAN broadcast scan message in a single scanning process, which specifically includes the following steps: S21: In a single scanning cycle, all node devices after power-on perform self-test actions respectively. During the self-test 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, and the first node device chooses to receive the downlink CAN broadcast scan message from the CAN bus, and sets its own position number to 1.

[0007] Preferably, the method further comprises the following steps: S5: After receiving the uplink CAN heartbeat message, the main controller sends a downlink CAN control message including a corresponding position number and a device ID to the target node device to be controlled based on the CAN bus; The target node device receives the downlink CAN control message based on the CAN bus, and after executing the control action, sends an uplink CAN feedback message including its own position number and device ID to the main controller based on the CAN bus.

[0008] Preferably, in S5, the main controller sends the downlink CAN control message to the target node device, further comprising the following steps: S51: In a single control cycle, if all device IDs in the downlink CAN control message sent by the main controller do not completely cover all device IDs in the uplink CAN heartbeat message sent by all node devices, the main controller continues to send the downlink CAN control message to the uncontrolled node device until all node devices receive the corresponding downlink CAN control message, and the single control cycle ends.

[0009] Preferably, the scanning cycle is repeated at a specific time interval, and the specific time interval at least includes the total time taken for the main controller to send the downlink CAN control message to all target node devices, and the total time taken for all target node devices to send the uplink CAN feedback message to the main controller.

[0010] Preferably, in S4, each node device repeatedly executes step S3 until all node devices complete the setting of their own position numbers, further comprising the following steps: S41: When the device ID recorded in the uplink CAN heartbeat message sent by all node devices respectively matches the device IDs of all node devices recorded locally in sequence, the main controller suspends the repeated scanning of the node devices until any node device is powered off, and then the main controller restarts the scanning of the node devices.

[0011] Preferably, in S4, the main controller obtains data corresponding to the position numbers and device IDs of all node devices, further comprising the following steps: S42: within a single scanning cycle, if the main controller receives data corresponding to the location numbers and device IDs of all node devices and there are two identical sets of device IDs, the main controller outputs a node device ID conflict alarm.

[0012] Preferably, after the main controller outputs the node device ID conflict alarm in S42, the following steps are further included: S43: the main controller obtains data corresponding to the position number and the device ID of the conflicting node device with the device ID conflict, and the main controller sends a downlink CAN configuration message including the position number and the new device ID to the conflicting node device based on the CAN bus, and the conflicting node device receives the downlink CAN configuration message based on the CAN bus, and automatically configures a new device ID; The conflict node device resends the uplink CAN heartbeat message including the correct position number and device ID based on the CAN bus.

[0013] Based on the same concept, the present invention also provides a node online scanning configuration system applied to CAN bus communication, which is used to execute the node online scanning configuration method applied to CAN bus communication as described in any one of the above, including a main controller and a plurality of node devices; The main controller is electrically connected to the CAN bus, and is used to implement online scanning configuration and control functions of several node devices; Several of the node devices are electrically connected to the CAN bus respectively, and adjacent node devices are electrically connected in sequence. The node devices are used to perform operation tasks according to the control instructions of the main controller.

[0014] Preferably, any of the node devices is respectively provided with a data conversion module, and the data conversion module includes a front single-line serial communication interface and a rear single-line serial communication interface, and the node device is respectively electrically connected to another adjacent front node device through a forward unidirectional serial port line, and is electrically connected to another adjacent rear node device through a backward unidirectional serial port line.

[0015] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: The present invention provides a node online scanning configuration method and system applied to CAN bus communication, which utilizes the unidirectional characteristics of data transmission between a front node device and a rear node device to realize the automatic position numbering and number dynamic adjustment functions of each node device, and then can meet the functions of quickly locating the node device and realizing point-to-point precise control through the characteristics of the correspondence between the device ID and the position number, and can significantly reduce the time for configuring the device ID. In addition, the node device with the device ID conflict can be detected, which is convenient for troubleshooting and equipment maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A first flow chart of a node online scanning configuration method applied to CAN bus communication provided by the present invention; Figure 2 A second flow chart of a node online scanning configuration method applied to CAN bus communication provided by the present invention; Figure 3 The present invention provides a structural schematic diagram of a node online scanning configuration system applied to CAN bus communication. DETAILED DESCRIPTION

[0017] The following is a further detailed description of a node online scanning configuration method and system for 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 become more apparent from the following description and claims.

[0018] First embodiment See also Figures 1 to 3 This embodiment provides a node online scanning configuration method applied to CAN bus communication, which is used to realize the function of automatically setting the position number of the node device in sequence, and specifically includes the following steps: S1: The main controller sends a downlink CAN broadcast scan message based on the CAN bus; S2: In a single scanning cycle, the first node device at the front receives the downlink CAN broadcast scanning message based on the forward unidirectional serial port line, and sets its own position number to n; S3: The first node device transmits the downlink CAN broadcast scan message and its own position number information to the second node device located 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; S4: Each node device repeats step S3 in sequence until all node devices have completed their own position number setting, and all node devices send uplink CAN heartbeat messages based on the CAN bus respectively. The main controller obtains the configuration data corresponding to the position numbers and device IDs of all node devices based on the uplink CAN heartbeat messages.

[0019] Specifically, in this embodiment, the main controller is electrically connected to the CAN bus, and each node device is not only electrically connected to the CAN bus separately, but also connected hand in hand with the remaining node devices adjacent to the front and rear. In a single scanning cycle, after the first node device in front receives the downlink CAN broadcast scan message, it can set its own position number to n, and package the downlink CAN broadcast scan message and its own position number n to form a new downlink CAN broadcast scan message. After the second node device behind the first node device receives the downlink CAN broadcast scan message output by the first node device, it can set its own position number to n+1, and package the downlink CAN broadcast scan message and its own position number n+1 again to form a new downlink CAN broadcast scan message, which is transmitted to the third node device behind the second node device..., and so on, until all node devices have completed their own position number setting, that is, in this embodiment, the position number of the first node device that receives the downlink CAN broadcast scan message is automatically set to 1, and the subsequent node devices are automatically set to 2, 3, 4... based on the sorting position (the order of receiving the downlink CAN broadcast scan message).

[0020] It can be seen 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 uplink CAN heartbeat messages output by each node device. The main controller can determine the specific device ID of the node device through the node device position number, thereby realizing online scanning of the node device, and subsequently realizing point-to-point precise control functions for node devices with specific device IDs.

[0021] It is worth noting that the first node device, second node device, etc. mentioned above do not specify the specific position of the node device in the CAN bus, but are only used to express that the first node device is an adjacent preceding node device of the second node device.

[0022] The following is a detailed description of the specific implementation steps and functions of a node online scanning configuration method for CAN bus communication provided in this embodiment: Preferably, in this embodiment, in S2, the first node device receives the downlink CAN broadcast scan message in a single scan process, which specifically includes the following steps: S21: In a single scanning cycle, all node devices after power-on perform self-test actions respectively. During the self-test 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 chooses to receive the downlink CAN broadcast scan message from the CAN bus and sets its own position number to 1.

[0023] 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 receives the downlink CAN broadcast scan message through its forward unidirectional serial port line respectively. The position number of each node device is determined based on the time sequence in which the downlink CAN broadcast scan message arrives at each node device in turn.

[0024] It is worth noting that in this embodiment, there are differences in the power-on time of different node devices. Therefore, within a single scanning cycle, only the position numbers of the node devices that have been powered on within the single scanning cycle can be automatically set. In the next scanning cycle, the position numbers of the node devices that have been powered on will be automatically adjusted based on the power-on and power-off conditions of each node device.

[0025] Preferably, in this embodiment, the following steps are also included: S5: After receiving the uplink CAN heartbeat message, the main controller sends a downlink CAN control message including a corresponding position number and a device ID to the target node device to be controlled based on the CAN bus; Among them, the downlink CAN control message is a broadcast message, that is, any node device based on the CAN bus can receive this downlink CAN control message. 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 corresponding control instruction recorded in the downlink CAN control message.

[0026] The target node device receives the downlink CAN control message based on the CAN bus, and after executing the relevant control action, sends the uplink CAN feedback message including its own position number and device ID to the main controller based on the CAN bus to realize the data feedback function.

[0027] Furthermore, in this embodiment, in S5, the main controller sends a downlink CAN control message to the target node device, and further includes the following steps: S51: In a single control cycle, if all device IDs in the downlink CAN control message sent by the main controller do not completely cover all device IDs in the uplink CAN heartbeat message sent by all node devices, the main controller continues to send downlink CAN control messages for uncontrolled node devices until all node devices receive the corresponding downlink CAN control message, and the single control cycle ends.

[0028] In this embodiment, the multiple downlink CAN control messages sent by the main controller to each node device are not sent at the same time, so the main control module can also record all device IDs in the downlink CAN control messages that have been sent, and compare this device ID with all device IDs in the uplink CAN heartbeat messages sent by all node devices, until the downlink CAN control messages for all device IDs are sent, which proves that the command control of all node devices has been completed.

[0029] Preferably, in this embodiment, since there are differences in the power-on time of different node devices, the scanning cycle will be repeated at a specific time interval, and the specific time interval at least includes the total time taken for the main controller to send downlink CAN control messages to all target node devices, and the total time taken for all target node devices to send uplink CAN feedback messages to the main controller. That is, in this embodiment, the scanning cycle and the control cycle are performed alternately, wherein any scanning cycle and the control cycle adjacent thereto share the same position number and configuration data corresponding to the device ID.

[0030] Preferably, in this embodiment, in S4, each node device repeatedly executes step S3 until all node devices complete the setting of their own position numbers, further comprising the following steps: S41: When the device ID recorded in the uplink CAN heartbeat message sent by all node devices respectively matches the device IDs of all node devices recorded locally in sequence, the main controller suspends the execution of repeated scanning actions on the node devices until any node device is powered off, and then the main controller restarts the execution of scanning actions on the node devices.

[0031] 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 have completely covered the device IDs of all node devices recorded locally, it proves that all node devices have been powered on and have established communication connections with the main controller. At this time, if the node devices are not powered off, the number of node devices communicating with the main controller remains unchanged, and the position number of each node device remains unchanged. Therefore, the main controller suspends the repeated scanning of the node devices at this time, reduces the amount of communication on the CAN bus caused by continuous broadcast scanning, optimizes system performance and resource utilization, and improves the response speed of the system.

[0032] Preferably, in this embodiment, in S4, the main controller obtains data corresponding to the position numbers and device IDs of all node devices, further comprising the following steps: S42: Within a single scanning cycle, if the main controller receives data corresponding to the location numbers and device IDs of all node devices and finds two or more identical device IDs, the main controller outputs a node device ID conflict alarm.

[0033] In this embodiment, the duplication of device ID may be caused by manual configuration errors of the node device ID, node device initialization failure or lost configuration, etc. When two groups or more node devices share a 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 within the scanning cycle, the main controller suspends the execution of subsequent control actions and outputs a node device ID conflict alarm.

[0034] Further, after the main controller outputs the node device ID conflict alarm in S42, the following steps are also included: S43: The main controller obtains data corresponding to the position number and the device ID of the conflicting node device with the device ID conflict, and sends a downlink CAN configuration message including the position number and the new device ID to the conflicting node device based on the CAN bus. The conflicting node device receives the downlink CAN configuration message based on the CAN bus and automatically configures a new device ID. The conflicting node device resends an uplink CAN heartbeat message including a correct location number and a device ID to the main controller based on the CAN bus.

[0035] In this embodiment, since the position number is unique and is generated in sequence according to the order of the node devices, when the device ID is the same, the conflicting node device with the device ID conflict can still be determined by the position number, and then a new device ID is reallocated to the conflicting node device with the device ID conflict to solve the device ID conflict problem.

[0036] In summary, this embodiment provides a node online scanning configuration method applied to CAN bus communication, which utilizes the unidirectional characteristics of data transmission between the front-end node device and the rear-end node device to realize the automatic position numbering and dynamic number adjustment functions of each node device, and then through the corresponding binding characteristics of the device ID and the position number, it can meet the functions of quickly locating the node device and realizing point-to-point precise control, and can significantly reduce the time for configuring the device ID. In addition, it can also detect node devices with device ID conflicts, which is convenient for troubleshooting and equipment maintenance.

[0037] Second embodiment See also Figure 3Based on the same concept, this embodiment provides a node online scanning configuration system applied to CAN bus communication, which is used to execute the node online scanning configuration method applied to CAN bus communication as described in any one of the first embodiments, including a main controller and several node devices.

[0038] Among them, the main controller includes a PLC or 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.

[0039] Several node devices are electrically connected to the CAN bus respectively, and adjacent node devices are electrically connected in sequence. The node devices are used to perform operation tasks according to control instructions output by the main controller.

[0040] Among them, any node device is provided with a data conversion module, which includes a CAN bus interface, a front single-line serial communication interface and a rear single-line 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 electrically connected to another adjacent front node device through a forward unidirectional serial port line, and is electrically connected to another adjacent rear node device through a rear unidirectional serial port line.

[0041] In this embodiment, the main controller can send a downlink CAN broadcast scan message via the CAN bus. The first node device located at the front of the CAN network receives the downlink CAN broadcast scan message via the CAN bus and sets its position number to 1. Then, the first node device reassembles 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 via a unidirectional serial port line. The latter node device sets its position number to 2 based on the position number 1 of the first node device, and reassembles 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 setting of the position numbers of all node devices in sequence.

[0042] By utilizing the online scanning and automatic numbering mechanism, the location number of the node device can be quickly determined, and based on the corresponding binding relationship between the node device location number and the device ID, the subsequent main controller can accurately control each node device in a point-to-point manner without interfering with other node devices, with better accuracy and safety. At the same time, when any node device fails, the operator can quickly and accurately locate the specific faulty node device based on the location number, thereby improving maintenance efficiency. As new node devices are added or existing node devices are removed, the system can dynamically adjust and update the location number of the node device, thereby supporting flexible expansion of the system.

[0043] The embodiments of the present invention are 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, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the protection scope of the present invention.

Claims

1. A node online scanning configuration method applied to CAN bus communication, characterized in that: The steps include: S1: The main controller sends a downlink CAN broadcast scan message based on the CAN bus; S2: In a single scanning cycle, the front first node device receives the downlink CAN broadcast scanning message based on the forward unidirectional serial port line, and sets its own position number to n; S3: The first node device transmits the downlink CAN broadcast scan message and its own position number information to a second node device located adjacent to and behind the first node device through a backward unidirectional serial port 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 their own position number setting, and all node devices send uplink CAN heartbeat messages based on the CAN bus respectively. The main controller obtains the configuration data corresponding to the position numbers and device IDs of all node devices based on the uplink CAN heartbeat messages.

2. The node online scanning configuration method applied to CAN bus communication according to claim 1, characterized in that: In S2, the first node device receives the downlink CAN broadcast scan message in a single scanning process, which specifically includes the following steps: S21: In a single scanning cycle, all node devices after power-on perform self-test actions respectively. During the self-test 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, and the first node device chooses to receive the downlink CAN broadcast scan message from the CAN bus, and sets its own position number to 1.

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

4. The node online scanning configuration method applied to CAN bus communication as claimed in claim 3, characterized in that: In S5, the main controller sends the downlink CAN control message to the target node device, further comprising the following steps: S51: In a single control cycle, if all device IDs in the downlink CAN control message sent by the main controller do not completely cover all device IDs in the uplink CAN heartbeat message sent by all node devices, the main controller continues to send the downlink CAN control message to the uncontrolled node device until all node devices receive the corresponding downlink CAN control message, and the single control cycle ends.

5. The node online scanning configuration method applied to CAN bus communication as claimed in claim 4, characterized in that: The scanning cycle is repeated at a specific time interval, and the specific time interval at least includes the total time taken for the main controller to send the downlink CAN control message to all target node devices, and for all target node devices to send the uplink CAN feedback message to the main controller.

6. The node online scanning configuration method applied to CAN bus communication as claimed in claim 3, characterized in that: In S4, each node device repeats step S3 until all node devices have completed the setting of their own position numbers, further comprising the following steps: S41: When the device ID recorded in the uplink CAN heartbeat message sent by all node devices respectively matches the device IDs of all node devices recorded locally in sequence, the main controller suspends the repeated scanning of the node devices until any node device is powered off, and then the main controller restarts the scanning of the node devices.

7. The node online scanning configuration method applied to CAN bus communication according to claim 1, characterized in that: In S4, the main controller obtains data corresponding to the position numbers and device IDs of all node devices, further comprising the following steps: S42: within a single scanning cycle, if the main controller receives data corresponding to the location numbers and device IDs of all node devices and there are two identical sets of device IDs, the main controller outputs a node device ID conflict alarm.

8. The node online scanning configuration method applied to CAN bus communication as claimed in claim 7, characterized in that: After the main controller outputs the node device ID conflict alarm in S42, the following steps are further included: S43: the main controller obtains data corresponding to the position number and the device ID of the conflicting node device with the device ID conflict, and the main controller sends a downlink CAN configuration message including the position number and the new device ID to the conflicting node device based on the CAN bus, and the conflicting node device receives the downlink CAN configuration message based on the CAN bus, and automatically configures a new device ID; The conflict node device resends the uplink CAN heartbeat message including the correct position number and device ID based on the CAN bus.

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

10. The node online scanning configuration system for CAN bus communication according to claim 9, characterized in that: Any of the node devices is respectively provided with a data conversion module, and the data conversion module includes a front single-line serial communication interface and a rear single-line serial communication interface. The node device is respectively electrically connected to another adjacent front node device through a forward unidirectional serial port line, and is electrically connected to another adjacent rear node device through a backward unidirectional serial port line.

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