CAN bridge data transmission method

Abstract

The present invention discloses a CAN bridge data transmission method, comprising the following steps: receiving information of a CAN device from an input interface, and then outputting it to a CAN-BUS bus through an output interface; wherein the received information is electrically isolated and then physically filtered before being forwarded to the output interface. The present invention adopts a multi-stage isolation filtering method to effectively isolate interference when multiple CAN devices send information at the same time, thereby ensuring the stability and reliability of the output signal, thereby preventing the device from shutting down.

Description

Technical Field

[0001] The invention relates to a data transmission method, in particular to a CAN bridge data transmission method. Background Art

[0002] CAN bridge, also known as CAN bridge, is a device used to connect different CAN networks. It is mainly used in industrial automation and automotive industries to ensure smooth data communication between different devices. The main function of CAN bridge is to establish connections between different CAN networks to achieve seamless data transmission and effectively reduce electromagnetic interference. Therefore, it is widely used in industrial automation scenarios that require long-distance data transmission.

[0003] Chinese patent document CN102916861A discloses a CAN communication circuit including a CAN controller and a CAN isolation transceiver, wherein the CAN controller is connected to one end of the CAN isolation transceiver through a serial data output line and a serial data input line, and the other end of the CAN isolation transceiver is connected to the CAN communication physical bus. The CAN isolation transceiver is connected to the physical bus through two bus terminals with differential transmission and reception functions. A matching resistor is connected in parallel at both ends of the bus to improve the anti-interference ability and reliability during data transmission. A CAN communication interface is developed in the upper computer, and the information of the control system is displayed on the CAN communication interface. The advantages of the present invention are: the system has a long communication distance, strong instantaneous anti-interference ability, low radio frequency interference, and good stability.

[0004] In this prior art, although the anti-interference capability of the CAN communication circuit is improved, in actual application, especially when multiple CAN devices are used to send information at the same time, it is easy to cause the device to crash and fail to work, thereby affecting the normal transmission of information. Summary of the invention

[0005] In order to solve the technical problem in the prior art that multiple CAN devices are prone to device downtime when sending information at the same time, the present invention provides a CAN bridge data transmission method, comprising the following steps: receiving information of the CAN device from an input interface, and then outputting it to the CAN-BUS bus through an output interface; wherein the received information is electrically isolated and then physically filtered before being forwarded to the output interface.

[0006] In the prior art, device downtime refers to a state in which the device suddenly stops working during operation and cannot respond or perform tasks normally. This situation is usually caused by hardware failure, software problems, network interruption or power failure. In addition to excluding these common reasons, it is found that the reason for device downtime is that when multiple CAN devices are used to send information at the same time, the CAN bus is subject to multi-source interference, resulting in bus conflicts and device downtime. Compared with the prior art, in this solution, the use of multi-stage isolation filtering can effectively isolate the interference when multiple CAN devices send information at the same time, ensuring the stability and reliability of the output signal, thereby preventing the device from downtime.

[0007] Preferably, when the received information is electrically isolated, it includes power isolation and data isolation. In this solution, the multi-level isolation of data using power isolation and data isolation can further improve the stability and reliability of signal output and prevent equipment from downtime.

[0008] Preferably, after the information is electrically isolated, the processed information is transmitted to the microcontroller unit for processing, and then the information processed by the microcontroller unit is isolated and physically filtered. This solution can further improve the stability and reliability of signal output and prevent equipment from crashing.

[0009] Preferably, when receiving information from the CAN device from the input interface, filtering is performed according to a preset filtering mechanism, and the filtered information is forwarded and output. In this solution, filtering the information can filter out unnecessary information and ensure that only the required information is transmitted, thereby effectively reducing the load of the CAN bus and improving communication efficiency.

[0010] Preferably, when filtering information, the ID of the information is identified and filtered. In this solution, by identifying the information ID, the information is identified and filtered, which can improve the filtering efficiency of the information, thereby improving the communication efficiency.

[0011] Preferably, the information is pre-processed by the physical filter layer when it is received. In this solution, the information is pre-processed by the physical filter layer first, which can filter out the information with greater interference, and can further enhance the anti-interference ability and security of information transmission.

[0012] Preferably, during the transmission process, the processed information is forwarded to the output interface for output through a routing mechanism. In this solution, the use of a routing mechanism for information transmission can effectively increase the transmission distance of the information, thereby meeting the long-distance communication requirements.

[0013] Preferably, multiple groups of input interfaces are provided, each input source is independently connected to each input interface, and each output is connected in parallel to the CAN-BUS bus through the output interface. In this solution, when multiple groups communicate, the many-to-one transmission method can realize the interconnection communication between multiple devices, which improves the flexibility and scalability of information transmission.

[0014] Preferably, multiple groups of input interfaces and output interfaces are provided, and each input source is independently connected to each input interface, and output to the CAN-BUS bus by the corresponding output interface. In this solution, when multiple groups communicate, a one-to-one transmission method is adopted, which can ensure that multiple devices can communicate independently without interfering with each other, thereby improving the security and stability of information transmission.

[0015] Preferably, there are multiple output interfaces, and the output interfaces forward the input information according to different baud rates required. In this solution, a group of input information can be forwarded to multiple different devices at different baud rates, meeting the diverse communication needs in a complex network environment.

[0016] Preferably, the RS485 bus is used for internal transmission of information. This solution can improve the transmission efficiency and reliability of information during the transmission process.

[0017] The present invention has the following beneficial effects: 1. The present invention adopts a multi-stage isolation filtering method, including physical filtering and electrical isolation design, to achieve a high isolation of 2500VRMS and a typical transient immunity of 50kV / µs, further enhancing the anti-interference ability and safety of the system.

[0018] 2. The present invention has a relay function and can route and forward CAN data, thereby effectively increasing the transmission distance and meeting the needs of long-distance communication.

[0019] 3. The present invention can support arbitrary configuration of the baud rate of each channel and can be flexibly adjusted according to actual needs, thereby improving the flexibility and adaptability of communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The schematic diagram of the RS485 bus communication circuit in the embodiment of the CAN bridge data transmission method of the present invention; Figure 2 It is a schematic diagram of a CAN communication circuit in an embodiment of a CAN bridge data transmission method of the present invention; Figure 3 It is the wiring diagram of the CAN bridge in the present invention; Figure 4 (a) is a schematic diagram of the microcontroller unit circuit; Figure 4 (b) is the schematic diagram of the download / debug port circuit; Figure 4 (c) is a schematic diagram of the reset circuit; Figure 4 (d) is a schematic diagram of the crystal oscillator circuit; Figure 5 This is the schematic diagram of the CAN independent interface circuit; Figure 6 This is the schematic diagram of the power supply circuit; Figure 7 This is the schematic diagram of the ADC reference voltage circuit; Figure 8 This is the schematic diagram of the electromagnetic interference suppression circuit; Fig. 9 This is the schematic diagram of the indicator light circuit. DETAILED DESCRIPTION

[0021] The following is further described in detail through specific implementation methods: The embodiment is basically as shown in the attached Figure 1 As shown: CAN bridge data transmission method, comprising the following steps: Receive information from CAN devices from the input interface; when receiving information, identify and filter the information ID through a preset filtering mechanism, identify the ID of the required target information, filter out unnecessary information, and only receive the required target information to reduce bus load and improve communication efficiency.

[0022] The received information is preprocessed through the physical filtering layer; during preprocessing, the CAN messages with greater interference are preprocessed; Electrically isolate the pre-processed information, including power supply isolation and data isolation; The electrically isolated data is transmitted to the microcontroller unit for processing; the circuit of the microcontroller unit and related circuits are shown in Figure 4 (a)-Figure 4 (b).

[0023] The processed data is subjected to physical filtering; the use of physical filtering can reduce unnecessary interference in the data; The data that has completed the physical filtering processing is forwarded to the output interface through the routing mechanism and output to the CAN-BUS bus.

[0024] During the above transmission process, when multiple CAN devices are connected, there are multiple access modes: ① Multiple inputs and one output: There are multiple groups of input interfaces, each input source is independently connected to each input interface, and each output is connected to the CAN-BUS bus in parallel through the output interface; ② One output and one input correspondence: There are multiple groups of input interfaces and output interfaces, each input source is independently connected to each input interface, and is output to the CAN-BUS bus through the corresponding output interface; ③ One input and multiple outputs: There are multiple output interfaces, and the output interface forwards the input information according to the required different baud rates. Figure 3As shown, in this embodiment, six groups of independent CAN interfaces are provided, such as Figure 5 As shown, it includes three input interfaces and three output interfaces, among which the independent RS485 communication circuit is as follows Figure 1 As shown, the independent CAN communication circuit is as follows Figure 2 shown.

[0025] In the above process, a power supply circuit is used for power supply. The power supply circuit is as follows: Figure 6 As shown, the input voltage is 6~36V DC, the output is 5V 3A DC, and the ADC reference voltage circuit used is as follows Figure 7 Since electromagnetic interference will be generated during data transmission, a suppression circuit is also used in this embodiment to suppress the electromagnetic interference. The suppression circuit is as shown in FIG. Figure 8 During data transmission, the indicator light is used to indicate power and faults. Fig. 9 shown.

[0026] In this embodiment, the Controller Area Network (CAN) 2.0 standard and ISO11898-1 / 2 / 3 are strictly followed during the transmission process to ensure the compatibility and efficiency of the communication protocol. The output transmission of this embodiment works at the data link layer, which is responsible for key tasks such as data frame transmission control, error detection and recovery.

[0027] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. The CAN bridge data transmission method comprises the following steps: The information of the CAN device is received from the input interface, and then output to the CAN-BUS bus through the output interface; the characteristic is that the received information is electrically isolated and then physically filtered before being forwarded to the output interface.

2. The CAN bridge data transmission method according to claim 1, characterized in that: When the received information is electrically isolated, it includes performing power isolation operation and data isolation operation on the received information.

3. The CAN bridge data transmission method according to claim 2, characterized in that: After the electrical isolation of the information is completed, the processed information is transmitted to the microcontroller unit for processing, and then the information processed by the microcontroller unit is subjected to the isolation physical filtering processing operation.

4. The CAN bridge data transmission method according to any one of claims 1 to 3, characterized in that: When receiving information from the CAN device from the input interface, the information is filtered according to a preset filtering mechanism, and the filtered information is forwarded and output.

5. The CAN bridge data transmission method according to claim 4, characterized in that: When filtering information, the ID of the information is identified and filtered.

6. The CAN bridge data transmission method according to claim 5, characterized in that: When information is received, it is pre-processed through the physical filtering layer.

7. The CAN bridge data transmission method according to claim 6, characterized in that: During the transmission process, the processed information is forwarded to the output interface for output through the routing mechanism.

8. The CAN bridge data transmission method according to claim 7, characterized in that: The input interface is provided with multiple groups, each input source is independently connected to each input interface, and each output is connected in parallel to the CAN-BUS bus through the output interface.

9. The CAN bridge data transmission method according to claim 7, characterized in that: The input interface and the output interface are both provided with multiple groups, each input source is independently connected to each input interface, and is output to the CAN-BUS bus through the corresponding output interface.

10. The CAN bridge data transmission method according to claim 7, characterized in that: The output interface is provided with a plurality of output interfaces, and the output interface forwards the input information according to different baud rates required.

11. The CAN bridge data transmission method according to claim 7, characterized in that: Use RS485 bus for internal transmission of information.

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