Solution to the problem of CAN to Modbus TCP conversion

1.设备上电后，网口/CAN口指示灯异常 
1. After the device is powered on, the network/CAN port indicator light is abnormal 

核心原因：供电故障、接口接触不良。解决：检查DC24V供电正负极及稳定性；更换屏蔽网线、CAN接头并拧紧；异常则排查硬件损坏。 
Core reasons: power supply failure, poor interface contact. Solution: Check the positive and negative poles and stability of the DC24V power supply; Replace the shielded network cable and CAN connector and tighten them; If there is an abnormality, check for hardware damage. 

2.电脑/PLC无法ping通设备 
2. The computer/PLC cannot ping the device 

核心原因：IP网段不符、网络配置错误。解决：确保电脑与设备IP在同一网段（如192.168.1.xxx），子网掩码统一为255.255.255.0；关闭防火墙，用直连网线测试。 
Core reasons: IP network segment mismatch, network configuration error. Solution: Ensure that the computer and device IP are in the same network segment (such as 192.168.1. xxx), and the subnet mask is uniformly 255.255.255.0; Turn off the firewall and test with a direct wired cable. 

3.ModbusTCP主站提示通讯超时 
3. Modbus TCP main station prompts communication timeout 

核心原因：从站地址、端口不匹配。解决：核对从站地址（默认多为1）、502端口，主从端保持一致；缩短超时时间至500-2000ms。 
Core reason: The slave address and port do not match. Solution: Verify the slave address (usually 1 by default) and port 502, ensuring consistency between the master and slave ends; Shorten the timeout to 500-2000ms. 

4.CAN侧无数据，TCP侧有连接 
4. There is no data on the CAN side, but there is a connection on the TCP side 

核心原因：CAN参数不匹配、终端电阻缺失。解决：统一CAN波特率（250K/500Kbps）和ID格式；总线首尾接120Ω终端电阻，测CAN_H与CAN_L电压（2.5-3.5V）。 
Core reasons: CAN parameter mismatch, missing terminal resistance. Solution: Unified CAN baud rate (250K/500Kbps) and ID format; Connect a 120 Ω terminal resistor at the beginning and end of the bus, and measure the voltage (2.5-3.5V) of CAN_S and CAN_L. 

5.数据交互乱码/数值错误 
5. Data exchange garbled/numerical errors 

核心原因：数据格式、地址映射错误。解决：统一数据格式（INT/FLOAT）和字节序；核对CAN数据与Modbus保持寄存器（4x区）映射地址，避免重叠。 
Core reason: Data format and address mapping errors. Solution: Unified data format (INT/FLOAT) and byte order; Verify the mapping address between CAN data and Modbus hold registers (4x area) to avoid overlap. 

6.设备运行中频繁掉线 
6. Frequent disconnections during device operation 

核心原因：供电不稳、电磁干扰。解决：加装稳压电源，CAN总线用双绞屏蔽线并单端接地；升级设备最新固件，修复稳定性BUG。 
Core reasons: unstable power supply, electromagnetic interference. Solution: Install a voltage regulator power supply, use twisted pair shielded wires for the CAN bus, and ground it at one end; Upgrade the latest firmware of the device and fix stability bugs. 

7.多设备组网，部分无法通讯 
7. Multiple devices networking, some unable to communicate 

核心原因：IP冲突、交换机过载。解决：分配唯一静态IP；选用工业级交换机，开启风暴抑制功能，避免网络瘫痪。 
Core reasons: IP conflict, switch overload. Solution: Assign a unique static IP address; use industrial grade switches and enable storm suppression function to avoid network paralysis. 

8.CAN侧部分从站无数据上传 
8. There is no data upload from the CAN side station 

核心原因：CAN ID冲突、滤波错误。解决：确保所有CAN从站ID唯一；关闭错误滤波功能，单独测试故障从站是否上线。 
Core reasons: CAN ID conflict, filtering error. Solution: Ensure that all CAN slave IDs are unique; Turn off the error filtering function and test separately whether the faulty slave station is online. 

9.部分寄存器数值不变/跳变 
9. Some register values remain unchanged/jump 

核心原因：刷新频率不匹配、总线丢包。解决：调整数据刷新频率，主站读取频率不高于CAN上传频率；缩短总线距离，必要时加中继器。 
Core reasons: mismatched refresh rate and bus packet loss. Solution: Adjust the data refresh frequency to ensure that the main station's reading frequency is not higher than the CAN upload frequency; Shorten the bus distance and add repeaters if necessary. 

10.恢复出厂后无法重新配置 
10. Unable to reconfigure after factory reset 

核心原因：软件不兼容、操作错误。解决：安装厂家原装配置软件；恢复出厂后断电重启，配置完成后保存并重启设备生效。 
Core reasons: software incompatibility, operational errors. Solution: Install the manufacturer's original configuration software; After factory restoration, power off and restart the device. Once the configuration is complete, save and restart the device to take effect. 

通用技巧：先排查硬件供电、接线，再检查软件配置；单设备测试排除组网干扰，借助调试工具快速定位故障。 
General technique: First check the hardware power supply and wiring, then check the software configuration; Single device testing eliminates network interference and quickly locates faults with the help of debugging tools. 

如果您的项目需要用到CAN转ModbusTCP设备，可以加微信13019325660或前往沈阳广成科技官网具体咨询。 
If your project requires CAN to Modbus TCP devices, you can add WeChat 13019325660 or visit the official website of Shenyang Guangcheng Technology for specific consultation.