Jetson Orin Nano RJ45 pymodbusTCP Connection Issues

Issue Overview

Users have reported difficulties in establishing a successful connection between the Nvidia Jetson Orin Nano Dev board and a Mitsubishi PLC using an RJ45 Ethernet cable with the pymodbusTCP communication protocol. The specific symptoms include:

• Error Message: When executing the command to write a single coil, the system responds with "False," indicating a failure in communication.

• Context: The issue occurs during attempts to connect to the PLC using the following Python code:

  from pyModbusTCP.client import ModbusClient
  b = ModbusClient('192.168.0.150', port=502)
  b.write_single_coil(0x2000, True)
  

• Comparison with PC: The same command works successfully on a PC after proper network configuration, suggesting that the issue may be specific to the Jetson Orin Nano setup.

• Frequency: This problem appears consistently when users attempt to set up the connection without proper IP configuration.

• Impact: The inability to communicate with the PLC hampers functionality and user experience, particularly for applications relying on Modbus communication.

Possible Causes

Several potential causes for this issue have been identified:

• Configuration Errors: Users may not have configured the network settings correctly, particularly the IPv4 IP Address and Netmask.

• Driver Issues: There may be a need for additional drivers compatible with the aarch64 architecture of the Jetson Orin Nano.

• User Errors: Skipping necessary configuration steps during network setup can lead to communication failures.

• Environmental Factors: Issues such as faulty Ethernet cables or network hardware could also contribute to connectivity problems.

Troubleshooting Steps, Solutions & Fixes

To address the connectivity issues between the Jetson Orin Nano and Mitsubishi PLC, follow these comprehensive troubleshooting steps:

1. Verify Network Configuration:

   • Ensure that you have created a new wired connection for your Ethernet cable.
   • Manually set the IPv4 IP Address and Netmask during connection creation. This is crucial as default settings may not work.

2. Check Ethernet Connection:

   • Confirm that the RJ45 Ethernet cable is properly connected and functioning.
   • Test with another cable or port if possible.

3. Install Necessary Drivers:

   • Investigate whether additional drivers are required for your specific setup. Check compatibility with aarch64 architecture.
   • If needed, download and install any relevant drivers.

4. Test Communication:

   • After configuring your network settings, rerun your Python script to test communication with the PLC.
   • Use debugging statements in your code to track any errors or issues during execution.

5. Use Alternative Tools for Testing:

   • If issues persist, consider using other Modbus testing tools or software on different devices to ensure that the PLC is operational and reachable.

6. Review Documentation:

   • Consult Nvidia’s documentation for any specific requirements or configurations related to networking on the Jetson Orin Nano.
   • Look for updates regarding pymodbusTCP or related libraries that might address known issues.

7. Best Practices for Future Connections:

   • Always configure your network settings before attempting to connect devices.
   • Document any successful configurations for future reference.

By following these steps, users can effectively troubleshoot and potentially resolve their connectivity issues with the Mitsubishi PLC using the Jetson Orin Nano.