The Industrial Raspberry Pi Forum

Hello, I just want to ask for your help regarding the USB Port number. Im trying to connect to a 'Serial in' Node in Node-red where im using the USB Connection on the front of the Revpi Core 3. The problem is when the configuration only shows it to be 'connected' when I chose the "/dev/ttyAMA0". But the problem is that it wont read the serial port data. For context, Im using an external Weighing Scale via RS232 -> Usb connection, and the data would not show up in the debug node neither on the Gauge node. I also tried the /dev/ttyUSB0, /dev/ttyUSB1, /dev/ttyACM0, /dev/ttyACM1. None of this are working. Thank you in advance for the help.

Hello haziqshmsul,
To troubleshoot this issue, you can follow these steps:

• Check Hardware Connections:

Ensure that the USB-to-Serial adapter is properly connected to the USB port on the RevPi Core 3.
Verify that the RS232 cable is securely connected between the weighing scale and the USB-to-Serial adapter.

• Check Serial Adapter Driver:

Confirm that the USB-to-Serial adapter is recognized by the Revolution Pi. You can do this by running the command in the terminal to list connected USB devices. Make sure your adapter is listed.

• Identify the Correct Serial Port:

Run the following command to list all available serial ports on your system: Look for the appropriate serial port that corresponds to your USB-to-Serial adapter. It might be something like /dev/ttyUSB0, /dev/ttyUSB1, etc. Make note of the correct port.

• Node-RED Configuration:

In Node-RED, configure your "Serial in" node to use the correct serial port (e.g., /dev/ttyUSB0) that you identified in the previous step.
Ensure that the baud rate and other communication settings in the "Serial in" node match the settings required by your weighing scale (baud rate, data bits, parity, stop bits).

• Debugging in Node-RED:

Add a "Debug" node to your Node-RED flow to see if any data is being received from the serial port. Connect the "Serial in" node to the "Debug" node, deploy the flow, and monitor the debug output.

• Check Weighing Scale Configuration:

Confirm that your weighing scale is configured to communicate over the RS232 interface with the correct communication settings (baud rate, data bits, parity, stop bits).

• Power Cycle and Restart:

Sometimes, a simple reboot or power cycle of the RevPi Core 3 can resolve communication issues.

• Verify Serial Adapter Compatibility:

Ensure that the USB-to-Serial adapter you are using is compatible with Linux and Revolution Pi. Some adapters may require additional drivers or may not work properly with certain devices.

• Additional Troubleshooting:

If you still face issues, you may want to consider using a USB-to-Serial adapter with better Linux support, or consult the documentation and support resources for your specific weighing scale to ensure correct configuration.

Best Regards,

Ulrich Kouatang Biakoup | Technical Support