EVAL-CN0359-EB1Z polling over RS485 not working

Hello,

I am trying to automate data logging on a CN0359 eval board and I cannot get the poll command to work.

The command I have been trying to use "1 poll\n"

Some of the things I have tried:

  • I have tried multiple different USB to RS485 converters
    • One which has worked with other devices: USBG-COMi-M
    • These are capable of outputting at the baud rates I have tested
    • I have tried wiring them backwards, B->A  A->B, just for good measure
  • I have tried using Putty, TeraTerm, and Python
  • I have tried setting my board to different RS485 addresses and baud rates
  • I have tried sending 2 spaces before my command, like in the user guide. ex "  1 poll\n"
  • I have tried using other commands. ex "1 setvolt 2.5" and they do not update values on the board.
  • I have tried re-flashing the board with the newest firmware
  • I have tried sending commands from an arduino through a serial to RS485 converter shield, which I know works with other devices.

Throughout all of this I have never gotten any response.

All other functions of the board are working correctly.

Any ideas would be greatly appreciated.

  • 0
    •  Analog Employees 
    on Feb 1, 2021 3:48 AM

    Hi osullivan,

    I just have a few questions to verify.

    • When you set the board to different RS485 addresses, did you send the command still as "1 poll" or as "<address> poll"?
    • By "All other functions of the board are working correctly", are you referring to the other RS485 commands? You also mentioned that the other commands do not update the values on the board.
    • Can you send me a link to the USB to RS485 converter that you are using?

    Regards.

  • Hi ACatapang,

    • I was sending "<address> poll\n", and I was always matching the address I set on the board.
    • None of the RS485 commands are working, but all other functions of the board are working. It is reading the conductivity and temperature correctly and all of the menus on the board work as they should. Sorry for any confusion here.
    • Here is the converter I have been using:
    • Here is how I have the converter configured:
      • Pin 1   Data-  (A)  ->  3 A
      • Pin 2   Data+ (B)  ->  2 GND
      • Pin 6   GND         ->   1 B
      • Baud: 115200
        • Same as on the board, I have also tried 9600 on the board and on the serial connection.
      • Data bits: 8
      • Stop bits: 1
      • Parity: None
      • I have the dip switches set to [on, off, off, off] for RS-485 Half Duplex, and when I enable Echo [on, off, off, on] I get the same message I sent out back in.
      • This is how I am wiring it. I am using the terminal blocks, not the DB-9 connector on the converter:
      • This is how my serial connection to the USB to RS485 converter is set up. I could not find anything about the data bits, stop bits, or parity bits in the documentation or code so I have kept them as their defaults:
      • Pinout:
      • Dip Switch Settings:

     

    Regards.

  • Sorry for the awful formatting, I was copy-pasting to and from Word because my posts keep getting removed (I think because of the link), and now I cannot edit my comment without it being removed again...

    This part should read as follows:

    • Here is how I have the converter configured:
      • I have the dip switches set to [on, off, off, off] for RS-485 Half Duplex, and when I enable Echo [on, off, off, on] I get the same message I sent out back in. 
      • This is how I am wiring it. I am using the terminal blocks, not the DB-9 connector on the converter:
        • Pin 1   Data-  (A)  ->  3 A
        • Pin 2   Data+ (B)  ->  2 GND
        • Pin 6   GND         ->   1 B
      • This is how my serial connection to the USB to RS485 converter is set up. I could not find anything about the data bits, stop bits, or parity bits in the documentation or code so I have kept them as their defaults:
        • Baud: 115200
          • Same as on the board, I have also tried 9600 on the board and on the serial connection.
        •  Data bits: 8
        • Stop bits: 1
        • Parity: None
  • 0
    •  Analog Employees 
    on Feb 3, 2021 12:45 PM in reply to osullivan

    Hi osullivan,

    I don't see the figure you have for the converter but the wiring for the RS485 terminal block is half duplex and the A terminal of one device should be connected to the A terminal of the other and the same for the B terminal.

    I  also think setting the dip switches for echo just creates a loopback wiring within the converter which is why you get the same message back.

    Regards.

  • Hi ACatapang,

    That is how I have been wiring the device and the USB to rs485 converter together.

    I tested with two different boards, I have tested 3 in total now, and I still cannot get any of them to do anything over rs485. Is there anything else you would recommend I try?

    Regards.