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My battery management system card is not communicating via RS485 with STM32

Associate III


I have a SEPLOS brand battery management system card, and I want to read temperature and voltage data from this card. Initially, I will use an STM32F407VGT6 board to read data from the SEPLOS battery management system card via RS485. I am sending the commands first to get the data, but although the data is being sent, I cannot perform the reading operation. What do you think could be the reason for this problem?

The PDF I will send below contains an information sheet about how I should read data from the SEPLOS brand battery management system via RS485. Please look at the PDF and my code to see if you can find where I might be making a mistake.


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thank you for answer


Please use the </> icon to paste in code, not attach as bitmaps, thanks.

I'd perhaps be concerned about how you have it wired to the STM32, the pins, the RS485 driver, and how you gate that as an output.

Use a scope or logic analyzer to review the signals you generated on the wires, and the responses, if any, from the BMS


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I checked my connections and there are no issues. I am sending you the code again.
Senior II

How is your main loop()? Can you post the code using <> method? After sending read request do you do the read ?


Have you tried using a SEPLOS USB adapter with a terminal program on a PC to determine that the SEPLOS is functioning correctly ?

Hello @sezear07  and welcome to the community.

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Normally to get response from the client you have to send read request in the form of write and wait for read with timeout.

I am sending it below

Yes, SEPLOS has its own programs, and with these programs, I can read temperature and voltage data.

Thank you for reply