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CAN bus Network Problem

gunahmt
Associate II

Hi everyone,

I got a problem when i setup my can bus network. 

data 115200 Brate -> stm32f746vg(120 OHM //) --> CAN BUS----DEV1 --3M CABLE-- DEV2 --3M CABLE-- DEV3 (120 OHM //)

    DEV1,2,3 = STM32F091CC

I need to explain my installation. i have 4 device on can bus line. 

First device collect data from rs485 and send it to the can bus. RS485 working with 115200 baudrate, CANBUS working with 125kbps.

My first tests were between two devices. Between stm32f7 and stm32f0, without 120ohm. I send data fast as can with terminal. I use hercules for terminal. stm32f0 answer to me back all time in tests. I used filter on DEV but the filter doesnt effect communication, i tried it without filtering and same problems accours. stm32f7 collect any data without filtering, it works well to. 1,2,3 thats devices id, std_id with device id. 

When i connect the other devices to bus (more than 2 ) problems accours.

if do you have any question about up here ask with (1) mark. 

Problem is;

I send data to can bus with id1 ,dev1 answers back.(I'm sending data as fast as I can to try canbus) After that, i try to the id2 and it's works to. i start the send data to dev3(120 ohm parallel), after about 30 attempts it doesn't answer back. After that, no device responds. CanBus is exploded but how ? when i try to send data to main mcu stm32f7 from dev1,2,3 transmitting works well. dev1,2,3 is not receiving any more data. (2)

What should be the problem? Hardware or Software ? If the software was problematic, wouldn't it occur while trying between 2 devices? (3)

Thank you for helps.

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