Theshed
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| posted on 1/6/23 at 11:21 AM |
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CAN bus help
This might be a bit obscure but I know there are some seriously good programmer types on here. To start with I accept I am an idiot.....
I have a power distribution unit badged as a Bosch Power Box 180 but it is the same as the OBR PCM2 ('the PDU' . My issue is with CAN
communications. I have a lawicel CANUSB interface. When I fist started to program the unit I managed to make it communicate with the PC based software
without difficulty. It used 11 bit source addresses for send and receive. So thinking I was clever I added a CAN Keyboard. That is J1939 and uses 29
bit identifiers.
Like an idiot I was just playing around trying to get the keyboard to do something. I used some software designed for the same keyboard but with
OpenCan. At some point I attempted to send a file - I thought to the keypad but fear I sent it to the PDU.
What then happened is that I have lost communication between the PDU and the computer (via the interface). This has been driving me nuts and I have
completely failed to restore communication.
The Can bus is now limited to 2 devices - the interface and the PDU.
I think that the can bus is properly terminated (assuming that the PDU internal termination resistor is turned off in the software.
I know that the PDU is active for 2 reasons. If I set the PC connection speed to anything other than 500k bits/s it shows an error. When I use 500k
Bits/s the error light on the interface goes from steady to flashing.
I have used a can monitor to capture the messages sent by the PDU on start up. The message starts with 05580F00000785 followed by data bytes.
I think that is a 29 bit identifier. It seems that I have sent this in error when messing about. The default 11 bit identifiers (which worked
previously) are transmit - 55 and receive 785 (I think but I might have those the wrong way around). Those need to be specified in the pc software
along with the same for the interface (but reversed). I can select 11 or 29 bit as an option in the software.
So.....
Can anybody tell me what 05580F00000785 tells me about the CAN Id? I think it is a 29 bit identifier with a source and destination address plus 80F.
If I can work out what is being transmitted I hope I can set the correct send/receive address in the pc software and get communications back.
Please do not just tell me I am an idiot - I know that already
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coyoteboy
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| posted on 1/6/23 at 01:03 PM |
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Send the chaps over at canable.io a question?
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Theshed
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| posted on 1/6/23 at 01:31 PM |
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Ohh thank you I had not discovered them. If I have to watch another you tube video I will go mad!
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coyoteboy
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| posted on 1/6/23 at 01:35 PM |
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I have only recently started to dabble with one nor their devices but I'm sure if anyone can help poke about in an unknown system, it's
likely to be them.
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