CAN Bus Problems

Discussion in 'The Projects Forum' started by Kyle MEnsing, Mar 5, 2015.

  1. Kyle MEnsing

    Thread Starter New Member

    Mar 5, 2015
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    I have two CAN bus systems that I would like to share a component but not all be connected together. I have tried diodes on the CAN lines but I could not get the component to connect this way. I mad a splitter cable that would allow one to pass through normally and the other I was hoping would just receive CAN data but not connect the systems. Is there a way to share this component on the CAN bus without having one large system?
     
  2. Papabravo

    Expert

    Feb 24, 2006
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    The only way that I know for sure will work is to have separate CAN controllers on the shared component. It will participate in the transactions of both networks without interference. A simple look at the CAN physical layer should convince you that what you want to do is quite plainly impossible. All nodes on a CAN network must participate in the network protocol. If only one node disagrees then the whole frame gets busted. That is part of the built in reliability. Where do people get these quaint notions that they can do anything they want with carefully crafted architectures?
     
  3. Kyle MEnsing

    Thread Starter New Member

    Mar 5, 2015
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    0
    It seemed like a simple concept until i started playing with it. Then I was slowly figuring out it was nearly impossible. But you do give me a new idea. I have 2 CAN0 and CAN1 on my system. I might be able to utilize one on each. Thanks!
     
  4. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    The guys a Bosch spent a great deal of time and effort working out the details of the CAN physical layer. It is both clever and ingenious, but the rules must be followed for a very good reason. It all breaks down when "inventors" try to screw around without realizing the implications of their decisions.
     
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