Adding a CAN Bus between 2 controllers

Discussion in 'Embedded Systems and Microcontrollers' started by Free user, Jan 9, 2013.

  1. Free user

    Thread Starter New Member

    Jan 7, 2013
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    So this is my story:

    I have 2 devices connected through a CAN Bus. For test reasons**, I want to add another CAN Bus between the same 2 devices and run the same messages between them at the same frequency.

    **Actually I want to test the CPU capacity of one of the devices that will be connected to many controllers in the real application.

    I used the high level protocol CANOpen. I am struggling with the setup of the new configuration of the system. Apparently the CAN open protocol (which is an open source stack I downloaded from internet) can only work for one CAN bus on the same device ( story with an ID...)

    Do someone know something about it? Every opinion or remark could help!!
     
  2. tshuck

    Well-Known Member

    Oct 18, 2012
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    675
    Why exactly do you want another bus? The CAN bus allows for multi-master communication, meaning any device can transmit provided no other is...If all you want is data verification, why not have a device on the bus reading data and outputting the data to an external device?
     
  3. Free user

    Thread Starter New Member

    Jan 7, 2013
    3
    0
    It is mainly because my first bus is almost fully loaded (70 % of its max load), this is due to the high frequency of the data being transferred between the 2 nodes.

    One of the 2 devices of the network will be connected via another CAN bus, and the test aims to evaluate the capacity of the device CPU...
     
  4. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    Well, you probably won't be testing the device CPU through a CAN bus as the CAN bus is the limiting factor here, most CPUs are clocked to be much faster than the CAN bus allows.

    I suppose you could give the device commands to perform calculations and respond when done, that way, you could get an idea of CPU capability.

    I'm not sure adding another CAN bus would be representative of the CPU capability. Usually, to the best of my knowledge, a device supports a single CAN bus interface since there is usually no need for a second.

    I'm still not seeing the benefit of adding another CAN bus. Take the device out and perform tests on the CPU's capabilities.
     
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