controller area network

Discussion in 'Computing and Networks' started by cktcrazy, Jun 14, 2011.

  1. cktcrazy

    Thread Starter New Member

    Mar 27, 2011
    16
    0
    hi

    i am now working on CAN protocol
    once i came across a question on CAN in an interview
    the question asked : Can it be possible to achieve a speed of 2mbps in CAN network???

    i little bit puzzled here!!!

    here my view is if we use a crystal of of maximum tolerance we can achieve this speed and using the appropriate bit setting.

    bit i am not confirmed

    has any one having any solution to this question ???

    i will be obliged if any views ??

    thanks waiting from your response .

    from cktcrazy
     
  2. AlexR

    Well-Known Member

    Jan 16, 2008
    735
    54
    Read the CAN standard!
    It states that the CAN bus supports bus data rates of up to 1Mbit/s (dependant on bus length, stub length etc) so if you are running at 2Mbit/s you are not conforming to the standard and therefore you can't call it a CAN network.
     
  3. Papabravo

    Expert

    Feb 24, 2006
    10,135
    1,786
    There is not enough delay budget at 2 Mbps for the signal to travel down the cable and back if the length of the cable is any reasonable length. You can't even hardly do 1 Mbps with opto-isolators which some systems require. It is all in the way the CAN physical layer works. We even got special cable with foam dielectric to increase the speed of propagation, and still could not go very far at 1 Mbps.
     
  4. davejo

    New Member

    Aug 1, 2012
    6
    0
    Hi.

    CAN is a multi master based network in which communication occur's in the form of messages ! each message consists of an Identifier (who is sending) and eight bytes of data.
    Baud rate depends upon length of the network ! but not more then (1 Mbps).
    It is 1 Mbps at network length of 40 m and less. and length can be increased by compensating data rate ; for example 125 kbps @ Network length of 500 m.

    Thanks
     
  5. cork_ie

    Member

    Oct 8, 2011
    348
    58
    There are so many CAN standards now days that there no longer is a Can standard.

    Yes is the answer to the original question . Maxim for example is one manufacturer of a 2Mb/s transceiver http://www.alldatasheet.com/datasheet-pdf/pdf/73100/MAXIM/MAX3053ESA.html
     
  6. cork_ie

    Member

    Oct 8, 2011
    348
    58
    Sorry but what you say is not quite correct , possibly was 10 years or more ago. I am working with automotive CAN every day of the week and speeds have got faster with several newer higher layer implementations including transmission over optic fibre.
     
    Last edited: Oct 5, 2012
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