Microcontroller Based PLC Designing

Discussion in 'Electronic Design' started by [email protected], Apr 21, 2006.

  1. Guest

    Hi ,
    I want to design a PLC which use two 8051 Microcontroller in
    place of Microprocesser in which one operate as a execution unit and
    second as a control
    unit.Any body have an idea how to interface them.
    , Apr 21, 2006
  2. Guest

    What ever for? There probably is a more pointless exercise, but it
    escapes me for the moment.
    , Apr 21, 2006
  3. You're about 20 years late. I can buy a PLC with
    everything for 120$

    Rene Tschaggelar, Apr 21, 2006
  4. What don't you like about it? The other option would be to try to use
    a pre-emptive scheduler to keep the PLC part consistent timing, since
    high-quality control algorithms run on most 8051s will be much slower
    than can be tolerated in the PLC loop. I've done the latter on
    Freescale microcontrollers and it's messy too. As far as interfacing--
    it's pretty situation-dependent. Maybe he could use SPI or I2C or
    whatever with some simple protocol to allow the chips to talk to one
    another. Or even just dedicate a port and some handshaking lines.

    Best regards,
    Spehro Pefhany
    Spehro Pefhany, Apr 21, 2006
  5. Guest

    Yes you are right . I am 20 year late but I am not going to run any
    factory with ... I just want to learn .
    , Apr 22, 2006
  6. Only if you cycle time is very short, then
    splitting the communication from the control
    loop makes sense. However, the communication
    between the controller has to be very
    efficient and short.

    I'd set this cycle time below 1ms, where a
    split of the solution in two controllers is

    The 8032 family is outdated, kept for legacy
    reasons to use the already existing tools.
    Rather have a look at the newer families
    such as PIC and AVR in the 8 bit world.

    Rene Tschaggelar, Apr 22, 2006
  7. He mentioned the 8051. There are 8051s that run at 100MIPS.

    Best regards,
    Spehro Pefhany
    Spehro Pefhany, Apr 22, 2006
  8. That still is the same family. With one
    index (far-) pointer. And most are clock
    div 12. Yawn.

    Rene Tschaggelar, Apr 22, 2006
  9. Ian Bell Guest

    Today most are NOT clock div 12.

    Ian Bell, Apr 22, 2006
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