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Can I replace PLC with microcontroller for project

Discussion in 'Microcontrollers, Programming and IoT' started by Daljeet12, Nov 29, 2019.

  1. Daljeet12

    Daljeet12

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    Jun 16, 2018
  2. Minder

    Minder

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    Apr 24, 2015
    A PLC has essentially a micro controller as its core, the difference is that the PLC has all the I/O conditioned with Opto modules etc.
    Another nice feature of a typical PLC is that the (ladder) logic can be displayed on a PC screen and the (on/Off) condition of each I/O can be seen.
    You could however make up I/O using Opto22 modules etc.
    A micro should be equally as efficient, if not more, as a PLC has an update time taken to update all I/O conditions table.
    M.
     
  3. Nanren888

    Nanren888

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    26
    Nov 8, 2015
    Some PLCs do a lot of conditioning of inputs for you. For example, you tell it that you only want to create an event when some signal changes beyond a particular amount, or out of some control zone.
    Some also have support for various commonly-used functions.
    The standards define multiple ways to programme them, ladder logic, structured text, often something that looks like microcontroller assembler, but runs on a virtual processor.
    That hardware signal conditioning that Minder mentioned, opto isolation and often filtering is often really useful.
    So, in a similar way to Minder's answer on the hardware signal conditioning, nothing that one can't implement oneself, but often a PLC is a very convenient way of doing it all with a minmimum of work.
    There are some really small PLCs by the way.
     
  4. Bluejets

    Bluejets

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    Oct 5, 2014
    Old pc system that I use for a crank grinder for miniature engines.
    Might be useful for reference so you can get some idea of the complexity of starting from scratch so to speak with a uC.
     

    Attached Files:

  5. Daljeet12

    Daljeet12

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    Jun 16, 2018
    It' seems PLC is not efficient for the project
     
  6. Minder

    Minder

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    596
    Apr 24, 2015
    A PLC should be perfectly capable,
    The operation appears to be a point-to-point procedure which is well within the capability of a PLC.
    An issue often appears when servo positioning is required, especially if interpolated moves are required.
    Some PLC's have add-on modules to take care of this, but gets expensive.
    M.
     
  7. Bluejets

    Bluejets

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    718
    Oct 5, 2014
    Can you expand on how you determine this?
     
  8. Minder

    Minder

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    Apr 24, 2015
    If your concern was because I mentioned the relatively lower I/O refresh rate for the PLC, it would inconsequential, especially in this application.
    M.
     
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