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Augusto Chagas
Augusto Chagas
Associate
February 23, 2018
Question

X-NUCLEO-PLM01A1 - Doubt about this shield

  • February 23, 2018
  • 3 replies
  • 1366 views
Posted on February 23, 2018 at 18:14

Hello people.

I was studying the datasheet of Shield X-NUCLEO-PLM01A1.

This Shield is intended to implement Power Line Communication on DC voltage lines.

Why use two lines of cable pair for communication between the boards ???

It was not to use only the 12Volts power cable to communicate the data between the boards ???

Can someone clarify me ??

Did I misunderstand the proposal of this shield?

Thank you in advance for your support.

#x-nucleo-plm01a1
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    3 replies

    Andrew Neil
    Andrew Neil
    Super User
    February 23, 2018
    Posted on February 23, 2018 at 20:25

    You mean this: 

    http://www.st.com/en/ecosystems/x-nucleo-plm01a1.html

      ?

    Why use two lines of cable pair for communication between the boards ???

    Why not?

    Isn't that the usual way to do power-line comms?

    A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
    Augusto Chagas
    Augusto ChagasAuthor
    Associate
    February 25, 2018

    Posted on February 25, 2018 at 19:37

    Hello Andrew,

    You mean this: 

    /external-link.jspa?url=http%3A%2F%2Fwww.st.com%2Fen%2Fecosystems%2Fx-nucleo-plm01a1.html

      ?

    Yes, I mean talk about X-NUCLEO-PLM01A1.

    Why not?

    Isn't that the usual way to do power-line comms?

    About Power Line Communication (PLC), I understand that it has the proposal to reduce communication cables with the use of the power cables.

    In the document below, on page 8, the interconnection is done using one pair of data cables and another pair of cables for electric power supply.

    If the X-NUCLEO-PLM01A1 board requires this pair of cables for data communication it does not implement Power line communication.

    http://www.st.com/content/ccc/resource/technical/document/user_manual/group0/b1/d4/f8/cf/48/55/4b/90/DM00379016/files/DM00379016.pdf/jcr:content/translations/en.DM00379016.pdf

     Would it be possible to eliminate some pair of cables and maintain power along with data communication in just a couple of cables?

    If this is not possible, I think the board does not fulfill the role that Power Line Communication technology proposes.

    If you have to use a pair of communication cables, there is no PLC justification, it is better to use another two wire communication technology.

    Why my curiosity? I am doing a graduation job where the proposal is to reduce cables in an electric vehicle using the Power Line Communication technology. This way I need some device that makes the communication of data on power lines with DC voltage.

    Thanks for your support, Andrew.

    Andrew Neil
    Andrew Neil
    Super User
    February 25, 2018
    Posted on February 25, 2018 at 19:52

    Remember that these are just demo/evaluation boards.

    In real life, you'd extract power from the power lines - but the demo board don't do that.

    A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
    AGand
    AGand
    Visitor II
    October 17, 2018

    Hello,

    This is really a good question. I also have the same question.

    As we are saying communication over a power line, why do we need the extra two lines (i.e. PLM and GND) to connect two boards as we are already connecting boards by power cables. I am curious to know more about PLC communication. Any link or page to get more info about it, would be highly appreciated.

    Thanks & Regards,

    Akash

    Tesla DeLorean
    Tesla DeLorean
    Guru
    October 17, 2018

    The power-line stuff is rather a niche, you really should start a conversation with your local sales office and establish contact with FAE's or support staff who can understand your project and requirements.

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