Data Transmission Over Live Power Lines

  • Thread starter Godfrey Mungadze
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Godfrey Mungadze

Hi List, I was wondering if any of you guys knows how to transmit data over live power lines using Visual Basic 5 or Citect 5.30? Say you have two computers in the same building or room, and you want them to exchange data over live power lines with at least 220v; How can you do that?

Johan Bengtsson

---------- Forwarded message ---------- From: [email protected] To: [email protected] Subject: RE: SOFT: Data Transmission Over Live Power Lines What you need is some hardware, quite similar to a modem, at each computer that is able to communicate via the power lines. A "normal" modem is changing the digital information transmitted on a serial port to signals that can be transfered thru telephone lines. For older, low speed modems this was done by sending a sound with one frequency for a logical zero and one frequency for a logical one. (This process is called MODulating the signal) The reciever then listened for these two frequencies and decided if the current signal sounded mostly as a logical zero or one. (This process is called DEmodulating the signal). A modem is capable of both, that's where it got it's name from. If you want to transmit signals over a power line you basically do the same thing, but it is harder since the power lines contains more noice for one thing, and of course higher (and more harmful) voltages. That is the basic theory, you can develope it further as far as you want from that. For the simple process with two computers connected like this the applications don't have to be aware of the power line at all (it is talking to something it beleves is a standard modem), but of course you can do whatever you want like multidrop and so on if you design (or use an existing) protocol that will handle it. Some devices exist to do this, for example Lon have this possibility, but I don't know one comercially available device that simply plugs to the com-port of a computer or similar. Someone else on the list might however... /Johan Bengtsson ---------------------------------------- P&L, Innovation in training Box 252, S-281 23 H{ssleholm SWEDEN Tel: +46 451 49 460, Fax: +46 451 89 833 E-mail: [email protected] Internet: ----------------------------------------
You don't specify the amount of data or transmission speeds needed so I will mention one possible solution. Take a look at Echelon's Powerline solution. You do mention having two or more computers so this actually makes it easier. In each computer you would have interface hardware (PCLTA-20 for PCI slot interface, or SLTA-20 for serial interface). On top of that you could run the LonWorks DDE server which would provide the drivers and interface to the LonWorks network. On top of the DDE server you write your VB application to send or receive data. The Echelon PLT-22 powerline transceiver is limited to approx 5Kbps but it is good for any voltage/frequency and is very robust. If the computers on the same transformer they will likely communicate - even if on different phases. If you need some help with this, please contact me. Regards, Fred Graham Graham Controls Consulting Specializing in LonWorks technology 770.887.9024 (voice) 770.216.1668 (fax) [email protected]
It's vaporware right now, but 3COM is developing a line network cards that plug into a outlet - Power-Line Carrier (PLC) :) They say bandwidth will range from 50 to 350 kbps. So far as Windows is concerned, it'll probably look like a regular network. I know there are other vendors working on the same goal, but I can't seem to recall their names. A web search should turn them up. If you're not in a rush for a solution you may want to look into these. Jeff Dean [email protected]

Gordon Dafoe

Hey, check out I believe they have what your looking for. Go to the products and look at the kit for developing your own systems. They have gotten the noise out and claim 11Mbs speed. Good Luck, GWDafoe

Muhammad Bilal

i wonder if if any body could give me a detailed over view on such transmission (including schematics if possible)