Powerline communication

Hi,

I need a technology to transmit serial data but just with the two wires of my DC power supply. I am working with an system already maded and I can't add more wires, so my goal is to transmit the serial data through the same power line.

Is there any IC already developed?

There are ready made systems that provide a home computer network by simply plugging into the mains electricity outlets, so technically this is certainly feasible. The manufacturers of those systems may possibly also make lower voltage systems.

One common current application of serial data along low voltage power lines is the DCC (Digital Command Control) system used on model railroads, which basically does what you want, except for the power being ~12 Volts AC.

However, simply isolating your signal from the supply at each end of the line with (suitably calculated) capacitors could provide the solution you need, but the smoothing capacitance on the power lines may attenuate your signal.

Yes as commented it is done all the time, for instance power-over-ethernet (POE) does the exact same thing.. Technically you can use USB with isolation. Linear Technology may do something like that, I know we have asked them to develop that because we want I2C or PMBus, isolated.

Basically all that is required is a center tapped transformer whereby the +5V is the center tap. The transformer is cap coupled to one end of the tx/rx bus. So if you can manage I2C then transmitting over power is easy.

What sort of serial data are you dealing with and at what clock frequency? If you can send me that I can recommend a solution. Who knows you may get lucky and be able to use a ethernet isolation transformer.

Good news is that no special chips would be required.

Hi Daniel,

Yitran's IT700 IC could be the right solution for you.

You will be able to seamlessly interface with the IT700 serial and communicate over the two wires DC.

see more info here: "http://www.yitran.com/index.aspx?id=3351(Yitran IT700)":http://www.yitran.com/index.aspx?id=3351

Feel free to contact me at : guyellen@yitran,com

Regards,

Guy

You need to know that these power line data systems are for AC first of all and will not work as is for DC. My conceptual Data_Over_DC is how to modulate the DC yet keep it out of the load & power supply.

The PLM-24 is a serial UART device specifically for AC. Now if you modify the connection transformer turns ratio then you could adapt the PLM-24, because it is only how the line gets modulated that is different. That means you would need a different turns ratio on the connection transformer. Also if the modulation carrier frequency is high enough the filtering L/C shown in my concept wouldn't be required because it is inherently there anyway.

Since TR1 is sold separately you could perhaps specify a custom turns ratio.Pins i & 2 on the connector, on end goes to +5VDC, the other end would go to ground. Again if the carrier frequency is high say 10MHz, the L/C in my concept would not be required, just as it isn't required in the power line modulation application.

Worth looking into because it is simple.

Sorry I did not convert my photo schematic from .jpg to pdf, Anyway here is the 2nd of the two files in the discussion.

Hi

What you are after is a protocol known as X10 communication
So here are some notes for you as well as a Visual basic program and various other bits of information with reference to X 10 communications across power lines

ftp://ftp.x10.com/pub/manuals/technicalnote.pdf

http://ww1.microchip.com/downloads/en/AppNotes/00236a.pdf

http://www.harrington.force9.co.uk/Projects/FireCracker/FireCracker.htm

http://www.yolinux.com/TUTORIALS/LinuxTutorialX10SmartHomeNetworking.html ( interesting i wonder if we can use the RPI to do this as well then ! hmmm ) Also the amicus bourd also includes the functions already to go if you fancy that ) www.myamicus.co.uk/

http://www.cleverhome.com.au/X10-home-automation.shtml

http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en012050 (Also Interesting fancy that ) stack of articles on the net re this

http://x10-lang.org/home/faq-list.html

http://idobartana.com/hakb/X10AM1.PDF

http://www.cix.co.uk/~pplunkett/x10.htm (this even tells you how to construct the transformer

That should help you ( Fascinating stuff Dreams are made of this )

Would you belive that Im unemployed and despite having contacted god knows how many firms They cant seem to reply "Amazing !"

So much so that I need to do this as well and I’m 50 years old now I love this don’t you Talk about insulting You have got to see this for a good laugh notice the phone number just in case you cant get there I had no idea we had telephone number’s where we simply now dial in binary Did you??

Obviously according to the government and the Department of health and pensions we have I don know what your supposed to do if you need to call them I wonder if they could answer this as well for me

Just a bit of general chat to liven this up a little Today’s newspaper had a member of the public write in to complain about the libraries not having windows 2010 at every library “True they don’t most of the computers are old P4 Pentium processor " , but then if the government really wanted to save on capital and license fees plus the poor oild tax payer and create employment aha “

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Hi,

Please see below link for your reference.

http://www.ti.com/solution/power_line_communication_modem

http://www.atmel.in/products/other/power_line_communications/default.aspx

http://www.echelon.com/technology/power-line/

If you go to elektor electronics page this week which is at

http://www.elektor.com/news/powerline-communication-soc-for-led-lighting.2409121.lynkx

You will see a brief but interesting article on a new device for power line communications using latest semiconductor devices

Please also see the following link

http://green.tmcnet.com/topics/green/articles...rii-mini-gv7013-soc-connectivity-solution.htm

Or

http://www.vancouversun.com/mobile/business/b...ine+Communication+Lighting/7952713/story.html

Which i thought might be interesting as well for you

Plus of course the specification which can be found here

http://www.homeplug.org/tech/homeplug_gp/

Good luck with this and hope this helps you as well