Post by thread:[EE] sending a clock over DC power lines

Somewhere in the back of my mind.....I recall reading/hearing/seeing about sending data over DC power lines. One example was for ham rotor controls, to eliminate the multiconductor cables, it just sent a serial data stream over the DC power. So, this application is to send a 65mS clock over the DC power lines (24VDC). Anyone done this before, or have a link to a circuit? --------------------------------- Bored stiff? Loosen up... Download and play hundreds of games for free on Yahoo! Games.

> So, this application is to send a 65mS clock over the DC power > lines (24VDC). Anyone done this before, or have a link to a circuit? not done it before but i belive the basic principle would be to modulate it onto a carrier and then couple that carrier to the line. much easier if you control the other stuff on the line than if you don't.

peter green wrote: >> So, this application is to send a 65mS clock over the DC power >> lines (24VDC). Anyone done this before, or have a link to a circuit? >> > not done it before but i belive the basic principle would be to modulate it onto a carrier and then couple that carrier to the line. > > much easier if you control the other stuff on the line than if you don't. > > > I did it once to control about 20 trains on 1 rail system. The trick I used was very simple, but worked great: put a few diodes in series with the power supply and put an mosfet across those diodes, now you modulate te DC power. Maybe you also take a look at Power over Ethernet. -- cheers, Stef Mientki http://pic.flappie.nl

{Quote hidden}> -----Original Message----- > From: spam_OUTpiclist-bouncesTakeThisOuTmit.edu [.....piclist-bouncesKILLspam@spam@mit.edu]On Behalf > Of stef mientki > Sent: 09 March 2007 23:01 > To: Microcontroller discussion list - Public. > Subject: Re: [EE] sending a clock over DC power lines > > > peter green wrote: > >> So, this application is to send a 65mS clock over the DC power > >> lines (24VDC). Anyone done this before, or have a link to a circuit? > >> > > not done it before but i belive the basic principle would be to > modulate it onto a carrier and then couple that carrier to the line. > > > > much easier if you control the other stuff on the line than if > you don't. > > > > > > > I did it once to control about 20 trains on 1 rail system. > The trick I used was very simple, but worked great: > put a few diodes in series with the power supply > and put an mosfet across those diodes, now you modulate te DC power. sounds rather lossy. the way i'd do it is put an inductor in series with the power and load (remember for noise sensitive loads to put a paralell cap after the inductor) then couple your signals and and out of the line with capacitors.

part 1 876 bytes content-type:text/plain; (decoded 7bit) > So, this application is to send a 65mS clock over the DC power > lines (24VDC). Anyone done this before, or have a link to a circuit? Alan, this works well between two PICs. The original circuit was from a Plessey handbook describing a 100 ohm twisted pair link between an MV500 IR encoder/transmitter and MV601 receiver/ decoder. I used this at the time for wired 5-bit commands to motor controllers, as well as wireless IR Basically the Vcc for each chip is held stable by the electrolytics and the bit in between carries the data. The receiving pin can be a comparator or ADC input, or add another transistor to boost the pulse to logic level. Components and practicality will depend on what current is passing through the wire to supply the transmitter. For short clicks though, the transmitter's reservoir cap should cope part 2 1388 bytes content-type:image/gif; (decode) part 3 35 bytes content-type:text/plain; charset="us-ascii" (decoded 7bit)

On Fri, 2007-03-09 at 14:08 -0800, alan smith wrote: > Somewhere in the back of my mind.....I recall reading/hearing/seeing about sending data over DC power lines. One example was for ham rotor controls, to eliminate the multiconductor cables, it just sent a serial data stream over the DC power. > > So, this application is to send a 65mS clock over the DC power lines (24VDC). Anyone done this before, or have a link to a circuit? Haven't done it, but have a look at DCC control used in model railroading (i.e. http://www.dccwiki.com/Main_Page), might give you some ideas. TTYL

On 3/9/07, stef mientki <s.mientkiKILLspammailbox.kun.nl> wrote: > peter green wrote: > >> So, this application is to send a 65mS clock over the DC power > >> lines (24VDC). Anyone done this before, or have a link to a circuit? > >> > > not done it before but i belive the basic principle would be to modulate it onto a carrier and then couple that carrier to the line. > > > > much easier if you control the other stuff on the line than if you don't. > > > > > > > I did it once to control about 20 trains on 1 rail system. > The trick I used was very simple, but worked great: > put a few diodes in series with the power supply > and put an mosfet across those diodes, now you modulate te DC power. > Maybe you also take a look at Power over Ethernet. Another way will be to supply the DC from a constant current generator (high output impedance) and modulate either the current at the input of the current generator or modulating directly in the line using a series capacitor. Depends how clean must be the 24V line at the load side, that should be the starting point.