Way back in 2000 I was part of a company (nSine) in the UK. We developed powerline networking and could actually send MPEG-4 video over powerline. Unfortunately when the tech bubble burst so did the company. I was chatting with the founder of the company a few weeks ago and in hindsight we wish we'd concentrated a bit more on the appliance side but the money was all for networking over powerline.
The biggest problem was also lack of co-operation between competing technology companies. Oh and as more and more switching type power supplies were connected to the AC Mains the more electrical noise was introduced. So the standards for emitted noise were very low and our signals had to fit below that level. That's one place were government regulations could have really helped. By setting 'accidental' emissions really low but allowing signal emissions to be above that but still below some other level. The third and really most interesting problem was that even a household power line is still a star based signal transmission line with taps. Easier in the UK and Europe because of the 220VAC. More difficult in the USA/CANADA because split phase 220VAC/110VAC. Even X-10 has had problems with that. Anyway, as a transmission line it has reflections and null points at high frequencies and it's pretty well impossible to add termination like you would for an RF antenna or CAN bus network that requires 120 ohm resistors at each end and cable with an effective impedance of 120 Ohms. AC Power line also has a bandwidth of only 3MHz to 30MHz some of which is in the HAM bands. And a house running high speed power line networking can turn into an interesting emitter of noise in the various radio bands. So we used four modulation frequencies and a modified Controller Area Network (CAN) protocol to allow CSMA/CR (Carrier Sense, Multiple Access with Collision Recovery). Now a null point right at an outlet socket at one frequency would not be a null at a different frequency. Alas, the IP disappeared into a large Chinese corporation and that's the end of it at the moment. John Dammeyer > -----Original Message----- > From: Gene Heskett [mailto:[email protected]] > Sent: December-12-19 4:36 AM > To: [email protected] > Subject: Re: [Emc-users] Need a power signal independent of linuxcnc. > > On Thursday 12 December 2019 05:22:45 Gregg Eshelman via Emc-users > wrote: > > > The X10 protocol has been used much more recently than 40 years ago. > > Several manufacturers have made, and some still make, X10 based > > equipment. Even IBM got into it for a while. The originating company > > is still in business at x10.com > > Yes, true. But has there been any new production in 30 years? It looks > like its all NOS. CM11a's haven't been available for a very long time. > Decades. They should have added 5 bucks and made it usb compatible 20 > years ago when usb replaced seriel ports. > > Now there seem to be a plethora of competing products, nearly all useing > different proprietary protocols. heyu is attempting to track them and > become compatible but other than heyu's own src code there is not a list > of compatible stuff you can buy at Lowes. > > As a co-author with Jim Hines of EZHome and EZCron for the Amiga's, I > have tracked that scene nearly as well as the heyu folks have. I'd love > to find a competing products appliance module that was newly designed > and didn't depend on a plastic molded alternate action relay. Crydom has > done it since the early '80's now with no moving parts, I am switching > the primarys of 6 toroid and one conventional transformers in my machine > controls with crydoms or their lookalikes for much of a decade with no > problems with them, why can't x10. That relay gizmo has never been 100% > reliable after about the first 100 operations. > > > On Wednesday, December 11, 2019, 10:19:29 PM MST, Gene Heskett > > <[email protected]> wrote: > > > > On Wednesday 11 December 2019 21:43:44 jrmitchellj . wrote: > > > An X10 appliance module would be a better option for that.� Lamp > > > modules are essentially dimmers. > > > > > > --J. Ray Mitchell Jr. > > > [email protected] > > > > Does that make a huge diff to a switch mode psu? > > > > Using an appliance module means the lubricant in that alternate action > > relay is 40+ years old. I have a couple of those, controling Christmas > > lights on the front deck, and they have reached the age at which even > > 3 bangs from heyu a second apart will not reliably switch them.� > > Attempts to re-lubricate them have not been successful here. > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
