Could something like https://www.digikey.com/catalog/en/partgroup/afbr-1528cz/66628 be useful? They are about $12 each but operate at 5Mbps so perhaps you could multiplex some of the signals. There is also an eval kit https://www.digikey.com/products/en/development-boards-kits-programmers/eval uation-and-demonstration-boards-and-kits/787?k=hfbr-1506amz You can get 10-foot fibre patch cables with SMA terminations to avoid making your own.
> -----Original Message----- > From: Gene Heskett [mailto:ghesk...@shentel.net] > Sent: Thursday, April 20, 2017 2:51 PM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] Fiber optic control for CNC > > On Thursday 20 April 2017 11:22:03 Todd Zuercher wrote: > > > Fanuc has been using fiber optic connections for more than 30 years. > > And I work with an old SCM machine with a Num 1040 control that has a > > bank of fiber optic remote io that is one of the things holding me > > back from trying to convert it to Linuxcnc. > > > This has been a wish of mine for a long time. We need some cheap stuff that > can be the equ of an opto-isolator, but with a piece of glass or plastic fiber up > to several feet long as the optical media between them. > With power on the rx end, signal losses in the plastic fiber could be easily > compensated. I can visualize stepper drivers incorporating it, probably at no > more cost for the pair of fiber sockets than they cost for the full opto- > isolation BOM right now. > > All we would need would be an HE IR LED with a molded in funnel to guide the > fiber tip to the chip face in the LED. Some sort of a jacket on the fiber to > prolong its life if rubbing on something, or to prevent optical crosstalk would > be needed. The major design problem AISI is in gripping the fiber to anchor it > at both ends, with long term gripping pressure imprinting itself on the fiber > creating radiation leaks. Even glass will do that, but usually over time frames > that exceed the life of the rest of the machine since technically, glass is a > super-cooled liquid, flowing visibly over the lifetime of the observer. > > The led makers have now had 40+ years to design such a package, and I fail to > understand why it has not happened. > > Or has it, and I missed the announcement? Thats a plausible excuse given my > age and retired status. If anybody would have it on this side of the pond, > digikey, and I've only found one candidate so far. Intended to be a remoteable > indicator, the led is conventional shaped, available in several colors. Pricing > starts at $2.15 with a 6" light pipe, Available up to 3940" long. :) With the far > end of that pipe facing into an avalanche mode transistor, mounted exactly > the same as the led, and substituted for the BOM that puts the opto-isolation > into the stepper drivers input circuits, it ought to be essentially free! What > sort of speed would have TBD. But I'd certainly have to think its faster than > the 200 to 300 kilohertz we can now drive a $35 M542 stepper driver. > > Look at <http://www.bivar.com/portals/0/products/FLPRX.X-XX.pdf> > > And see what you think of it. > > One of those in red led, looking at one of these: > > <http://www.everlight.com/file/ProductFile/PLR135-T9.pdf> > > Would I think, be a good test bed. Need some smd bypassing of the rx supply, > and I'm not sure what buffering might be needed to make it actually drive the > opto's in the stepper driver. Pulse time distortions are quite small and the > data rate can be as high as 16 megabaud. > > Now if I can find where to source the fiber cable it uses in say 10' > pieces, I could try it out in this lathe conversion. With 10 40" > assemblies, I could put feet and sheet metal between the pi-7i90 and the > noise makers already installed. With 30 of them I could replace the copper > leaving the pi's box, except for the power cord, with fiber, and enjoy the > peace and quiet. > > And I've got Dennis Strander at DigiKey furiously sending out requests for > more info. W/O the fibers, we're under a $5 bill a connection so far. I can live > with that. We'll see what falls out of my email box in the next few hours. > > > ----- Original Message ----- > > From: "Gregg Eshelman" <g_ala...@yahoo.com> > > To: "Enhanced Machine Controller (EMC)" > > <emc-users@lists.sourceforge.net> Sent: Thursday, April 20, 2017 > > 4:39:08 AM > > Subject: [Emc-users] Fiber optic control for CNC > > > > Looks interesting. Can't have a ground loop when there's no wires. > > http://hackaday.com/2016/03/20/add-fiber-optic-control-to-your-cnc/ > > > > ---------------------------------------------------------------------- > >-------- Check out the vibrant tech community on one of the world's > >most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > >_______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ---------------------------------------------------------------------- > >-------- Check out the vibrant tech community on one of the world's > >most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > >_______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > 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) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > ---------------------------------------------------------------------------- -- > Check out the vibrant tech community on one of the world's most engaging > tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
