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Groups > comp.arch.embedded > #28324
| From | Rob Gaddi <rgaddi@highlandtechnology.invalid> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: RS485 over optical fiber cable |
| Date | 2018-11-05 09:12 -0800 |
| Organization | A noiseless patient Spider |
| Message-ID | <prptml$8c9$1@dont-email.me> (permalink) |
| References | (6 earlier) <prhkck$e2s$1@dont-email.me> <prhq40$63i$1@news2.open-news-network.org> <pri8lu$ks7$1@dont-email.me> <nnd$57b76d55$1ed3244c@8c0251ac87d7ae23> <provm8$i8m$1@dont-email.me> |
On 11/5/18 12:40 AM, pozz wrote: > Il 02/11/2018 23:57, Stef ha scritto: >> On 2018-11-02 Tauno Voipio wrote in comp.arch.embedded: >> [...] >>> The bias resistors are still necessary to handle an idle line. >> >> With "fail safe" receivers, a termination resistor alone will >> keep the differential voltage low enough for the receiver to see >> 'idle'. But if ypou can ad bias, why not do it? >> >> >> Why is Pozz trying to do this without termination? >> On RS485, use termination! Never had trouble with termination, >> have had trouble without. > > I try to clarify my questions on termination resistors. > > I can really use them. The higher power dissipation is interesting in my > battery-powered application, but I think I will have enough energy. So > this isn't a problem. > > I will use a termination resistor on both sides. My concerns were on the > resistor correct value. If I need a termination, I need to use a correct > resistor value. Is it critical? > > The other problem with signal ground, I know it is better to connect it > together with A and B. However it would be much more simple and cheap to > use a simple couple instead of a full CAT5E cable. > > >> Just remembered an occasion where I had to source a resistor in a >> remote location with no electronics shop anywhere nearby. And then >> climb a 70m ladder to install it. Then you really wonder why they >> originally did not install a termination resistor. :-( Depending on the application, you may also be able to save power by disabling the transmitter when you're not transmitting. You'll need to think about the implications for the receiver: the failsafe logic, etc. But if you're only transmitting 1% of the time, you only need to be dumping current into those termination resistors 1% of the time. -- Rob Gaddi, Highland Technology -- www.highlandtechnology.com Email address domain is currently out of order. See above to fix.
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RS485 over optical fiber cable pozz <pozzugno@gmail.com> - 2018-10-30 15:00 +0100
Re: RS485 over optical fiber cable raimond.dragomir@gmail.com - 2018-10-30 07:26 -0700
Re: RS485 over optical fiber cable pozz <pozzugno@gmail.com> - 2018-10-31 12:41 +0100
Re: RS485 over optical fiber cable raimond.dragomir@gmail.com - 2018-10-31 05:55 -0700
Re: RS485 over optical fiber cable Grant Edwards <invalid@invalid.invalid> - 2018-10-31 14:03 +0000
Re: RS485 over optical fiber cable John Speth <johnspeth@yahoo.com> - 2018-10-31 09:35 -0700
Re: RS485 over optical fiber cable Grant Edwards <invalid@invalid.invalid> - 2018-10-31 16:48 +0000
Re: RS485 over optical fiber cable pozz <pozzugno@gmail.com> - 2018-11-02 14:44 +0100
Re: RS485 over optical fiber cable Richard Damon <Richard@Damon-Family.org> - 2018-11-02 11:00 -0400
Re: RS485 over optical fiber cable upsidedown@downunder.com - 2018-11-02 20:42 +0200
Re: RS485 over optical fiber cable raimond.dragomir@gmail.com - 2018-11-02 08:18 -0700
Re: RS485 over optical fiber cable Mike Perkins <spam@spam.com> - 2018-11-02 15:22 +0000
Re: RS485 over optical fiber cable Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2018-11-02 21:31 +0200
Re: RS485 over optical fiber cable Mike Perkins <spam@spam.com> - 2018-11-02 20:12 +0000
Re: RS485 over optical fiber cable Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2018-11-02 23:57 +0100
Re: RS485 over optical fiber cable upsidedown@downunder.com - 2018-11-03 01:18 +0200
Re: RS485 over optical fiber cable Mike Perkins <spam@spam.com> - 2018-11-03 19:05 +0000
Re: RS485 over optical fiber cable Richard Damon <Richard@Damon-Family.org> - 2018-11-03 17:36 -0400
Re: RS485 over optical fiber cable gnuarm.deletethisbit@gmail.com - 2018-11-03 19:49 -0700
Re: RS485 over optical fiber cable upsidedown@downunder.com - 2018-11-04 07:50 +0200
Re: RS485 over optical fiber cable pozz <pozzugno@gmail.com> - 2018-11-05 09:40 +0100
Re: RS485 over optical fiber cable Richard Damon <Richard@Damon-Family.org> - 2018-11-05 06:45 -0500
Re: RS485 over optical fiber cable Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2018-11-05 09:12 -0800
Re: RS485 over optical fiber cable Grant Edwards <invalid@invalid.invalid> - 2018-11-02 18:21 +0000
Re: RS485 over optical fiber cable upsidedown@downunder.com - 2018-11-03 00:02 +0200
Re: RS485 over optical fiber cable pozz <pozzugno@gmail.com> - 2018-11-02 14:36 +0100
Re: RS485 over optical fiber cable "Mat Nieuwenhoven" <mnieuw@zap.a2000.nl> - 2018-10-31 16:32 +0100
Re: RS485 over optical fiber cable upsidedown@downunder.com - 2018-10-31 22:41 +0200
Re: RS485 over optical fiber cable Chris <c@b.a> - 2018-10-31 12:16 +1100
Re: RS485 over optical fiber cable upsidedown@downunder.com - 2018-11-02 06:52 +0200
Re: RS485 over optical fiber cable Robert Wessel <robertwessel2@yahoo.com> - 2018-10-31 09:11 -0500
Re: RS485 over optical fiber cable peter jakacki <peterjakacki@gmail.com> - 2018-11-12 19:57 -0800
Re: RS485 over optical fiber cable upsidedown@downunder.com - 2018-11-13 08:09 +0200
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