You are right, there are more bandwidth but there may be collisions. I do not now about the switches but for old HUBs the full bandwidth can't be used because of collision and there actually is a statistical upper limit below maximum capacity. Worst case delay is of course higher.
For ethercat full bandwidth can be utilized without collisions even if there are several devices. I have chosen ethernet because I think it will be good enough, it is available in almost all computers and there are cheap development boards available with 100Mbit ethernet. I think Ethercat make a lot of sensors for manufacturers since there are no collisions or statistics involved so they could prove the system work correct but for a machine built to be used by yourself this proof is rather useless. Nicklas Karlsson On Sun, 15 Mar 2015 10:58:38 -0700 (PDT) "Peter C. Wallace" <p...@mesanet.com> wrote: > On Sun, 15 Mar 2015, Karlsson & Wang wrote: > > > Date: Sun, 15 Mar 2015 18:34:13 +0100 > > From: Karlsson & Wang <nicklas.karls...@karlssonwang.se> > > Reply-To: "Enhanced Machine Controller (EMC)" > > <emc-users@lists.sourceforge.net> > > To: Klemen Dovrtel <klemen_dovr...@yahoo.com>, > > "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > > Subject: Re: [Emc-users] Ethernet! > > > > I have tried Ethernet and it works but if you connect to a switch, hub or > > similar with more devices there may of couse be real time problems. > > Ethernet > > is cheap and readily avaiable although Ethercat I expect to be better if > > the > > extra bandwidth is needed. > > > > Nicklas Karlsson > > > Actually regular Ethernet GigE is better for bandwidth than Ethercat > (AFAIK EtherCAT is limited to 100 mbit by current hardware) > > > > > > > > > On Sat, 14 Mar 2015 18:09:24 +0000 (UTC) > > Klemen Dovrtel <klemen_dovr...@yahoo.com> wrote: > > > >> I am also interested in rt ethernet. Can you please point out which > >> instruction are these, > >> RegardsKlemen > >> > >> > >> On Friday, March 13, 2015 3:54 PM, sam sokolik > >> <sa...@empirescreen.com> wrote: > >> > >> > >> I still cannot believe that it is possible. I have been testing 2.7+ > >> uspace for a while now. It defiantly opens up options. > >> > >> Building the latest rt-preemt using peters instructions and .config made > >> the latency on this laptop much much better. I am running a 2khz servo > >> thread for a day now. > >> > >> http://electronicsam.com/images/KandT/testing/0313150923b.jpg > >> > >> Realtime communication over Ethernet is just darn awesome! > >> > >> I would not use a laptop for normal machine running - but for developing > >> systems - it sure will be nice. > >> > >> Thanks Peter, Micges, Jeff and everyone else that has made this a reality. > >> > >> sam > >> > >> ------------------------------------------------------------------------------ > >> Dive into the World of Parallel Programming The Go Parallel Website, > >> sponsored > >> by Intel and developed in partnership with Slashdot Media, is your hub for > >> all > >> things parallel software development, from weekly thought leadership blogs > >> to > >> news, videos, case studies, tutorials and more. Take a look and join the > >> conversation now. http://goparallel.sourceforge.net/ > >> _______________________________________________ > >> Emc-users mailing list > >> Emc-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-users > >> > >> > >> > >> ------------------------------------------------------------------------------ > >> Dive into the World of Parallel Programming The Go Parallel Website, > >> sponsored > >> by Intel and developed in partnership with Slashdot Media, is your hub for > >> all > >> things parallel software development, from weekly thought leadership blogs > >> to > >> news, videos, case studies, tutorials and more. Take a look and join the > >> conversation now. http://goparallel.sourceforge.net/ > >> _______________________________________________ > >> Emc-users mailing list > >> Emc-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ------------------------------------------------------------------------------ > > Dive into the World of Parallel Programming The Go Parallel Website, > > sponsored > > by Intel and developed in partnership with Slashdot Media, is your hub for > > all > > things parallel software development, from weekly thought leadership blogs > > to > > news, videos, case studies, tutorials and more. Take a look and join the > > conversation now. http://goparallel.sourceforge.net/ > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > Peter Wallace > Mesa Electronics > > (\__/) > (='.'=) This is Bunny. Copy and paste bunny into your > (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
