On Wed, 17 Jan 2018 16:41:59 -0500 Gene Heskett <ghesk...@shentel.net> wrote:
> On Wednesday 17 January 2018 11:10:53 Nicklas Karlsson wrote: > > > On Wed, 17 Jan 2018 09:27:25 -0500 > > > > Dave Cole <linuxcncro...@gmail.com> wrote: > > > The text below is at the end of the SOEM page from the link below. > > > https://openethercatsociety.github.io/doc/soem/index.html > > > > > > So how does this work?? The SOEM software itself is GPL, but if > > > you implement an Ethercat master, you need to get a license ?? > > > > Why a license? > > > > I have nothing about sharing my work but copyright issues i something > > different. > > > > Then in european union I read something about interoperability so you > > are always allowed to make your own device to talk to other device. > > > > > That's an interesting approach. > > > > > > If the SOEM code is all GPL, then how could adding GPL code to GPL > > > code result in something other than GPL code ? > > > > > > From a practical standpoint, I think we need to figure out how to > > > get networked drives connected to LinuxCNC if we want LinuxCNC to > > > live on. At some point analog servo drive interfaces will become > > > like 5 1/4" floppy drives... They were once common. > > > > Yes. > > > > Michael Büsch already implemented a profibus master. I have it running > > against an IO module and millions of these kind of devices have been > > sold. I think he implemented on Rasberry and I had some timing issue > > before running on ordinary computer but have not looked further > > because I have been busy with something really good for servos and > > looking for a new woman. > > > > Bandwidth required to replace an analog signal may be surprisingly > > high and for a control loop even though there are plenty of bandwidth > > it need to split in many small messages. Ethercat solve this problem > > in a similar way as cascade coupled shift registers. > > > > > > Nicklas Karlsson > > > I think this might be right up PCW's alley. He is already selling some > cards that expand via an rj45 jack. Perhaps he could chime in here as to > the advantages and disadvantages of adapting the firmware to be > something like this, but call it something other than ethercat. > > Changing the subject a bit while I ramble, we have some amazingly cheap > rs485 devices about, costing less than a buck each in bags from ebay. Yes rs485 is a cheap and a very good driver. UART however have limited speed and not the least clock accuracy problem at higher speed. With a device with as many UART ports as needed this might be a very good solution, speed could also be adapted to cable length then long cables are needed. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
