2011/2/6 Mark Wendt (Contractor) <mark.we...@nrl.navy.mil>: > On 2/6/2011 1:47 AM, Kim Kirwan wrote: > <snippage> >> >> But look at the (current) EtherCAT hardware page >> (there in the green block at the top): >> http://www.etherlab.org/en/ethercat/hardware.php >> >> It seems to say they have a universal driver that supports all network >> cards that are currently supported in linux, but that you can't use it >> with RTAI. So although yes, the universal driver can run the network in >> real-time, it's not able to run in real-time under a real-time OS. > > For some reason, I'm not quite getting the distinction. What's the > point of a RT network if it's not going to run under a RTOS?
Ulf mentioned, what software was installed (quoting http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Etherlab): * linux kernel 2.6.32.10 * rtai 3.8.1 * etherlab master 1.5 from development branch from source forge http://sourceforge.net/projects/etherlabmaster. I checked out version 968a531e5a89 * emc2-ethercat glue module (source code below, original on [[ContributedComponents#EtherCAT Digital I O]] * emc2 2.4.3 (or later should do, too) I would like to ask Ulf to share his experience, because now it looks like etherlab master _did_ work on RTAI patched kernel. > Could be our biggest problem is going to be the slave port. Now, we're > using a relatively simple and cheap parallel port breakout board to the > drivers. How do we inexpensively make a slave card work RT at the > driver end of the link? It needs to be able to accept the signals from > the master, then convert those signals to step/dir, or servo loops, and > in the case of servo loops, be able to communicate the loop back to the > controller. Yupp, the slave device needs something special. Like this: http://www.xilinx.com/products/ipcenter/Beckhoff-ET1815.htm http://www.beckhoff.com/english/ethercat/et1815_et1816.htm The second page mentions licences and royalties, but, as one professor once told me: "you don't get, if you don't ask". So I see only one way to find out, if it is possible to manufacture ethercat slave devices for a reasonable price - ask them. Is there a chance that someone from electronics field contact them on this matter? >> And just to clarify a point, it wouldn't bother me at all if the >> EMC2 master PC had to have at least one real-time-only network >> interface in this proposed scheme. I don't see why we want to make >> Samba and BitTorrent available over the same network as the CNC RT >> control signals. Even if they can be tunneled or whatever. The RT >> network should IMHO connect only EMC2 and the CNC machine slaves, >> nothing else. >> Additionally, RTnet.org mentions an RT-Firewire, so maybe those who >> have been wanting EMC2 to run over USB would accept Firewire? > > Eh, Firewire usage is fading faster than parallel port. My latest > laptop and desktop systems don't have any Firewire ports on them But I am sure that Your laptop has both RJ-45 port and Wifi. 2 separate network controllers - so no problem to separate communication with CNC machine and browsing web via wireless. The last e-mail from Yi-Shin on the other thread brought me to thought that actually there already is a room for FPGA based I/O cards working on ethercat - many people have expressed their willingness to use laptops to control their CNC machines and there are _plenty_ of laptops with RJ-45 port (and most probably also Wifi), but without LPT port. Viesturs ------------------------------------------------------------------------------ The modern datacenter depends on network connectivity to access resources and provide services. The best practices for maximizing a physical server's connectivity to a physical network are well understood - see how these rules translate into the virtual world? http://p.sf.net/sfu/oracle-sfdevnlfb _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
