Hi all! ----- Original message ----- > On Fri, 28 Feb 2014 10:47:45 -0500, you wrote: > > > The original Smooth Stepper also suffered from USB issues which seemed > > to be related to grounding or isolation issues?? > > It had a design problem on the board with a built in ground loop. It > caused the USB to loose the link frequently for some. Twas totally > unusable for several well known and experienced Mach users, myself > included. I was one of the original beta testers, I could never get it > stay on line for more than a few minutes. It went in the trash when > support dried up for several months and there was no signs of a > redesigned board appearing. > > > > > The later designed, Ethernet Smooth Stepper device does not seem to > > exhibit similar issues. > > So I'm told.
I can confirm that Ethernet is fine for interfacing hardware that is supposed to work reliably. We have a machine with LinuxCNC interfacing an MCU/FPGA board over Ethernet. The PC has a dedicated NIC for this purpose, as the link is driven by RTnet in realtime. There is UDP pingpong traffic every 2ms and since I fixed an issue with ARP requests, it runs very smoothly. Oh yes, the position control loops reside in the MCU and run at 5kHz, so the 500Hz update rate from LinuxCNC is enough. I suppose that higher update rates should be possible with this link, but not with the PC in question. This one shows latency jitter in the range of 500us, with or without RTnet... When I've learned something about hardware interfaces and reliability in the past two or three years then it is to stay as far away from USB as possible whenever something else than a classical HID (Mouse, keyboard, flash drive, etc.) should be connected to a computer. Bye, Philipp > > Steve Blackmore > -- > > ------------------------------------------------------------------------------ > Flow-based real-time traffic analytics software. Cisco certified tool. > Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer > Customize your own dashboards, set traffic alerts and generate reports. > Network behavioral analysis & security monitoring. All-in-one tool. > http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Flow-based real-time traffic analytics software. Cisco certified tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer Customize your own dashboards, set traffic alerts and generate reports. Network behavioral analysis & security monitoring. All-in-one tool. http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
