On Thursday 26 November 2020 10:24:18 Thomas J Powderly wrote: > For Gene and others interested in RPi for LCNC > > https://www.youtube.com/watch?v=qL530kJUmII > I suppose ts nice for him, but the video of the machine moving at the end is very disappointing. His interfacing looks to be severely crippling the maschines ability to move, I suspect because the latency is relatively poorer, and cannot issue the steps to move the machine in a timely manner, which going thru a parport synthesis seems to be imposing. Software stepping would appear to be the problem.
My early setup, now about 4 years old, started out on an 1 gig rpi3, using a very short spi cable to a Mesa 7i90HD plus a triplet of 7i42TA's, is now, with the newer stepper servo's, moving my Sheldon lathes carriage at over 150 IPM with the 3NM version on Z, and the smaller 2NM is moving the crossfeed at 75 IPM, mainly it can't move far enough to get any faster. From a 2 gig rpi4. And doing it ghostly quietly. And its loafing despite the fact its doing far more than running a 3 axis mill thru a crippling sainsmart bob. The intelligence available from the Mesa card offloads 90% of the job from the pi. That bob has opto's in its inputs that can't pass a 5 kilohertz signal from and encoder reliably. If one of my D525MW mobo's should die, I'd have no second thoughts ordering up a duplicate of the hardware I'm running the sheldon with. It could do it on either 4 axis mill, far more stably that the wintel boards have been. Uptime on that pi is 57 days right now. It just doesn't crash. Raspian buster updated a library I had to reboot to install and use. I put a small ups on it about a year ago and uptime was about 200 days when I rebooted it. Yes, its been an education getting it that way, but now it Just Works. > TomP > > > > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
