On Saturday 15 August 2020 13:13:36 John Dammeyer wrote: > > From: Bari [mailto:bari00...@gmail.com] > > Honestly asking, why spend the time? > > It's a good question. > > > Did a PC abuse people in any way during the 00's or maybe the 90's? > > The PC is complicated and people are obliged to use an OS they really > have no control over. (Unless they want to learn the complete Linux > OS ins and outs). > > > The Orange Pi is generating steps� >400Khz and runs LCNC for cheap > > and is not a PC. > > Same issue. Still Linux and still a complex OS along with video > cards+USB+hard drive support that appear to screw up latency with > parallel port outputs. > > > I'm looking for pathology to support a theory for anti-x86 PC > > machine control sentiment. > > I don't think it's anti-PC as much as PC + external motion control > card. Where in the past with low end VGA cards one could get high > speed low latency it's now PCs w/o parallel ports and built in video > that makes a PC a bit of a crap shoot. > > > What am I missing here? Is this anything more than PC bad and > > micro-controller good? > > Enter the 'micro-controller' which is much faster with more memory > than many of the PCs from 20 years ago and a simpler RTOS and it > appears like the perfect solution. > > However, we're back into project definition and user interface issues > at this point. > > The BeagleBone running MachineKit and its two additional PRUs already > is an inexpensive 32 bit solution. And it has video although rendered > rather slowly. But we're back into still running Linux under the > covers and the video is the limitation. > > So I agree with Bari, before promoting the low level solution as this > processor or that processor is great and now let's make a CNC system > how about defining what exactly is wanted. Not just to get rid of the > PC. > > Perhaps the proponents of such a system might create a list starting > with the user interface which will include display and user input > mechanism along with I/O requirements. Specify that first. > > Then start looking at what sort of open source hardware is out there > that will fit the specifications. > > The other direction appears to be: "Wow! I really like the STM32 or > OrangePi or XXXX! I want to replace LinuxCNC with that because I know > it can do 300kHz stepping and it works on a 3D printer." > > So what are the specifications of this 'replacement'? > Screen size and resolution and graphical abilities? > Networking capabilities including Ethernet _and_ Controller Area > Network? User interface including touchscreen, keyboard, keypad, > mouse, trackball, MPG (and how many)? Closed Loop motor control or > open loop motor control? > If closed loop is there an encoder from each motor in and PWM out? > Step/dir or Smart Serial? > How many axis? > Ancillary devices like Tool Changers? Pick and place for automatic > placement of raw stock and removal of finished stock for dark room > operation? > > I believe until a clear definition is posted of exactly what the > hardware must control, choosing a processor or processor module is > pointless. And when I say clear definition I mean a document that > could be given to a developer in a locked room; it has to be complete. > > John Dammeyer
Thats a pretty tall order, John, and we both know it. Looking at the various *-pi's, some of which are actually driving machines quite well, some may not think these are a pc, but despite their credit card size, they ARE a pc. I don't know exactly what Bari is doing with his *.pi, but if you take inventory of everything I am doing with this rpi4, I think most will be impressed. I'd go so far as to say amazed. Cutting air making 50 copies of the chess pawn with that rpi4, I went online with firefox, fully expecting to see it screwing with my exercise, but in an hours worth of browsing the network news sites, I did not detect a single instance of the lathe stalling. So the next thing is to establish just exactly what is wrong with linuxcnc running on some flavor of processor which is running linux that may have been compiled using the linux tools of that processor family. So lets see if a waterproof argument can be made. > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users 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-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
