> From: Bari [mailto:[email protected]] > 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 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
