On Friday 01 February 2013 21:36:06 Gregory Perry did opine: Message additions Copyright Friday 01 February 2013 by Gene Heskett
> >________________________________________ > >From: andy pugh [bodge...@gmail.com] > >Sent: Friday, February 01, 2013 7:17 PM > >To: EMC developers > >Subject: Re: [Emc-developers] Python Library for the BeagleBone PRUSS > > [snip] > > >The point is that LinuxCNC as it currently exists handles hardware > >physical limitations internally. What this means is that the > >millisecond-by-millisecond servo-thread position updates match the > >programmed velocity and (especially) acceleration limits of the > >hardware. Any jitter in the position updates due to the update not > >being on-schedule is likely to lead to a physical F=ma type problem. > > What's a typical hardware configuration for LinuxCNC then? I see a lot > of mention of x86 Atom machines being used. How are you interfacing > LinuxCNC with high powered MOSFETs to drive servos for example, > especially if USB is not an option? > That can be whatever pulls your trigger. Here, and I am by no means middle of the road, I have a pair of single box computers with a D525MW board in it. Running the most recent Ubuntu 10.04.4 LTS cd install, having downloaded the install image from linuxcnc.org. It is driving a CNC4PC interface board, a C1G, one of many that Arturo Duncan sells, a versatile but no brains parport breakout. Two computers. two of those boards, one each for the steroids built micro-mill and the mini-lathe. The mills motor power box has that C1G interface card, which in turn is driving 4 each of the 2M542 motor drivers, about $50 USD per motor on fleabay, running X,Y,Z and A/B/C axises depending on how I have a motorized rotary table mounted. It also does make a PWM output that can drive the spindle in either direction via a PMDX-106 interface which controls the OEM variable speed spindle from the computer. No encoder on that spindle so its doing it rather blindly, no 'rigid' threading capability. There are 3 each 262oz nema 23 motors on X,Z and A/B/C, with a 425oz motor on the home made Z drive. The lathe has a power box with 2 or those same drivers in it, running on a home made power supply of about 39 volts where the mill is running on 28 volts. Its spindle is encoded so threading is all done in software, no gears except a 2/1 on the Z screw are under the change gears cover now. A 2nd 425 oz motor hangs off the rear of the carriage and runs the ball screw in the cross feed drive. The interface there is the 2nd C1G. Others will have their own ways to 'skin that cat' of course. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> Griffin's Thought: When you starve with a tiger, the tiger starves last. I was taught to respect my elders, but its getting harder and harder to find any... ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_jan _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
