On Wed, Apr 24, 2019 at 2:07 AM Gene Heskett <[email protected]> wrote:
> On Wednesday 24 April 2019 03:42:00 andy pugh wrote: > > > On Wed, 24 Apr 2019 at 01:30, Gene Heskett <[email protected]> > wrote: > > > Several, your personal config probably makes a far bigger difference > > > than the actual version number of the kernel since you have to be > > > pretty well up on YOUR hardware to re-configure the kernel you are > > > about to build. > > > And there is the problem. I have never yet managed to get that step > > right and make a version that works on my PC. > > (I tried and failed with the NTULinux repo last night) > > URL? > > > And the problem to be solved here is building a kernel that can ship > > with LinuxCNC and work with _any_ kernel. > > > > Is it, in fact, currently impossible to provide an RTAI LinuxCNC ISO > > with any kernel newer that the one we ship with Wheezy? > > IDK Andy. Has the current rtai kernel been tried on stretch? Nah, its 32 > bit, claims PAE but is not. Stretch is 64 bit. > > > If that is the case then perhaps it is time to abandon RTAI > > altogether? > > Might be, I have only 1 preempt-rt versions running here, not on software > stepping though, both on mesa cards, a 7i90HD+3 ea 7i42TA's running the > Sheldon, and the 5i25/7i76D running the G0704. But I've not changed the > kernel on the 6040, that machine WAS formerly softstepping the old HF > micro so its still running the live iso's kernel. But I've no clue if > software stepping would run on it. If I software step it, it would be > buckets slower, 10 ipm or so rapids, where its doing 200 now. And I'd > have to share all my home switches for lack of i/o. > > I hope at the end of the day, that we don't have to abandon software > stepping as thats the lowest cost entry point. SOftware stepping on PC hardware with Linux is "hard" but software stepping otherwise is cheap and easy. I have right here on my desk a little machine that uses a Raspberry Pi with "stock" Unbuntu 18.04 and it runs two servo DC motors or steppers with nearly perfect accuracy using a $3 "Real time processor". As I type, I'd using Fusion 360 to design an enclosure for the parts and connectors. I'm looking at a 180x120x40 mm box that house the Pi3 and a driver for up to 15 amps per motor and do A/B encoder interrups at about 100KHz. $60 total. Size but not cost will be reduced what I can make a custom PCB My point is that "cost of entry" need not be a PC with a Mesa card. It could be a Pi3 with one (or more) $3 STM32 board. Both the STM and Mesa can do steps and read encoders way-faster than is required. USB work well. It is 10X faster then needed for this purpose. Thge BBB is very atractive because it in effect has the above Pi3 and STM32 eqivalent (the PRUs+) all on one board. The Beagal Bard Blue would be PERFECT as it has low power H-brindges and conecters for A/B encodrs on-board. A small mill or router would not even need motor drivers. high-power cables could plug into the BBB. (BB Blue) But this is a $100 board. Double the cost So the entry cost should be under $100 including the PC and smaller size motor drivers. If a person already owned a small notebook PC the entry level price should be closer to $20. I've been using these parts to drive motors of all kinds and they are "bomb proof" you can't kill them. they have reverse plolarity, short and temperaure protection It is a simple H-bridge with PWM control. https://www.ebay.com/itm/30A-Mini-VNH2SP30 <https://www.ebay.com/itm/30A-Mini-VNH2SP30-Stepper-Motor-Driver-Monster-Moto-Shield-module-For-Arduino/311579385639?epid=1675425525&hash=item488b941f27:g:~D8AAOSwHsRYEv~K> I combine two of the above with one these https://www.ebay.com/itm/STM32F103 <https://www.ebay.com/itm/STM32F103C8T6-Minimum-System-Developmen-Board-Module-Core-Learning-For-Arduino/323747797666?hash=item4b60df5aa2:g:ilcAAOSw9m5cAggN> and have abuot a $10 total for a universal driver/controller and the PID loop and encoder inputs are on the $2 STM32.. The STM32 connects to the Pi3 or notebook PC with USB. I'm slightly frustrated because I'd prefer to see MK run on the above stack but it doesn't so I have DIY solution. and Mk?LinuxCNC is confined to the garage. > But for my uses, today > I'd have to figure on at least a 5i25 as a driver card, and that > unavoidably raises the entry bar for new users by what, 80 bucks? A sad > state of affairs. Your call. > 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) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
