On Thursday 06 August 2015 10:23:30 andy pugh wrote: > On 6 August 2015 at 15:12, Gene Heskett <[email protected]> wrote: > > Control is very stiff, but still not rpm > > accurate, asking for 2100 revs gets about 2650. > > There is a closed-loop spindle speed + orientation sample HAL file > here: > http://git.linuxcnc.org/gitweb?p=linuxcnc.git;a=blob;f=configs/sim/axi >s/vismach/VMC_toolchange/spindle.hal;h=867a593045fc6a20a227b08173f632ec >583db328;hb=3a6ab378e8c5d6759914e08f61cd28e6bd526e3d
Interesting. I am assuming the positioning loop is intended to hold the spindle in a fixed position, such as in broaching a keyway, or fixing to a keyed r8 collet for tool changing? If I had a tool changer it would be useful, but so far mine is the usual 2 armed changer. With my present 67 slot wheel, accuracy would be 360/268=1.34328358209 degrees. Marked for future reference, thanks. All this would be moot to me, if the mesa 5i25 encoder had an edge detected output. That is not to say that a hardware edge detector could not be constucted and used for this, but how would one go about the latching and resetting in order to synchronize it to the read/write cycles of the servo-thread? I have a breakout for port P2 on this card, so its not impossible. I am out of pins on the cards own rear connector, P3 as of hooking up a probe for contact detection yesterday. Unforch, almost anything else except this BOB, on fleabay, is surplus from the Mach3 people, and not readily usable to us due to the Mach compatible cards having pins we use dedicated to something else and basically designed for Mach use only. You even have to use a gender changer on the cable since we're used to male-male cabling. I have one of those. It would be a PITA to try & use it fully. So there is the $100 and up stuff from cnc4pc, or this cheap, slower than warm molasses opto equipt version. However, my hot air rework made short work of excising an opto in the pwm output path and jumpering it straight to the line driving it. And it now works very well even at a 60 kilohertz pwm speed frequency. To Peter C. Wallace: All this brings up a need for an edge detected output pin from the encoders, one that is read by the read, and cleared by that same read after being recorded into a .hal variable. Could that be added to a future version of the firmware? That would simplify the hal code needed to do this job. 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
