On Thursday 12 June 2014 19:20:24 rayj did opine And Gene did reply: > I wondered if that might be a problem. I'm thinking I could use a > manual pulse generator to square it up at startup and have a set of > home switches that could be touched off on as necessary to assure that > the system is still square. If it isn't then the operation would be > stopped and it could be manually squared again. > With a box in the data line so you could do that manually, it ought to be doable.
> It is my understanding that the usual cause of missed steps is heavy > loading of the motor. Assuming this is minimized, I think this might > be a viable system. Two ways to lose it actually. Accelerations that exceed what it can do are one, and heavy loading would be the other, both coming into more obvious play when the motor voltages are less than 30 volts. Even 30 volts rules out using the single chip drivers as that is about the point where they let out all the smoke & don't work any more. > Keep in mind that this a hobby setup, so other things besides pure > economics drive the decisions. Here, I have just 2 machines, an old HF micromill with the LMS bigger table kit, 4 axis's, running on a medical grade (for whatever thats worth) 28 volt 12.5 amp supply. And a 7x12 lathe running on a home made supply making about 38 volts and 5 or so amps. Both are using the 2M542 driver, up to 4.2 amps & 50 volts. The difference in PSU voltage translates to the lathe being able to move at 3 or 4 times the mills speed, with the mill getting stally when I ask it for 15 ipm. The lathe with the additional 10 volts can move the X at a little better than 60 ipm. That 2M542 driver seems to be bulletproof, when I threw out the A-3977 based single chip drivers because yet another had blown, I bought a spare, and 2+ years later it is still in its packing box in a drawer of the tool chest. Careful shopping on ebay can probably buy them at about 50 bucks a driver. Highly recommended by great-grandpa Gene, I don't think you'll need to replace them, at least in this decade, handily outlasting me. Yeah, I am that old, I'll be 80 in October. :) > Raymond Julian > Kettle River, MN Oh, and let me welcome you to one of the best kept secrets in CNC. LinuxCNC. 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> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ HPCC Systems Open Source Big Data Platform from LexisNexis Risk Solutions Find What Matters Most in Your Big Data with HPCC Systems Open Source. Fast. Scalable. Simple. Ideal for Dirty Data. Leverages Graph Analysis for Fast Processing & Easy Data Exploration http://p.sf.net/sfu/hpccsystems _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
