This sounds like an impressive setup. I'm not familiar with the KL-8082H particularly, so it's hard to say if having the drivers handle the feedback would be better than piping it through linuxcnc. My assumption is that if the drivers already handle it, you'd get the benefit of their controller / tuning, potentially saving some effort.
In terms of controlling motion proportional to spindle load, you may actually be able to do that already if you have a spindle encoder. If your spindle motor's speed varies in proportion to the load applied, then you could used spindle-synchronized motion to reduce the feed rate if the motor speed drops. I imagine a grinding wheel of a decent size would have enough inertia that you could use a relatively low-resolution encoder, or even an index pulse. On Sun, Jan 5, 2014 at 10:54 PM, Andy <a...@evanspt.com> wrote: > Robert, thank you for your response and the time you've put into this. > I've been thinking about this and wonder what the ultimate solution for > my situation could be. It likely will involve variable feed rates, > however I've been wondering how I could tie the feed rate to the motor > load. I'll try to get my head around this as I move forward on my project. > > I don't remember what I shared before about my application and history. > In early 2010 I did some experimenting with EMC2 and a single axis > linear actuator for creep-feed grinding, and rapidly gained the > confidence to put together a 4 axis machine, basically configured as a > mill with a rotary indexer. I was doing all this on my own nickel to > develop a process for making a family of parts for a customer. This was > put together using Gecko drives and steppers with then current version > of Ubuntu and EMC2. The machine came together beautifully with the > mechanical aspects (ball screw installations, motor hardware, limit > switches, etc.) and with the configuration of EMC2. I had hired a > friend who was electrically and computer savvy to help me and we had a > great time overcoming every obstacle in our path. And the results still > work great! > > The customer's orders for the product have fluctuated in the years > since, and we have been able to use this machine to good effect, except > that last fall they finally gained some market traction and the > production needs took a jump (Yay!). Back when I finished the first > machine, I had an opportunity to pick up another donor machine for what > I envisioned as rev 2 for this project. It is a Harig Slicer with a > larger enclosure, higher HP spindle, already outfitted with motor mounts > and a ball screw on one axis. I have worked on this slowly in the > interim, primarily replacing the hydraulic longitudinal axis drive with > ball screw. With the uptick in orders, I have accellerated my attention > on this project, trying to apply our learnings from Grinder #1. G1 had > been placed in a subcontractor's shop these past couple years and I have > recently brought it back to my place (the subs could no longer keep up > on their part time basis) and I'm able to keep it running two shifts per > day. > > So now I am working to get the Harig (G2) into production, although it > has taken a back seat to my attention on reinstalling G1 and resuming > production. G2 has the latest software releases and I have gotten as > far as powering the drives and motors but have not done any final > calibrations. I may have a limit switch or two to hook up. I've also > got an MPG to work. > > Driver settings. I've got some numbers that allow it to move, but I > read right here that I should be sure of these numbers! ;-) > > I couldn't find the KL-8082H on: > http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Stepper_Drive_Timing > > So I will be happy to share what I learn. There is some information on > this document: > > http://www.automationtechnologiesinc.com/wp-content/uploads/downloads/2012/06/KL-8082H.pdf > > > But in my ignorance I lack confidence in my interpretations. Maybe some > of you know something about these drivers? (Shouldn't have bought them, > maybe?) They are closed-loop steppers, and I bought them from > Automation Technology Inc but the guy basically pleads ignorance with > LinuxCNC and says most of his stuff is going to the Mach/Windows > users. I wished I'd fleshed this out on this list before I bought 'em... > > These drivers are supposed handle the encoder feedback and do any > necessary travel corrections. As I understand, LinuxCNC has the > capability to use the encoders, so maybe I would be better off with > Geckos and wiring the encoders back to EMC2? > > Thanks, > Andy E > > > > > > > > > ------------------------------------------------------------------------------ > Rapidly troubleshoot problems before they affect your business. Most IT > organizations don't have a clear picture of how application performance > affects their revenue. With AppDynamics, you get 100% visibility into your > Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics > Pro! > http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. 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