Peter C. Wallace wrote: > On Mon, 12 Oct 2009, Chris Morley wrote: >> I'm having a little problem with a hostmot2 stepper setup. >> I get following errors that I can't track down a reason for. > > Is it possible you simple dont have enough hardware headroom to reach you max > velocity? With 200 usec StepLen and 200 uSec StepSpace, the maximum step rate > the hardware can generate is = ~2500 Hz, I just glanced at the ini file but > doesn't a Scale of 2800 mean 2800 steps per inch? If so the maximum velocity > should be about 10% less than 2500/2800 (10% for headroom). about .8 inches > per second.
I agree it's a "max physical step rate" vs "trajectory-planner max commanded velocity" problem, but i think there is no headroom problem. Max physical speed is 2500 steps/second / 2800 steps/inch = 0.893 inch/second. But the ini file tells the TP to go at MAX_VELOCITY=1.67 inch/second. So you'd expect it to fall behind and get a following error quickly. But Chris Morley's pastebinned hal file (<http://pastebin.com/m2fa4c0ba>, line 51 & 52) uses the maxvel=0 trick that Chris Radek suggested, so the old headroom hassle is gone. The stepgen does *whatever* the trajectory planner tells it to, within the limits of the timing parameters. This is nice for the human that is configuring the machine: they only have to tweak [AXIS_?]MAX_VELOCITY, they dont have to remember to also tweak MAX_STEPGEN_VELOCITY (or whatever) to be MAX_VELOCITY * 1.10. -- Sebastian Kuzminsky ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
