-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 6/1/2013 7:20 PM, Ed Nisley wrote: > On 06/01/2013 12:39 PM, Charles Steinkuehler wrote: >> I particularly like the acceleration control in LinuxCNC. It >> seems smoother than the Arduino code. > > At least on the Marlin firmware branch of the RepRap tree, the > interrupt handler switches from one-step-per-interrupt to > two/interrupt at 10 k step/s, then to four/interrupt at 20 k > step/s, with abrupt step timing changes. These pictures show the > step pulses to the X axis of my M2 during the ramp up to 450 mm/s > at 5000 mm/s^2: > > https://www.dropbox.com/s/llrx2ik6vlq4ne9/X%20Axis%20450%20mm-s%2050%20mm%20-%20100%20us-div%2041.9%20ms%20dly.png > > https://www.dropbox.com/s/z4w4mg6wklnhvpm/X%20Axis%20450%20mm-s%2050%20mm%20-%20200%20us-div%2019%20ms%20dly.png > > The top trace is the motor winding current, the bottom trace is the > Step pulse from the Arduino to the driver chip. The pulse clusters > on the right side show how a single interrupt produces multiple > steps, with the *average* rate remaining constant. However, speeds > over about 112 mm/s (on the M2, anyway) have irregularly spaced > Step pulses.
I've captured some 'scope traces with the PRU doing a pretty good job of generating a 40 KHz step rate (500 mm/s on my MendelMax), and there's still some increase possible (on the PRU side, anyway...this speed is a bit much for my printer currently). Pics: https://plus.google.com/106079792142766516843/posts/QXgP5ghn5Wf Video: http://www.youtube.com/watch?v=ZsjJOSWD2c8 - -- Charles Steinkuehler [email protected] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlGrW/gACgkQLywbqEHdNFzR+wCeINv7s15qfheZSfuTlsAofiJS dBAAoMRQs6aVPCy/U6fWcExmDYgL1pL3 =ceUt -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ Get 100% visibility into Java/.NET code with AppDynamics Lite It's a free troubleshooting tool designed for production Get down to code-level detail for bottlenecks, with <2% overhead. Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap2 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
