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'm getting ready to disconnect the stock RAMBo board and hitch up LinuxCNC through a Mesa card and some stepper driver bricks to the M2; I think it'll be happier with regular Step pulses! -- Ed softsolder.com ------------------------------------------------------------------------------ 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
