> > > > I get the general idea. But I am still a little shy on the details. > > > > It sounds on a LPT port setup the host sends every individual step to the > > port. > > Now if the motor has an encoder LinuxCNC could read the position every > 1ms > > and make it a host based closed loop system. And I get the appeal. > > But people are also using LinuxCNC with a BOB and Open Loop Steppers > > without an encoder. > > So it sounds like the feedback is missing there. > > Its still there but internal to the stepgen component >
But without an encoder this can only be the meant-to-be position - not the real position. > You said they are velocity commands. So it should be something along the > > lines of: > > > > "x+1000 steps in 1500ms" > > "y-100 steps in 500ms" > > > > Simpler that that, linuxCNC simply sends the step rate > (scaled for the hardware) > I guess with the feedback loop that is indeed enough. I would love to just have a look. Is this the right place to dig in? https://github.com/LinuxCNC/linuxcnc/tree/2e75b091a23e3312b9e57a88941714701f3709b8/src/hal/drivers/mesa-hostmot2 > > > On top of that the Mesa card will report back the position of the motors > > (steps from 0?) every 1ms to the host. > > > Not steps from 0 but rather relative position as a signed 32 bit number > 16.16 (whole steps.fractional steps) > > (LinuxCNCs position is a FP double) > Relative position since when? The last motion command? Thanks for bearing with all my questions :) cheers, Torsten _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
