On Sunday 05 July 2009, Jeffrey Pease wrote: >I am working on tuning my homebuilt HobbyCNC machine with EMC 2.3. I >am using the HobbyCNC EZ driver board to interface with my PC. I have >things working, but am working on tweaking the ini settings to get as >high of feedrate as I can reliably. > >One mysterious issue I've seen that I'm trying to figure out is that >very, very rarely, a movement command to the milling machine will make >an axis move the correct distance in the INCORRECT direction. This can >happen either when running a gcode program or manually jogging the >axis in a direction. If it occurs during a jog, usually all I have to >do to fix it is stop jogging and then start again. > >The computer interfaces with the driver board using the normal STEP, >DIRECTION signals for each axis over the parallel port. > >The question is, where do you think this issue is being introduced? It >seems unlikely that EMC2 could be getting the direction wrong in >isolated cases, but, to me, it seems equally unlikely that the driver >board is driving a particular direction incorrectly in isolated cases. >This might also be a symptom of operating at too high of a feedrate >(in the current case I have been trying to make 40 inches per second >work), but I'm hoping to hear from someone who has seen and fixed this >issue before I try dropping the feedrate. Like I say, this issue crops >maybe .05% of the time - very rare, but enough to affect the overall >reliability of my machine. > >Any ideas? > I'd just toss this out cuz its the best idea I can come up with, but it seems to me that you are either violating the direction valid time that board needs, or the signals are interchanged somehow.
Doesn't stepconfig have some setting ability regarding the timings? I haven't run it recently myself. Make sure the direction is changed enough in advance of issuing the step pulses. And double check your pins vs signals. > >---------------------------------------------------------------------------- >-- _______________________________________________ >Emc-users mailing list >Emc-users@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) The NRA is offering FREE Associate memberships to anyone who wants them. <https://www.nrahq.org/nrabonus/accept-membership.asp> Sales staff sold a product we don't offer. ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
