another thought. can you take out the pid loop completely? that way the pwmgen just gets the Zpos-cmd and thats the end of it, no following to worry about. or do i need to do a bit more reading?
It just hit me how that would work, Z doesnt have to be constantly moving, it's more like moving a sliding pot up or down setting the power. On Mon, Dec 15, 2008 at 8:04 PM, Eric H. Johnson <ejohn...@camalytics.com>wrote: > Jim, > > I have done that too, but the problem with using the spindle is that the > system stutters when the spindle speed changes. Using Z allows smoothly > changing laser power on the fly. I make Z values very small, then use large > multipliers on the PWM scale so that laser power can change quickly without > getting slowed down much by the kinematics. I have also been playing with > using an angular axis instead of a linear axis for the laser. > > There was some discussion a year or so ago about high speed I/O, which I > would still like to do for laser writing and 3D engraving. That would > require updating a PWM output as fast as every 200 microseconds (5Khz) or > gating an output perhaps as fast as 50 microseconds. > > Regards, > Eric > > I'm not sure if theres a reason you used Z to power the laser, but have you > considered wiring the laser to a spindle speed output? then you wouldnt > have to be programming moves in Z in order to power the laser (at least > thats how it seems it works to me?) then you just connect the spindle speed > as read from the program to a scale if necessary then to the pwmgen. then > instead of moving Z you could use m03 s#### to set power, 0 to 100 would be > simple for a percent power setting, or if you scale it to the laser's mw, > you could program by that. > > just some ideas, sorry i hav nothing to contribute about what you really > asked about > > > > > ------------------------------------------------------------------------------ > SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. > The future of the web can't happen without you. Join us at MIX09 to help > pave the way to the Next Web now. Learn more and register at > > http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
