On Saturday 06 July 2013 15:53:41 Chris Morley did opine: > > Date: Sat, 6 Jul 2013 13:23:15 -0500 > > From: el...@pico-systems.com > > To: emc-developers@lists.sourceforge.net > > Subject: Re: [Emc-developers] "Open" Development > > > > EBo wrote: > > > Seriously though, we should > > > > > > be able to merge Araisrobo's code and add spindle synchronized. > > > > Well, it is pretty obvious to me that jerk limiting and having the Z > > axis follow the spindle are in conflict. So, I think the jerk > > limiting may need to be turned off when in a spindle-sync move. > > Generally, sane G33.1 operations won't cause excessive jerk, so that > > probably is OK. One also may need to control the rate of spindle > > reversal, which you need to do anyway to allow Z to keep up. > > > > Jon > > I am not an expert, just interested. I don't follow your reasoning. > Jerk limiting is about having the TP ask for movement that is possible > for the machine to actually produce. > infinite jerk is impossible for a machine to produce movement for. > While we can ignore it in relatively slow and small machines, I can not > see why you would want to turn it off in some cases. > It seems if you have the TP request infinite jerk, then you are must > realize that your are asking the machine to NOT follow the TP command > for a small instant. > I don't see how G33.1 is any different then other machine movements. > > Chris M
I know for a fact that in the G76 situation, the actual lock phase of spindle vs z is a function of spindle speed, caused by the finite time to accelerate the z to a speed whereby it can then remain locked. That doesn't start until the index signal has been received And, without verifying it by breaking a tap, or fubaring a hole, I would assume the initial startup in the G33.1 cycle is subjected to that same limitation. The limitation manifests itself in the G76 cycle as a sideways miss-cut of the thread should you 'adjust' the spindle speed in the middle of cutting a thread. There may be other 'canned' cycles similarly limited to constant speed spindles only, but I haven't found them, yet... 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) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> You can observe a lot just by watching. -- Yogi Berra A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
