On Sun, Feb 3, 2013, at 03:59 PM, EBo wrote:
> > possibly, but a more principled hack would be to interface it at the > point where it calls the low lever Catmull-Rom spline, and just evaluate > it in reverse. I do not know how difficult that would be, but it would > require the ability to move in the negitive direction. I have written > things like this for moving along splines with custom code, but I would > have to look into how to do this in EMC-s low level motion planning. > Probably the easiest thing to do would be to set up a "reverse-motion" > pin in HAL, and then evaluate it internally, or modify the adaptive move > command to allow positive/negitive feedback voltage which would imply > forward/reverse of motion. Anyway that is my thought off the cuff. > Where things get ugly is when you try to do this in a general way. For example, what happens if you ask for negative feed while in a spindle synchronized move (single-point threading or rigid tapping)? Actually, that issue must have already been dealt with - adaptive feed would cause the problems in that case even for positive scale factors. But that was just an example. What about probing moves? What about the blend between successive non-co-linear straight lines? What about a profile that consists of many 0.002" long lines? Can you back up more than 0.002"? Sure, you can say "an EDM will never make a spindle synchronized move", but changes to the motion module need to do sane things regardless of what kind of a machine is being controlled. -- John Kasunich jmkasun...@fastmail.fm ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_jan _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
