Andy Pugh wrote: > 2009/10/22 Michael Haberler <[email protected]>: > >> yes - I ran into the problem when switching to hm2 which doesnt >> currently provide position-interpolated >> >> > > Which is an interesting point. It seems that a hardware quadrature > counter is likely to be counterproductive if you have a low-count > encoder. > I'm not sure it is COUNTER-productive, but if the spindle encoder resolution times the maximum spindle speed doesn't exceed the ability of the software encoder counter, than it doesn't GAIN anything. > With a software encoder you need to hit the balance between having > enough pulses per servo thread to always get a position update, but > not have more than one encoder edge per base-thread. Quite a balancing > act with a typical 20:1 base to servo thread ratio, and not one that > can work at any but a small range of speeds. > > Is there any reason not to use position-interpolated by default? There might be. I don't know how position-interpolated works, but I assume it might introduce a delay in the position reports. This is of no consequence if your spindle speed stays relatively unchanged throughout your threading operations, and you don't reverse the spindle. I could think of some sort of threading operation where you made a finish pass at a different spindle speed, and of course there is rigid tapping, where you need to keep the thread synchronized when the spindle is reversed. So, any significant delay could be a real problem there.
Those are the only places I know of where interpolation could cause a problem. Jon ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
