Mark Cason wrote: > On 10/27/2009 03:27 PM, Chris Radek wrote: > >> For lathe threading you don't need to know it. For tapping you >> do. >> >> > That part I understand, but, if a spindle is under computer control, > then the computer should already know which direction the spindle is > turning, right? > No. You can't expect the spindle to reverse at the exact instant it is commanded to do so. If the spindle was running forward, and you command it to reverse, it continues to move forward for a while, decelerates and finally starts moving backward. A quadrature encoder detects exactly when that happened. With a sigle pulse/rev or a single track encoder, you have no idea exactly when the reversal ocurred.
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
