On 15 October 2017 at 18:58, John Dammeyer <jo...@autoartisans.com> wrote:
> Anyway, back to the Beagle and the QEP. A 1000 line encoder on the spindle > and 1000 line encoder on the lead screw motor results in 4000 PPR for each. > To turn a 1:1 thread they both have to be turning the same rate. Say you > are doing high speed threading of leadscrew pitch (8TPI) at 2400 RPM. > That's 40 RPS or 25mS per turn. If the Beagle PRU cycle time is 10uS then > it's there to read the QEP counter 2500 times per revolution. (25mS/10uS = > 0.144 degrees of spindle rotation) . It's worth bearing in mind that you typically wouldn't thread 8tpi at 2400rpm. Even if your counter can't manage maximum spindle speed you may still be able to use the lathe perfectly happily. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1916 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
