Thank you John and Andy - We will be running at a max speed of 900 RPM, so will have 150kHz encoder pulses, which will certainly be too much for software encoder counting. I thought about electronic gearing, but didn't see any support for that in the hostmot2 components. I'll start out with the standard elements since double precision is used, but I'll keep in mind the custom vhdl idea, as it is indeed elegant. Not sure I want to take the time for that right now though.
-- Ralph ________________________________________ From: andy pugh [bodge...@gmail.com] Sent: Wednesday, December 13, 2017 7:16 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] synchronized servo motors with phase control On 13 December 2017 at 15:08, John Kasunich <jmkasun...@fastmail.fm> wrote: > One thing to be aware of: If your application runs the motors in the same > direction for long periods of time, absolute position will keep increasing > even though relative position doesn't change. If HAL still uses single > precision (32bit) floats, you eventually might start losing resolution. If > HAL uses double precision it will probably take a very long time before that > happens. But you are still looking at small differences between large (and > constantly increasing) numbers - never a good thing. It uses double. (and the actual position output is calculated from an internal 64-bit buffer of individual counts) -- 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 ------------------------------------------------------------------------------ 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
