On Tue, 24 Oct 2017, John Kasunich wrote:
Date: Tue, 24 Oct 2017 08:47:02 -0400
From: John Kasunich <jmkasun...@fastmail.fm>
Reply-To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
To: emc-users@lists.sourceforge.net
Subject: Re: [Emc-users] One final Q re using a dc spindle motor
On Tue, Oct 24, 2017, at 08:14 AM, andy pugh wrote:
On 24 October 2017 at 12:10, Gene Heskett <ghesk...@shentel.net> wrote:
Correct, except encoder.nn.velocity is fed thru a last 4 edges averager
to remove some of the noise in the encoders output. That unforch also
affects the spindle to Z phaseing in the G33.1 backout.
You might want to filter the velociity, but I see no point in
filtering the position, which is what G33.1 uses
You could also try using the DPLL timer to take jitter out of your
encoder sampling. That's a pretty simple setting with the right
firmware (one that ends in "D" for DPLL)
I'm pretty sure Gene's "4 edge average" is dealing with mechanical
errors in his homebrew spindle encoder rather then sampling jitter.
The 4 edges mean that it averages over a full quadrature cycle and
thus deviations from proper 90 degree quadrature phasing are
masked.
John Kasunich
jmkasun...@fastmail.fm
I have considered capturing a timestamp per quadrature state change (4
timestamp registers) then the drivers velocity estimation code could have the
option of chosing time deltas from the same quadrature edge as the previous
servo thread reading, but usually find I have other things to do...
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Mesa Electronics
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