On Mon, 14 Dec 2020, Gene Heskett wrote:
Date: Mon, 14 Dec 2020 19:34:36 -0500
From: Gene Heskett <ghesk...@shentel.net>
Reply-To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
To: emc-users@lists.sourceforge.net
Subject: [Emc-users] calibrating the BS-1 battle
Greetings all, math whizes in particularly;
I couldn't keep the halmeters out of floating point for displaying
integer numbers when testing at 75+ turns, and I just spent several
hours running it backwards because there is no reset to zero for the
mesa encoders.
setp hm2_card.0.encoder.nn.reset true
setp hm2_card.0.encoder.nn.reset false
will reset the encoder position
So the last attempt was only for ten trips past the home switch. That
kept the halmeters out of sci notation. Tracking the encoders rawcounts
with two sample-holds, first freezing the rawcount at the first switch
passing, the second freezing the raw count at the 10-11 transition. Then
subtracting the first from he second gave 2400114 rawcounts difference.
Divide that by 10 to get 1 turns worth, then divide that by 360 to get 1
degres worth which is a scale of 666.6983333.
Have I missed anything in my math?
It seems to be working ok, even turns in the right direction now. :)
With around 3 hours at max speed. the psu warmed a bit, the motor warmed
a little more, maybe to 90F, the heat sink on the driver (Look for IBT-2
ON EBAY, its about $7) may have warmed 5F above ambient if that. Within
its voltage limitations of nominally 27 volts, running on 24, no heat
and it makes the motor do almost exactly what you asked. Oh, and claims
it can handle a motor drawing 43 amps.
Now if I could get rid of the bias in stopping points, it always stops
about .0016 degrees lower than requested. From either direction. The
almost in the previous paragraph.
That is plenty close enough for the girls I've gone with. And my first
attempt at making a servo work seems to be a success. It can move around
15 degrees a second which is slower than I'd like, but not by that much.
Thanks all.
Cheers, Gene Heskett
--
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-Ed Howdershelt (Author)
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- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>
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Peter Wallace
Mesa Electronics
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