On Thu, 19 Mar 2020, Gene Heskett wrote:
Date: Thu, 19 Mar 2020 05:48:08 -0400
From: Gene Heskett <[email protected]>
Reply-To: "Enhanced Machine Controller (EMC)"
<[email protected]>
To: [email protected]
Subject: Re: [Emc-users] crazy, but Peter, its still a wurlitzer
On Wednesday 18 March 2020 22:56:31 Gene Heskett wrote:
I disconnected the 3 signals from the spindle encoder leaving the
ground and 5 volts in place. To my great surprise, turning a tooth
still crashed it. Getting out my looking glass, I came to the
conclusion I had a boatload of hair sticking out of most of the solder
joints, raising the chances of something actually contacting something
it wasn't supposed to. Clipped it off, crashed the pi while
remounting the encoder.
Humm, since the index is mounted opposite end active, and the 5 volts
to that ATS667 had to go thru a sot I had milled in the wall of its
mounting pocket, the solder joint stuck up enough to contact the bull
gear tooth on its way by, which was shorting the 5 volts for a
fraction of a second as it went by. Looking in various places I noted
that the endoder has a quadrature error output pin but that it has to
be enabled before is has any output.
Peter: can it be setp'd true without screwing up its other functions?
Yes
PS: where can I find a man page describing how to program this stuff as
programmed into a 7i90HD by one of the SPI variants?
I dont think the man page describes the quadrature error bit
Theres also a bug in the quadrature error handling in most firmware
so requires updating the firmware and the driver (the driver was fixed
somewhere in 2.8)
Note the the interface (SPI,EPP,PCI,Ethernet etc) has no bearing on
operations other than things specifically related to the interface
So thats tomorrow, and I am hoping that the sign of the average will
tell Peter which way I need to move the A chip to reduce the error.
I dont actually think the quadrature error will help in this instance.
Its mainly useful to detect things like impulse noise thats common to A/B
Its likely to be a very noisy output as the variability can easily be
seen in the halscope. TBT, this bull gear has been nearly destroyed by
80 years of having tons of overpressure when the backgear is engaged,
and its so common a condition its obvious the guy in charge of
adjusting that during final assembly had never been instructed on how
to do it properly.
Anyone else with a Sheldon should put it in backgear and listen.
If you are hearing or feeling a rumble, lift the lever toward
disengagement and listen for the rumble to go away, and the remaining
noise is much quieter and reminds you of a bell. Loosen the handle and
adjust the eccentric until it sounds like that when fully engaged. The
other dead giveaway is if any of the tooths flat tips are worn smooth.
If that condition exists, the teeth on the smaller of the 2 mating
gears are being pinched and bent at the root of the tooth and will
eventually break off from metal fatigue.
I got lucky and have not busted a tooth yet, but several people on the
Sheldon list have not been so lucky.
Cheers, Gene Heskett
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>
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Peter Wallace
Mesa Electronics
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