On 11/3/22 08:30, andy pugh wrote:
On Thu, 3 Nov 2022 at 09:23, andrew beck <andrewbeck0...@gmail.com> wrote:
looking for a way to set the index pulse high on the mesa card input before
triggering a m19 for tool change as a safety check
The mesa index is a physical pin, so you would need to route out via a GPIO
But I don't understand your analysis of the problem, or the proposed fix.
If you just want to zero the encoder at a random point (which is what
toggling the index at a random point would do, if it did anything) then you
can do that via HAL.
Is it possible that the problem is that the spindle is simply not "homed"
sometimes? ie it has not yet passed through index with the index-enable
set, so the encoder counts are not aligned to the index mark?
In that case your tool change could run an explicit homing cycle prior to
toolchange.
M64 P04 ; set index-enable
G4 P0.1
M65 P04 ; toggle the tristate back
M3 S100 ; spin the spindle briefly
G4 P1 ; wait for at least one full rev
M19 P0 ; carry on.
As the index-enable is a bidirectional pin a bit of HAL is needed, using
the tristate-bit component.
That should be set up with the in-pin permanently high and the enable
connected to motion.digital-out-NN (NN = 04 in the example above)
An interesting thread Andy.
I've considered doing something to aid in tool changing on my go704
which has an R8 spindle.
But the spindle locking consists of a home made clamp ring carrying a
spring loaded pin I clamp
to the outside of the spindle housings bearing barrel when I want to do
a lot of it. It engages a
6mm hole in the spindle nose to immobilize the spindle while cranking on
the drawbolt.
It also carries the camera I'd like to use for edge finding, but the fix
that made the camera
work a couple months back, apparently never made it into master, so the
camview tab is once again a
blank white screen. Insert frustrated Sigh here.
Is there an unwritten rule that says it's never going to work in linuxcnc?
Not mounted ATM because it can get in the way.
And, using an an 8 point 10mm socket in an impact screw driver, the
impact is good enough to get an
R8 tight just by grabbing the spindle by hand. If I could find a pin
driver small enough to push the
locking pin in, and use something like the above to engage the pin, then
cause the spindle to move
until the pin drops in then turn it backwards to assure full penetration
of the pin, then I'd be tempted
make a motorized suspension to disengage the socket when the tool has
been changed, or to drop
the socket onto the drawbolt to be used in a semi-auto mode.
Sawing the handle off the tool, and rigging a pair of dc to dc SSR's in
place of the tools
trigger and direction switches, would allow me to actually change a tool
with only 2 hands.
Normally it needs at least 3...
And by activating the spindle with a zero speed, would hold it
stationary enough for the
ratchet screwdriver to do the job. I do not do that now as a stopped
spindle is free.
Sawing up the tool itself is a minor problem. Picking a tool to saw up
presents a long term
problem because the batteries fail and replacement batteries can't be
found 5 years later.
Either that, or add yet another psu big enough to sub for the battery.
A 20 volt tool head should run on a 24 volt supply scavenged from a 3d
printer, so those
are cheap enough. So are motors, belts, and linear bearings from failed
3d printers, which
I have a house full of. So driving the tools vertical transport is only
a problem if I can't print it.
The Z drive from a dead printer could supply all of that. And that stuff
I have underfoot.
Progress reports as it happens. ATM I'm rebuilding bigger 3d printers,
waiting on parts.
And fix my camview, again. Please...
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, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>
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