On 12/5/23 08:17, Leonardo Marsaglia wrote:
Hello guys, and thanks for all the replies!
Well, we swapped the majority of the capacitors on the board and we still
get the alarm on the PSU. I'm almost inclined to consider this a LCNC
project and start doing the conversion.
One thing I'm considering before doing that is if It's possible to use the
original Fanuc Servo motors replacing only the drives. I know the drives
will not be usable because they communicate with their own Fanuc serial
protocol, but maybe there's a chance I can use the same motors.
I'm attaching a picture of the X axis motor so you can see. I guess it
should be possible to control it, but I don't really know how the encoder
works. I know there's a Hostmot encoder module for Fanuc but I don't know
anything about them so swapping the servo motors is another option too. I
have several servo motors here just in case this happened so I can use them.
Thanks again a lot for your help guys! Sorry that I don't reply
individually :)
If it comes down to replacing the fanac motors, Leonardo, there is a new
kid on the block that greatly simplifies the linuxcnc install.
Called closed loop stepper/servo's.
1. PID's in linuxcnc aren't needed, they are self contained in the
drivers. They do exactly as motion tells them to do
2. Very power efficient, they do not run at full current all the time.
The internal PID's in the drivers error controls the current to move the
motor. Motor stays cold if its not working hard.
3. Later drivers from Hanpose are rated for way more voltage, their
drivers cl42 and cl57 are rated for up to 90 volts, and the driver for
the bugger nema 34's is good for over 100 volts. With that sort of
voltage, steppers limited top speeds are not an issue.
4. they have a logic error output so if they can't get there, they'll
shut linuxcnc down in its tracks in the next servo threads time. I have
5 of these motors in service here, 4 for quite a while, a 5th A axis on
my go704 added just recently. with the motors for the XYZ of that go704
on a fedex truck someplace right now.
This has been tested here, works, but has yet to occur while running a
job. The drivers will see the impending error, and hit the motor with
everything the power supply has, and will in not successful, shut
themselves down to protect both them and the motor, but signal linuxcnc.
I've positioned a chuck jaw in front of a chip carrying tool and run
that tool into the chuck jaw at speeds way above cutting speeds, the
carbide chip hits the jaw, the motor is shut down so the freedom bounces
the chip about 10 thou away from the chuck jaw, the chip is not damaged
and the chuck jaw is not marked.
But that has yet to occur while actually doing work. So far, for me,
they Just Work, coolly and quietly. Like Casper the ghost is turning the
cranks on my 11x54 Sheldon lathe.
One warning though, stay away from hall effect encoders like the 42C
sized nema-17's uses, must have optical encoders. The time delay in
converting the hall effect things into a usable feedback signals makes
them move in notches, the optical stuff is as smooth as warm butter. The
42C is ideal for a 3d printer but has been an unmitigated disaster
because the parts look like they are shingled. For something like
steering an rc vehicle they will work, but they will NOT move smoothly
under load. That conversion delay causes a Nyquist error in the feedback
loop. Opticals are instant feedback.
Bigger & higher voltage supplies for these motors have been slow to
appear but 60 volt 6.7 amp 400 watters are now available, in machine
control sizes, on per motor, at sub $40 USD are available and more,
higher voltage stuff is coming. I'm rebuilding two bigger 3d printers
with these motors and supply's, and layer shifts will be history. At 500
to 1500mm second speeds where the usual $300 starter printer is limited
to 50 or 60mm second speeds. We finally have a stepper that just works,
without burning your hand if you touch it. So please consider them if
you have to replace the fanuc's..
Take care & stay well, Leonardo.
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
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