On 7/1/22 06:36, Leonardo Marsaglia wrote:
You will find it noticeably slower than the intel stuff we are getting
used to.
1. It will have latencytest figures in the 12 u-second are when it not
doing
anything else. More than good enough to run LinuxCNC.
2. Use until I say different, raspios buster. The python in raspios
bullseye is too new for LinuxCNC.
3. most other activity except for running Firefox won't bother the
machine its running.
Firefox is an IRQ pig, and the machine WILL stutter.
4. if like me, you've a whole passel of hand controls of it, I have a
pair of mpja.com's
$22 100 ppi dial encoder's on the apron, straddling the x motor drive,
one running X jog,
one runs Z jog and back when I was running it with the slower pi3, I
setup a second,
200 Hz "jog thread" and put all the hand stuff in it, in execution order
of course. Based
on the theory that the human hand can't move any faster than that. It
still acts and
feels like realtime to me, but it freed up the servo-thread to get the
real work done on
the pi3b. And I never tried to make it back to a more normal
servo-thread when I
installed a pi4 and booted it from the same armhf based card. If that
interested, I'll
put some more stuff up on my web page. I need to write up a README on
how to install
the kernel I've been using yet, but the tarball can be had from my site
as of a few days ago.
The install is simple but the foundation frowns on unofficial kernels so
I had to invent my
own install procedure using a card reader
5. uptimes are from power outage to power outage, I can't remember the
last time I
actually had to reboot it. I've a small USP on it, and a 20kw standby in
the back yard.
Hi Gene, I hope you're doing well!
Since all the machines I use for LCNC only run LCNC I think the RPi4 should
work well for me. The only thing that's always pushing me back is the
price. I can purchase mother + micro + RAM and go with an intel PC and I
even have money left for the SSD with what they ask for a RPi4. But I
really dig into the idea of having something as compact as the PI for all
the logic.
Take care :)
I forgot to mention the vanishing power requirements. The pi4b, and its
interfacing + monitor total to about 21 watts, so it runs 24/7 here.
Lathe power is enabled by the F2 button via SSR's, so the rest of the
system is dead and cold when its off. I've done that with all 4 of my
machines.
As for well, at 87 that's relative, now it takes me all day to do what
I did before breakfast 50 years ago. But I'm still having fun impressing
the frogs. I've got my web page working again, address in the sig so
you can see what I've been up to the last couple of months.
If you've time to look.
Take care and stay well.
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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