#linuxcnc Logs
Sep 27 2022
#linuxcnc Calendar
12:42 AM CaptHindsight[m]: boozeman: still steaming hot?
12:51 AM CaptHindsight[m]: Bookworm where?
12:55 AM randy: morning
12:56 AM boozeman[m]: https://www.debian.org/devel/debian-installer/
01:43 AM CaptHindsight[m]: boozeman: thanks I was just wondering where and if the new LCNC debs were before or after certain fixes that occurred last week
01:43 AM CaptHindsight[m]: it's all sorted out
04:23 AM Tom_L: morning
04:58 AM JT-Cave: morning
04:58 AM JT-Cave: 47°F
05:23 AM -!- #linuxcnc mode set to +v by ChanServ
05:28 AM Deejay: moin
06:15 AM Alicrow-phone: I'm using halscope, set to trigger on the commanded velocity, and checking where the position feedback changes.
06:18 AM Alicrow-phone: The rotary encoders are optical. I'm not sure about the linear encoders.
07:37 AM JT-Cave: Tom_L, http://paste.debian.net/1255168/
07:38 AM JT-Cave: almost got it...
07:41 AM JT-Cave: http://paste.debian.net/1255169/
07:41 AM JT-Cave: now I think I've solved the puzzle...
09:36 AM boozeman[m]: I am installing Debian 11 to HP Elite 8300 now. We'll see if it's better or worse than the Lenovo M910Q
09:48 AM solarwind: There was a type of oil that should not be used for bronze/brass, I forgot which
09:48 AM solarwind: was it any containing phosphorus?
09:57 AM roycroft: sulphur
09:57 AM solarwind: roycroft ah ok thanks. So that means definitely no gear oil in brass bushings right?
09:58 AM roycroft: there are gear oils made for brass, but most do contain sulphur
10:06 AM solarwind: Thanks. What's the best way to measure the inside diameter of small bores? For example, I want to measure the inside diameter of a 1/2" bushing
10:06 AM solarwind: My telescoping bore gauge set doesn't go quite that small
10:16 AM roycroft: https://www.amazon.ca/dp/B0006J4QK0
10:16 AM solarwind: Oh wow that is incredible, I love it!
10:17 AM cpresser: solarwind: or something like this: https://www.messmittelonline.de/3-Punkt-Innenmikrometer--0-001-8-10mm.html
10:17 AM roycroft: https://www.amazon.ca/dp/B01ADK0STO
10:20 AM roguish[m]: JT-Cave: hey, did we get paid today????? SS
10:29 AM JT-Cave: only on wednesday
10:42 AM Alicrow-phone: I think the delay I'm seeing is likely a mixture of the motor taking a few milliseconds to spin up, and mechanical slop in the worn-out belt and possibly the ballscrew as well.
11:01 AM boozeman[m]: HP Elite 8300 1 hour test and 95.200 us. Not good at all
11:21 AM fogl: hello
11:23 AM fogl: i am reading linuxcnc installation instructions and it seems preempt-rt is preferred kernel option. It says rtai is experimental only and causes problems.
11:24 AM fogl: Is this true? I am achieving quite low latency figures on preempt-rt (40000 ns latency)
11:26 AM jpa-: https://forum.linuxcnc.org/38-general-linuxcnc-questions/40827-preempt-rt-vs-rtai-etc-explained
11:33 AM fogl: Is there no .iso for RTAI kernel? Can i also install RTAI on top of Ubuntu instead of Debian?
11:40 AM CaptHindsight[m]: fogl: no current RTAI ISO, LCNC has to be built against the RTAI kernel, they come as a matched set
11:43 AM CaptHindsight[m]: fogl: what hardware is this on (cpu, chipset, etc)? Have you turned off all power management in the BIOS as well as virtualization, speed stepping etc etc?
11:44 AM CaptHindsight[m]: are you planning on using Mesa cards or an LPT card?
11:48 AM fogl: both
11:53 AM fogl: i have a custom ethernet card and an lpt port for pendant connection
11:55 AM CaptHindsight[m]: which kernels are compatible with your "custom ethernet card" ?
11:56 AM CaptHindsight[m]: and "both" what? I am a terrible mind reader.
11:56 AM fogl: lpt port card and mesa like custom ethernet board
11:57 AM fogl: i am using standard ethernet card on pc side, but cistom ethernet card with analog out on cnc side
11:58 AM CaptHindsight[m]: looks like you'll have to experiment with your custom card and find out
11:58 AM fogl: i am runnung debian with preempt rt
12:00 PM CaptHindsight[m]: is 40000 ns latency ok for your custom card?
12:01 PM CaptHindsight[m]: how is anyone to know what will work with your black box?
12:02 PM jpa-: if you are using ethernet card, you pretty much need preempt-rt
12:02 PM jpa-: AFAIK the RTAI realtime stuff cannot do ethernet communication
12:02 PM CaptHindsight[m]: jpa-: based on Mesa?
12:02 PM CaptHindsight[m]: RTAI does ethernet
12:03 PM jpa-: hmm, ok
12:03 PM CaptHindsight[m]: he has a secret black box and is asking us what will work
12:05 PM CaptHindsight[m]: jpa-: Mesa's Ethernet card drivers are for preempt_rt only but with RTAI now being able to be used in user space it's unknown
12:06 PM CaptHindsight[m]: I haven't heard of any testing yet
12:08 PM CaptHindsight[m]: but if you are just using Mesa Ethernet then you don't need RTAI except maybe if you are also using a LPT card at the same time for RT
12:10 PM fogl: I just want to test the latency to compare performance of rtai and preempt rt.
12:12 PM CaptHindsight[m]: fogl: http://linuxcnc.org/docs/2.8/html/getting-started/getting-linuxcnc.html#cha:Installing-RTAI is the easiest way to find out
12:13 PM CaptHindsight[m]: http://linuxcnc.org/downloads/ see the bottom
12:43 PM fogl: will try that, thank you
12:56 PM boozeman[m]: Those who has HP Elite 8300 SSF or USDT, show your grub config. With isolcpus=2,3 I got latency over 80 us. This has 8gigs of memory and i5-3570S 3.1GHz processor.
01:14 PM MrSunshine_ is now known as MrSunshine
01:16 PM Tom_L: JT-Cave, looks good
01:26 PM Tom_L: there is one scenario it will get out of sync however it isn't a valid comment
01:30 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/cnc/JT-SHOP/mesact/parser.png
01:31 PM Tom_L: if the comment line is indented, it gets out of sync. it isn't a valid line but could happen. i'll let you decide if it's worth it or not
01:31 PM Tom_L: i think you got it...
01:34 PM Tom_L: it does throw #7 off though
01:35 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/cnc/JT-SHOP/mesact/parser1.png
01:38 PM Tom_L: i'm not sure i'd worry with it
01:45 PM CaptHindsight[m]: boozeman: try: isolcpus=3 so you only isolate the highest core that LCNC uses for RT, turn off all power management in BIOS along with any virtualization and speed stepping, etc etc
01:49 PM perry_j1987: how goes it
01:54 PM boozeman[m]: CaptainHindsight (@_discord_702231000050040894:jauriarts.org) Will try that. all bios shenanigans are made already
01:54 PM boozeman[m]: sudo s
01:59 PM boozeman[m]: There's that quitet isolcpus=x,x and sometimes the grub_commandline reminiscent of modem init strings from the golden 90s 😄
01:59 PM CaptHindsight[m]: boozeman: isolcpus=3 leaves cores 0, 1 and 3 free for non-realtime but based on the cache structure can sometimes end up far worse than isolcpus=2,3
02:00 PM perry_j1987: just peekd at pi4 availability man the yare still out everyweher heh
02:00 PM CaptHindsight[m]: boozeman: "With isolcpus=2,3 I got latency over 80 us" on the base or servo thread, it matters
02:01 PM CaptHindsight[m]: perry_j1987: lots of alternatives
02:01 PM pcw--home: It _was_ possible to get good latency on that hardware:
02:01 PM pcw--home: http://freeby.mesanet.com/elite8300-preempt-rt.png
02:01 PM perry_j1987: whats the best option for this mesa 7i96 and a sbc board
02:01 PM CaptHindsight[m]: compare BIOS versions
02:01 PM pcw--home: I'll post results with a recent kernel later today
02:02 PM CaptHindsight[m]: older Intel cpus are getting worse latency with newer kernels, and it's just the opposite with AMD
02:02 PM pcw--home: In general I would not use a SBC
02:03 PM CaptHindsight[m]: https://forum.linuxcnc.org/18-computer/46077-potential-all-in-one-single-board-computers
02:04 PM CaptHindsight[m]: some allwinner H616 boards are now only $27ea
02:05 PM CaptHindsight[m]: https://www.aliexpress.com/i/3256801637347870.html even lower
02:07 PM boozeman[m]: ah servo thread. I have Mesa 7i96S here
02:07 PM CaptHindsight[m]: so it's a non issue at 80,000
02:07 PM boozeman[m]: there is also no turning back to older bioses because spectre/meltdown exploit fixes
02:08 PM CaptHindsight[m]: also why the newer kernels are slower on older Intel
02:08 PM pcw--home: For Ethernet cards in general optimizing the latency test results is not very useful, in fact you may have better Ethernet latency with no isolcpus even if you get better test latency
02:09 PM pcw--home: with isolcpus
02:10 PM pcw--home: For Mesa Ethernet cards, the only important latency related thing is that you can run the servo thread without timeouts
02:12 PM pcw--home: This requires testing running LinuxCNC (the latency test only tests "dispatch" latency)
02:12 PM JT-Shop: Tom_L, interesting, indented as in a space before the #?
02:12 PM JT-Shop: oh I see the first one now
02:13 PM JT-Shop: I just need to do something like if line.strip().startswith(test): to fix that I think
02:14 PM JT-Shop: I wonder if lcnc chokes on spaces before a comment?
02:26 PM perry_j1987: so allwiner h616 boards are good for linuxcnc and mesa 7i96 eh?
02:31 PM pcw--home: 1G of memory would be very limiting (at least for complex backplots)
02:33 PM perry_j1987: im using an old gae350 mini-itx board right now for this lathe
02:35 PM perry_j1987: i do have enough room in the cabinet to just mount the mini itx board and could use a pico psu off the lathe's psu
02:41 PM CaptHindsight[m]: pcw--home: I asked around and people don't seem to mind missing the backplots
02:42 PM CaptHindsight[m]: i was surprised
02:42 PM CaptHindsight[m]: so that opens up even more low cost ARM boards
02:42 PM CaptHindsight[m]: my lower limit was 2GB of RAM before
02:42 PM perry_j1987: what are backplots
02:43 PM CaptHindsight[m]: https://linuxcnc.org/docs/html/gui/images/axis-currentandselected.png
02:43 PM CaptHindsight[m]: the line drawings
02:44 PM perry_j1987: ah ya i never use those
02:44 PM perry_j1987: there are orange pi nano 2 on ebay for 39 stateside already
02:44 PM perry_j1987: not much price diff and lot sooner
02:45 PM CaptHindsight[m]: depends on if you need 1 or 2 vs 50 or 200
02:45 PM perry_j1987: https://www.ebay.com/itm/394106527346?hash=item5bc2945e72:g:ZRQAAOSwJE5inxfp&amdata=enc%3AAQAHAAAA4FQRrySh4NEbhNQmrN7bJCvd7vWAgxRXUb8nnZqJNpBMQF42JXy53P3bv3zt%2BEXWY79ngGqX0LFMPz4dKdgK%2BSEBLYUmVkQ6N85rMYRE6%2BRnd%2FeQe%2BREIgqpOzuJQ2g4DsxwyBQikluFAuyQLbC05b248fA94hfRVGuXnOL17UE6NE1bYPIoxGlj2NVQHXOADXFQN7U2XLPdNsl8sEY21Ed%2F8tLACd89rCyMr%2F%2BTCWJ7dbfybD0ePB6XWpg9JMcyDuGP84rLEXAWOYtw%2FFBvPRZ4SKQLEOfOoZ3rEmCM1TEh%7Ctkp%3ABk
02:45 PM perry_j1987: 9SR9L_tobwYA
02:45 PM perry_j1987: gah https://www.ebay.com/itm/394106527346
02:45 PM CaptHindsight[m]: see ^^ another backplot not user :)
02:46 PM CaptHindsight[m]: if short on space https://www.anandtech.com/show/15642/dfi-unveils-credit-card-amd-ryzen-embedded-board
02:48 PM perry_j1987: lol
02:50 PM CaptHindsight[m]: I wish someone in China would make a compute module with the embedded x86 SOC used
02:50 PM CaptHindsight[m]: they have dual 2.5GB nics and Vega 3 GPU's
02:52 PM CaptHindsight[m]: https://dfi-america.com/estore/ghf51.html $368
02:53 PM XXCoder: https://youtu.be/lkyr-T1XiNQ interesting
02:53 PM XXCoder: flashing warning at one point
02:55 PM CaptHindsight[m]: XXCoder: was developed by Ford 10+ years ago
02:55 PM CaptHindsight[m]: I thought about converting a machine here for that
02:57 PM XXCoder: not surpised but its cool
02:58 PM XXCoder: what you'd use for cam though
02:58 PM CaptHindsight[m]: think of it like a ball mill
02:58 PM CaptHindsight[m]: with lots of overlap
03:00 PM CaptHindsight[m]: one side is moves just like a mill and the other side is just the opposite/mirrored moves
03:01 PM XXCoder: it'd have to be 6 axis machine
03:01 PM XXCoder: maybe anyway
03:03 PM CaptHindsight[m]: sure or two 5+ axis machines, one on each side
03:04 PM CaptHindsight[m]: you could set one up to be a mirrored slave of the other
03:04 PM JT-Shop: I would hate to have a 4 or more axis machine...
03:05 PM CaptHindsight[m]: or one 5-axis machine with 10 joints
03:05 PM CaptHindsight[m]: split into two
03:05 PM CaptHindsight[m]: Kuka used two robots since they sell robots
03:06 PM CaptHindsight[m]: mane 10 years of R&D at kuka, i could work there and hardly work at all
03:07 PM CaptHindsight[m]: sorry 5 years
03:39 PM JT-Shop: it took me 7 hours over the last two days to find a ferrule that was crimped onto the insulation 10 years ago on a leak checker
03:40 PM jdh: I spent several days chasing down one of those. it was a 24v return
03:41 PM jdh: everything downstream would just stop sometimes. half the IO modules in the rack would drop power
03:48 PM JT-Cave: Tom_L, indented comments are valid and are now saved
04:18 PM Tom_L: JT-Cave, A comment line is started with a ; or a # mark. When the ini reader sees either of these marks at the start a line, the rest of the line is ignored by the software
04:18 PM Tom_L: in the ini docs
04:18 PM Tom_L: dunno if 'started' includes blank space or not
04:20 PM Tom_L: i may hook up a 7i96s and try this config with and without to see
04:20 PM Tom_L: after while
04:31 PM JT-Shop: I tested indented comments and lcnc doesn't care it seems but you test as well
04:33 PM JT-Cave: http://paste.debian.net/1255229/
04:33 PM JT-Cave: Tom_L, ^^
04:33 PM Tom_L: yeah lcnc doesn't care
04:33 PM Tom_L: just tried it
04:33 PM Tom_L: new fix?
04:33 PM -!- #linuxcnc mode set to +v by ChanServ
04:38 PM Tom_L: looks good
04:38 PM Tom_L: not sure what else to try to break it :)
04:39 PM Tom_L: did you account for line extensions? i forget the symbol.. maybe '/' ?? or does lcnc suppor them?
04:39 PM Tom_L: you wouldn't get those in the ini file though.. nothing is that long there
04:39 PM Tom_L: maybe in a hal file
04:49 PM Tom_L: heh, kid gave notice yesterday, got walked out today and starts his new job tomorrow at 6AM.
04:49 PM Tom_L: the new place has some 6 axis mills i'm told
04:50 PM XXCoder: fun
04:50 PM Tom_L: and if i understood right, 2 spindle machines
04:51 PM Tom_L: he figured he'd get walked out and was kinda hoping for it so he didn't have to hang around another 2 weeks
04:51 PM XXCoder: 2 spindle. not very common
04:51 PM Tom_L: they've got some BIG machines
04:56 PM Tom_L: https://www.youtube.com/watch?v=kI-j_U9Oqn0
04:56 PM Tom_L: similar i think
04:57 PM XXCoder: thats flipping big router
04:58 PM XXCoder: and its 4 axis! insane
04:58 PM Tom_L: 5
04:58 PM XXCoder: oh whats 5th?
04:58 PM Tom_L: i'm not qualified to know :)
04:59 PM XXCoder: lol ok
04:59 PM Tom_L: the spindles are on a cradle
04:59 PM Tom_L: so x y z a and i dunno what b would be
04:59 PM XXCoder: so it can rotate
04:59 PM XXCoder: B is usually along y axis rotation
04:59 PM Tom_L: did you see it tilt?
05:00 PM XXCoder: yeah thats why I said 4 axis :D
05:00 PM Tom_L: i dunno
05:00 PM XXCoder: A spin axis is along x, b is y, and finally, c is along z
05:00 PM XXCoder: A and C is pretty common
05:28 PM XXCoder: oh jackman is finally done with retrofit
05:28 PM XXCoder: 2 years
06:12 PM CaptHindsight[m]: for making 3 of the same thing at once
06:14 PM Tom_L: heh, good or bad..
06:27 PM CaptHindsight[m]: https://youtu.be/0QrynzJ_lZ4?t=108
06:28 PM XXCoder: thats cool
06:28 PM XXCoder: think I saw it before but alwways nice to be reminded
06:31 PM XXCoder: I wonder how they recycle tc stuff
06:31 PM XXCoder: do they just grind it all down to dust or what
07:33 PM CaptHindsight[m]: yes
07:33 PM CaptHindsight[m]: the mention that in the video
07:34 PM CaptHindsight[m]: https://www.youtube.com/watch?v=nPmGVPFITiY
07:35 PM XXCoder: ok
07:50 PM Tom_L: XXCoder, back on that 5 axis.. i looked at the heads and i think they rotate too
07:50 PM Tom_L: the video didn't show that
07:50 PM Tom_L: that would be #5
07:50 PM XXCoder: yeah that was my best guess
07:50 PM XXCoder: so its xyzab
07:51 PM Tom_L: you can see hydraulic lines going in on the side of each and how they pivot
08:12 PM Alicrow-phone: Replaced the belt on the y axis, fixed a pretty crazy bad rigidity issue with the motor housing. Still getting about the same amount of delay between applying power to the motor and getting a reading from the encoders.
08:13 PM Alicrow-phone: Really thought that would have done SOMETHING to help.
08:14 PM Alicrow-phone: Fuck, if this were a machine for my woodworking, I'd just be like "okay, whatever, I'll take what I can get", but it's for my wife, and her machine shop. And in machining, everything needs to be pretty much perfect.
08:15 PM Alicrow-phone: So we've spent about $10k on this thing so far, and I don't even know how many hours of work trying to fix it up, and I dunno if we can even make it usable after all that.
08:16 PM CaptHindsight[m]: Alicrow-phone: can you get a wrench on the motor shaft or its coupling? Turn by hand and look for play, lash, bending, warping etc etc
08:17 PM CaptHindsight[m]: have pics?
08:20 PM * Alicrow[m] uploaded an image: (2625KiB) < https://libera.ems.host/_matrix/media/r0/download/jauriarts.org/eRnCklkraTtVnOJQiwQgxldF/IMG_20220927_211838.jpg >
08:21 PM Alicrow[m]: Much easier to upload stuff on Discord.
08:22 PM Alicrow[m]: There doesn't seem to be substantial backlash, but this is the only ball screw we didn't have rebuilt.
08:23 PM Alicrow[m]: Also, the delay happens even if we only turn it in one direction, so it shouldn't be backlash causing it.
08:24 PM Alicrow[m]: We were getting about 5 ms of delay with the old rotary encoder, which is attached to the motor via a small belt in the back. So seems like 5ms to get the motor to start spinning, and then another 5ms before the table actually moves?
08:25 PM Alicrow[m]: And of course at slower speeds, it takes even longer.
08:27 PM CaptHindsight[m]: what if you turn the motor shaft with a wrench/lever
08:28 PM CaptHindsight[m]: do you notice things moving before the table moves
08:28 PM CaptHindsight[m]: or turn the ballscrew
08:28 PM CaptHindsight[m]: is there any play in the ballnut
08:29 PM CaptHindsight[m]: is there play in the ballscrew fixity bearings on either end?
08:30 PM CaptHindsight[m]: there must be movement somewhere
08:30 PM CaptHindsight[m]: how is the encoder connected to the ballscrew?
08:31 PM Alicrow[m]: Their is no real measurable backlash, nor do i notice it by hand.
08:31 PM Alicrow[m]: It's a linear encoder connected to the table.
08:46 PM pcw--home: Here's a 8300 with a recent kernel:
08:46 PM pcw--home: http://freeby.mesanet.com/8300.5.18.png
08:47 PM pcw--home: about an hour with youtube fireplace running