#linuxcnc Logs

Mar 21 2022

#linuxcnc Calendar

02:34 AM MrSunshine: alltså, om man använder en potentiometer som spänningsdelare .. då borde det väl egentligen kvitta om den är 10k eler 5k eller whatever så får man ut samma på centertappen vid samma position på dem ?
03:03 AM randy__ is now known as randy
03:08 AM t4nk_freenode: to show you my discontent with you did, MrSunshine, I will NOT translate this message,
03:08 AM t4nk_freenode: but I will read and interpret it myself
03:08 AM t4nk_freenode: and I will also give you a reply
03:09 AM t4nk_freenode: ok, I can't ;)
03:09 AM t4nk_freenode: you are talking about using a potentiometer as a voltage divider
03:14 AM randy: morning
03:14 AM silopolis[m]: <pcw-home> "silopolis Step/Direction, CW/CCW..." <- Thanks 🙏
03:15 AM silopolis[m]: Morning
03:15 AM randy: MrSunshine: when using it as an voltage divider, the "ratio" should be always the same regardless of the resistor value
03:16 AM t4nk_freenode: God morgon randy ;)
03:16 AM randy: so, e.g. center position with 10k poti -> 5k & 5k (measured at wiper to bots other inputs) = 1:1; with 5k -> 2k5 & 2k5 = 1:1
03:17 AM silopolis[m]: Another n00b one for yall science pits... Am I right to think analog motor control only works for speed and torque mode, unless an external encoder is used for position?
03:18 AM silopolis[m]: Inversely, step/pwm+dir only works for position mode?
03:23 AM CaptHindsight[m]: analog input or Step + Dir maybe used for open or closed loop
03:24 AM CaptHindsight[m]: an encoder may be used for position or velocity feedback to close the loop
03:41 AM -!- #linuxcnc mode set to +v by ChanServ
04:07 AM -!- #linuxcnc mode set to +v by ChanServ
04:29 AM Deejay: moin
04:49 AM Tom_itx: morning
04:50 AM Tom_itx is now known as Tom_L
05:09 AM JT-Cave: morning
06:06 AM -!- #linuxcnc mode set to +v by ChanServ
06:50 AM perry_j1987: mornin
07:52 AM perry_j1987: well good morning MrSunshine lol
11:10 AM solarwind: What's the most machinable aluminum alloy when all other factors are not important?
11:10 AM solarwind: Machinability and ability to take a good surface finish are largest priority. Strength, weldability, corrosion resistance, etc. all don't matter
11:13 AM perry_j1987: i've pretty much just stuck with 6061
11:13 AM JT-Cave: mcmaster carr has a chart
11:31 AM Tom_L: 7075 is hard but machines ok 6061 is usually the go to for machining
11:36 AM roguish[m]: solarwind: www.matweb.com
11:38 AM t4nk_freenode: these c-beams are 6063
11:40 AM t4nk_freenode: though I'd be hoping to machine With them, not At them of course ;)
11:43 AM roguish[m]: t4nk_freenode: 6063 it the typical architectural alloy
11:43 AM coralgoat: http://linuxcnc.org/docs/2.8/html/getting-started/system-requirements.html#cha:system-requirements says to use X86 or Raspberry Pi 4.
11:43 AM Tom_L: 2021 is like machining bubble gum
11:44 AM Deejay: try freezing the bubble gum :)
11:44 AM coralgoat: Is Raspberry Pi 4 as good as X86 or should I go with x86?
11:45 AM Tom_L: if all you're doing is cnc either is fine
11:46 AM coralgoat: I just joined the channel are 7075, 6061 and 2021 referring to aluminum?
11:47 AM t4nk_freenode: yeah, I just looked it up, https://materialsdata.nist.gov/bitstream/handle/11115/173/Aluminum%20and%20Aluminum%20Alloys%20Davis.pdf
11:51 AM roguish[m]: coralgoat: yes. they are all aluminum alloys
11:52 AM coralgoat: roguish[m], thanks
11:54 AM coralgoat: I was looking at https://www.linuxcnc.org/downloads/ for linuxcnc 2.8 I was thinking of going with debian with a preempt-rt kernel.
11:55 AM roycroft: coralgoat: if you have a smart board like the mesa line to offload your motion control, a rpi will be fine
11:56 AM roycroft: if you are going to handle the motion control with the main cpu, then you would be best sticking to an x86 machine with low latency on the parallel port
11:56 AM coralgoat: roycroft, okay I will use x86 then.
11:57 AM Tom_L: mesa boards are awesome though
11:58 AM roycroft: consider that an x86 machine + parallel adapter (most don't come with that these days) + hard drive/memory, etc. + breakout board is going to cost you US$200-$300
11:58 AM roycroft: a rpi4 + mesa ethernet based motion control board will cost the same or less
11:58 AM roycroft: but consider also that mesa boards are almost impossible to source right now due to supply side shortages of some of the components for the boards
11:59 AM solarwind: Tom_L yeah looks like 6061T6 is the go-to for pretty much any general purpose use
11:59 AM solarwind: brass is such a lovely metal. Only problem is welding is impractical due to zinc's boiling point being so close to the melting point of the metal
11:59 AM coralgoat: Can someone link to an example of a mesa board that I could use with a Raspberry Pi 4.
12:00 PM Tom_L: or T651
12:00 PM Tom_L: (age hardened)
12:00 PM solarwind: coralgoat any of the ethernet ones
12:00 PM roycroft: will you be using stepper motors or servo motors?
12:00 PM solarwind: roycroft most modern servo drives take step/dir inputs
12:01 PM roycroft: the 7i96 is good for many stepper applications
12:01 PM roycroft: that + an rip4 + a case and ps for the rpi will cost less than US$200
12:01 PM roycroft: if/when you can find them
12:01 PM solarwind: I use the PCIe mesa cards because I like a low latency interconnect
12:02 PM solarwind: and any cheap computer will have more computing power than a raspberry pi
12:02 PM coralgoat: roycroft, In the shop there is a CNC machine that is not currently in use and I thought I would get it running with linuxcnc. I will check if it has stepper or servo motors later this week whin I go in.
12:02 PM Tom_L: but you shouldn't be using that pc for anything but cnc
12:02 PM solarwind: well yeah
12:02 PM Tom_L: so it's back to it really doesn't matter
12:03 PM solarwind: But I still like having the extra headroom and lower latency interconnect
12:03 PM roycroft: an rpi4 has more than enough power to run linuxcnc with a mesa ethernet board doing the motion control stuff
12:03 PM solarwind: also I don't have to run real time linux
12:03 PM Tom_L: if you have a cnc you do
12:04 PM solarwind: Not with the PCIe cards
12:04 PM solarwind: with the ethernet ones, you do
12:04 PM coralgoat: Is it okay to use a USB parallel port adapter or should I buy a pcie card that provides a parallel port for the x86 desktop?
12:05 PM solarwind: coralgoat they almost always have a parallel port already
12:05 PM Tom_L: coralgoat, no
12:05 PM solarwind: it's just hidden on the motherboard
12:05 PM solarwind: you just need a cable to bring it out
12:05 PM Tom_L: usb isn't realtime
12:05 PM solarwind: check the manual for the motherboard and just buy the appropriate cable
12:06 PM roycroft: besides being cheap and drawing little power, i like that the rpi is so small
12:06 PM solarwind: That's the best way because it goes through the chipset, which goes through PCIe
12:06 PM roycroft: i have a din rail mount for mine that fits inside the control chassis for my router
12:06 PM roycroft: so i don't have to find room to park a computer next to the machine
12:07 PM coralgoat: solarwind, do you mean that the motherboard may have a parallel port on the motherboard?
12:08 PM coralgoat: I would have to open it up and check for a parallel port on the motherboard.
12:08 PM roycroft: that's increasingly less common, and if it does, you need to do a latency test to see if it will perform real time operations reasonably
12:09 PM roycroft: and you really need an optically isolated break out board if you're going to operate your drivers using a parallel port
12:09 PM roycroft: all of which is doable, of course
12:09 PM coralgoat: I will not use the USB parallel port adapter I have with linuxcnc.
12:10 PM roycroft: no, you will not
12:10 PM roycroft: you may try, but if you do, in the end you will decide not to use it
12:12 PM coralgoat: I am not sure how optically isolated the parallel port break board that this CNC machine has is.
12:13 PM coralgoat: Is there a good amount of optical isolation?
12:14 PM coralgoat: What is a good way to find out the optical isolation of the parallel port break out board?
12:15 PM solarwind: LOL
12:15 PM solarwind: the manual, or take it apart and check for optoisolator ICs
12:16 PM coralgoat: solarwind, thanks
12:16 PM solarwind: If they're open drain/open collector outputs, that's also a hint
12:16 PM solarwind: optoisolator ICs are almost always DIP/through hole
12:17 PM solarwind: coralgoat the MESA cards have good isolation though. I think* they're all isolated, check the specific I/O card to be sure
12:20 PM coralgoat: I am going to look into mesa boards. What is a good search term that I should use?
12:23 PM Tom_L: coralgoat, in regard to the rpi4: https://www.youtube.com/watch?v=g0OLIth_cOI
12:23 PM Tom_L: coralgoat, go to mesaus.com for boards or mesanet.com
12:25 PM roycroft: or watch for pcw or jt to be active here and ask them
12:25 PM roycroft: pcw makes them
12:25 PM roycroft: both pcw and jt sell them
12:25 PM roycroft: and both know the products intimately
12:27 PM roycroft: both are fairly active here, although jt is retired now, so he's often busy at work
12:34 PM coralgoat: Tom_L, thank for those links.
12:40 PM coralgoat: I was looking at https://www.linuxcnc.org/downloads/ for linuxcnc 2.8 I was thinking of going with Debian 10 Buster with a preempt-rt kernel.
12:40 PM coralgoat: https://www.debian.org/releases/ shows that 10 Buster is now oldstable.
12:40 PM coralgoat: Does anyone know if Linuxcnc can work on Debian 11 Bullseye current stable?
12:44 PM coralgoat: I was thinking of trying http://linuxcnc.org/docs/2.8/html/getting-started/getting-linuxcnc.html#_installing_on_debian_buster_with_preempt_rt_kernel but with Debian 11 Bullseye. Has this been done already?
01:15 PM roycroft: it has, but i forget who has done it and how it worked out
01:16 PM roycroft: you might check the mailing list archives for more information
01:22 PM roycroft: so i'm wondering what's up with kwax today
01:23 PM roycroft: today is j.s. bach's birthday, but it's not a "major" birthday
01:23 PM roycroft: he was born in 1685, so he's 337 years old today
01:23 PM XXCoder: 337 years young ;)
01:24 PM roycroft: but they're playing almost all bach today - they don't usually do that for any composer unless it's a major birthday, like beethoven's recent 250th
01:25 PM roycroft: i don't really mind - i like bach - but it just seems odd
01:29 PM coralgoat: Can http://www.linuxcnc.org/iso/linuxcnc-2.8.2-buster.iso be installed without an internet connection on the computer it is being installed to?
01:30 PM roycroft: the iso can be installed in an isolated environment
01:30 PM roycroft: one used to be able to run it off a thumb drive without installing it
01:31 PM roycroft: i'm not sure if that's still the case
01:34 PM coralgoat: roycroft, when you said "the iso can be installed in an isolated environment" do you mean on a computer without an internet connection?
01:36 PM coralgoat: I am asking because some Debian netistall ISOs need an internet connection.
01:41 PM roycroft: yes
01:41 PM roycroft: and any netinstall distro will require access to an ftp server, either on the local network or on the internet
01:42 PM roycroft: but the linuxcnc iso was designed to be a stand-alone installer
01:47 PM coralgoat: roycroft, thanks
01:54 PM roycroft: as i suggested earlier, you may be able to run it directly off a thumb drive
01:55 PM roycroft: that would be useful if you decide to use a pc and not a raspberry pi - you would be able to run a latency test on your hardware to see if it's suitable for running linuxcnc without a separate motion control board
02:18 PM silopolis[m]: > Another n00b one for yall science pits... Am I right to think analog motor control only works for speed and torque mode, unless an external encoder is used for position?
02:18 PM silopolis[m]: I realise this was not very clear.... Let's try again! 😅
02:18 PM silopolis[m]: Using motors in speed mode implies having an encoder on the axis to close the position loop, right?
02:36 PM JT-MachineShop: coralgoat, just download the full version not the net install one
03:12 PM Tom_L: rain
03:14 PM roycroft: it is drizzling here as well
03:14 PM roycroft: but tomorrow will be partly sunny, and the high will be 21 degrees
03:15 PM XXCoder: drizzle alllll day today
04:41 PM coralgoat: Is there a deb package for Debian Bullseye stable?
04:42 PM coralgoat: For linuxcnc
04:43 PM coralgoat: I am guessing that https://www.linuxcnc.org/dists/buster/2.8-rtpreempt/binary-amd64/linuxcnc-uspace_2.8.1_amd64.deb is for buster based on the url.
04:43 PM randy: coralgoat: http://buildbot.linuxcnc.org/dists/buster/
04:46 PM coralgoat: randy, thanks for sharing that link that is a buster directory and when I go to it's parent there are other directory names that match Debian versions but there is no Bullseye directory.
04:47 PM randy: yes. looks like theres no bullseye package yet from buildbot :/
04:47 PM coralgoat: So I guess there is no Debian 11 Bullseye deb package.
04:47 PM roycroft: i'm not one to advocate running old, unsupported operating systems or applications, but for something like linuxcnc, i don't think it's necessary to run the most recent version of the underlying os
04:48 PM roycroft: buster will be supported for quite a while yet
04:48 PM roycroft: and machines running linuxc should not be directly on the internet, for the most part
04:48 PM CaptHindsight[m]: isn't the LCNC package at Debian only for Sid?
04:48 PM XXCoder: yeah id prefer just install whole os pack than setup linuxcnc
04:48 PM roycroft: if the machine is in a prvate network, security updates are not as critical as those exposed to the public internet
04:49 PM roycroft: my view is that running it on bullseye is right now primarily more for developers and folks who like to tinker with the software
04:49 PM CaptHindsight[m]: coralgoat: there was lots of LCNC work to get Python up the 3 from 2, so be glad it for that
04:50 PM roycroft: for folks trying to get work done, the buster distro is fine fo r now
04:50 PM CaptHindsight[m]: "real users"use Gentoo anyway :)
04:51 PM Tom_L: what debian version for linuxcnc is kindof a non issue really unless you live on the bleeding edge of life
04:51 PM Tom_L: i'm still running wheezy ;)
04:51 PM CaptHindsight[m]: https://en.wikipedia.org/wiki/Debian_version_history no debian 11 or 12 packages yet :)
04:52 PM roycroft: and while i'd probably have upgraded the wheezy machine by now, if it's on a private network i don't see anything wrong with still running wheezy
04:52 PM CaptHindsight[m]: I enjoy Debian for using both a release number and name but never at the same time
04:53 PM CaptHindsight[m]: like Debian 7 mentioned
04:53 PM coralgoat: CaptHindsight[m], I appreciate all the effort that have gone into linuxcnc and I look forward to using it.
04:53 PM CaptHindsight[m]: try the Debian 10 packages
04:54 PM CaptHindsight[m]: coralgoat: i wish you "much success"
04:55 PM Tom_L: sid has no number
04:56 PM Tom_L: he's a bad bad boy
04:56 PM CaptHindsight[m]: I'm pretty sure that Debian uses the pet names of the 12 dwarfs girlfriends for each release number
04:56 PM Tom_L: no, toy story characters
04:57 PM CaptHindsight[m]: i though that was just a rumor
04:57 PM Tom_L: nope
04:57 PM coralgoat: This is interesting: http://linuxcnc.org/2022/03/03/LinuxCNC-in-Debian/
04:58 PM CaptHindsight[m]: like on the surface it's from Toy Story, but the real story is mush more strange than reality
04:58 PM Tom_L: yeah that was a recent accomplishment
05:44 PM JT-MachineShop: I'm still running Ubuntu 10.04
06:02 PM JT-MachineShop: rain here tonight through Thursday... glad I got all the rounds split and stacked
06:04 PM Tom_L: supposed to get colder i think
06:04 PM Tom_L: and continued rain
06:04 PM JT-MachineShop: nothing below freezing
06:05 PM Tom_L: 35 on wednesday
06:05 PM JT-MachineShop: I still have one round left in the stump but it will wait for another day
06:05 PM Tom_L: 33 Fro
06:06 PM Tom_L: fri
06:06 PM JT-MachineShop: prob have to quarter it the cut it off
06:06 PM Tom_L: got that handle finished
06:06 PM Tom_L: http://ruemohr.org/~ircjunk/tempimage/p1230203.jpg
06:06 PM JT-MachineShop: Friday here is 65°F and sunny... going to be a day to go to a winery
06:06 PM Tom_L: test fit
06:06 PM XXCoder: nice
06:07 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/rue/Can_Holder/B2_proto/B2_proto_handle.JPG
06:08 PM Tom_L: i guess some ole guy had been making those up there for years
06:08 PM Tom_L: by hand
06:08 PM Tom_L: mostly
06:08 PM roguish[m]: mid 70's now.......... tomorrow low 80's
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