#linuxcnc Logs

Dec 22 2020

#linuxcnc Calendar

12:27 AM skunkworks: https://www.youtube.com/watch?v=Ppx84yumQdY
12:33 AM XXCoder: old software
12:33 AM XXCoder: 6 sigificant digits
12:33 AM XXCoder: is last 2 or 3 accurate?
01:33 AM Deejay: moin
02:08 AM alex_joni: skunkworks: yeah, but does it run Mach?
04:43 AM howto: good day JT-Cave Tom_L and rs[m] i have the histogram results for the laptop as requested few days ago
04:45 AM howto: min us is -182,9 and max us is 182,8. would a mesa card work with this laptop?
04:49 AM howto: after 15021 seconds
04:59 AM alex_joni: howto: what kind of mesa card?
05:02 AM alex_joni: howto: I mean what kind of interface do you plan to use on the laptop?
05:03 AM alex_joni: but generally speaking laptops are a bad choice for machine control (mostly because of power management, and lack of interfaces)
05:29 AM JT-Cave: hey alex_joni
05:51 AM Tom_L: morning
05:59 AM JT-Cave: morning
06:04 AM Tom_L: finally got wheezy up to date
06:04 AM Tom_L: once i got past my own ignorance
06:05 AM JT-Cave: what was wrong?
06:07 AM Tom_L: i kept forgetting to install once i updated :)
06:07 AM Tom_L: i don't do it often enough
06:07 AM JT-Cave: that would do it for sure
06:08 AM Tom_L: rpi converts the 2.7 files different than wheezy
06:08 AM Tom_L: the joint & spnidle stuff
06:08 AM JT-Cave: odd
06:09 AM Tom_L: iirc rpi added joint.0. and axis.x. but wheezy didn't add joint just axis.0. which should be a letter instead
06:10 AM Tom_L: and both missed the motion.spindle stuff
06:10 AM Tom_L: but it's fixed and works
06:11 AM Tom_L: someone should add buster to the buildbot docs page
06:12 AM JT-Cave: the only person that can do that is seb_kuzm1nsky
06:12 AM Tom_L: ahh
06:14 AM Tom_L: i like the rapid retract on rigid tap feature
06:15 AM Tom_L: haven't tried it but plan to
06:15 AM JT-Cave: not seen that
06:15 AM Tom_L: they added an I option as a spindle multiplier
06:17 AM JT-Cave: to g84?
06:19 AM JT-Cave: ah g33.1
06:20 AM gregcnc: how does that work?
06:21 AM JT-Cave: I never could understand why they never made a rigid tapping canned cycle
06:28 AM alex_joni: hey JT-Cave
06:28 AM alex_joni: (was out for lunch)
06:30 AM gregcnc: they did just add G84 so there is hope
06:30 AM howto: i was planing to use mesa 7i92m or 7i98 on dell precision m6600
06:30 AM howto: and i was asked to do a latency test histogram
06:31 AM howto: the machine is stepfour basic 540 or cooltool...whatever you wanna call it
06:32 AM howto: the idea was to choose the right card so that when i configure it with linuxcnc I do not get the rtapi task1 latency error
06:33 AM howto: rm[s] i have the histogram you asked for a few days ago
06:33 AM howto: rs[m] *
06:34 AM howto: i forgot even who asked for the histogram
06:36 AM howto: if i have -182,9 us and +182.8 us in a test of 15021 seconds on the laptop is it good or is it bad?
06:36 AM gregcnc: laptops don't often work well
06:38 AM howto: gragcnc what does the latency histogram numbers i gave 2 mesages ago tell you about my configuration?
06:38 AM howto: gregcnc sorry
06:39 AM howto: do you know how to interpret the latency histogram?
06:40 AM howto: have i done a 4 hour test for nothing or can someone tell me if the numbers are ok or not for my laptop?
06:41 AM gregcnc: first, understand that the test is testing the computer. It does not help choose a card
06:41 AM JT-Cave: gregcnc, g84 has been there since 2.1 at least
06:41 AM gregcnc: it always said unimplemented
06:42 AM JT-Cave: http://linuxcnc.org/docs/2.1/html/gcode/mill_canned/index.html
06:42 AM gregcnc: http://linuxcnc.org/docs/2.7/html/gcode/g-code.html#_g84_right_hand_tapping_cycle
06:44 AM JT-Cave: 2.5 it changed to unimplemented
06:44 AM gregcnc: does it actually work?
06:44 AM howto: can someone tell me what -182,9 us and +182.8 us in a test of 15021 seconds on the laptop means?
06:45 AM howto: on the latency histogram
06:45 AM gregcnc: howto this is a large value and problematic
06:45 AM gregcnc: I don't know if mesa card will help?
06:46 AM howto: how much should it be the most?
06:46 AM howto: i mean for the worst case scenario?
06:47 AM howto: that could be correctedwith a mesa card?
06:47 AM gregcnc: mesa doesn't correct things. it does allow a less than optimal computer
06:48 AM JT-Cave: interesting that 2.8 says The G84 cycle is intended for tapping with floating chuck and dwell at the bottom of the hole.
06:48 AM gregcnc: some PC can be fixed with tweaks to BIOS and other things, some can't
06:48 AM gregcnc: i'm sure dwell is optional, dwell is not used except for releasing tap holders
06:49 AM howto: good. would my less than optimal computer with those numbers be able to get rid of the rtapi task 1 problem?
06:49 AM howto: by using a mesa card?
06:49 AM gregcnc: I think 180us is too much even for mesa, but not surprising for a laptop
06:50 AM gregcnc: laptop have power and thermal management trickery which doesn't help
06:50 AM howto: gregcnc how much should this number be at the most? so i can try to bring it down.
06:51 AM gregcnc: as low as possible. I'm not sure what mesa requires 50us is for sure OK
06:53 AM howto: so for higher than 50 us a mesa card won't solve the issue.
06:55 AM howto: i am going to try to bring the number down than
06:57 AM gregcnc: howto PC hardware is tricky. it may look OK and when you get it setup with mesa doesn't work
06:57 AM gregcnc: maybe due to other factors
06:58 AM howto: with normal latency test i always get 6 figure numbers
06:58 AM gregcnc: some people test various PC, then reliable systems are used
06:59 AM howto: i saw a lenovo laptop that works but had to invest in other stuff and didnt bought it
06:59 AM gregcnc: searching turned up nothing for M6600 with linuxcnc so it's hard to say whether it can be made to work
07:00 AM howto: of course dell is responsible they intetionaly make things not to work for productivity...and no. Photoshop is not productivity
07:00 AM howto: they took the apple path
07:01 AM gregcnc: pc just aren't made specifically for this application
07:01 AM gregcnc: https://forum.linuxcnc.org/18-computer/38838-hardware-latency-tests-used-pc-s
07:02 AM howto: gregcnc linuxcnc is made to run on a pc not on a ufo from what i read
07:03 AM gregcnc: put PC are not built for realtime applications, which Linuxcnc is
07:03 AM gregcnc: the linux versions which come with linuxcnc distro are specifically built for this
07:03 AM howto: the manufacturers are intentionally make them worse so you can do only games and other brain zombification things
07:03 AM gregcnc: but is still very hardware dependent
07:04 AM gregcnc: this isn't just a software you install
07:04 AM howto: gregcnc hermle uses a pc for their machines
07:04 AM howto: i saw a core i5 at 1,8 ghz if i'm not mistakin'
07:04 AM gregcnc: no they don't
07:06 AM howto: gregcnc please explain your statement. A pc is made for realtime application. Some people saw pentium I at 200 mhz work on these things better than my core i7 laptop
07:07 AM howto: gregcnc apple intentionately makes their laptops worse just becasue people buy them anyway
07:07 AM gregcnc: who cares
07:07 AM gregcnc: they make. people buy
07:08 AM howto: anyway i saw normal pc on hermle...so the statement that a pc is not made for realtime falls abruptly
07:08 AM gregcnc: the hermle most definitely is using a second dedicated computer to run the machine
07:08 AM howto: i am going to try to bring those microseconds down
07:10 AM gregcnc: that thread may have some ideas
07:10 AM gregcnc: a few were working with laptops
07:10 AM JT-Cave: hmm the latency-histogram is too big for my 7" touch screen
07:16 AM JT-Cave: for mesa <100us works
07:34 AM rs[m]: hmm. seems freenode shadow-muted me again
07:34 AM XXCoder: dunno
07:35 AM rs[m]: I answered howto 2 hours ago ;) but messages got eaten
07:36 AM rs[m]: IIRC pcw said with a 1khz loop and stepper system with mesa card, you could even miss 1 or two 1ms intervals completely without things going belly up
07:36 AM rs[m]: not great, not terrible
07:38 AM rs[m]: https://youtu.be/ocBVLMHK6c8?t=103
07:38 AM XXCoder: i hate woobly camera
07:39 AM gregcnc: https://forum.linuxcnc.org/forum/18-computer/21442-is-latency-an-issue-when-using-a-mesa-card#21450
07:47 AM gregcnc: so what actually needs to be done?
07:48 AM XXCoder: everything nesscary
07:51 AM gregcnc: "Its possible to make hardware step generation resistant to 1 mS range latencies with some small changes in the stepgens feedback loop (use the actual thread actuation time for its calculations rather than the nominal value)"
07:52 AM rs[m]: it is possible this change is already in the code, that post is from 2012
07:52 AM gregcnc: why would we even bring up latency with mesa then?
07:53 AM Tom_L: who brought it up?
07:53 AM rs[m]: howto brought it up
07:53 AM gregcnc: someone trying to build a machine
07:53 AM gregcnc: 1ms is huge
07:54 AM Tom_L: gregcnc, why are you excited about G84 over G33.1?
07:54 AM gregcnc: i'm not JT asked why there is no rigid version of G84
07:54 AM Tom_L: oh
07:56 AM gregcnc: I saw something like 800us in a HP 8000 SFF when the fan hit full speed otherwise it ran quite well, don't remember details
08:21 AM rs[m]: your typical self-built stepper machine isn't that accurate. in 1ms, with typical milling-speeds, the machine travels a few 10 µm at most
08:23 AM JT-Cave: wow my planer pulley is out for delivery
08:26 AM gregcnc: 600mm/min?
08:37 AM rs[m]: 600 mm/min = 10 mm/s = 10µm/ms
08:37 AM gregcnc: SLOW
08:37 AM rs[m]: what would you consider a typical feedrate
08:46 AM gregcnc: rs[m] what is step frequency at 600mm/min?
09:01 AM rs[m]: my point is, if you are using a cheap chinese router "mill" with feedrates in the ballpark of 1000mm/min, you don't need ms servo loop, because your machine is accurate to 0,05mm at best.
09:09 AM gregcnc: if I'm shooting for 600mm/sec i'm not spending money on mesa
09:16 AM skunkworks: mm/sec?
09:16 AM skunkworks: I think you would be.. :)
09:18 AM gregcnc: lol oops mm/min my first machine did 2m/min software stepping with pII 500MHz and 2um resolution
09:20 AM Loetmichel: hehe... wife just called. She accidentally gave her nurses a 50€ note for the thankyou-box instead of a 20... now she is short on cash in the physical therapy hospital... and asks if i can bring her a few 100,- plus if i could drive by the grocery store and bring some sweets and snacks... apparently they are insanely expensive in the hospitals cafeteria :)
09:44 AM unterhaus: anyone ever order from vbeltguys?
10:51 AM jymmmm: Morning
12:19 PM Tom_L: afternoon jymmmm
12:20 PM jymmmm: Tom_L: Hey, that it is , still 10:20am here =)
12:21 PM Tom_L: so should i call this brunch?
12:26 PM jymmmm: That works and gives me ideas for food =)
12:53 PM * skunkworks got a second printer port working for the terco...
12:53 PM skunkworks: Should be enough i/o
12:53 PM * skunkworks was craving a jog wheel.
12:54 PM Tom_L: skunkworks, not using mesa on it?
12:55 PM skunkworks: I will - this is sort of a - how well does the printer port work
12:55 PM Tom_L: headin out to check out that rapid retract on the G33.1
12:55 PM skunkworks: cool!
12:55 PM skunkworks: I have not tried that. Or the lathe cycles..
12:56 PM Tom_L: you have 2.8 installed?
12:56 PM skunkworks: yes
12:56 PM skunkworks: buster
12:56 PM skunkworks: too
12:56 PM Tom_L: finally updted wheezy on the mill with it
12:56 PM Tom_L: and the test rpi4
12:57 PM skunkworks: I ended up using the xfce live cd from debian
12:57 PM Tom_L: buster won't run on the mill MB
12:58 PM Tom_L: not good enough anyway
12:59 PM MrHindsight is now known as CaptHindsight
01:30 PM * JT-Shop goes to put the new pulley on the planer...
01:39 PM Tom_L: https://www.youtube.com/watch?v=xL2zajQw2Rg
01:39 PM Tom_L: G33.1 with the I option
01:45 PM Tom_L: I set to 2
01:46 PM JT-Shop: does it speed up the spindle for the retract?
01:46 PM JT-Shop: I can't tell watching the video
01:46 PM Tom_L: yeah it's hard to see there. i put a piece of tape on the chuck but you can't really tell
01:47 PM Tom_L: you can sorta hear the spindle pitch difference
01:48 PM JT-Shop: cool
01:48 PM Tom_L: i didn't wanna over do it the first time, maybe i'll try 4x
01:48 PM Tom_L: which would be 2k rpm retract
01:54 PM JT-Shop: they got the jack shaft installed at the range and have been testing it with a cordless
01:54 PM JT-Shop: guy said it works great
02:05 PM Tom_L: nice
02:05 PM Tom_L: the I option doesn't like more than 2 on my mill
02:05 PM Tom_L: it has a hard time keeping sync with steppers
02:07 PM Tom_L: JT-Shop, what'd you end up using for cable?
02:09 PM Tom_L: are you using 1 jack shaft or 1 per lane?
02:09 PM Tom_L: independent control would be best
02:20 PM JT-Shop: one per lane, not sure what he used, I've not been out there since I dropped off the jack shaft
02:21 PM JT-Shop: I think he said he had 3/16 rope of some sort
02:21 PM JT-Shop: prob para cord
02:26 PM Tom_L: figure out what you're gonna control the steppers with?
02:30 PM JT-Shop: not exactly, going to use a Rpi4 with 7" touch screen and a 7i96 as a show and tell because I have it on hand
02:31 PM JT-Shop: plc options click + serial stepper drive or higher end plc with 24v stepper drive both with touch screens
02:31 PM JT-Shop: so 3 choices as I see it
02:34 PM Tom_L: decided against the rpi
02:35 PM JT-Shop: not yet
03:25 PM roycroft: thank goodness
03:25 PM roycroft: the rain has finally stopped for a couple days
04:08 PM JT-Shop: got the lost replacement pulley for the planer today...
04:10 PM pink_vampire: hi
04:11 PM XXCoder: hey pink
04:11 PM JT-Shop: hi pink
04:13 PM pink_vampire: hi everyone
04:13 PM pink_vampire: long time
04:14 PM XXCoder: hows things going
04:14 PM pink_vampire: https://i.imgur.com/UP8nYaV.png
04:14 PM pink_vampire: apparently there is negative pages
04:17 PM XXCoder: lol
04:18 PM JT-Shop: if you hear Rod Serling's voice when you press the negative page button your in trouble
04:19 PM pink_vampire: I want to add cable chain to the Y axis of my printer
04:40 PM JT-Shop: https://www.lumberjocks.com/projects/70524
05:41 PM JT-Cave: hmm should get my replacement mirror Saturday for the Uplander
05:43 PM Tom_L: hope it's not coming USPS
05:44 PM JT-Cave: actually the mirror is coming fedex
05:44 PM JT-Cave: the rest of the planer parts are coming usps and they keep saying it's on time for Monday delivery
07:02 PM -!- #linuxcnc mode set to +v by ChanServ
07:13 PM sinned6915: any suggestions for sourcing 18-4 shielded wire for stepper hookups??
07:16 PM Tom_L: https://www.amazon.com/50-FEET-18-AWG-SHIELDED/dp/B01GZ50P7Q
08:21 PM jdh]: lowes/homedepot