#linuxcnc Logs

Dec 14 2020

#linuxcnc Calendar

12:33 AM enleth: roycroft: CO2 lasers basically emit a coherent beam of radiant heat, it's as far as you can get from anything you could call "light" while still being able to focus it
12:39 AM enleth: thus, any safety data for CO2 lasers should be considered unapplicable by default to any other type of laser
12:39 AM enleth: nvz: ^
12:39 AM enleth: and vice versa
02:23 AM -!- #linuxcnc mode set to +v by kornbluth.freenode.net
03:40 AM Deejay: moin
04:46 AM Eric__: Is there such a thing as a quiet 150mm fan?
04:46 AM Eric__: the one that came with my bridgeport is not
04:48 AM Loetmichel: the PC 150mm fans are more or less all pretty quiet
04:48 AM Loetmichel: depends on how much volume per second you need i guess
05:02 AM JT-Cave: morning
06:08 AM Tom_L: morning
06:11 AM XXCoder: hey
08:33 AM JT-Shop: wonderful 2 shipments are in transit arriving late from usps
08:34 AM Tom_L: no surprise there
08:34 AM gregcnc: I just had one take a month from IL to TX
08:35 AM gregcnc: oh it made a stop in portland
08:36 AM Tom_L: i swear the loaders just shove them on any truck so they can be done
08:41 AM enleth: your stuff is just taking the scenic route
08:53 AM gregcnc: stuff happens. but when it's important or disappears, it's problem
09:29 AM jymmmm: Monring
10:09 AM Eric__: I have a shipment that just left nebraska, see how this goes
10:43 AM Loetmichel: *giggle* $me probably just saved someone from landing in the ditch... accidentally drifted around a "closing in" exit on the highway. Didnt see it was slightly wet before. (there is a reason there is a 40kph speed limit). Saw the car behind me SLAMMING on the brakes ("nodding") before crawling into said 270° exit... at the speed the driver was before he would have definetly been in the
10:43 AM Loetmichel: ditch.
10:55 AM sensille: can anyone tell me what the INL of a rotary encoder means? if it says +/1 1deg, does it mean that the encoded is off by 1deg in the worst case?
11:08 AM Eric__: 1 degree sounds like a lot, but I will admit to never thinking about the subject before
11:08 AM Eric__: what brand, how many counts?
11:40 AM sensille: ams, 14 bit resolution
11:40 AM sensille: magnetic
11:45 AM gregcnc: what are you using this for?
11:48 AM Eric__: 14 bit resolution and 1 degree max error seems like somebody didn't do an error budget
11:49 AM Eric__: I searched for ams rotary encoder and the first one I found said .05 degree after blah blah blah
11:50 AM sensille: https://ams.com/documents/20143/36005/AS5048_DS000298_4-00.pdf
11:50 AM sensille: INL, page 8
11:51 AM sensille: gregcnc: i'm looking for a suitable encoder for a closed loop stepper
11:52 AM sensille: maybe those are just for a different purpose
11:53 AM gregcnc: stepper is listed as an application, but it depends on how accurate you need like anything else
11:53 AM sensille: better than a half step :)
11:54 AM sensille: but maybe i'm just interpreting that number wrongly
11:55 AM gregcnc: I think that is normal for hall encoders
12:00 PM Eric__: sensille what interface hardware are you using?
12:01 PM Eric__: seems like I have seen mesa cards that will handle spi/i2c encoders
12:01 PM sensille: the linear encoder from ams says 5um. that's actually around the same, if i set the magnet distance of 2mm as 360deg
12:01 PM Eric__: otherwise they seem like a pain
12:02 PM sensille: it is for a printer and i feed them into an fpga
12:03 PM sensille: so the problem is that for the rotary encoder they use only one magnet. i would need a ring with several magnets for higher precision
12:03 PM gregcnc: no they use one magnet
12:03 PM sensille: yes
12:04 PM sensille: and with a ring of many magnets (and a different encoder) it would be better
12:04 PM sensille: the as5311 can handle such a ring
12:04 PM gregcnc: why not use the typical optical encoder?
12:04 PM sensille: i would prefer the magnetic ones because they're very small
12:05 PM sensille: but it looks like they're unusable. maybe unless i calibrate them with an optical one
12:05 PM gregcnc: why encoders on a printer?
12:06 PM sensille: because i want to do stupid things :)
12:06 PM sensille: and because i want to learn about the sources of errors
12:06 PM gregcnc: ok
12:06 PM sensille: i want to get a better understanding of how the steppers react
12:07 PM Eric__: could be interesting
12:07 PM gregcnc: closed loop steppers exist
12:08 PM Eric__: if you want to generate errors, needs to be a router instead of a printer
12:09 PM sensille: in a printer you move around 1kg at 1g acceleration. not really high forces, but good enough to produce ringing for example, with a nema17
12:09 PM sensille: as i can see the errors in the print, i can hopefully also capture them with a sensor
12:11 PM gregcnc: stepper damper?
12:11 PM gregcnc: is it the motor, screw, or frame resonating?
12:13 PM sensille: i suspect a bit of everything
12:14 PM gregcnc: I think if you want to measure motor resonance you need much more resolution than 1/2 step
12:15 PM sensille: the resolution is actually 14 bit. but the precision is only 1/2 step
12:15 PM sensille: so it could be useful for measurement, but not for closed loop
01:01 PM Eric__: anyone ever use a safety relay?
01:01 PM Eric__: I am thinking that I want to combine things like drive faults to shut down my mill
01:10 PM skunkworks: I have played with one...
01:10 PM skunkworks: (was going to make a video - but time..)
01:11 PM skunkworks: our big cnc's are just using a normal multi contact relay for the safty relay.. (don't tell anyone)
01:29 PM Eric__: there are relays with multiple inputs?
01:31 PM Eric__: I could daisy chain the fault outputs to drive a single relay, i think
01:51 PM sensille: wired-or with diodes?
02:56 PM Eric__: Have to study the drive electronics again to see what would work.
03:08 PM Eric__: there is a relay output that says the drive is ready, but fault requires setting up an optional output
03:10 PM Eric__: maybe I'll use the ready output relay, which opens when there is a fault
03:13 PM Eric__: diode and is close, but startup is a problem
03:26 PM JT-Shop: Tom_L, the shooting lane is 75' long with barn door track for the target retriever system... need a simple 1/2" jack shaft
03:28 PM Tom_L: cool
03:29 PM Tom_L: threaded shaft?
03:30 PM JT-Shop: just a key slot I think
03:30 PM JT-Shop: he wants to use steppers so the targets can go to preset positions
03:31 PM Tom_L: my new garage opener uses timing belt
03:31 PM Tom_L: i was thinking about preset positions using switches?
03:32 PM JT-Shop: my chamberland lift master has a timing belt
03:32 PM Tom_L: same
03:32 PM JT-Shop: he doesn't want any wire down range
03:32 PM Tom_L: i can see why
03:33 PM JT-Shop: he said "everything" gets shot
03:33 PM Tom_L: true
03:33 PM Tom_L: not quite following your idea though
03:34 PM JT-Shop: not having much luck finding anything
03:34 PM Tom_L: a long screw or a shaft driven cable?
03:34 PM JT-Shop: I just need a shaft on a couple of bearings with the pulley below and the stepper above maybe on a 2-1 belt reduction
03:34 PM Tom_L: a steel cable on 2 pullies driven at the front with a stepper etc
03:35 PM Tom_L: hmm
03:35 PM JT-Shop: 3/16" rope
03:35 PM Tom_L: i should visit a shooting range :)
03:35 PM JT-Shop: I've never been to one
03:36 PM Tom_L: there are at least a couple here
03:36 PM Tom_L: it's been years since i've been in one
03:36 PM JT-Shop: I'm guessing I'll use a couple of mounted bearings and a shaft with a shaft collar
03:36 PM Tom_L: a friend used to match shoot
03:37 PM Tom_L: the rope will have to be tight or it will sag and eventually it will stretch
03:38 PM Tom_L: maybe a spring tensioner on the back end
03:38 PM JT-Shop: yea I know, I told him to put a takeup on the turnaround pulley
03:38 PM JT-Shop: spring might be a better idea
03:38 PM Tom_L: with a guard in front of it somehow
03:39 PM JT-Shop: every 10' or so on the ceiling is an ar500 plate on a 45
03:40 PM Eric__: It seems like a clothesline setup like the plain folk around here use would work
03:41 PM JT-Shop: basically what he is trying to do but has a barn door track to keep the target at a constant height
03:41 PM Tom_L: http://www.guilfordsportsmen.org/bulletinfiles/RangeDesignGuide.pdf
03:41 PM Tom_L: you can see the tracks on the front page there
03:42 PM Tom_L: maybe you can harvest something there
03:42 PM Tom_L: hah those look like garage door openers
03:42 PM Eric__: the guides in that pdf look a lot more bulletproof than barn door rail
03:43 PM Tom_L: there are a few images there
03:44 PM JT-Shop: https://www.tractorsupply.com/tsc/product/national-hardware-5116-box-rail-galvanized-12-ft
03:44 PM JT-Shop: that's what he has
03:44 PM Tom_L: so the rope _could_ be inside that
03:44 PM Tom_L: with bearing hangars in the trough
03:45 PM JT-Shop: one rope is outside and one inside
03:45 PM Tom_L: they could both be inside if you had a U on top of the trolley to guide the return one
03:46 PM Eric__: I think that would be tight
03:46 PM Tom_L: maybe given the distance
03:46 PM Eric__: just hang it from L brackets
03:46 PM Tom_L: you said _everything_ gets shot though :)
03:46 PM Eric__: I think i would find some hardware that rides on flat plate, be really hard to shoot that
03:47 PM Eric__: plus you can easily get 20' lengths
03:48 PM Eric__: double up the track he has and mount one above to hold the return wire.
03:49 PM Eric__: or just give up and deliver the targets with a quadcopter
03:50 PM gregcnc: the commercial units seem stought
03:51 PM gregcnc: if they have volume the game will be avoiding down time
03:54 PM Tom_L: 83 is a dwg of their drive unit and rail
04:15 PM JT-Shop: his is setup similar
04:19 PM Tom_L: he'll want a \ guard on everything hanging
04:20 PM Tom_L: those commercial trollies are angled
04:23 PM Tom_L: i'm wondering if lead will get up in his rail and jamb the rollers
04:30 PM JT-Shop: I imagine lead will be everywhere
04:36 PM JT-Shop: if an output has an off to on response time of 20us and on to off response time of 20us how fast can it make step pulses?
04:39 PM pcw_home: if response time means delay, 25 KHz, but it might be as low as 12.5KHz or so if response means slow rise/fall time
04:40 PM JT-Shop: it says typ 5us max 20us for off to on and on to off
04:41 PM JT-Shop: even 12,000 steps a second on a stepper is pretty fast I think
04:42 PM JT-Shop: looks like the click plc has one high speed input and one high speed output
04:42 PM pcw_home: Yeah thats more than 600 RPM with 1/4 stepping
04:44 PM JT-Shop: I need to setup one of my leadshine clones with my plc and mess with it a bit 600 rpm is pretty fast for a target retrieval I think
04:48 PM Tom_L: depends how big the pulleys are
04:50 PM JT-Shop: not very big about 2" or so
04:50 PM Tom_L: not sure about this either but you might loop the rope around the drive pulley once for better grip
04:50 PM Tom_L: might wear the rope though
04:51 PM JT-Shop: that's what he was thinking too
04:52 PM Tom_L: keep the knot right behind the target hangar
04:56 PM perry_j1987: g'evening guys
04:56 PM perry_j1987: i 3d printed a motor cover for this steppers online nema23 only to realize steppers online nema23 has a non standard hole pattern lol
04:57 PM perry_j1987: was all excited to make up some new cables and install the thing tonight after things close
04:59 PM Tom_L: JT-Shop, get some rope like mower pull cords
04:59 PM Tom_L: less stretchy
05:01 PM JT-Cave: rope is not my department :)
05:03 PM JT-Cave: but I'll pass that suggestion on to the owner
05:07 PM Tom_L: it's in the weave
05:08 PM JT-Cave: seems they feel stiff to me when I replace one
05:09 PM Tom_L: https://static.usnetting.com/img/rope/polyester.jpg
05:10 PM Tom_L: that type of weave i think
05:11 PM Tom_L: or climbing rope
05:11 PM Tom_L: that thin stuff they use for carrying acessories
05:11 PM Tom_L: like 6000 lb test or so
05:11 PM JT-Cave: I suggested paracord
05:11 PM Tom_L: basically the same thing i think
05:13 PM Tom_L: i've got some regular climbing rope and it doesn't stretch much
05:19 PM Tom_L: https://www.usnetting.com/rope/kevlar/
05:19 PM Tom_L: kinda pricey
05:20 PM XXCoder: bit under dollar a foot
05:22 PM Tom_L: iirc i paid .65/ft for mine quite some time ago
05:23 PM Tom_L: but it's something like 5/8 rope
05:24 PM Tom_L: not sure what regular nylon goes for
05:26 PM Tom_L: that 1/8" kevlar would be plenty heavy enough
05:56 PM JT-Cave: hmm this might be easier on a Rpi4...
06:05 PM Tom_L: the target thing?
06:05 PM JT-Cave: yea
06:05 PM jdh]: what are you shooting?
06:06 PM JT-Cave: a sure step stepper drive is $250 plus a click plc for $100
06:08 PM Tom_L: 1 per lane?
06:09 PM Tom_L: how many lanes did you say? i forgot
06:10 PM JT-Cave: 10
06:10 PM Tom_L: must be a big house
06:10 PM JT-Cave: he added on to it lol
06:10 PM Tom_L: roughly 5-6' per lane?
06:11 PM Tom_L: maybe 4-5
06:11 PM JT-Cave: yea 5' maybe
10:18 PM skunkworks: https://www.youtube.com/watch?v=vnIabBllhmg
10:19 PM XXCoder: https://www.caranddriver.com/news/a31409442/samsung-solid-state-battery-revealed/
10:19 PM XXCoder: might br amazinh in future
10:19 PM XXCoder: did it go wrong way after homing?
10:20 PM skunkworks: no.. It goes to the end of travel.
10:20 PM skunkworks: the home switch is within the motion of the machine.
10:22 PM XXCoder: im not sure whats happening
10:23 PM XXCoder: it looks like it went to trigger switch, back off then move in faster
10:25 PM skunkworks: yes - depending if the machine is on the home switch or not..
10:26 PM skunkworks: back off home switch - travel back to it - then slowly back back off to find home. once found - move to home position.
10:26 PM XXCoder: hey https://youtu.be/wv7mMS5xKks looks like someone used what someone in here made
10:26 PM XXCoder: or something
10:27 PM skunkworks: I used what I made on here..
10:27 PM skunkworks: ;)
10:27 PM XXCoder: oh thats your channel too
10:27 PM XXCoder: sorry my memory suck lol
10:28 PM skunkworks: That's ok.. There isn't any sort of consistancy to think that one person made all the videos.
10:41 PM XXCoder: lol ok
10:41 PM skunkworks: I come from the willy nilly school of video production
10:42 PM XXCoder: my personal is full of random videos
10:42 PM XXCoder: my hobby videos is mainly focused on cnc stuff but havent uploaded anything for few years
10:43 PM skunkworks: XXCoder: this isn't you?
10:43 PM skunkworks: https://www.youtube.com/user/XXCoder/videos
10:44 PM XXCoder: doh i got which account is which backwards
10:44 PM XXCoder: yeah thats my random one
11:20 PM CaptHindsight: "The researchers say that using silver-carbon instead of lithium metal "
11:20 PM CaptHindsight: "The layer of silver-carbon measures only five micrometers thick"
11:20 PM CaptHindsight: silver also tends to migrate
11:20 PM XXCoder: seems that its lot more tough though
11:20 PM XXCoder: 1000 recharges
11:21 PM XXCoder: that means car can go quite a distance, 500,000 miles
11:21 PM CaptHindsight: not sure why, they don't say
11:21 PM CaptHindsight: so might just be speculating vs more reliable, since silver migrates
11:22 PM CaptHindsight: maybe they handle that someway but don't emntion it
11:22 PM XXCoder: possibly patented and secret part
11:22 PM XXCoder: i just hope its indeed that much better
11:22 PM CaptHindsight: patent or secret, but not both :)
11:22 PM XXCoder: true or maybe two aspects, one patented and one secret lol
11:23 PM CaptHindsight: secret patents would be too useful to screw people over
11:23 PM CaptHindsight: public is already bad enough
11:25 PM XXCoder: yeah. though I just hope evenually there will be more
11:25 PM XXCoder: not just for car for example. also come in AA-smiliar cells used on laptops and such batteries
11:25 PM XXCoder: as well as elsewhere
11:25 PM XXCoder: in different forms, like phone batteries
11:25 PM CaptHindsight: won't be low cost
11:26 PM XXCoder: sounds like bump in cost from lathinium ion yeah
11:26 PM XXCoder: i'd accept it for batteries that dont fade as much.
11:26 PM CaptHindsight: it would be a premium first
11:26 PM XXCoder: i still hope for finally huge upgrade to capactors. those last million charges or more
11:27 PM XXCoder: charge much faster too
11:27 PM CaptHindsight: hello, how may I take advantage of you today?
11:27 PM XXCoder: send send me billion dollar loan, 0% interest, no due date