#garfield Logs

Sep 08 2020

02:02 AM rue_mohr: zhanx_workshop_, wait a sec... you on twitter?
02:08 AM zhanx_workshop_: nope
02:08 AM zhanx_workshop_: i dont do social media really
02:08 AM rue_mohr: ok, thought I caught on to something
02:12 AM rue_mohr: I'm buying rhinestones from china for making jewel indicators...
02:20 AM rue_mohr: apparently chineese hunt with slingshots and glass balls
02:39 AM rue_mohr: all 8mm rgb leds have a controller chip in them
02:39 AM rue_mohr: there are 3 types of controller chips
02:39 AM rue_mohr: apa106
02:39 AM rue_mohr: ws2811
02:40 AM rue_mohr: and P9823
02:43 AM rue_mohr: ah, found one thats normal
02:43 AM rue_mohr: https://www.aliexpress.com/item/10000194171407.html
02:43 AM rue_mohr: thats a normal led, right?
02:51 AM rue_mohr: zhanx_workshop_, your still up?
02:52 AM rue_mohr: https://www.aliexpress.com/item/32959410939.html power indicator, what colour?
02:56 AM rue_mohr: ok I need to stop shopping and go to bed
03:00 AM rue_mohr: https://www.aliexpress.com/item/32867137645.html OMG hell HAS risen!!!
03:14 AM zhanx_workshop_: blue and why do you need the screws? i was digging a hole
03:16 AM rue_mohr: I need to make indicators
03:16 AM rue_mohr: the hex screws are almost the right starting shape
03:18 AM zhanx_workshop_: k
03:18 AM rue_mohr: there may also be a suitable pipe fitting
03:19 AM rue_mohr: I cant sleep, being awake isn't helping
03:31 AM rue_mohr: I cant find hose barb and caps
03:31 AM rue_mohr: in brass
03:38 AM rue_bed2: china prices on that stuff aren't really too awesome anyhow
08:11 AM aandrew: Tom_L: I can't tell what the "open under load" rating of that contactor is, so I'd conservatively say no
08:11 AM aandrew: Tom_L: is there a reason you don't trust the e-stop input of the VFD?
02:21 PM rue_mohr: ugh
02:21 PM Tom_L: got an estop, 24v and 110v contactor
02:22 PM Tom_L: now i have to review all my pinouts
02:26 PM rue_mohr: I was in a 24" crawlspace
02:27 PM rue_mohr: putting heat trace and insulation on the fire line
02:27 PM rue_mohr: and a freaking compression fitting came apart
02:27 PM Tom_L: fun
02:27 PM rue_mohr: 150psi out a 1" pipe, and my reflex is to try to cap it off with my hand
02:28 PM Tom_L: i'm not sure i need the contactor for the vfd
02:28 PM Tom_L: if i use it's 'enable' signal
02:28 PM Tom_L: ?
02:28 PM Tom_L: but i may put it on the power to the stepper drivers
02:28 PM rue_mohr: depends how safe you want the disconnect to be
02:28 PM Tom_L: i got 2 but haven't decided quite how i'm going to use them
02:28 PM rue_mohr: the vfd can stop the motor faster than disconnecting the power
02:28 PM Tom_L: i may take the 110v one back for another 24v one
02:29 PM rue_mohr: I could have mentioned that
02:29 PM Tom_L: and switch the vfd on one and the stepper drivers on the other one
02:29 PM rue_mohr: it can do active braking
02:29 PM rue_mohr: I'm soaked
02:29 PM rue_mohr: luckily, I'd taken my phone off cause there was no reception in there
02:29 PM Tom_L: or just use one on the stepper drivers and ena on the vfd
02:30 PM rue_mohr: fished my flashlight out after, pulled the batteries, its drying
02:30 PM Tom_L: hook the estop to a dpdt relay to drive each of the contactor coils
02:30 PM Tom_L: it's already in there unused
02:31 PM Tom_L: that way i can keep the 48v supply on having 5v for the control boards
02:31 PM rue_mohr: I think the second reflex was to try to push the pipe back in
02:31 PM Tom_L: heh
02:31 PM rue_mohr: but, by then the logic had kicked in
02:31 PM rue_mohr: as it had just said "you cant hold off the water with your hand"
02:31 PM Tom_L: my basement craw is about 15" wide
02:31 PM rue_mohr: it then moved on to "JUST GET OUT"
02:32 PM Tom_L: on the sides
02:32 PM rue_mohr: this is a nice one, concrete skim bottom
02:32 PM rue_mohr: brand new
02:33 PM Tom_L: the trick is to not hook yourself on anything and decide to panic
02:33 PM rue_mohr: I'd just fit the last peice of insulation tape
02:34 PM rue_mohr: I have a little voice saying that it didn't see the pipe slip,
02:34 PM rue_mohr: its not listening to the one saying how fast it would have moved
02:35 PM Tom_L: under pressure?
02:35 PM rue_mohr: 150psi
02:35 PM Tom_L: who's to fix that?
02:36 PM Tom_L: sounds like a plumber not a sparkie
02:36 PM rue_mohr: the sprinkler fitter that did it
02:36 PM rue_mohr: yea, I scrambled to get someone there and get the water shut off
02:36 PM rue_mohr: at that point, its out of my hands
02:37 PM Tom_L: i'm gonna have to remove one of the transformers or i won't have room to mount the contactor
02:37 PM Tom_L: it should do fine without one
02:38 PM Tom_L: question is exactly how to tie the digital estop in with the physical one
02:38 PM rue_mohr: did you know the VA on those?
02:39 PM Tom_L: which?
02:39 PM Tom_L: i'll take a pic
02:39 PM rue_mohr: the left, right and middle one
02:39 PM Tom_L: oh
02:39 PM Tom_L: 48v 6A ea
02:39 PM Tom_L: supposedly
02:40 PM Tom_L: i could probably get by with just one
02:40 PM rue_mohr: ok
02:40 PM Tom_L: they're wired in parallel
02:40 PM Tom_L: all 3
02:40 PM rue_mohr: so, measure your draw...
02:40 PM Tom_L: don't really have a good meter to do that
02:41 PM Tom_L: it'd have to go thru my fluke leads
02:41 PM Tom_L: and i'm not sure how much they'd take
02:42 PM rue_mohr: I need to find dry pants..
02:42 PM rue_mohr: no 20A leads?
02:42 PM Tom_L: on your lunch break?
02:42 PM Tom_L: no
02:42 PM rue_mohr: yea, and change clothes
02:42 PM Tom_L: meter is only good for 10A anyway
02:43 PM rue_mohr: well, you might be under that
02:43 PM Tom_L: how would it act if they weren't big enough?
02:43 PM Tom_L: just get hot?
02:43 PM rue_mohr: dropped steps
02:44 PM Tom_L: they run ice cold right now
02:44 PM Tom_L: well, nearly
02:44 PM rue_mohr: oh, well if their rated 6A, go by that
02:44 PM Tom_L: that's what the guy told me
02:44 PM rue_mohr: even if their a bit overloaded their fine
02:44 PM Tom_L: they're pretty hefty
02:44 PM rue_mohr: not that I suggest keeping them overloaded
02:45 PM Tom_L: one is ~3x bigger than the original sherline transformer
02:45 PM Tom_L: i just used all 3 because he had 3 on hand surplus so i got them all
02:46 PM Tom_L: i can always put it back
02:47 PM Tom_L: is is ok to use a relay contacts to drive the contactor coils?
02:47 PM rue_mohr: ?
02:48 PM Tom_L: so, small dpdt relay using one leg of each to drive 2 contactors coils
02:48 PM Tom_L: then the contactors would connect the stepper drivers on one and the vfd on the other
02:52 PM rue_mohr: sure
02:52 PM rue_mohr: tho I wonder if they could shut down faster on their own
02:52 PM rue_mohr: I can see it as a safety lockout
02:52 PM rue_mohr: mine hits a disable on the stepper drives
02:59 PM Tom_L: then i don't need the contactors unless i just hook them up to the physical estop
02:59 PM Tom_L: but i'll probably wire it in series with the estop signal
03:04 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/cnc/Mill_Steel/Wiring/contactor1.jpg
03:04 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/cnc/Mill_Steel/Wiring/contactor2.jpg
05:49 PM aandrew: Tom_L: no, I mean a DI on the VFD should serve as an e-stop
05:50 PM aandrew: definite purpose is usually a lighter contactor - not sure what those two are rated (looking up the codes in a moment or few)
05:54 PM aandrew: looks like they have an AC1 rating of 40A
05:54 PM aandrew: I'm a little rusty, but I'd wager the input side of a VFD is not very inductive; you've got semiconductor switches (diodes or SCRs) feeding a big fucking cap bank
06:50 PM Tom_L: i haven't fully decided how i'm going to do it
06:51 PM Tom_L: i may just use enable on the vfd
08:10 PM rue_shop1: also keep in mind the vfd can be programmed to do a brake-stop
08:10 PM rue_shop1: dc injection
08:10 PM rue_shop1: forces the motor to a stop pretty fast
08:11 PM rue_shop1: play when you get it, I can give you a hand
08:12 PM rue_shop1: testing DC brake, have the motor secured down
08:12 PM Tom_L: there aren't that many options on this one
08:12 PM Tom_L: plenty but maybe lacking some
08:13 PM Tom_L: i planned on bench running it first with a pot on the analog input
08:14 PM Tom_L: it's got an internal brake resistor but the say if you use it alot, get an external one
08:26 PM aandrew: yeah but you can only really do that if you have a DC braking resistor or if your VFD can backfeed
08:27 PM rue_mohr: I saw one that use a constant current brake of some kind
08:27 PM rue_mohr: damn it stopped fast
08:27 PM aandrew: my boss back then developed DC injection braking using regular old (SCR) soft starters
08:27 PM aandrew: we could stop the 50hp test motor so fast it would flip off the cart
08:28 PM Tom_L: i moved the mill a bit and took the control off the wall mount tonight so i can get to it easier
08:29 PM rue_mohr: so I got some uln2981
08:30 PM rue_mohr: with that and a 2803 I can make 4 H bridges in just 2 chips
08:30 PM aandrew: nice
08:31 PM rue_mohr: so, I have another power supply design issue
08:31 PM rue_mohr: that resistor decade box I used a push-on/push-off power siwtch
08:32 PM rue_mohr: I usually use a small rocker switch
08:32 PM rue_mohr: but they booth have issues on small equip, having to hold it down while switching things on/off
08:32 PM Tom_L: 100 ohm 100w brake resistor
08:33 PM rue_mohr: so, I had an idea for one of the other cases, to use a 2 position turn power switch
08:35 PM rue_mohr: twitter is going crazy
08:35 PM rue_mohr: mostly over the allen key wood screw
08:35 PM Tom_L: you gettin any smoke from the W coast fires?
08:35 PM rue_mohr: who uses an alley head on a wood screw????
08:35 PM rue_mohr: I think so, its smokey here
08:36 PM Tom_L: ever wear a mask for it?
08:36 PM rue_mohr: no, often wished I had one
08:36 PM Tom_L: just wondered how bad it got..
08:36 PM rue_mohr: brutal on your throat after a while
08:36 PM Tom_L: yeah i already have issues like that
08:41 PM aandrew: rue_mohr: you got fires up there?!
08:43 PM aandrew: I've seen hex heads on ikea wood screws, but not that specific kind of head
09:20 PM rue_mohr: yea
09:21 PM rue_mohr: I immediatly think of havign to thread one into wood with a angle key
09:22 PM rue_mohr: wait, I can think of a type os switch the 80's had that I'v not considered yet
09:23 PM rue_mohr: chrome recessed toggle
09:23 PM rue_mohr: paddle handle
09:57 PM Tom_L: new version of linuxcnc was released to night
09:58 PM Tom_L: here's the bucket list: http://linuxcnc.org/2020/09/08/LinuxCNC-2.8.0/
11:02 PM rue_mohr: mhm