#emc | Logs for 2004-12-29

[00:00:07] <an0n> bye Imperator_
[00:00:17] <Imperator_> bye
[00:00:57] <an0n> that's how they look
[00:00:58] <an0n> :)
[00:01:43] <robin_sz> they do look nice, I'll give you that
[00:02:06] <an0n> hehe
[00:02:30] <gezr> thats like a model R/C engins throtle right?
[00:02:34] <an0n> no
[00:02:35] <robin_sz> yep
[00:02:39] <an0n> it's for a full size car..
[00:02:42] <gezr> chicken/egg
[00:02:49] <an0n> lumenition is competition stuff :)
[00:02:50] <robin_sz> similar design
[00:03:01] <gezr> thats what I meant, ive only seen that on small things
[00:03:06] <robin_sz> sure?
[00:03:10] <an0n> yeah
[00:03:23] <an0n> it's 48mm through it ;)
[00:03:33] <an0n> err 45
[00:03:39] <robin_sz> It will be fine on full throttle,
[00:04:19] <gezr> gezr has changed the topic to: robin_sz I guess I better get to learning how to code hu?
[00:04:21] <ChanServ> ChanServ has changed the topic to: Welcome to the Enhanced Machine Control forum | Regular Developer's meetings every Sunday between 14:00 & 18:00 GMT
[00:04:23] <robin_sz> but they have poor charecterstics on low/mid throttle .. the air hits two restrictions, the front opening and the rear opening
[00:04:27] <gezr> hahaha
[00:04:37] <gezr> cant use the /t feature in this client
[00:04:59] <gezr> Its been far too long since ive used things I guess
[00:05:09] <robin_sz> even the model car guys swap roller throttles for really small butterfly carbs if they can afford it
[00:05:20] <robin_sz> still .. they do look nice ;)
[00:05:40] <an0n> hehe
[00:05:58] <robin_sz> I was listening to a nice engien again today
[00:06:32] <an0n> what kind of engine?
[00:06:35] <robin_sz> V8, fuel injected
[00:06:49] <an0n> nice :)
[00:06:51] <robin_sz> open pipes ...
[00:07:07] <robin_sz> tacho starts at 7k, redlines at 12K
[00:07:13] <an0n> neat :)
[00:07:17] <an0n> *jealous*
[00:07:23] <robin_sz> loud ...
[00:07:31] <an0n> the redline of my engine that I am building is about 9k rpm
[00:07:49] <robin_sz> this is a 1967 F1 engine ...
[00:07:55] <an0n> :D
[00:07:57] <an0n> neat!
[00:08:44] <robin_sz> I cant imagine how much the car is worth ...
[00:08:51] <an0n> what are you going to put it in?
[00:08:56] <an0n> or is it in a f1 car?
[00:08:59] <robin_sz> oh its not mine
[00:09:03] <an0n> ah ok :D
[00:09:05] <robin_sz> its in a classic F1
[00:09:25] <robin_sz> BRM
[00:09:43] <an0n> cool
[00:09:46] <an0n> :)
[00:09:53] <an0n> anyway, I need to go to bed now
[00:09:59] <an0n> laters!
[00:10:07] <robin_sz> you go ... have a nice one
[00:19:15] <gezr> hmm
[00:22:40] <robin_sz> hmm?
[00:22:54] <gezr> yeah,
[00:23:07] <gezr> the new of Irc will wear off soon I hope
[00:23:13] <robin_sz> heh
[00:23:22] <gezr> after 8 years of it, I got out of it
[00:23:33] <robin_sz> I like IRC, I waste too much time on it though
[00:23:37] <gezr> I hope the stuff with the segmot is going well, or hasnt stopped
[00:23:44] <gezr> I have an alternative running:)
[00:23:50] <robin_sz> segmot ...
[00:23:51] <robin_sz> well
[00:23:58] <robin_sz> AIUI, it works fine
[00:24:03] <robin_sz> 98% of the time
[00:24:05] <gezr> aiui?
[00:24:10] <robin_sz> as I understant it
[00:24:17] <gezr> ah
[00:24:31] <robin_sz> but every now and then it craps itself
[00:24:33] <gezr> cradek took a huge step forward last night
[00:24:37] <robin_sz> right
[00:24:40] <robin_sz> thats handy :)
[00:25:04] <gezr> hmm
[00:25:08] <gezr> hehehe
[00:25:09] <robin_sz> theres a 'buffer underun' problem thats been there for many momnths
[00:27:15] <gezr> what I would like to do is learn how one G0 X2. from the program, passes through emc
[00:27:39] <gezr> i doubt it, ts has win and lin clients
[00:30:07] <gezr> ah ha
[00:31:49] <gezr> hey, emcmot is the normally used one?
[00:32:22] <gezr> nevermind
[00:41:43] <gezr> ill be back in a bit
[00:52:29] <gezr> back
[00:52:32] <gezr> didnt miss a beat
[00:58:12] <robin_sz> its getting late .. wife has gone to bed
[00:59:28] <gezr> I imagine
[00:59:53] <robin_sz> and tomorow I have all 3 kids for the whole day
[00:59:58] <robin_sz> that will be hard
[01:00:50] <robin_sz> tiring and difficult
[01:00:55] <robin_sz> ick.
[01:01:03] <robin_sz> better go .. I need the sleep :)
[01:01:13] <gezr> take care :)
[01:01:19] <robin_sz> night
[01:09:28] <gezr> okay, rs274ngc gets to look at the command first I think
[01:26:28] <gezr> no I dont know, just more looking I guess
[02:11:05] <gezr> well im totally lost
[02:19:41] <jepler_> hi guys
[02:20:35] <gezr> howdy jepler_
[02:20:42] <jepler_> today was a good day. I got my retrofit CNC machine to run its first g-code with emc! http://axis.unpy.net/index.cgi/01104286247
[02:21:43] <gezr> cool
[02:23:22] <jepler_> (you'll miss the joke if you don't visit the website)
[02:32:02] <gezr> ive got code on the brain, i probably missed the joke but its awsome :)
[02:32:52] <gezr> thats soo sweet
[02:33:51] <gezr> wait, im talking about the etch a sketch, no mill photo
[02:34:56] <jepler_> that's the "mill"
[02:35:18] <gezr> hahahahaha
[02:35:23] <gezr> thats sweet
[02:35:46] <gezr> I love it
[02:36:17] <jepler_> I may buy a sherline to retrofit in 2005, but for now this is the only CNC machine I have
[02:36:47] <gezr> i ordered some brass to make some chess pieces, and then 3 feet of acme, and 2 nuts to use as a machine for noe
[02:36:49] <gezr> now
[02:36:59] <gezr> didnt spend much at all
[02:37:24] <gezr> Ive had 2 ball bearing drawer slides lying around and thought about a way to make a simple machine today
[02:37:51] <gezr> one fixed axis using one slide | y max travel 12inches or so
[02:38:41] <jepler_> hm, I'm trying to envision this
[02:38:45] <gezr> the other slide atatched to the y one, where the motor rides on a wheel to move with y, its motion --
[02:39:21] <gezr> so I have a xy table and then I have some springs, and some solenoids, ill use to retract with spring, and down with solenoid a pen, so I can make pictures
[02:39:46] <jepler_> I doubt I can add even that simpe a z-axis to my machine
[02:40:19] <gezr> you wouold have to hack the etch-a-sketch
[02:40:31] <jepler_> yeah, and it's not made to be opened and then closed again
[02:41:38] <gezr> well why even hack it, you could do what imdoing using strings and make the pen carrier sorta heavy, ridding on 3 or more marbles, with the pen/stylus in the middle
[02:41:48] <gezr> thats all thats inside the sketch I think
[02:42:25] <gezr> then you could have a paper copy,
[02:43:39] <gezr> I love stuff like that, I had to buy the brass rod today, its for chess pieces for my brother xmass present, the rod and nuts were like 20 bucks I think
[02:44:38] <gezr> hey, are you able to follow through the code, a commanded move of g0 x10. where the tool is at x0y0?
[02:46:19] <gezr> when I look at the code and maybe im not looking right, I dont see where or how, its read, g0 oh okay, were gonna rapid move, where are we now, where are we gonna go, oh its a straight move of one axis, which axis, how far... stuff like that
[02:48:08] <jepler_> I don't follow you
[02:48:44] <jepler_> you're asking how emc works when parsing g-code?
[02:48:55] <gezr> not so much how, but where
[02:49:09] <gezr> when looking at the source
[02:49:51] <jepler_> the rs274ngc parser (in src/rs274ngc_new) reads the g-code line by line, and makes calls to the "canonical machining functions"
[02:50:44] <jepler_> these are functions with names like STRAIGHT_TRAVERSE
[02:51:11] <gezr> is that in emc2 or emc?
[02:51:14] <jepler_> in emc
[02:51:21] <jepler_> I've never looked at emc2
[02:52:09] <gezr> there they are ah
[02:52:11] <jepler_> emctask/emccanon.cc implements these functions, does some extra calculations, and puts a different representation of the actions into a global variable "interp_list"
[02:52:58] <jepler_> that's where I get fuzzy. I think the next step involves transmitting the items in the interp_list over to the realtime side for motion planning
[02:53:29] <jepler_> the rs274ngc_new parser of emc1 is describe pretty well in this document: http://www.linuxcnc.org/handbook/RS274NGC_3/RS274NGC_3TOC.html
[02:53:32] <gezr> okay
[02:54:29] <gezr> one more question, this is probably directly related to c, when I see something like G_1 thats just another way of saying what I see as G1?
[02:56:31] <jepler_> Yes, G_1 refers to G1. What's going on there is that rs274ngc defines some codes like g64.1 which are decimal fractions. rs274ngc_new multiplies those by 10 so that it can treat them as integers. So G_1 is a constant equal to 10, which is the value stored somewhere to indicate that the current motion mode is "g1" (straight feed)
[02:56:45] <jepler_> this is done for all G-codes afaik, but not for M-codes.
[02:57:11] <jepler_> er, I guess I mean G61_1, there's no G64_1
[02:58:25] <gezr> right I saw that in the code
[02:58:46] <gezr> I didnt really see a direct G_1 to g1 but I may not have been in the right place
[02:59:14] <gezr> they would call a 64.1 probably a 641 I think
[02:59:26] <gezr> but okay
[03:00:08] <gezr> im gonna just drag on you guys to explain this simple stuff to me
[03:00:58] <jepler_> "read_g" would parse G1 in the input file and set the state variable block->g_modes[1] to G_1
[03:01:04] <jepler_> in rs274ngc_pre.cc
[03:06:32] <gezr> okay, then there is more stuff reguarding read_g starting on 8805
[03:12:20] <jepler_> one thing about emc: they are layers and layers and layers of it
[03:12:24] <jepler_> l~N
[03:12:26] <jepler_> argh
[03:13:17] <gezr> layers dont matter if I have a starting point, the rest I can bug my friends about, last guy I asked to look at emc outside of emc almmost lost his mind, well he didnt do that, he left programing and is becomming a lawyer
[03:14:08] <gezr> jepler_ : your in the us right?
[03:14:19] <jepler_> gezr: yes. lincon, nebraska to be more exact.
[03:14:33] <gezr> ah cool, Conway arkansas here
[03:16:36] <jepler_> not a part of the country I've been to
[03:17:32] <gezr> I work about a block from the (anything I say from this point on could be taken the wrong way, no matter how I try to say it,) the library,
[03:19:32] <jepler_> the web says conway is 43k people. that's a good size for a town to be.
[03:20:06] <gezr> yeah, its nice
[03:21:33] <jepler_> I'm going to head off .. good luck with figuring out emc.
[03:21:51] <gezr> take care, and thanks for letting me ramble
[03:28:41] <cradek> jepler_: congratulations on your new machine!
[03:28:54] <jepler_> cradek: thanks
[03:30:47] <cradek> sounds like it's awfully fast
[03:30:51] <cradek> that's cool
[03:31:00] <cradek> is it running on your laptop or bdi?
[03:31:11] <jepler_> on the laptop with bdi-live
[03:31:25] <cradek> great
[03:31:30] <cradek> did you find a flexible coupling that works?
[03:31:42] <cradek> (I notice the drawing isn't very round, but it's not awful either)
[03:32:13] <jepler_> if I draw the globe twice in a row, it's clear that it's lost a few steps. But not as many as the nonroundness would seem to imply
[03:32:20] <jepler_> I think it's mostly an EMC tuning issue
[03:32:58] <cradek> you're sure it's losing steps and it's not the etch?
[03:33:44] <jepler_> I'm not sure
[03:34:12] <jepler_> another test was to draw a circle (two arcs) 26 times. It repeated very closely every time, but the square looked rather .. boxy
[03:34:19] <jepler_> er, the circle looked boxy
[03:34:44] <cradek> at the quadrant boundaries or elsewhere?
[03:34:48] <jepler_> yes
[03:34:55] <cradek> which?
[03:35:04] <jepler_> the top, bottom, left, and right seemed flattened
[03:35:21] <cradek> strange
[03:35:50] <cradek> I see something like that on the right of your globe
[03:36:36] <jepler_> yeah
[03:37:32] <jepler_> all of the arc-like bits are flattened. You can see a pattern that one is flattened "up" and the next is flattened "down".
[03:37:32] <cradek> I can't picture what would cause that
[03:37:56] <cradek> probably has to do with the wires on the pulleys inside
[03:38:46] <jepler_> alternating verticals are drawn from bottom-to-top or top-to-bottom
[03:39:02] <cradek> I see the pattern in the verticals now that you mention it
[03:39:03] <jepler_> so the flattening-direction and movement-direction are related
[03:40:11] <cradek> you didn't have any problems with using your laptop (controller missed realtime deadline)?
[03:40:22] <jepler_> no messages like that
[03:40:48] <cradek> that's encouraging
[03:41:03] <cradek> after my luck I thought maybe all laptops were useless for RT
[03:41:26] <cradek> but maybe it's just mine (or APM that requires switching to real mode)
[03:41:34] <jepler_> I didn't try f.e. closing the lid switch while it was running .. or building a kernel .. but without taunting, it worked well for most of an hour
[03:41:58] <cradek> slick
[03:42:26] <jepler_> should I worry if my steppers get warm, or only if they get too warm to touch?
[03:42:39] <cradek> warm is fine - hot is even sometimes fine
[03:42:59] <cradek> you're running them within the specs, right?
[03:43:05] <gezr> how much v are you feeding them?
[03:43:21] <cradek> mine have never even gotten warm, but I suspect they're grossly underdriven
[03:43:39] <cradek> it would be nice if emc could idle down the motors, but it can't
[03:43:47] <jepler_> 12V (the value written on the motor casing) but with two windings on at a time
[03:43:48] <gezr> you can I dont know the exact numberrs but can really toss the voltage at them
[03:44:00] <cradek> oh right
[03:44:00] <jepler_> I also don't know if that's 12V in bipolar or unipolar operation
[03:44:14] <cradek> oh, that would be a big difference wouldn't it
[03:44:20] <cradek> surely it's unipolar
[03:44:37] <cradek> how warm?
[03:44:55] <gezr> they can run safely hot enough to burn after a few seconds of touching
[03:45:00] <gezr> they are built that way
[03:45:27] <cradek> that would make me really nervous, but I agree I have read that most steppers can get pretty hot
[03:45:31] <jepler_> I dunno, not so hot there's any discomfort in touching them. They're just nice and warm
[03:45:48] <cradek> after being on an hour? that's perfectly fine
[03:45:52] <gezr> try em at 24v if you can
[03:46:10] <gezr> they wont be eating so much current at that v
[03:46:11] <jepler_> gezr: my driver board is too simple for that. No chopper or anthing
[03:46:46] <gezr> single ic?
[03:46:50] <gezr> per stepper?
[03:46:53] <jepler_> yes
[03:46:59] <jepler_> ULN2803, a simple darlington driver chip
[03:47:04] <gezr> oh yeah
[03:47:18] <gezr> you can still toss v at it, v comes into the motor, and the chip opens the gate right?
[03:47:28] <jepler_> right
[03:47:44] <gezr> do your chips get hot as well?
[03:47:47] <jepler_> the parts cost for the board is somewhat under $10, I think
[03:47:58] <jepler_> the chips get a little bit warm .. I think I calculated that they dissipate ~1W each
[03:48:12] <cradek> you need a nice close-up photo of the board while it's still shiny
[03:48:18] <gezr> those darlingtons can sink a bunch of current too
[03:48:19] <cradek> you can also stress that it was made with emc
[03:48:39] <jepler_> cradek: reload the page
[03:48:56] <jepler_> there's a photo of the unpopulated board there
[03:49:01] <cradek> ahhh
[03:49:03] <cradek> that's beautiful
[03:49:19] <jepler_> backlit, so you can't see how shiny the copper is but I still think it's nice
[03:49:23] <jepler_> it looks sooooo cleanly cut
[03:49:33] <jepler_> "It's a simple constant-voltage L/R drive. I made the circuit board using EAGLE, and milled it on my friend's real CNC machine."
[03:49:35] <cradek> yeah
[03:49:40] <cradek> (You can use my name)
[03:49:47] <cradek> it's perfectly made
[03:50:20] <cradek> a work of art
[03:50:46] <gezr> that is nice
[03:50:51] <cradek> haha
[03:51:00] <cradek> "my Chris's ... machine"
[03:51:04] <jepler_> oops
[03:51:16] <jepler_> fixed
[03:51:30] <jepler_> I have to go do fun stuff like wash the dishes and feed the cats now. see you guys around.
[03:51:39] <gezr> your both in the same town?
[03:51:42] <jepler_> yeah
[03:51:46] <gezr> ah cool
[03:51:46] <jepler_> old friends
[03:52:13] <cradek> ok, goodnight
[03:52:21] <gezr> ffree samples
[03:52:26] <gezr> you need free samples
[03:52:34] <cradek> of what?
[03:52:38] <gezr> chips
[03:52:44] <gezr> they will send you like 6 free
[03:52:47] <gezr> Im trying to remember
[03:52:59] <gezr> allegro
[03:53:18] <gezr> unc5804b
[03:53:23] <gezr> they are nice stepper chips :)
[03:53:45] <jepler_> I was reading about some of their chips today. I think they're what the xylotex boards are based on.
[03:53:52] <gezr> yeah
[03:54:00] <cradek> and you found that you can't buy them anywhere, right?
[03:54:11] <gezr> I need to order some more
[03:54:19] <gezr> you get them directly from alegro
[03:54:27] <gezr> I may have 2 extra
[03:54:38] <gezr> i roasted one on accident
[03:55:19] <gezr> oh one more thing, do you have a good huge resistor between the motor and its input V?
[03:55:28] <gezr> your probably gone, I shouldnt try and keepyou,
[03:55:35] <gezr> cradek : maybe you know if he does?
[03:55:52] <gezr> that will also cut the heat down
[03:56:05] <cradek> no, he's not using L/4R drive, just simple switching with V= the motor rating
[03:56:31] <gezr> okay
[03:56:45] <cradek> the design is entirely as basic as possible while still working
[03:56:55] <gezr> all very cool
[03:57:12] <cradek> those were the design criteria: working, cheap, simple (in about that order)
[03:57:42] <gezr> :)
[03:59:01] <gezr> so what is yoru hobby the machining or the computing?
[04:00:14] <cradek> oh both
[04:00:30] <cradek> I have more hobbies than anyone should
[04:01:04] <gezr> im either just starting off or too far behind, I hope you havent given up on the motion stuff yet
[04:01:25] <cradek> I am an ok amateur machinist, an ok programmer, an ok musician, an ok lots of other things.
[04:02:03] <cradek> no, I just got home too late to work on it tonight. I'll work on it at least a little bit more, and if I can't figure out exactly what's up, I'll band-aid it so it runs until someone smarter looks at it.
[04:02:08] <gezr> I work as a machinist, ive always loved computers and programing, just never really learned much as far as programing
[04:02:20] <cradek> sounds like a great opportunity to learn something new
[04:02:55] <gezr> as long as I dont start thinking im asking stupid stuff like i used to get into
[04:03:04] <cradek> I also fix mechanical watches (it is probably what got me into miniature machine work) and antique radios
[04:03:17] <cradek> I like to work on cars some
[04:03:36] <gezr> I have a good friend with a drinking problem who does the antique radios thing or did, he has a full blown shop now dedicated to machining
[04:04:00] <gezr> well I shouldnt say that about him, I dont spend enough time with the guy, he is really fun
[04:04:27] <cradek> I enjoy it. It's nice to restore old things that have quality we don't have now.
[04:04:39] <cradek> (it's the same with watches)
[04:05:13] <gezr> Ijust want to make extremely cheap machine tools for home use that dont have to travel on a boat to get to a us destination
[04:05:27] <cradek> that would be nice.
[04:05:44] <cradek> maxnc is pretty cheap... It would be hard to beat them
[04:05:54] <gezr> the earlier talk about different castings moved things up a bit
[04:06:59] <gezr> I go to a localharbor frieght fromtime to time, they have that 400$ mill, and all I can think at that moment is what I would want to make myself
[04:07:54] <gezr> ive worked on some really nice machines
[04:08:31] <cradek> what $400 mill is this?
[04:08:50] <gezr> the designe I have in my head now, can be set up to be, a hobb, 3 axis mill, 4 axis mill, 5 axis mill, vertical lathe
[04:10:11] <gezr> and would look good, on a dinner table
[04:10:46] <gezr> oh, let me find a link, I thik grizzly sells one as well
[04:11:15] <gezr> http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=47158
[04:11:18] <cradek> for small stuff I like my Sherline equipment
[04:11:21] <gezr> my bad 300$
[04:11:42] <gezr> its not bad, its not what I need though
[04:12:12] <gezr> my current fettish, is gear cutting
[04:13:11] <cradek> that's a very cute machine
[04:13:25] <cradek> I wonder if you could start with it and make something useful
[04:14:16] <gezr> i bet I could
[04:15:02] <cradek> I wonder what the spindle bearings are like
[04:15:13] <cradek> it might just be a cheap drill press not made for side pressure
[04:15:47] <cradek> doesn't say if it uses acme threads
[04:15:53] <gezr> there are lots of articles on the web about those size machines, its 50% on thumbs up and thumbs down
[04:16:24] <gezr> lots of articles on mods for them as well, Im pretty sure they use acme threads
[04:16:33] <gezr> but i think its metric stuff graduated in inch
[04:16:43] <cradek> don't follow
[04:16:56] <cradek> you mean the lead screws are metric thread?
[04:17:00] <gezr> I think so
[04:17:15] <gezr> but the handwheels are graduated in inches
[04:17:34] <gezr> you move the crank .001 inch, it moves .001 inch,
[04:17:43] <gezr> but the accual thread is a metric pitch
[04:17:59] <gezr> its been a while since I really specked one out
[04:19:05] <cradek> that doesn't make sense... what would the markings on the wheels look like?
[04:19:50] <gezr> im looking
[04:21:26] <gezr> I dont think they go to 100 or 200 divisions, its more like 120/rev
[04:21:56] <gezr> http://www.mini-lathe.com/Mini_mill/Main/mini-mill.htm
[04:22:26] <gezr> http://www.mini-lathe.com/Mini_mill/Features/features.htm#Graduations
[04:22:28] <gezr> there it is
[04:23:01] <gezr> oh okay its not a metric thread, but not a 10 pitch, heck it may be a metric thread
[04:24:07] <cradek> ugh
[04:24:14] <cradek> 0625/rev is insane
[04:24:15] <gezr> sorta strange hu?
[04:24:31] <gezr> all those mills are farm raised,and sold to whom ever
[04:24:44] <gezr> they arnt bad
[04:25:04] <gezr> screws can be replaced, and the likes, many modifications on that page are shown
[04:25:59] <gezr> they have heaver machiens as well
[04:27:02] <gezr> http://www.monarchmt.com/PMC.htm is what I want to build,in baby form
[04:27:13] <gezr> ive accually ran that machine
[04:32:25] <cradek> oops, it's time for bed here
[04:32:29] <cradek> goodnight
[04:32:34] <gezr> night
[04:33:37] <gezr> ill probably never make it