#emc | Logs for 2007-08-23

[00:08:39] <robin_sz> sigh ... bought a new phone
[00:08:41] <robin_sz> sigh
[00:08:45] <robin_sz> shoot me now.
[00:09:22] <robin_sz> probably the worst bit of technology I have ever EVER had the misfortune to own
[00:39:30] <cradek> this is perverse - I hacked emc to have the same quirks my bridgeport does, so I can check and preview my gcode
[00:39:50] <cradek> instead of locking up, though, emc gives an error message!
[00:49:33] <Degas> Hello guys i´m back
[00:49:40] <Degas> I was dinning
[00:49:55] <Degas> well, i restored the config files, it solved my problem
[00:49:58] <Degas> Thanks a lot!
[02:47:12] <Skullworks-PGAB> OK - here is an off the wall question.
[02:48:36] <Skullworks-PGAB> Could a rotary axis be hidden/embedded in classic ladder - such that it would not show up in a gui EMC2 front end.
[02:49:23] <cradek> sure, you can have extra pid loops/stepgens/etc in hal that emc itself doesn't know about
[02:49:57] <cradek> imagine a rotary table used as a tool changer turret
[02:50:12] <Skullworks-PGAB> the application is to put a servo on a rotary table - mount the rotary table on a lathe and bolt a turret front on it
[02:50:35] <Skullworks-PGAB> exactly
[02:50:40] <cradek> sounds fun
[02:50:40] <tomp> hehe java batik now running squiggle & the hektor simulation, i can get file writes with the data now for halstreamer.. but cpu is at 100% and it's taking forever to trace 1 pass ( well it can run like a rendering farm, while i sleep ;)
[02:52:36] <Skullworks-PGAB> so - use a 4" on a 7x12 lathe - might be able to fit 8 tool positions - but might only work with 6
[02:52:57] <Skullworks-PGAB> Need to model it up in Solidworks
[02:53:06] <cradek> hell I should do this, I think I have a rotary table that could work
[02:53:28] <cradek> first tool changer on a sherline lathe, I bet
[02:53:44] <Skullworks-PGAB> nice part is you could make both turrets - and swap them off the rotary table.
[02:53:58] <Skullworks-PGAB> Seig - cast iron
[02:54:31] <Skullworks-PGAB> 7 x 12 from Homier is $299
[02:54:54] <cradek> well I already have this one and it's already cnc
[02:55:30] <Skullworks-PGAB> I can buy one of those Rubbermade carts - put all the PC & Powersupplies etc on the lower shelf
[02:55:45] <Skullworks-PGAB> lathe on top
[03:02:33] <Skullworks-PGAB> cradek - we have a monster Hwacheon lathe with an oversived turret - the design allows the tool Centerline to be below the turret centerline
[03:23:56] <ds2> Mmmmm minilathe with tool changer
[03:23:57] <Adam> Hello all
[03:27:43] <toast> some lathes take CAT-40
[03:27:57] <toast> and have an 80-100 slot toolchanger
[03:28:06] <toast> i think this is a brilliant idea, ablit slower
[03:41:25] <ds2> on the lathe tool part or for live tooling?
[04:00:13] <chester> Testing testing
[06:11:10] <Jymmm> SWPadnos: you awake?
[06:11:24] <SWPadnos> almost asleep. what's up?
[06:28:24] <Twingy> anyone up for a RS274X -> G-Code demo video?
[11:29:43] <anonimasu> hi
[11:29:43] <anonimasu> hi
[11:29:45] <anonimasu> ^_^
[11:53:48] <fenn> meep
[12:09:26] <anonimasu> what's up?
[12:10:23] <fenn> reading about sony's psychic phenomena research
[12:10:33] <fenn> http://www.remoteviewer.nu/index.php?name=News&file=article&sid=723
[12:12:27] <fenn> yoichiro sako has 172 patents
[12:15:20] <anonimasu> ok
[12:18:55] <anonimasu> im going to machine some stuff..
[12:19:03] <fenn> what stuff?
[12:23:30] <anonimasu> a housing for a sensor
[13:30:36] <jepler> skunkworks_: Estimated delivery: Aug 28, 2007
[13:31:17] <skunkworks_> aww.
[13:31:23] <archivist> horse drawn UPS
[13:31:57] <skunkworks_> it seems to take forever for stuff to come from CA
[13:31:59] <archivist> its horrible waiting for a new toy
[13:32:33] <Dallur> just be glad it's not USPS
[13:33:27] <archivist> USPS to the UK is by boat
[13:33:32] <skunkworks_> actually I have had really good luck wht usps priority. I always get it within 2 days after purchasing it.
[13:33:39] <jepler> archivist: you should move over here to what we like to call the "first world"
[13:33:43] <Dallur> usps international is always > 1 month and can take up to 3 months, I suspect they ship the stuff around the world before it gets delivered
[13:33:45] <jepler> har har
[13:34:16] <archivist> jepler er this is the first world
[13:34:41] <jepler> archivist: american rednecks disagree
[13:34:52] <Dallur> to bad the second world does not exist anymore
[13:35:03] <skunkworks_> was that france? ;)
[13:35:35] <Dallur> 1.st world == Western Europe and USA
[13:35:51] <Dallur> 2nd world == USSR and allies
[13:36:23] <Dallur> most of which are now just considered to be a part of "Europe"
[13:36:36] <jepler> don't worry, I am saying it tongue-in-cheek
[13:36:40] <archivist> 1st world UK, 2nd world ... the rest
[13:36:45] <archivist> hehe
[13:37:04] <jepler> in fact I'd love to get back to the UK for another vacation
[13:37:05] <Dallur> archivist: and USA is just a colony right ?
[13:37:10] <skunkworks_> heh
[13:37:19] <archivist> Dallur, yup
[13:38:27] <SWPadnos> reality: first world = middle east, China, and India
[13:39:04] <skunkworks_> yah - who do you get when you call for tech support..
[13:39:29] <SWPadnos> well, I'm speaking historically, but I guess everything goes full circle at some point ...
[13:41:32] <archivist> Egypt-Rome-France(for 5mins)-UK-USA-China
[13:42:40] <SWPadnos> Egypt = middle east, but you forgot that Indian and China both have recorded history going back around 5000-6000 years as well
[13:42:46] <SWPadnos> s/Indian/India/
[13:43:10] <SWPadnos> (as do the Israelis and Egyptians)
[13:43:42] <skunkworks_> there was a neat show on how they had ways to drill for oil, gas and salt thousands of years ago.
[15:08:35] <CIA-24> 03jepler 07TRUNK * 10emc2/src/hal/drivers/pluto_step.comp:
[15:08:35] <CIA-24> add "speed range" to pluto-step, which allows a trade-off between resolution
[15:08:35] <CIA-24> at low velocity and highest speed. recompile firmware.
[15:08:36] <CIA-24> 03jepler 07TRUNK * 10emc2/src/hal/drivers/pluto_step_firmware/ (5 files):
[15:08:36] <CIA-24> add "speed range" to pluto-step, which allows a trade-off between resolution
[15:08:36] <CIA-24> at low velocity and highest speed. recompile firmware.
[15:10:04] <cradek> jepler: neato.
[15:11:09] <SWPadnos> "floating point" step generation ;)
[15:11:11] <jepler> cradek: I haven't fully tested the "trade-off" yet but I wanted to get it out of my local tree
[15:11:37] <SWPadnos> is the divider in powers-of-2, or divide-by-n?
[15:11:40] <jepler> powers-of-2
[15:12:01] <SWPadnos> ok, that should wok nicely (either would, but 2^n should give better range)
[15:12:39] <SWPadnos> FWIW, the G-Rex does the same thing
[15:12:54] <jepler> oh really
[15:13:17] <jepler> they didn't choose a big enough FPGA that there was room for "big enough" accumulators?
[15:13:37] <jepler> that would sure have been my first choice
[15:13:39] <SWPadnos> hmmm. actually, the G2002 did that, I'm not sure the G-Rex still does
[15:14:41] <SWPadnos> well, the FPGA is 50kgates, and Mariss says it's totally full
[15:15:17] <SWPadnos> which I believe, because it does have a lightweight microprocessor embedded in it :)
[15:15:44] <jepler> that could do it
[15:16:27] <SWPadnos> the 6 step generators and motor encoders, plus SPI for the digital I/O also contribute
[15:17:30] <jepler> the updated docs including an explanation of "speedrange": http://linuxcnc.org/docs/devel/html/man/man9/pluto_step.9.html
[15:19:25] <SWPadnos> hmmm. 76 Hz minimum may be a little high. if there's a spare bit or two for the divider, I'd use it
[15:20:31] <jepler> when the speed is very low, emc will switch between commanding zero speed or commanding minimum speed
[15:20:58] <SWPadnos> oh - this is a load-time parameter, not changed on the fly (?)
[15:21:05] <jepler> yes
[15:21:18] <SWPadnos> ah - then it isn't like the G-Rex :)
[15:21:20] <jepler> it also applies to all the step generators
[15:21:39] <cradek> doesn't anything slower than one step per servo cycle become unnecessary, since emc can generate one step at a time in that case?
[15:22:00] <jepler> there's this weird interplay between the servo rate, the minimum step rate, and fractional step feedback
[15:22:40] <SWPadnos> you still want to be able to generate lots of steps, but a G1 X10 Y0.1 F10 needs very low rates on the Y axis
[15:22:41] <jepler> you can get as low a step rate as you want on average, but the steps are issued at a somewhat irregular rate
[15:36:32] <skunkworks_> jepler: are you planning on getting one of the parallel port mesa cards?
[15:39:11] <jepler> skunkworks_: probably
[15:39:18] <jepler> skunkworks_: whether I'll actually put it to use is another thing altogether
[15:39:29] <jepler> huh I wonder what I changed
[15:39:38] <skunkworks_> what are you going to do with all those gates? ;)
[15:39:46] <skunkworks_> you will be swimming in them
[15:39:49] <jepler> I was able to enlarge the velocity registers from 11 to 15 bits and it still fits
[15:39:59] <jepler> I should say, I wonder what *else* I changed
[15:41:24] <jepler> I guess I mean from 12 to 16, the new size is reg[15:0] in vhdl
[15:41:35] <jepler> increasing it beyond 16 bits requires more changes..
[15:54:19] <jepler> but if I can enlarge it 4 bits and still fit, that gives the same benefits as the speed range selection
[15:54:43] <cradek> yeah, it almost worked OK before...
[16:02:36] <jepler> if the irregularity was 1/16 as big (4 bits more resoultion) it might not be noticed
[16:04:25] <SWPadnos> howdy Ray - long time no see
[16:04:27] <cradek> hi ray
[16:05:10] <jepler> hi ray!
[16:05:19] <SWPadnos> argh - time to restart Mozilla. I've got a stuck window on screen - it loads pages fine, but doesn't respond to mouse/keyboard events :(
[16:05:26] <SWPadnos> bbias
[16:08:01] <rayh> hi guys
[16:08:22] <rayh> how do I change my cloak here.
[16:08:34] <SWPadnos> unbutton it at the top ... :)
[16:08:56] <archivist> * archivist covers his eyes
[16:09:04] <SWPadnos> it's just a cloak
[16:09:08] <skunkworks_> that is an odd question
[16:09:16] <cradek> I think you have to ask a freenode admin, but I don't know how to find them
[16:09:28] <archivist> #freenode
[16:10:36] <archivist> or read the FreeNode faq but I never worked it out
[16:13:39] <jepler> the FAQ says "/quote stats p" but that lists 0 people
[16:16:18] <plattschnauze> Hallo , I still have a problem witth running my robot on EMC. in manuel mode I can run it as fast as i want, in Auto or MDI i could take F.. as high as i want, but my Robot is not nearly as fast as in Manuel. It work but to slow. Is it possible that the Cycletimes or periods had to be Change ??
[16:22:22] <skunkworks_> you mean jogging the machine is fast - but mdi or auto is slow?
[16:24:11] <plattschnauze> yes
[16:25:30] <skunkworks_> could you pastebin.ca your ini file? - I don't know if I can help..
[16:25:42] <skunkworks_> could it be the limits in the traj section?
[16:26:52] <skunkworks_> [traj] section of the ini - I would think jogging may only use the limits for each axis/joint but coordinated motion would first limit by the traj and individual axiss.
[16:27:43] <skunkworks_> (I am not an expert)
[16:28:18] <plattschnauze> same says alex, but it doesnt change anything , move them up or down makes no sens
[16:29:50] <fenn> skunkworks_: that sounds right to me
[16:30:39] <skunkworks_> plattschnauze: could you pastebin.ca your ini?
[16:34:36] <skunkworks_> fenn: thanks - Sometimes I make stuff up that sounds good to me ;)
[16:48:21] <Adam-alt> Is there a setting in EMC for a spindle speed multiplier? My spindle has a few belt options and I wish to just leave it on a high ratio.
[16:49:15] <Adam-alt> I will be putting an encoder on the motor side aswell, so the encoder will need the mulitplier aswell to display the correct spindle speed.
[16:53:17] <fenn> i think you would have to cook something up with halvcp and hal to multiply the spindle speed by the belt ratio
[16:55:42] <fenn> the scale component should do what you want
[16:56:26] <fenn> or if you didnt want to use halvcp you could just set the ratio with halcmd (through a shell script probably)
[17:01:06] <Adam-alt> ok I will look into that stuff, I havent started any software yet, just hardware.
[17:03:12] <Adam-alt> I guess my other option is to just find the same pully for the motor and run a 1:1 ratio
[17:27:25] <fenn> Adam-alt: different belt ratios is a good thing, you should keep it
[17:31:38] <skunkworks_> adam-alt: is it a toothed belt? if not - you cannot put the encoder on the motor side of the belt. There will be slipage
[17:31:59] <skunkworks_> (like a timing belt.)
[17:44:23] <fenn> as long as he's not using it for position it should be fine
[17:44:37] <fenn> if the belt is tightened properly
[17:44:42] <skunkworks_> right - I figured it was for rigid tapping..
[17:46:13] <Adam-alt> No tapping just for speed display
[17:46:22] <Adam-alt> its just a V-Belt
[17:48:30] <Adam-alt> my motor gives me around 3400rpm, on a bridgeport copy - I think that will be enough for the machine... I dont want it to vibrate too much.
[17:51:40] <fenn> i dont really get why they still make machines with v belts
[17:52:18] <Adam-alt> Yeah I like a geared head myself
[17:52:37] <fenn> i'm a big fan of round-tooth belts
[17:52:50] <fenn> its so simple and works so well
[17:53:17] <Adam-alt> I've been spoiled with Maho-Deckel's now I have a bridgeport copy that I need to retrofit from an 1980's control.
[17:53:48] <fenn> the dialog control?
[17:54:10] <fenn> there was a brief flash of interest in making a dialog emulator for emc
[17:54:20] <fenn> lets see if it went anywhere
[17:54:38] <Adam-alt> I am upgrading from an anilam crusader
[17:55:54] <skunkworks_> jepler: http://www.electronicsam.com/images/eme.png
[17:56:18] <skunkworks_> http://www.electronicsam.com/images/me.JPG
[17:56:49] <Adam-alt> anyone know if you can extend the shaft of an induction motor out of its rear-end?
[17:57:07] <jepler> skunkworks_: is that from image-to-gcode?
[17:57:15] <jepler> mm I could use a beer
[17:57:15] <skunkworks_> yes
[17:57:38] <skunkworks_> I like how you can read the guinnes
[17:59:16] <skunkworks_> jepler: do you see the terminal in the lower left? Is that error normal? I get it every time I run image to gcode. It seems to work ok.
[17:59:51] <fenn> jeez is this ass-backwards or what: http://www.practicalmachinist.com/ubb/ultimatebb.php/topic/6/2104/4.html#000132
[18:04:12] <jepler> skunkworks_: huh I don't know
[18:07:10] <skunkworks_> jepler: trunk. 3 different computers.
[18:07:23] <skunkworks_> like I say - it doesn't seem to effect anything
[18:07:25] <skunkworks_> that I can see
[18:13:29] <skunkworks_> with files that size - the plot and preview need to be shut off.
[18:13:39] <skunkworks_> on a 1.7ghz
[18:14:16] <SWPadnos> how big are the files?
[18:16:20] <skunkworks_> I don't know - how can you tell? I did image>gcode without it making and intermediate file.
[18:16:59] <SWPadnos> hmmm. I wonder if file | properties will tell you
[18:17:27] <SWPadnos> or file|info or whatever it's called :)
[18:17:51] <jepler> I wonder too
[18:18:15] <skunkworks_> yes - well it is odd
[18:18:47] <skunkworks_> 56K file size -- 74k lines of gcode.
[18:18:54] <skunkworks_> isn't that odd?
[18:18:57] <SWPadnos> oh, and are you saying that the AXIS plot/preview is slow, or the image-to-gcode process is slow?
[18:19:16] <SWPadnos> that is odd. I'd expect more lines of code for that file size
[18:19:48] <SWPadnos> err - wait a minute. I'd expect more coffee to help me analyze that :)
[18:20:17] <jepler> I think 56K is the size of the image file, not the size of the generated gcode
[18:20:34] <skunkworks_> ah
[18:20:42] <SWPadnos> out of curiosity, where is the G-code in this case?
[18:20:51] <jepler> SWPadnos: somewhere in /tmp
[18:21:03] <SWPadnos> ok, so there is a real file then - not just a pipe
[18:21:08] <jepler> yeah
[18:21:20] <SWPadnos> that's good (and necessary, AFAIK)
[18:21:21] <skunkworks_> heh - it says it should take 12min to run.. It has been running for 15min and maybe 1/4 done.
[18:21:28] <skunkworks_> that is at 300% feedrated
[18:21:34] <jepler> skunkworks_: yeah I've had complaints that the estimate is not too accurate
[18:21:53] <SWPadnos> what's the programmed feedrate vs. the [TRAJ] max?
[18:22:44] <skunkworks_> I think I had the feedrate set to 100ipm - the max feed per axis is 200ipm
[18:23:04] <skunkworks_> it dips down to 12ipm as it is scanning with an accel set at 25in/s/s
[18:23:28] <jepler> the estimate assumes that the F requested is actually achived, among other limitations
[18:23:47] <skunkworks_> I set the taj section to 5.777 in/sec
[18:24:00] <skunkworks_> which is 346in/min
[18:24:26] <skunkworks_> that is sqr(axisa^2+axisa^2+axisa^2)
[18:24:28] <SWPadnos> I guess with lots of small segments, it would end up much slower
[18:24:34] <skunkworks_> oops a,b,c
[18:24:38] <SWPadnos> sqrt(), hopefully :)
[18:24:43] <skunkworks_> right
[18:24:44] <skunkworks_> ;)
[18:27:40] <jepler> bbl
[19:18:36] <JymmmEMC> howdy folks
[19:19:23] <skunkworks_> Hi
[19:21:10] <JymmmEMC> skunkworks So, you still gonna sell it?
[19:21:15] <skunkworks_> eys
[19:21:17] <skunkworks_> yes
[19:21:38] <skunkworks_> http://www.electronicsam.com/images/eme.png
[19:21:58] <skunkworks_> http://www.electronicsam.com/images/me.JPG
[19:22:30] <JymmmEMC> and the final result?
[19:22:39] <skunkworks_> tonight
[19:23:16] <skunkworks_> what is a good material to cut that in? to backlight it. white styrine?
[19:23:25] <JymmmEMC> dont forget to lightly sand and stain it after
[19:23:49] <skunkworks_> I was planning to cut it in plastic
[19:23:49] <JymmmEMC> backlight?
[19:24:02] <skunkworks_> and backlight it. what do they call it - lithograph?
[19:24:11] <JymmmEMC> I've never full sheet carved plastic like that
[19:24:28] <JymmmEMC> usually I use carved / uncarved areas to contrast
[19:24:49] <JymmmEMC> whats the max Z ?
[19:25:38] <skunkworks_> that picture is .1 depth
[19:26:57] <JymmmEMC> poor lighting made this pic unfocused.... http://farm1.static.flickr.com/84/206158222_cb5c34978c_m.jpg
[19:27:53] <skunkworks_> cool
[19:27:59] <JymmmEMC> that's clear acrylic
[19:28:57] <JymmmEMC> but like I mentioned, I use the carved / un carved areas to contrast
[19:29:49] <skunkworks_> http://www.cnczone.com/forums/showthread.php?t=41845&highlight=litho
[19:29:53] <JymmmEMC> but isn't lithograph 2D line art type?
[19:29:55] <skunkworks_> something like that
[19:30:05] <JymmmEMC> looking
[19:32:10] <JymmmEMC> corian is dense
[19:32:24] <JymmmEMC> got any delrin?
[19:32:31] <skunkworks_> no
[19:33:00] <skunkworks_> I was going to steal some styrene from work here or what ever else i could find. Just to try
[19:33:20] <skunkworks_> I have some abs I think also
[19:33:34] <JymmmEMC> Eh, too soft I think
[19:33:52] <JymmmEMC> you could try a small sample though
[19:34:22] <skunkworks_> I might have some colored lexan or plexiglass
[19:36:20] <JymmmEMC> oh, you could try counter top material
[19:36:36] <JymmmEMC> name slips my mind
[19:37:16] <skunkworks_> firmica?
[19:37:24] <JymmmEMC> yeah, that's it
[19:37:25] <skunkworks_> or something like that
[19:37:34] <JymmmEMC> Be sure to use a dust maks BIG TIME
[19:37:54] <JymmmEMC> dust mask
[19:38:05] <JymmmEMC> and not those $0.99 ones either
[19:38:14] <JymmmEMC> formica
[19:38:16] <skunkworks_> those are not dust masks ;)
[19:38:59] <JymmmEMC> the dust is just like asbestos
[19:39:41] <JymmmEMC> toxic
[19:41:41] <JymmmEMC> you could try those cutter boards too
[19:41:53] <JymmmEMC> carving/cutting boards
[19:45:01] <skunkworks_> hmm - I think I have an old one. :)
[19:52:20] <skunkworks_> looks like that picture should take about an hour to cut.
[19:57:21] <Adam-alt> how would somebody go about calibrating a 3 phase motor with a VFD to give a correct spindle rotation?
[19:57:41] <Adam-alt> rotational speed i should say
[19:58:46] <skunkworks_> you mean CWvsCCW?
[19:59:04] <skunkworks_> all you have to do is swap any 2 of the 3 wires.
[19:59:28] <Adam-alt> no I mean correct rpm
[19:59:54] <Adam-alt> if I put 2000 rpm into EMC and the VFD gives me 1500, what is a good way of measuring that?
[20:00:28] <skunkworks_> if you attach the encoder - you can look at the velecity in hal.
[20:01:01] <Adam-alt> I am not sure if I can attach an encoder to my motor, I would have to do a swap...
[20:01:16] <Adam-alt> I dont have any physical room to attachit
[20:01:26] <skunkworks_> the vfd should give you rpm in some mode
[20:01:30] <skunkworks_> I would think.
[20:01:36] <skunkworks_> in its display
[20:03:49] <Adam-alt> maybe there is a handheld tach that I can shoot the spindle with and then adjust the VFD accordingly.
[20:04:06] <skunkworks_> technically - the rpm of the motor is a direct relationship the the frequency of the 3phase. with the normal 60hz 3phase the motor spins say - 1800rpm. at 30hz it will run at 900rpm. take away a little slip.
[20:04:41] <Adam-alt> ok
[20:04:53] <Adam-alt> at 60hz I am at 3400 rpm then.
[20:05:26] <cradek> http://www.sherline.com/rpmgage.pdf
[20:06:06] <skunkworks_> cool
[20:06:23] <cradek> simple!
[20:06:32] <Adam-alt> how analog
[20:06:35] <cradek> works best with a neon bulb in a darkened room
[20:07:06] <cradek> I used this to calibrate my lathe spindle drive
[20:09:21] <alex_joni> hi guys
[20:09:37] <SWPadnos> Bonjour Alex
[20:09:40] <Adam-alt> hi
[20:10:21] <alex_joni> SWPadnos: bona sera
[20:10:44] <SWPadnos> Bon nuit
[20:11:10] <alex_joni> not quite.. I'm in italy right now :)
[20:11:20] <SWPadnos> ah - mea culpa :)
[20:11:35] <alex_joni> c'est pas d'probleme
[20:11:52] <SWPadnos> bon
[20:16:53] <alex_joni> what's up?
[20:19:35] <SWPadnos> not much - still trying to get the best cross-section of cost, performance, and availability for this analog board design :)
[20:20:09] <cradek> http://earz-mag.com/2007/March/Why_Ban_Comic_Sans.gif
[20:21:40] <alex_joni> hi chris
[20:21:44] <cradek> hi alex
[20:22:27] <alex_joni> * alex_joni has free wifi for tonights hotel
[20:23:45] <alex_joni> http://www.hvenice.it/homeenglish.htm
[20:24:00] <skunkworks_> that is always nice.. Normally around here - wifi is free in hotels. Not over there?
[20:24:08] <alex_joni> it even has "reduced electric fields"
[20:24:13] <alex_joni> skunkworks_: not always
[20:24:37] <alex_joni> and "Air-conditioning with 2 Totems functioning with methane without in house electric fields."
[20:24:45] <cradek> sorry alex, it says the hotel is only for me
[20:25:05] <skunkworks_> heh
[20:25:33] <cradek> it's a shame though, because I'll probably never go there
[20:25:33] <alex_joni> :-P
[20:25:44] <alex_joni> I'll give it back tomorrow
[20:25:43] <cradek> seems like a bad business plan.
[20:26:08] <Adam-alt> is it a big problem to mix servo drives and servos? I have stock X & Y drives and servos. I wish to add a Z on my quill and its going to be a big pain to match components up.
[20:30:01] <skunkworks_> Adam-alt: no
[20:30:56] <anonimasu> no
[20:31:00] <anonimasu> it's not a problem
[20:31:08] <Adam-alt> allright, figure I alraedy have a glass scale on it might aswell attach a servo.
[20:31:27] <anonimasu> though im not sure how well using glass scales togther with emc works
[20:31:52] <cradek> a position loop with any backlash is trouble, it will oscillate
[20:32:15] <anonimasu> yep
[20:32:29] <anonimasu> I wonder how commercial machines do it..
[20:32:31] <cradek> a position loop around a velocity loop is ok, but not a typical emc configuration
[20:32:45] <anonimasu> they do have backslash compensation(atleast the heidenhain ones)
[20:32:47] <Adam-alt> yeah it has a tiny bit of backlash
[20:32:54] <cradek> of course emc can do whatever you can manage to tune
[20:32:57] <anonimasu> probably all others too
[20:33:00] <anonimasu> yeah
[20:33:23] <Adam-alt> so what could I do for a quill feed if it has backlash?
[20:33:32] <cradek> put an encoder on the motor
[20:33:49] <anonimasu> cradek: would it be hard to use a linear encoder to correct for positioning errors?
[20:34:03] <cradek> anonimasu: well you could definitely make compensation tables by reading from your scales
[20:34:04] <anonimasu> cradek: feed it back into the loop, to correct for pitch errors and such..
[20:34:19] <Adam-alt> so have the encoder on the motor and the glass scale aswell?
[20:34:22] <anonimasu> yeah
[20:34:40] <anonimasu> but that's not something anyone has done before..
[20:34:43] <anonimasu> what I know of..
[20:34:47] <Adam-alt> haha
[20:34:50] <Adam-alt> then I am toast with that
[20:35:00] <SWPadnos> that won't be easy to tune, especially because you'd be the first EMC2 user to do it (as far as I'm aware, anyway)
[20:35:01] <cradek> there's a reason cnc motors typically have encoders on them...
[20:35:18] <anonimasu> cradek: well, most higher end machines have linear scales too :9
[20:35:19] <cradek> sure
[20:35:19] <anonimasu> :)
[20:35:33] <cradek> and that would be fine in emc, you could have two pid loops per axis
[20:35:51] <cradek> but you have to tune it. it would take patience + talent I think
[20:36:15] <anonimasu> couldnt you feed the current_pos - actual_pos
[20:36:22] <cradek> using the scales to generate compensation tables should be easy. if they have a DRO, it's *very* easy
[20:37:09] <anonimasu> cradek: im just speculating..
[20:37:18] <alex_joni> well.. good night guys, been a long drive till here
[20:37:24] <cradek> bye alex
[20:37:26] <alex_joni> still have 1000 miles to go
[20:37:32] <SWPadnos> bona sera Alex :)
[20:37:35] <cradek> hope the rest of the trip is enjoyable
[20:37:41] <Adam-alt> So I could skip the encoders and stick with the scales and generate compensation tables for them?
[20:37:42] <alex_joni> yeah, it's fun
[20:37:47] <anonimasu> no
[20:38:04] <anonimasu> you could skip using the scales and use encoders and generate compensation tables for your axis with the scales
[20:38:06] <cradek> bbl
[20:38:15] <SWPadnos> no - you can use the encoders, use the scales during setup (and periodically later on) to generate compensation tables, then forget the scales for the most part
[20:38:17] <SWPadnos> see you cradek
[20:38:51] <anonimasu> SWPadnos: though that limits the usability of scales..
[20:39:17] <SWPadnos> well, they're limited by (a) slow readout rates and (b) potential backlash between the motor and the feedback
[20:39:41] <SWPadnos> I think we said the same thing anyway :)
[20:39:42] <anonimasu> SWPadnos: last time I checked the cheap scales would do very high speeds..
[20:40:13] <SWPadnos> if they have quadrature output then that may be true, but I haven't really looked into scales enough to know
[20:40:35] <Adam-alt> my scales are quadrature
[20:40:36] <anonimasu> some have quad out some have vpp ~
[20:40:41] <Adam-alt> ancient but quad
[20:42:55] <anonimasu> you could always try using it..
[20:43:09] <skunkworks_> yah - you really have nothing to lose
[20:43:23] <skunkworks_> if your machine is tight - it may not even be a problems
[20:43:26] <skunkworks_> problem
[20:43:32] <anonimasu> im kind of wondering how the commerical machines do it..
[20:43:35] <anonimasu> because it works well :p
[20:43:48] <anonimasu> if they dont have any backslash or if they are very good at compensating it
[20:46:24] <Adam-alt> Yeah well the quill is just a gear right so there is going to be backlash and it will only ge tworse over time....
[20:46:35] <Adam-alt> or it is just geared...
[21:01:44] <skunkworks_> cradek: changing the g64 from p.001 to p.002 changes run time from 60min to <45 min :)
[21:02:26] <fenn> i think machines with linear scales usually have tachos on the motor
[21:02:34] <fenn> gives a better signal than encoders anyway
[21:03:13] <skunkworks_> I think that is how Adam-alt's machine is setup right now with its original controller
[21:04:39] <fenn> you should be able to just feed the tach output into the motion planner velocity feedback? but emc doesnt seem to have that anymore
[21:09:14] <Adam-alt> yeah the X&Y servos have tachos...
[21:09:47] <Adam-alt> the tachos are delt with on the drive boards.
[21:11:30] <Adam-alt> I can get a z-board and a suitable servo for it right now.
[21:12:41] <Adam-alt> i am worried about that oscillation that somebody was talking about earlier though. Damn quill has a tiny bit of play.
[21:29:03] <awallin> I like this guy's attitude! http://www.freesteel.co.uk/wpblog/2007/08/a-message-to-lawyers-contemplating-acts-of-legal-harassment/
[21:38:00] <awallin> hi Martzi
[21:38:13] <Martzi1> hi
[21:38:32] <awallin> whats up?
[21:38:48] <Martzi1> nothing special
[21:39:33] <Martzi1> It would be nice to have more time for mill building:)
[21:40:10] <awallin> yeah, same thing here. haven't got the DC servos installed yet... will take another 4-weeks at least before its done
[21:40:52] <Martzi1> I have now replaced all my steppers with servos
[21:41:07] <awallin> the cnc-fi googlegroup has been quite dead for a while. do you know if the finnish cnc-crowd hangs out somewhere else on the net?
[21:41:22] <Martzi1> #cnc.fi
[21:42:14] <Martzi1> in quakenet
[21:42:43] <awallin> ok... although I don't have much time for irc...
[21:45:10] <awallin> Martzi: are you good at programming? maybe you saw that I made some tests with a CAM-algorithm
[21:45:55] <Martzi1> hmm, I am not sure if I have seen
[21:46:21] <awallin> http://www.anderswallin.net/2007/08/drop-cutter-in-c-v2/
[21:46:21] <Martzi1> I have some programming knowledge
[21:48:58] <awallin> hopefully I'll have time to add some more algorithms during the winter
[21:49:16] <awallin> when the program does something useful I'm hoping more developers will get interested and help out
[21:49:39] <Martzi1> I can help
[21:49:47] <Martzi1> At least try
[21:51:05] <awallin> good. are you working under windows? the idea was to code it in .NET so that it would run under Linux/mono, but there are some issues with TAO- the OpenGL bindings which make it not work under linux right now
[21:51:44] <Martzi1> I can use both Windows and Linux
[21:52:42] <Martzi1> I disappeared?
[21:53:12] <Martzi1> Perhaps it was my clone
[21:53:56] <awallin> yeah, that was your alter ego
[21:54:25] <Martzi1> What is needed to put the building environment working?
[21:55:15] <awallin> the free Visual Studio Express (C#) from microsoft, and the Tao (http://www.taoframework.com/). that's under windows
[21:55:32] <awallin> for linux there is mono, monodevelop, and tao. but there are issues with tao as I said
[21:55:56] <awallin> and you need to have .NET 2.0 on yuor windows machine, but most modern machines should have that
[21:56:07] <Martzi1> i have it
[21:56:36] <Martzi1> Is express 2008 Beta 2 Ok?
[21:56:46] <Martzi1> or should I use older?
[21:56:47] <anonimasu> no
[21:57:02] <anonimasu> .Net 3.0 isnt compatible with mono
[21:57:05] <anonimasu> awallin: ltns!
[21:57:15] <awallin> hi anonimasu
[21:58:23] <anonimasu> 3what's up?
[21:58:52] <awallin> too much work and traveling... not much CAM getting done.
[21:59:07] <anonimasu> same with me at the moment
[21:59:22] <anonimasu> I feel a bit bad about it
[22:00:30] <awallin> no worries:) ... as we planned this is a 6-month thing to get to v1.0
[22:00:44] <anonimasu> yeah
[22:00:50] <anonimasu> :)
[22:00:53] <anonimasu> how's traveling?
[22:02:22] <awallin> dont ask... two weeks ago in Austin and Boston. Now I'm flying helsinki->JFK on saturday. 7-8h on a plane is "fun"
[22:02:37] <anonimasu> :/
[22:02:42] <anonimasu> what a pain
[22:06:50] <Martzi1> Ok, everything is installed and I can start coding;)
[22:07:46] <awallin> good. nice. if you do something significant and it doesn't brake everything let me know your gmail account and I can add you to the googlecode project. that way you can commit your changes via svn
[22:11:45] <Martzi1> ok
[22:12:19] <anonimasu> I need to go to bed
[22:12:20] <anonimasu> night
[22:12:24] <awallin> night
[22:12:25] <Martzi1> me too
[22:12:32] <Martzi1> night
[22:44:25] <Adam-alt> do VFD's generally protect from back emf?
[22:50:37] <awallin> some have terminals for connecting a dump resistor. I guess it's used with really big motors.