#emc | Logs for 2007-12-14

[01:03:40] <ds2> along the lines of the uboot q's earlier...anyone know the recipe to backup the current running uboot?
[01:13:51] <ds2> bah
[01:13:54] <ds2> wrong place n/m
[03:43:18] <christel> [Global Notice] Hi all, Just a quick line to let you know that we are expecting slight disturbance on some of our US routes between 0400 and 0600 hours pacific time (GMT-8) while some emergency maintenance is being performed. While it is a two hour window disruptions should only last for about 10minutes at some point during said window. Expect turbulence. Thank you for using freenode and have a great day!
[04:10:12] <Gamma-X> does emc2 support any of the tools made by centroid like a digitizer/probe?
[04:10:51] <eric_U> probly not
[04:11:08] <eric_U> but it's hard to say without more details
[04:11:30] <Gamma-X> hmmm. well..... would I havwe to program it myself? lol
[04:11:55] <eric_U> good news is, you can ;)
[04:13:08] <Gamma-X> eric_U yeah but i have no idea how to lol
[04:13:22] <eric_U> that could be a problem
[04:14:04] <eric_U> ebay purchase?
[04:14:55] <cradek> emc2 supports probing and tool length sensing
[04:15:25] <cradek> I know nothing about centroid's hardware if that's what you're asking
[04:15:35] <Gamma-X> cradek u know of those 2 devices? like where i can buy them?
[04:15:50] <cradek> sorry no
[04:15:52] <Gamma-X> cradek well id like to get both of those things but i dont care if its centroid.
[04:16:26] <cradek> I'm sure there are many options
[04:16:41] <cradek> the simplest probe you can make yourself, or you can spend $thousands
[04:16:51] <cradek> same for a length sensor I suppose
[04:17:16] <cradek> but emc2 doesn't care what you use as long as you get a signal into the machine that says when the thing touches
[04:20:48] <Gamma-X> cradek got any plans for one of them? lol
[04:21:03] <cradek> no, ask google
[04:21:35] <Gamma-X> tried
[04:22:20] <cradek> http://www.google.com/search?q=homemade+digitizing+probe
[04:23:55] <cradek> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Touch_Probe
[06:49:21] <Gamma-X> if I create a digitizer what kind of file would emc2 save it as?
[09:20:49] <anonimasu> cradek: you awake?
[09:39:23] <alex_joni> not this early
[09:39:30] <alex_joni> in 3h+ maybe
[09:39:58] <anonimasu> ok
[09:40:17] <anonimasu> do you have a clue about robot trajectory planning?
[09:40:28] <anonimasu> like some of the math behind it?
[09:44:40] <alex_joni> what do you need?
[09:45:12] <alex_joni> I just stumbled on some older notes: http://eneas.juve.ro/~juve/emc/tp.txt
[09:45:27] <anonimasu> alex_joni: as much as possible :)
[09:46:00] <anonimasu> alex_joni: im trying to get my head into the math
[09:48:57] <anonimasu> alex_joni: im pondering about the actual planning
[11:00:57] <dogfishguzzler> You guys will be happy to know I bought a book about basic electronics to minimize my simpler questions.
[11:01:51] <alex_joni> nice :)
[11:01:59] <alex_joni> I mean.. buying books is always nice
[11:02:32] <dogfishguzzler> Yeah I know, some people are crack heads, me, I love books lol
[11:03:12] <archivist> books becoma a bad habit /me is addicted
[11:03:19] <archivist> become
[11:03:42] <dogfishguzzler> So I'm not alone in my sickness
[11:03:48] <archivist> no
[11:04:02] <dogfishguzzler> With a nick like yours I shoulda known ;D
[11:04:10] <archivist> er yes
[11:05:11] <dogfishguzzler> The wife wants to go do karaoke tonight but I want to come home and play with my driver chip and book.
[11:05:21] <dogfishguzzler> I wonder if I should fake sick
[11:05:27] <alex_joni> you can always sing to it
[11:05:31] <alex_joni> it == driver :D
[11:05:36] <dogfishguzzler> haha
[11:05:38] <alex_joni> or maybe make it sing..
[11:05:55] <dogfishguzzler> I doesnt appreciate my voice.
[11:06:04] <dogfishguzzler> nobody does
[11:08:13] <dogfishguzzler> After many attempts in the past to memorize ohm's law I finally had an epiphany and I acually understand it now, no need to memorize. But going through the laws over the last couple days I have some situations where the law lies. I'll have to ask you guys about those things.
[11:08:57] <dogfishguzzler> I don't have time this morning but some things seems contradictory (sp?)
[11:09:10] <dogfishguzzler> See yall later
[11:12:03] <skunkworks_> I just wing it most of the time..
[11:16:25] <alex_joni> skunkworks_: still working on that restore?
[11:18:36] <skunkworks_> I am to the point that everyone should 'get buy' until the new drives are in.
[11:18:58] <skunkworks_> It will be a little hectic today :)
[11:19:19] <skunkworks_> * skunkworks_ should run and get some breakfast
[11:25:12] <anonimasu> new drives?
[11:25:43] <anonimasu> ohm's law is a lie?
[11:25:49] <anonimasu> zomg my universe just broke.
[11:26:09] <archivist> ohms law never lies
[11:26:17] <archivist> except on ac
[11:26:20] <anonimasu> I know, there are just cases where it's less true
[11:26:29] <anonimasu> like on ac stuff..
[11:30:36] <skunkworks_> phhh - ohms law. Bah - everything I do requires E=MC^2
[11:31:36] <skunkworks_> next day air is great.. order stuff yesterday.. get it today.. (only $70) :)
[11:34:40] <skunkworks_> now if only I could order stuff yesterday - today..
[11:39:33] <anonimasu> where ~-_-
[11:39:48] <anonimasu> skunkworks_: indeed nice
[11:39:52] <anonimasu> skunkworks_: what did you buy?
[11:40:16] <skunkworks_> I needed some replacement hard drives for a server.. Nothing really neat
[11:40:32] <skunkworks_> oops - got to love ups updates 'In Transit - On Time'
[11:40:44] <anonimasu> ah ok
[12:34:21] <skunkworks_> welcome back
[12:34:36] <skunkworks_> an you too jepler
[12:43:32] <archivist> hmm netsplit
[13:37:55] <jepler> skunkworks_: ??
[13:38:39] <skunkworks_> to me - it looked like a bunch of you disconnected and reconnected.. you where the scragler.
[13:38:54] <skunkworks_> (last one to reconnect)
[13:39:22] <jepler> oh
[13:39:50] <jepler> my client says there was a netsplit with about 30 people on your side of it
[13:41:28] <jepler> hi ray
[13:43:11] <rayh> Hi Jeff
[13:43:19] <alex_joni> hi ray
[13:43:29] <rayh> Hi Alex
[13:43:34] <alex_joni> what's up ray?
[13:43:42] <alex_joni> did broadband finally reach you?
[13:43:51] <rayh> Just being a bum this morning.
[13:43:56] <alex_joni> sorry.. strike that .. saw your IP
[13:44:05] <rayh> Nope. Less than a mile away
[13:44:10] <alex_joni> rayh@dial-pn1-19.wic.up.net
[13:44:16] <rayh> but a hill between.
[13:44:16] <alex_joni> well.. hopefully it'll get there
[13:44:42] <rayh> Been thinking about a teathered weather balloon.
[13:45:54] <steves_logging> steves_logging is now known as steve_stallings
[13:46:11] <steve_stallings> ... well, 1 mile of CAT 5 isn't that expensive....
[13:46:29] <steve_stallings> oh, and a couple of repeaters
[13:48:13] <rayh> Years ago I did have a 2 mile long phone line laying on the ground.
[13:49:24] <steve_stallings> I have installed over 1/4 mile of CAT 5 in the new office space and still have a bunch to go
[13:50:21] <alex_joni> steve_stallings: fiber optics are quite cheap nowadays
[13:50:33] <alex_joni> with utp converters on each end..
[13:50:54] <rayh> I put almost that much into a bar up here a couple years ago.
[13:52:14] <steve_stallings> yes, and fiber cares a lot less about the weather
[13:52:41] <rayh> I wonder how it stands up to wild things stomping on it.
[14:00:19] <alex_joni> rayh: the thick fiber has no issues with that
[14:00:54] <rayh> Okay.
[14:00:57] <alex_joni> I saw one which got caught on a train waggon ones.. it got dragged behind the train, and broke off about 20 telephone posts
[14:01:12] <rayh> phone brb
[14:01:23] <alex_joni> the thick cable was still in one piece, although the fibers inside were busted
[14:01:29] <rayh> Nice
[14:02:32] <alex_joni> I checked a local supplier.. about 0.3 EUR / m
[14:02:44] <alex_joni> so roughly .5$
[14:03:15] <alex_joni> that's still 1k$ for a mile (including converters), but without installing it
[14:04:40] <alex_joni> http://www.mondoplast.ro/index.php?pg=ft&id=1680
[14:06:18] <alex_joni> 30$ for a converter: http://www.mondoplast.ro/index.php?pg=ft&id=3136
[14:12:49] <rayh> I guess dialup is a price I pay for living in the wilderness.
[14:13:30] <fenn> rayh: i've been thinking about a tethered balloon
[14:13:52] <rayh> Me to
[14:13:55] <fenn> you could make a savonius turbine shaped balloon that would generate enough power to transmit a signal
[14:14:04] <fenn> like a windmill
[14:14:11] <rayh> There you go.
[14:14:18] <rayh> a repeater in the sky.
[14:33:42] <optimum> 'lo
[14:34:00] <optimum> I'm having some issues moving from 2.1.x to 2.2.2
[14:34:27] <alex_joni> optimum: go on :)
[14:35:15] <optimum> mostly it's a custom hal file with jogwheels and some buttons that doesn't seem to be valid in 2.2.2
[14:35:31] <alex_joni> what's the error?
[14:36:21] <alex_joni> optimum: btw, how's goeteborg this time a year?
[14:36:33] <optimum> HAL: ERROR: pin 'halui.feed-override.scale' not found, control_box.hal:22: pin 'halui.spindle.start' not found, control_box.hal:10: pin 'halui.program.resume' does not exist. Also it's complaining about some linkpp's I've got, is the syntax for net the same as linkpp?
[14:36:57] <optimum> a lot warmer than usual, its above zero almost all the time
[14:37:03] <optimum> oops, wrong nick
[14:37:09] <optimum> optimum is now known as lerneaen_hydra
[14:37:35] <lerneaen_hydra> there we are
[14:38:57] <alex_joni> lerneaen_hydra: heh :)
[14:39:03] <alex_joni> you didn't start halui as it seems
[14:39:11] <alex_joni> do you have HALUI = halui in the ini?
[14:39:26] <alex_joni> and for net you need a name: net name pin1 pin2 pin3 pin4 ...
[14:40:04] <lerneaen_hydra> oops, I don't think the stepconf-generated ini had halui loaded
[14:40:14] <alex_joni> lerneaen_hydra: nope it won't
[14:40:14] <lerneaen_hydra> would it be easiest to stick with linkpp then?
[14:40:38] <alex_joni> for this to work with stepconf, you'll have to add 'loadusr halui -ini /path/to/ini' in your custom.hal
[14:41:01] <alex_joni> lerneaen_hydra: no.. just add 'net fooname' instead of 'linkpp'
[14:41:43] <lerneaen_hydra> as it is now I've just used stepconf to generate a working .ini and pinout file, and then moved the new bits to the old file
[14:42:31] <alex_joni> * alex_joni wonders why
[14:42:47] <lerneaen_hydra> what would the best idea be, keep the old file and modify it to make it work or use stepconf and add an additional hal file for the jogwheel/button box?
[14:42:57] <alex_joni> I'd go with the first
[14:43:07] <alex_joni> but archive it first :D
[14:43:21] <lerneaen_hydra> yeah of course :)
[14:45:32] <lerneaen_hydra> hmm, was there some new syntax for loading multiple signals to one pin? control_box.hal:15: pin 'halui.mode.auto' was already linked
[14:46:18] <alex_joni> no.. just use net
[14:46:27] <lerneaen_hydra> hmm, funny
[14:46:30] <lerneaen_hydra> I am using net
[14:47:23] <lerneaen_hydra> http://pastebin.ca/815946 lines 10-16
[14:54:25] <alex_joni> lerneaen_hydra: on the second incantation you don't need to put the pin again
[14:54:33] <alex_joni> net runsignal parport.0.pin-12-in-not halui.program.resume
[14:54:39] <alex_joni> net runsignal halui.mode.auto
[14:55:06] <lerneaen_hydra> ah, ok. it worked with 2.1.x for some reason
[14:55:18] <alex_joni> I think it actually failed
[14:55:25] <alex_joni> but you didn't notice..
[14:55:36] <alex_joni> it's odd to link it to mode.auto too..
[14:56:20] <lerneaen_hydra> I didn't code that myself, someone here said that it's good to do that :)
[14:56:28] <lerneaen_hydra> I can't say I know a lot about HAL
[14:57:15] <alex_joni> haha: #linksp Xphase-A parport.0.pin-02-out <-- WTF?
[14:57:34] <lerneaen_hydra> yeah, found that in the file once, I have no idea how it appeared
[14:59:08] <lerneaen_hydra> hmm it's still complaining about line 15
[14:59:15] <lerneaen_hydra> already linked apparently
[14:59:43] <alex_joni> can you repastebin?
[15:00:15] <lerneaen_hydra> could stepconf have made a net with that name?
[15:00:28] <alex_joni> might be
[15:00:45] <alex_joni> * alex_joni doesn't know and is a bit too busy to look
[15:01:38] <lerneaen_hydra> http://pastebin.ca/815956
[15:01:57] <lerneaen_hydra> the first bit is the custom HAL code, the second is the one made by stepconf
[15:03:42] <alex_joni> ah.. you're linking 2 signals to the same pin
[15:03:46] <alex_joni> that's not allowed
[15:03:58] <alex_joni> just remove the lines with halui.mode.auto
[15:04:09] <alex_joni> that won't work anyways (imnsho) :P
[15:04:28] <lerneaen_hydra> hmm alright :)
[15:06:39] <lerneaen_hydra> hmm well now it loads at least
[15:07:00] <lerneaen_hydra> damn, still getting an unexpected realtime delay error :/
[15:07:49] <steve_stallings> steve_stallings is now known as steves_logging
[15:11:58] <cradek> http://www.youtube.com/watch?v=LA5qCIB0j6k
[15:12:15] <cradek> I had not seen this one before. more of our splash screen...
[15:12:33] <cradek> for a homemade machine made from MDF it looks like it works really well
[15:14:37] <skunkworks_> nice - I haven't seen that one either.
[15:17:11] <cradek> this one's called "ow, my start capacitor" http://www.youtube.com/watch?v=0q_q53wsyHU
[15:18:16] <skunkworks_> I have seen that one.. :)
[15:18:22] <skunkworks_> I like the comments.
[15:21:44] <lerneaen_hydra> hmm ok, two problems remain, the first is the default size of the limits region, which is very small, the second is that the maximum jog speed is 60mm/min, while the axis's max speed is 780, any ideas?
[15:22:29] <cradek> lerneaen_hydra: the various units settings in your ini file are probably wrong
[15:23:06] <lerneaen_hydra> ah, ok
[15:23:54] <lerneaen_hydra> hm, it seems consistant
[15:25:13] <cradek> pastebin...
[15:26:24] <lerneaen_hydra> http://pastebin.ca/815980
[15:26:53] <lerneaen_hydra> the .ini is generated with stepconf, the hal files are some unholy mixture of stepconf and manual editing
[15:27:11] <cradek> your limits are 8mm?
[15:27:43] <cradek> 8x8x4mm seems like an unusually small mill
[15:27:53] <lerneaen_hydra> O_o
[15:28:00] <lerneaen_hydra> that came from stepconf
[15:28:07] <cradek> uh-oh
[15:28:10] <lerneaen_hydra> I haven't set any values for limits
[15:28:25] <cradek> oh maybe those were the defaults on the screen and you didn't change them?
[15:28:40] <lerneaen_hydra> possibly
[15:29:30] <lerneaen_hydra> yep they're visible in stepconf
[15:29:42] <lerneaen_hydra> default is 8
[15:29:55] <lerneaen_hydra> possibly the same value as for inch based systems?
[15:30:01] <cradek> yeah, just silly defaults for mm
[15:30:07] <cradek> but you left them there :-)
[15:30:19] <lerneaen_hydra> what's the easiest way to disable limits? remove the lines in the ini?
[15:30:50] <cradek> the only think you can do is set them to large numbers
[15:31:05] <cradek> but I can't imagine a case where I would not want soft limits
[15:34:04] <lerneaen_hydra> yeah I'm going to add hardware limit switches later on
[15:34:16] <lerneaen_hydra> any idea as to the limit of 60mm/s when jogging?
[15:34:27] <cradek> until then, just jog to a known locatin for a home position
[15:34:36] <cradek> location
[15:34:41] <cradek> then you can have use soft limits
[15:35:07] <cradek> yes: MAX_LINEAR_VELOCITY = 1.00
[15:35:22] <cradek> looks like you want 13
[15:35:58] <lerneaen_hydra> ah, ight
[15:36:05] <lerneaen_hydra> *right
[16:03:32] <alex_joni> bbl
[19:06:03] <fenn_> fenn_ is now known as fenn
[22:19:16] <fenn> anyone wanna build one of these? http://www.youtube.com/watch?v=DnNWfJveZDI
[22:31:26] <dogfishguzzler> Some may remember this doc (The one for the driver chip I bought) http://www.google.com/url?sa=t&ct=res&cd=1&url=http%3A%2F%2Fusers.ece.utexas.edu%2F~valvano%2FDatasheets%2FNTE1857.pdf&ei=FQRjR9GsJJjces_mqUw&usg=AFQjCNGxbnNfynr7ILQnr0xJZZoFiFrFqg&sig2=ZnUpQ64JjpmgwF-geyiOzQ
[22:31:58] <archivist> fenn I note he has a harness!
[22:32:03] <dogfishguzzler> I'm trying to set pin 6 but I'm not sure what 'base drive current is'
[22:33:18] <archivist> page 5 tells you
[22:34:07] <dogfishguzzler> It tells me what the base currrent supplied to each lower transistors out is?
[22:34:17] <dogfishguzzler> output*
[22:34:53] <dogfishguzzler> Since the chip will only handle 350ma I'm assuming that's the 'base drive current'
[22:35:34] <dogfishguzzler> If I reverse the polarity will I kill the chip?
[22:35:50] <archivist> decide what current you wish to set within its capabilty and calculate the resistor pin 6 to ground
[22:36:22] <dogfishguzzler> that's what I'm trying to do archivist but I need the valuelbs
[22:36:32] <dogfishguzzler> value of lbs*
[22:36:48] <archivist> top calc gives that
[22:37:26] <archivist> ibs=iod*.86
[22:37:45] <dogfishguzzler> for some reason everytime I do it I come out with some ridiculously low number
[22:38:08] <dogfishguzzler> .0077 ohms or some crap
[22:39:06] <dogfishguzzler> Im getting no current through the circuit right now so I'm thinking I should set that pin and then try to reverse my polarity because my powers upply is'nt mark + -
[22:40:03] <dogfishguzzler> I'm getting 15V at the V+ pin but no current. The pc is putting 3V on the step and direction pins..
[22:40:13] <dogfishguzzler> but nothing\
[22:40:57] <archivist> ew never try reversing supplies
[22:41:15] <archivist> without KNOWING + and -
[22:41:38] <archivist> you will let the smoke out the device
[22:42:04] <dogfishguzzler> I used an led and when it lit up I assumed the wire that the long lead was touching was +
[22:42:28] <archivist> do you have a meter
[22:42:33] <dogfishguzzler> Yes
[22:42:52] <archivist> what does that tell you about + and -
[22:43:42] <archivist> and what is the voltage you are using
[22:43:45] <dogfishguzzler> Well in my mind I figured the power would only flow from + to - and the led would show me that
[22:43:48] <dogfishguzzler> 12V
[22:45:28] <dogfishguzzler> I also had to use 9 resistors to get the measly 35 ohms I needed but the resistors were only 1/2 watt so I ran to sets parallel. This seems odd to me but thats what I read I should do.
[22:45:40] <dogfishguzzler> two sets
[22:46:40] <dogfishguzzler> I have a feeling I'm not understand the use of resistors.
[22:46:55] <dogfishguzzler> Because I never saw that many resistors on a circuit of any kind
[22:47:06] <dogfishguzzler> Not the way I have them
[22:47:45] <dogfishguzzler> But if the resistors I have are rated at 1/2 wat and my circuit is using 4.2 watts dont I have to use 9 resistors?
[22:48:12] <dogfishguzzler> Just ran parallel to keep ohms where they need to be?
[22:48:57] <archivist> if all the current is through the resistor yes, series parallel to get the value/wattage
[22:49:38] <dogfishguzzler> The set of resistors I'm talking about is right after the supply and right before the V+ pin on my chip
[22:51:35] <dogfishguzzler> Cant I leave out the huge bank of resistors i have now and just set the bias pin correctly to limit current? And if I did that I would still need 4.2 watts worth wouldn't I?
[22:53:05] <anonimasu> hm
[22:53:15] <archivist> there should be no series R in the supply
[22:53:18] <anonimasu> dogfishguzzler: what are you talking about?
[22:53:34] <archivist> and the bias fo 350ma is 37 ohms at 12v
[22:54:17] <dogfishguzzler> But I cant just use a 40 ohm resistor thats rated for a half watt can I?
[22:55:08] <archivist> it is a bias resistor it does not have the full current through it
[22:55:48] <dogfishguzzler> When I get done with this project I'm buying a driver board. No more of this build my own experimentation.
[22:56:15] <dogfishguzzler> Too much to learn and everytime I think I understand something it turns out I don't
[22:58:11] <Gamma-X> dogfishguzzler i jsut chimed in but what were u experimenting with??
[22:59:01] <dogfishguzzler> trying to get this nte1857 driver chip to drive a small printer motor.
[22:59:12] <Gamma-X> ahhhh ok
[22:59:55] <dogfishguzzler> I just removed all the resistors and just put one 33ohm from pin 6 to ground. I still got nothing.
[23:00:03] <Gamma-X> im tryin to figure out what the best i/o card is for the money
[23:00:18] <dogfishguzzler> The xylotec ones look good for cheap three axis
[23:00:37] <dogfishguzzler> $155 aint bad
[23:01:31] <Gamma-X> i want to have 4 axis with some other things like digitizer and auto tool setter
[23:01:44] <Gamma-X> and i need to control a vfd with it.
[23:02:13] <seb_kuzminsky> gamma-x: servos or steppers?
[23:02:40] <Gamma-X> anilam servos from 1989
[23:03:25] <seb_kuzminsky> are you planning to read the encoders on the pc?
[23:03:46] <Gamma-X> yes sir.
[23:04:33] <dogfishguzzler> Thanks archivist, I gotta go but I appreciate your ahelp.
[23:04:42] <archivist> ok
[23:04:49] <seb_kuzminsky> how are you getting the encoder signals to emc? parallel port?
[23:05:05] <Gamma-X> seb_kuzminsky i was going with a i/o card.
[23:05:11] <Gamma-X> possibly a mesa?
[23:05:17] <alex_joni> good night all
[23:06:57] <Gamma-X> seb_kuzminsky any ideas?
[23:07:11] <Gamma-X> im retro fitting a supermax.
[23:09:50] <seb_kuzminsky> i tried reading encoders over the parallel port and found it too slow
[23:11:45] <Gamma-X> ahh ok
[23:12:00] <seb_kuzminsky> reasonable resolution is a couple of hundred edges per rev, which tops your rpms out around 1K or 2K
[23:12:39] <seb_kuzminsky> most servos want to spin much faster, so you end up holding back on your pulse duty cycle, which kills performance
[23:13:16] <seb_kuzminsky> i concluded that you need to offload encoder reading from the pc
[23:13:40] <Gamma-X> seb wich is done how?
[23:14:18] <seb_kuzminsky> something like an FPGA board or a dedicated microcontroller, connected via PCI or parallel port usually
[23:14:26] <archivist> some are using a pluto card
[23:14:41] <fenn> seb_kuzminsky: were you able to approach the theoretical limit of 2/base_period when reading encoders on the parport?
[23:15:01] <seb_kuzminsky> you send it pulse duty cycles for all your axis, it sends you accumulated encoder counts
[23:15:03] <Gamma-X> archivist pluto card?
[23:15:22] <seb_kuzminsky> then emc closes the pid loop on the pc and sends new pulse duty cycles
[23:15:24] <Gamma-X> if my cnc machine comes with glass scales should they be used with emc2?
[23:15:40] <seb_kuzminsky> fenn: heh, i dont have a machine yet, all i've done is poke around with little hal circuits
[23:17:34] <seb_kuzminsky> i was reading the parallel port pins at about 40 KHz, which is enough for 20 KHz or so quadrature edges
[23:17:43] <seb_kuzminsky> which isnt nearly enough for good servo performance
[23:17:57] <fenn> Gamma-X: i think it should be possible to use glass scales with emc2 but it won't be easy or straightforward (and may involve writing a new PID module)
[23:18:24] <seb_kuzminsky> gamma-x: what's the output from the glass scales?
[23:18:25] <fenn> but maybe you could do nested PID loops in hal
[23:18:46] <fenn> one for position, one for velocity (glass scale feeds position, tacho feeds velocity loop)
[23:19:14] <Gamma-X> seb_kuzminsky im not sure i get the machine at my house next week, i know its a supermax ycm-18.
[23:19:16] <seb_kuzminsky> i bet you can use the standard pid component, but you might need a new "encoder" module to provide feedback for the pid
[23:19:37] <Gamma-X> whats a pid?
[23:19:48] <Gamma-X> and ive heard i can put new encoders on
[23:20:02] <seb_kuzminsky> proportional/integral/derivative controller
[23:20:13] <SWPadnos> I think there are two problems with glass scales for motor feedback: 1) they don't all have fast enough position update rates and 2) they aren't attached to the motor
[23:20:29] <anonimasu> SWPadnos: I think you've got that wrong..
[23:20:37] <anonimasu> SWPadnos: they have fast update rates
[23:20:46] <seb_kuzminsky> swpadnos: 1 sounds disastrous, 2 isnt bad if there's low backlash
[23:20:50] <SWPadnos> new expensive scales will be fast enough, used older cheaper scales won't be
[23:20:59] <anonimasu> the cheaper scales are fast too
[23:20:59] <SWPadnos> or might not be
[23:21:07] <anonimasu> there's a spec.
[23:21:18] <SWPadnos> fast enough for a servo? maybe maybe not. it depends on the interface. not all scales have quadrature output
[23:21:34] <SWPadnos> anything with serial output is unlikely to be fast enough
[23:21:37] <anonimasu> SWPadnos: stop assuming.
[23:21:42] <anonimasu> they have quadrature output.
[23:21:51] <SWPadnos> but I want to make an ass of u and me :)
[23:22:06] <seb_kuzminsky> if they have quad output then gamma-x should be fine, no need to write new components
[23:22:10] <eric_U> depends on your motor
[23:22:39] <eric_U> the encoders on my motor have much finer resolution than almost any linear encoder
[23:22:55] <Gamma-X> but these are servos from 1989 lol
[23:22:56] <anonimasu> 40" sec
[23:22:59] <fenn> yep that's why they have the tacho's
[23:23:02] <anonimasu> is the spec for the chinese scales..
[23:23:05] <anonimasu> 60m/min
[23:23:06] <SWPadnos> eric_U hmmm. that would be surprising
[23:23:25] <SWPadnos> scales go down to 1 um or finer these days
[23:23:39] <seb_kuzminsky> swpadnos: nice! :-)
[23:23:39] <fenn> if it worked without tachometers they wouldn't have them
[23:23:57] <anonimasu> yep
[23:24:10] <eric_U> that's cause they were using velocity feedback
[23:24:20] <anonimasu> velocity feedback to the drive..
[23:24:24] <SWPadnos> anonimasu, when I talk about the sped, it's the speed at which you can get updates to the controller, not the speed at which it will track
[23:24:24] <anonimasu> and linear scales to the control
[23:24:30] <SWPadnos> s/sped/speed/
[23:24:40] <anonimasu> SWPadnos: as they have quadrature output
[23:24:54] <eric_U> back in the late 80's everything had a tacho, now almost nothing does
[23:25:04] <anonimasu> SWPadnos: I guess that's not really a problem..
[23:25:04] <SWPadnos> are you quite certain that all glass scales manufactured in the last 30-40 years have quadrature output?
[23:25:15] <anonimasu> the cheap chineese ones I looked at have quadrature output
[23:25:17] <SWPadnos> I'm not, but I'm no expert either
[23:25:19] <anonimasu> "sino" or whatever
[23:25:38] <eric_U> expensive ones require a converter
[23:25:57] <anonimasu> the heidenhain scales I have on the big mill is ~
[23:26:02] <anonimasu> signal..
[23:26:06] <SWPadnos> I think that's actually analog output that's used fora pseudo-resolver. I think you get terrible resolution if you durectly use that for quadrature (with signal conditioning, of course)
[23:26:27] <SWPadnos> gah - I can't spell when I have so much stuff in front of the kwyboard
[23:26:30] <SWPadnos> gah
[23:26:32] <anonimasu> 1┬Ám..
[23:26:52] <anonimasu> :)
[23:27:02] <anonimasu> still they arent sampled in quadrature..
[23:27:02] <eric_U> Not sure, but I think the 1um ones are using analog with converter
[23:27:11] <seb_kuzminsky> swpadnos: hey wait... 1 um isnt all that incredible actually
[23:27:19] <anonimasu> 0.001mm
[23:27:23] <eric_U> it is for an led :)
[23:27:43] <eric_U> but most linear encoders are 10 um or more
[23:27:44] <seb_kuzminsky> 256 line rotary encoder, 20 tpi lead screw, 1:1 motor:leadscrew coupling, quadrature decoding
[23:27:53] <Gamma-X> INPUT X, Y, Z - .0001 INCH / .01 MM
[23:27:59] <Gamma-X> that can be done from my cnc machine
[23:28:01] <seb_kuzminsky> 1.25 um linear resolution
[23:28:02] <Gamma-X> that help at all?
[23:28:22] <seb_kuzminsky> 256 lines isn't even that fancy
[23:28:39] <eric_U> my motors have either 2048 or 4096 lines
[23:28:40] <seb_kuzminsky> 20 tpi is maybe coarser than normal, but not an order of magnitude
[23:28:53] <seb_kuzminsky> eric_U: right, that sounds more normal for good servos
[23:28:57] <eric_U> .2 is most common
[23:29:23] <seb_kuzminsky> so that's .1 um on eric's motors (ASSuMEing the other approximations above are ballpark)
[23:29:23] <eric_U> geckos need 256 lines or so
[23:29:32] <seb_kuzminsky> 256 seems like the bare-bones minimum
[23:29:39] <SWPadnos> http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=9359307&PMT4NO=34544457
[23:29:48] <SWPadnos> 250-500 lines are recommended
[23:29:59] <SWPadnos> I have 1000-line encoders, and my (little) testing seems to work fine
[23:30:17] <seb_kuzminsky> 1.27 um resolution
[23:30:21] <eric_U> that's a nice encoder
[23:30:33] <seb_kuzminsky> (on the encoder swpadnos linked)
[23:30:50] <seb_kuzminsky> oh well, i gotta go, ttyl
[23:30:54] <eric_U> it says 1 micron resolution, so the inches are being fudged
[23:30:54] <SWPadnos> true
[23:30:56] <SWPadnos> see you
[23:31:32] <eric_U> there used to be encoders with resolution in inches, but they are gone now
[23:31:52] <anonimasu> yep
[23:31:52] <SWPadnos> good
[23:31:57] <SWPadnos> about time we started using metric
[23:32:13] <anonimasu> agreed
[23:32:14] <eric_U> long since time
[23:32:25] <eric_U> Jimmy Carter tried and failed
[23:32:33] <anonimasu> so did nasa
[23:32:35] <anonimasu> ^_^
[23:32:55] <eric_U> I thought the military did too, but I'm pretty sure they weren't serious
[23:33:09] <anonimasu> it's hard to get more conservative then that
[23:33:17] <anonimasu> err then the military..
[23:33:28] <eric_U> long time horizons
[23:33:40] <anonimasu> :)
[23:33:47] <eric_U> which seems strange
[23:34:38] <eric_U> metric hardware still more expensive from most U.S. industrial suppliers
[23:36:29] <BigJohnT> I'm testing my plasma cutter and I get STEPGEN: Channel 0: The requested maximum velocity of 26600 steps/sec is too high.
[23:36:40] <BigJohnT> I'm trying to get the input counts right
[23:36:45] <SWPadnos> I think people just got too mired in conversions that they lost sight of the fact that metric is a hell of a lot easier to deal with
[23:36:54] <eric_U> this reminds me of someone: http://portland.craigslist.org/mlt/tls/508327376.html
[23:37:04] <eric_U> yes, they tried to teach us metric with conversions
[23:37:19] <SWPadnos> BigJohnT, you need to reduce the BASE_PERIOD (ie, speed it up), or reduce the maximum velocity settings for each offending axis
[23:37:20] <eric_U> stupid approach, just go cold turnkey
[23:37:30] <BigJohnT> ok
[23:37:34] <eric_U> like they did with soft drinks
[23:42:04] <BigJohnT> SWPadnos: That did the trick. I can rapid at 300 IPM without missing a beat
[23:42:09] <BigJohnT> Now for 400 IPM
[23:42:12] <SWPadnos> cool
[23:42:14] <SWPadnos> heh
[23:42:31] <BigJohnT> yea it's way cool
[23:42:58] <BigJohnT> I did get a RAPTI error do you know anything about that
[23:43:13] <BigJohnT> didn't seem to cause a problem...
[23:44:33] <Gamma-X> anyone use the digitizing in emc2?
[23:48:18] <Gamma-X> ?
[23:48:38] <BigJohnT> not yet but I want to someday
[23:48:47] <SWPadnos> BigJohnT, it depends on which error you're getting
[23:49:01] <SWPadnos> I think there's one that isn't too critical, and one that is (and I don't remember the specifics of either)
[23:49:11] <BigJohnT> ok I'll have to wait till it come up again
[23:49:12] <SWPadnos> Gamma-X, yes, some people probe/digitize with EMC2
[23:49:28] <BigJohnT> I just got a joint 2 following error
[23:49:43] <SWPadnos> in fact, there were recently some improvements made so more intelligent probing algorithms can be used in a G-code program
[23:49:51] <Gamma-X> SWPadnos any body have any bad reviews of it?
[23:50:10] <SWPadnos> you end up with a file that has lines with I think 9 numbers on them
[23:50:12] <SWPadnos> dunno
[23:50:59] <fenn> hmm plaid drill press - what an excellent idea
[23:51:27] <fenn> you could do them in NFL team colors even
[23:57:44] <SWPadnos> gotta run. bbl
[23:57:46] <BigJohnT> On max_velocity does machine units per second mean 0.001" per second just a little confused
[23:58:01] <SWPadnos> it means units per second
[23:58:07] <fenn> machine units means inch or mm
[23:58:08] <SWPadnos> if you 've configured the machine for mm, it's mm/sec
[23:58:16] <SWPadnos> if you've configured it for inches, it's inches/sec
[23:58:21] <BigJohnT> ok
[23:58:25] <BigJohnT> it's inches
[23:59:46] <BigJohnT> so 375 IPM is equal to 375/60=6.25 machine units per second