#emc | Logs for 2008-12-14

[00:39:21] <Groundhog> I could use some help with gcnccam...
[05:22:37] <StPeteNick> hello, i just heard about this channel
[05:23:26] <StPeteNick> any luthiers here ? (guitar makers)
[05:26:08] <SWPadnos> hmmm. I don't know that anyone here makes guitars
[05:26:23] <SWPadnos> or other musical instruments, for that matter
[05:26:51] <StPeteNick> i attempted a violin top/back by hand ...cnc looks very interesting
[05:27:03] <renesis> it would be fun if i had a bigger machine
[05:27:15] <SWPadnos> if you're talking about scrollwork and inlays, you'll want a very precise machine
[05:27:30] <renesis> i dont think the vacuum table at old job would do the planks for guitars well
[05:27:47] <StPeteNick> ppl here do home brew machines though ?
[05:27:54] <SWPadnos> some, yes
[05:28:01] <StPeteNick> cool
[05:28:13] <renesis> desktop mills too
[05:28:14] <SWPadnos> it's usually either homebrew or retrofits
[05:28:24] <StPeteNick> i had an idea for anti-backlash nuts
[05:28:25] <renesis> tho youd prob be limited to neck work with something like that
[05:28:26] <SWPadnos> or conversions :)
[05:28:53] <StPeteNick> fiddle tops look doable from what i have seen
[05:29:07] <renesis> swpadnos: theres two people in another chan im in building homebrew setups
[05:29:33] <SWPadnos> oh sure - people do it all the time, just not a lot of homebrew in this channel on a regular basis
[05:29:35] <renesis> linear rails, ballscrews and MDF
[05:29:48] <StPeteNick> cool
[05:29:53] <renesis> one just finished, hes doing PCB milling on his
[05:30:00] <SWPadnos> there are also the folks building their own servo amps and stuff (here and elsewhere)
[05:30:18] <StPeteNick> i am going tyo go w/ steppers
[05:30:26] <renesis> stpetenick: steppers and step drivers are pretty cheap
[05:30:32] <StPeteNick> to go*
[05:30:38] <renesis> you can get very good results you just have t stay on top of it
[05:30:56] <StPeteNick> yup ...hobbycnc pro looks nice
[05:31:02] <renesis> once you have everything dialed in and get comfortable with speeds/feeds theyre very reliable
[05:33:15] <renesis> guitar bodies you need a decent Y, so yeh youre prob better off going homebrew if you dont want to drop closer to $10K on a machine and probably conversion costs/time
[05:33:19] <StPeteNick> ... i assume it's not much of a problem feeding linux text based g-code from a windoze machine
[05:33:31] <renesis> gcode is gcode is gcode
[05:33:39] <SWPadnos> you have to make sure the line endings are correct
[05:33:42] <renesis> its just text and linbreaks, basically
[05:33:47] <renesis> yeh
[05:34:10] <renesis> does mach choke on *nix text?
[05:34:18] <renesis> thats a bit sad =(
[05:34:32] <StPeteNick> ahh, if i could only do the molds in cnc, it would be great, ... stacked mdf
[05:34:33] <SWPadnos> install the package "tofrodos" when you get EMC2/Ubuntu installed, and you'll have a program called "dos2unix", which will convert for you
[05:34:47] <SWPadnos> and unix2dos, in case you need it
[05:34:57] <StPeteNick> i thought so
[05:35:07] <renesis> im pretty sure emc handles dos files ok
[05:35:25] <renesis> tho im not sure i guess
[05:35:27] <SWPadnos> I think it doesn't actually
[05:35:40] <renesis> yeh cuz i do cam work in windows
[05:35:48] <renesis> but from a mingw app =\
[05:36:01] <renesis> dunno if its outputting dos files or not
[05:36:10] <SWPadnos> there was an email on the user list from someone who had edited in notepad, and he was having problems which I believe ended up being (partly) a lot of ^M characters in his file :)
[05:36:15] <SWPadnos> probably
[05:36:19] <StPeteNick> you can sent the files to emc though no prob ...?
[05:36:20] <renesis> heh
[05:36:21] <SWPadnos> since it's on Windows
[05:36:51] <SWPadnos> networking shouldn't be an issue. I routinely connect my Linux machines to my Windows 2000 workstation and move files around
[05:36:55] <renesis> because i think when i vim or nano or whatever them, i get a [DOS] flag in the status files
[05:37:03] <StPeteNick> cool
[05:37:28] <SWPadnos> just use dos2unix first and everything will be fine (assuming you have good G-code :) )
[05:37:36] <renesis> yeh tru that
[05:37:47] <StPeteNick> ok, very cool
[05:38:23] <renesis> i wonder if pcb photoplotters care about rs274x linebreaks
[05:39:21] <SWPadnos> who knows
[05:39:22] <renesis> eagle prob outputs cam files the same in w32 and nix, anyway
[05:39:26] <SWPadnos> night time for me. good night
[05:39:30] <renesis> nite
[05:39:41] <StPeteNick> bye SWPadnos
[05:40:14] <StPeteNick> i have to go also, i just heard about this channel and had to check it out
[05:40:39] <StPeteNick> bye all, cool channel
[08:58:09] <tomaw> [Global Notice] Hi all. One of our larger client servers just dropped off the network for a few minutes. It's back now and hopefully stable, sorry for the downtime and thanks for using freenode!
[09:01:05] <[1]a-l-p-h-a> [1]a-l-p-h-a is now known as a-l-p-h-a
[13:33:37] <tomp> some good us military design guides http://www.bjg-design.com/designbook/start.htm
[13:50:44] <BigJohnT> FLOAT - a 32 bit floating point value, with approximately 24 bits of resolution and over 200 bits of dynamic range.
[13:50:56] <BigJohnT> what does this mean in non-geek english?
[13:52:17] <tomp> it takes up 4 consective bytes in memory. and is a really big number with a lot of decimal places in front and behind the dot :)
[13:52:47] <tomp> not an infinite number in front or behind, but a lot
[13:52:51] <BigJohnT> :)
[13:55:27] <tomp> and the float means, the posn of the dot moves, and where it is specified in the 32 bits, leaving less for the infront and the behind values to work with.
[13:57:07] <tomp> you can divy the rest up in fornt or behind, as you like , but, keep it all inside those 32 bits. so its limited for some math, but we think good enuf for cnc.
[13:58:06] <jepler> BigJohnT: "24 bits of resolution" means that there are about 7 digits of precision
[13:58:35] <jepler> so you can store 10000000 and 10000001 as distinct values in a 'float', but not if there's one more zero
[13:58:57] <BigJohnT> ok
[13:59:29] <jepler> did you take high school chemistry or physics, to learn about exponents? 3.0 x 10^25 and all that?
[13:59:38] <BigJohnT> no
[13:59:58] <jepler> then "200 bits of dynamic range" is harder to explain
[14:01:57] <jepler> it means that the biggest possible values are very big, about 30 digits if you wrote them out in regular numerals .. and the values closest to zero can have about 30 zeros from the decimal point to the first nonzero value
[14:02:49] <BigJohnT> so a float is stored as an exponent number?
[14:04:40] <tomp> is it very precise near zero ? and less precise when the 'whole number' gets real big ( like the 1000000 can not have loads of decimal places after it, while the number 11 can have loads behind it )
[14:04:47] <jepler> tomp: right
[14:05:04] <tomp> thats the 'dynamic range ' part
[14:05:05] <BigJohnT> ok, that makes sense
[14:05:55] <jepler> and yes the computer stores them in a kind of exponential notation, similar to the 3.0x10^25 you might see in scientific contexts .. except with everything based on 2 instead of 10
[14:07:26] <jepler> there are a few bits of this article that are written for a non-geek to understand: http://en.wikipedia.org/wiki/Floating_point
[14:07:45] <BigJohnT> LOL I was reading that :)
[14:15:44] <jepler> hmm is there something I don't know? Results 1 - 10 of about 137 for "it's 2009 now". (0.10 seconds)
[14:18:06] <BigJohnT> must be new math
[14:20:55] <alex_joni> probably missing digits for the required precision
[14:21:03] <alex_joni> so 2008.12 turns into 2009
[14:37:04] <tomp> ever look at the dashboard clock, see 10:01 and think "it's only 9 oclock" ?
[14:41:17] <anonimasu> yeah
[14:41:30] <anonimasu> :)
[14:41:49] <anonimasu> but more often then not it's "shit it's 03:00 not 10:00"
[14:41:51] <anonimasu> :p
[17:54:50] <alex_joni> archivist: around?
[17:55:07] <alex_joni> archivist: was it you spending time in #mysql ?
[18:01:14] <JymmmEMC> yep
[18:22:30] <alex_joni> archivist: if so .. can you join #cia, maybe you can be of some assitance with some mysql config issue BearPerson is having
[18:38:30] <alex_joni> Welcome! EMC (Enhanced Machine Controller) is a linux-based opensource CNC control. | Latest release: EMC 2.2.8 | http://www.linuxcnc.org | http://wiki.linuxcnc.org
[18:38:38] <alex_joni> alex_joni has changed the topic to: Welcome! EMC (Enhanced Machine Controller) is a linux-based opensource CNC control. | Latest release: EMC 2.2.8 | http://www.linuxcnc.org | http://wiki.linuxcnc.org
[18:39:21] <jepler> (packages for ubuntu dapper are not quite ready yet)
[18:56:00] <mshaver> Now installing 2.2.8 on Hardy! THANKS you guys!
[19:05:20] <alex_joni> mshaver: let us know if there are issues
[19:15:16] <mshaver> alex_joni: This is a _release version_, what could possibly go wrong?
[19:15:33] <alex_joni> ok :)
[20:06:12] <jepler> (I'm told the dapper packages are ready now too)
[20:18:38] <mshaver> OK, one problem. motion.feed-hold doesn't stop feeding during homing. If it matters, this is a machine with HOME_SHARED and IGNORE_LIMITS_DURING_HOMING. I don't know if this was any different in 2.2.7, but I was fooling around and discovered this now.
[20:19:39] <seb_kuzminsky> mshaver: hm
[20:23:25] <jepler> mshaver: I doubt it's different from 2.2.7..
[20:23:29] <jepler> would take a patch to fix it, though..
[20:25:17] <mshaver> I doubt it's different too. I'm sending out some software to a couple of guys. They'll likely never notice it, but I think it's something that should be fixed in TRUNK and included in 2.2.9.
[20:25:43] <mshaver> I've just been giving things an extra critical eye lately.
[20:25:56] <alex_joni> that's always more than welcome
[20:26:02] <alex_joni> (the critical eye part)
[20:26:07] <seb_kuzminsky> critical eyes (and good bug reports) is very valuable :-)
[20:27:43] <mshaver> seb_kuzminsky: Now that I've got my previous task done (getting software ready to send out), I'm going to collect some data on the ferror problem.
[20:33:37] <seb_kuzminsky> mshaver: if your asking to cruise faster than your stepgen timings allow, that might cause the ferror you're seeing
[20:34:00] <seb_kuzminsky> or faster than your stepgen.maxvel allows
[20:34:07] <seb_kuzminsky> ok i'm outta here, ttyl
[21:49:36] <alex_joni> * alex_joni is off to bed
[21:49:39] <alex_joni> good night all
[21:54:24] <skunkworks_> so.. Know why the vacumm pump quit last time. You have to keep oil in it.
[21:58:21] <skunkworks_> go figure
[21:58:34] <alex_joni> * alex_joni is gone figuring
[22:00:39] <skunkworks_> :)
[22:18:17] <skunkworks_> http://cnczone.com/forums/showpost.php?p=538614&postcount=16
[22:24:18] <cradek> skunkworks_: you can have negative TLO.
[22:26:29] <alex_joni> http://sourceforge.net/projects/tkbacktracer/
[22:26:41] <cradek> (if he could motorize the knee he'd be in good shape)
[22:35:20] <cradek> hm, weather forecast for tomorrrow says "much colder"
[22:46:45] <eric_u1> darn, I thought it was supposed to be warmer
[23:53:04] <mumptai> Hi
[23:53:27] <BigJohnT> hi