#emc-devel | Logs for 2006-07-11

[00:12:31] <anonimasu> yep
[00:12:35] <anonimasu> hey alex
[11:54:03] <jepler> dangit .. looks like bdi2 doesn't have readlink(1)
[12:07:03] <alex_joni> what's that used for?
[12:16:04] <jepler> alex_joni: nothing .. yet
[12:16:31] <alex_joni> err.. I meant what do you want to do with it?
[12:16:54] <jepler> replace some silly business in scripts/realtime with 'readlink -f'
[12:18:11] <jepler> the part beginning # it exists, is it a symlink?
[12:24:33] <jepler> I'm still trying to speed up startup & shutdown of emc2
[12:24:43] <jepler> I have it under 2 seconds to start, display axis, and stop (hot disk cacke)
[12:25:02] <jepler> but part of that is simplifications of the realtime script that won't work on older systems
[12:25:11] <jepler> oops, time to go to work
[12:28:27] <alex_joni> ok, talk to you later ;)
[13:43:29] <cradek> yay alex sent a dapper announcement
[13:44:13] <alex_joni> finally
[13:44:30] <alex_joni> really no need to wait forever
[13:44:49] <cradek> if I use a new machine for my lathe (not sure if I will yet) I'll try dapper
[13:45:11] <cradek> did you make a new install script and put it on linuxcnc.org?
[13:45:38] <jepler> that's OK, now that we support dapper we'll have to tell the people who want 64 bits that they need to wait
[13:45:46] <jepler> there's always something
[13:46:06] <alex_joni> cradek: yes
[13:46:15] <alex_joni> www.linuxcnc.org/dapper/emc-install.sh
[13:46:35] <cradek> yay
[13:47:07] <alex_joni> used that so the name stays the same (and the instructions to install are still relevant ;)
[13:47:21] <cradek> sounds good
[13:47:54] <cradek> I would rather have rtai-isolcpus + smp than 64 bit
[13:49:16] <jepler> this bit on the wiki front page should probably be updated:
[13:49:19] <jepler> " An entire special distribution of Linux is no longer needed to easily install and run EMC2; see the instructions for installing the EMC2 packages for Ubuntu 5.10 at http://timeguy.com/cradek/emc/ubuntu These packages are maintained by a member of the EMC board of directors and are kept up-to-date (and provide a very easy upgrade capability) as new Testing snapshots are made."
[13:49:35] <cradek> that's old
[13:49:42] <alex_joni> right
[13:49:59] <jepler> maybe we should decide whether to mention emc1 at all on the front pag
[13:50:00] <alex_joni> jepler: will you change it?
[13:50:01] <jepler> page
[13:50:25] <alex_joni> jepler: not sure :) .. there was a bugreport on emc1 recently though
[13:50:54] <alex_joni> but that was between the very few things I heard about emc1 in the last year or so
[13:51:35] <cradek> I don't see any reason to use emc1 anymore, except maybe on VERY old hardware
[13:51:48] <alex_joni> yeah, but emc2 runs on bdi2.x too
[13:51:55] <alex_joni> so that's up for debate
[13:52:50] <cradek> however I can imagine lots of ways to use parts of it (because of the PD license)
[13:52:50] <jepler> " An entire special distribution of Linux is no longer needed to easily install and run EMC2; see [the instructions for installing the EMC2 packages for Ubuntu] 5.10 and 6.06. These packages are maintained by a member of the EMC board of directors and are kept up-to-date (and provide a very easy upgrade capability) as new releases are made."
[13:52:59] <jepler> I
[13:53:07] <jepler> 'm not saying we should expunge all mention of emc1
[13:53:16] <cradek> s/a member of//
[13:53:46] <cradek> since these responsibilities are now shared among the board
[13:53:49] <jepler> but it's now irrelevant for most users, and I want to help avoid the user asking "but which version do I need?"
[13:54:12] <cradek> I don't think I've heard that happening
[13:54:19] <cradek> maybe it's not asked aloud I guess
[13:56:39] <alex_joni> lol.. did you see this? http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl/emcinfo.pl?Suppliers
[13:57:19] <cradek> heh
[13:57:24] <cradek> yay for wikis
[13:57:30] <alex_joni> yay for chips
[13:57:35] <cradek> I like the chips thumb up/down
[13:57:39] <alex_joni> yeah
[13:57:45] <cradek> do penguins have thumbs?
[13:57:50] <alex_joni> only 3
[13:57:52] <cradek> seems unlikely
[13:57:52] <alex_joni> ROFL
[13:58:27] <alex_joni> http://becausewehavethumbs.blogspot.com/
[13:59:14] <alex_joni> main poster is "Sarah the penguin"
[13:59:18] <alex_joni> so I guess that proves it :D
[14:31:35] <alex_joni> jepler: ever thought about getting one like this: http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=389038&is=REG&addedTroughType=categoryNavigation ??
[14:33:56] <jepler> I bought a 2x TC off ebay. with it and my 75-300mm at 300mm, AF is unreliable, and the images are not terribly sharp (possibly related to bad manual focusing). shutter times are long because the effective minimum aperture is F/11 or something
[14:34:26] <alex_joni> right.. they do say that you need a 2.8 lens or better for AF to work reliable
[14:34:34] <alex_joni> mine is 4-5.6 :(
[14:34:41] <alex_joni> the 75-300 I mean
[14:34:44] <jepler> yeah .. mine's similar
[14:39:09] <alex_joni> this would be a good lens: http://www.dpreview.com/news/0602/06022112canonef85f12l.asp
[14:46:53] <jepler> 85mm isn't any good for portraits on an EF-S camera
[14:47:11] <alex_joni> I use about 200 for portraits
[14:47:16] <alex_joni> but I need lots of light
[14:47:26] <alex_joni> hmm.. did you know there is a 50mm 1:1.0 one?
[14:47:30] <alex_joni> http://photo.net/photo/canon/canon-50-1.0.html
[14:47:32] <jepler> eek, and the price! ยค2,049
[14:49:49] <alex_joni> http://www.geocities.com/Yosemite/8917/ef50back.jpg
[14:49:52] <alex_joni> that looks crazy
[19:30:10] <jepler> cradek: did you take any screen shots of halscope while tuning your PIDs?
[19:30:20] <cradek> nope
[19:30:25] <jepler> darn
[19:30:28] <jepler> I like screenshots
[19:31:01] <cradek> the pid output varies a surprising amount to give good results
[19:31:16] <cradek> at first I was going for "smooth" pid output, which gave bad FE
[19:31:41] <cradek> later I got smart and worked on smooth FE, not worrying about what the pid output looked like
[19:32:39] <cradek> now do a "rapid" and stay within ~ .004 mm
[19:32:48] <cradek> now IT CAN
[19:33:27] <jepler> it seems surprising that the PID output would not be smooth, since everything I've read assumes the relationship between PID output and velocity is pretty constant
[19:33:45] <jepler> (this whole business in setting the PID's output range so the output is in "units per second"
[19:34:02] <cradek> well, my setup sucks
[19:34:12] <cradek> maybe on X (which doesn't suck) it'll look better
[19:35:37] <jepler> did you use the new pwmgen component?
[19:35:48] <cradek> if I reduce D the pid output looks much smoother, but the FE oscillates
[19:35:58] <cradek> it could be that I still don't know what I'm doing, of course
[19:36:27] <cradek> it's still set up for freqgen (I did this config before pwm), but I will switch it to pwm
[19:40:01] <jepler> what's the oscillation like? seems like if it's at 1 per motor or leadscrew rev it might be about a physical problem .. and if it's at 60Hz or 120Hz it could be power supply ripple.
[19:40:29] <cradek> good question
[19:40:37] <cradek> I'm 90% sure it's per motor rev
[19:40:37] <jepler> it would be interesting to command a duty cycle (no pid) and see how the derivative of the feedback position looks, too
[19:40:51] <cradek> I think the pulley on the motor is drilled off center a bit
[19:41:13] <cradek> I'll either plug it or get a new one
[19:41:44] <cradek> I thought I could get away with drilling it, but it really needs to be bored
[19:42:36] <cradek> (but boring a 4mm hole is going to be a pain in the neck)
[20:23:02] <anonimasu> cradek: it'll work ;)
[20:23:48] <cradek> what will?
[20:45:40] <alex_joni> hello all
[20:54:39] <jepler> hi alex_joni
[20:55:00] <alex_joni> real newbies today on the list
[20:58:38] <cradek> yes, thanks for answering them all
[20:59:33] <alex_joni> cradek: no reason to thank me ..
[20:59:51] <cradek> sure there is, it means I don't have to
[21:00:07] <alex_joni> yeah, but next time I bet you'll do it, so I won't have to ;)
[21:00:23] <cradek> maybe, but don't bet too much!
[21:00:25] <alex_joni> next time = 2.5 weeks :D
[21:04:53] <alex_joni> anyways.. heading to bed now :) night all
[21:05:03] <jepler> g'night
[21:05:23] <cradek> goodnight alex