#emc | Logs for 2007-07-29

[00:03:16] <fenn> what is that, an inverting buffer?
[00:04:42] <jepler> it looks like what you want is "up/down" PWM, not "pwm+direction". that is pwmgen output_type=2
[00:05:06] <jepler> type 2: up/down
[00:05:06] <jepler> Two output pins, up and down. For positive inputs, the PWM/PDM
[00:05:06] <jepler> waveform appears on up, while down is low. For negative inputs,
[00:05:06] <jepler> the waveform appears on down, while up is low. Suitable for
[00:05:06] <jepler> driving the two sides of an H-bridge to generate a bipolar out-
[00:05:08] <jepler> put.
[00:13:19] <floppy12> lol
[00:13:22] <floppy12> okay
[00:13:22] <floppy12> thank you
[00:13:37] <floppy12> ill test tomorrow
[00:13:50] <floppy12> UUUHHH NO... today ;(
[00:14:50] <Skullworks-PGAB> $44.82 ea (qty 10 pricing) for E5s encoders with index... plus connectors, add about $15 for 6ft shielded.
[00:17:15] <floppy12> jepler have you written the manual?
[00:17:16] <floppy12> insmod: error inserting ’/home/jepler/emc2/rtlib/hal_parport.ko’:
[00:17:21] <floppy12> *G*
[00:17:30] <jepler> floppy12: I've written parts of the manual
[00:17:48] <jepler> just like the rest of emc, many developers and users give their time to improve the manual
[00:18:09] <floppy12> yes
[00:20:27] <floppy12> jepler where stand this? [02:05] <jepler> type 2: up/down.................................
[00:21:03] <jepler> floppy12: in the terminal, type "man pwmgen"
[00:21:19] <jepler> floppy12: or online, http://linuxcnc.org/docs/2.1/html/man/man9/pwmgen.9.html
[00:21:34] <floppy12> thank you a lot
[00:21:43] <floppy12> i hope it work
[01:10:03] <a-l-p-h-a> those weird russians. http://www.dailymail.co.uk/pages/live/articles/news/news.html?in_article_id=471324&in_page_id=1770
[01:15:52] <Ziegler> how does one go about finding out the actual amount of backlash a machine has?
[01:20:30] <Skullworks-PGAB> use a dial indicator
[01:21:15] <Skullworks-PGAB> preload it a bit, then set the dial to zero
[01:21:50] <Skullworks-PGAB> command a .1: move and see if you get that
[01:22:18] <Skullworks-PGAB> then a -.1" (inc) move and see if you get back to zero
[01:23:10] <Skullworks-PGAB> the readings will tell you how much backlash is under no load
[01:23:18] <Skullworks-PGAB> (at that spot)
[01:23:43] <Ziegler> right
[01:23:45] <Ziegler> inc?
[01:23:55] <Skullworks-PGAB> (will be more or less if lead screw is worn in different places)
[01:24:01] <Skullworks-PGAB> incramental move
[01:24:06] <Ziegler> ok
[01:24:25] <Skullworks-PGAB> not from X.1 to X-.1 which would go .2"
[01:24:27] <Ziegler> noticed circles I was cutting
[01:24:40] <Ziegler> are a tiny bit elliptical
[01:25:13] <Skullworks-PGAB> yep 3-6-9-12 - where the axis drives have to reverse direction
[01:25:34] <Ziegler> yup
[01:25:48] <Ziegler> is shorter in the x than the y
[01:26:08] <Ziegler> going clockwise
[01:26:26] <Skullworks-PGAB> old CNC's had a 1/4 circle limit - had to continue on next line to go past a reversal point
[01:26:51] <Ziegler> I was doing small line segments anyway
[01:27:27] <Skullworks-PGAB> ah
[01:27:46] <Ziegler> having problems with my CAM program generating emc compatible G3's
[01:28:06] <Skullworks-PGAB> * Skullworks-PGAB likes new CNC's that cut a full circle with a G3 J-1.
[01:28:22] <Skullworks-PGAB> which post are you using
[01:28:45] <Ziegler> EMC mil
[01:28:50] <Ziegler> :D
[01:29:03] <Skullworks-PGAB> CAM maker/brand?
[01:29:20] <Ziegler> Bob CAM
[01:29:25] <Skullworks-PGAB> errrrrrrrrrrrr
[01:29:35] <Ziegler> bad?
[01:29:40] <Skullworks-PGAB> version 21 or 2007?
[01:29:44] <Ziegler> 21
[01:29:48] <Skullworks-PGAB> hmmm
[01:29:50] <Skullworks-PGAB> I have 221
[01:29:53] <Skullworks-PGAB> 21
[01:30:15] <Skullworks-PGAB> have not tried the post yet since the hardware is still ing process
[01:30:48] <Ziegler> program gets G3's right alot of the time
[01:30:54] <Ziegler> but it doesnt like it sometimes
[01:31:10] <Ziegler> using inch to the 4th or 5th decimal
[01:32:04] <Skullworks-PGAB> well EMC2 has a bad problem (if the manual is correct) that requires a X or Y value on any arc command
[01:32:23] <Ziegler> yeah I have noticed that
[01:32:37] <Skullworks-PGAB> most commercial CNC's don't.
[01:32:40] <Ziegler> you can force BCam to place them... at least I think I can
[01:33:17] <Skullworks-PGAB> well there is an "Output ALL Coordinates" option
[01:33:58] <Skullworks-PGAB> but that buts an X/Y/Z on very line
[01:34:07] <Ziegler> yeah
[01:34:07] <Skullworks-PGAB> puts
[01:34:20] <Skullworks-PGAB> file size balloons
[01:35:21] <Ziegler> yup... I got tired of messing with it, so I incremented the arc to line segments
[01:36:08] <Skullworks-PGAB> I am going down to pick up a powersupply tonite to build another linux box.
[01:36:32] <Skullworks-PGAB> I will be setting it up to run sims
[01:38:06] <Skullworks-PGAB> The arc issue is one that I think should be addressed
[01:39:08] <Skullworks-PGAB> It is a fossil remenant of Allen Bradley's NIST involvement in the early EMC developement
[01:40:24] <Skullworks-PGAB> and it remains one of the biggest compatability issues that keep people from adopting EMC2 in industry
[01:43:08] <Ziegler> interesting
[01:43:34] <Ziegler> how dug in is it? Ie.. how much effort to change?
[01:44:20] <Skullworks-PGAB> I have a great library of macros that I would love to port to EMC but they will error if this is so
[01:44:40] <Ziegler> :-\
[01:44:43] <Skullworks-PGAB> not sure - I think its coded in the interp
[01:45:07] <Skullworks-PGAB> but I doubt it would take much
[01:45:31] <Skullworks-PGAB> since most other values are accepted as modal until changed
[01:45:44] <Ziegler> who is the interpreter guru?
[01:46:17] <Skullworks-PGAB> JMK or Alex I guess
[01:46:39] <jmkasunich> not me
[01:46:45] <Skullworks-PGAB> Though ray might have a handle on it to
[01:46:49] <Ziegler> hehe
[01:47:39] <Skullworks-PGAB> * Skullworks-PGAB can't write C - only debug it
[01:48:44] <Ziegler> I can read it...
[01:49:01] <Ziegler> writing it... not usually with good results
[01:49:14] <Skullworks-PGAB> John K what are your areas of expertise?
[01:49:37] <Skullworks-PGAB> I know you've been doing alot of the Mesa drivers
[01:50:13] <Skullworks-PGAB> and you avoid stick GUI issues
[01:50:17] <Skullworks-PGAB> sticky
[02:01:27] <jmkasunich> I work on HAL and realtime stuff like the motion controller
[02:01:38] <jmkasunich> drivers are part of hal, so I work on those too
[02:02:07] <jmkasunich> homing code, jogwheels, that kind of stuff is what I do
[02:02:12] <jepler> in interp_convert.cc start by removing the lines near NCE_X_AND_Y_WORDS_MISSING_FOR_ARC_IN_XY_PLANE);
[02:02:30] <jepler> function convert_arc; lines 170 through 180 in my version
[02:03:01] <jepler> are full circles such an important case? They are of course a pathologically bad case for R-format arcs
[02:03:08] <jepler> so maybe the check should be made only for R-format
[02:03:22] <jepler> * jepler doesn't know what's best
[02:03:26] <Skullworks-PGAB> that would work
[02:03:40] <cradek> what's the exact incompatibility?
[02:04:15] <Skullworks-PGAB> well lets say you wanted to mill a full circle
[02:04:40] <Skullworks-PGAB> the command could be g3 i-1
[02:04:49] <cradek> ok
[02:04:56] <cradek> that's the whole problem?
[02:05:08] <Skullworks-PGAB> yeah mainly
[02:05:14] <cradek> so it has nothing to do with R format (you can't cut a full circle with R format no matter what)
[02:05:42] <Skullworks-PGAB> threadmilling macros will output an I | J and a Z
[02:05:52] <Skullworks-PGAB> yup
[02:06:32] <Skullworks-PGAB> even commerical machines sometimes error out on a valid arc command when an R value is used
[02:06:41] <cradek> if nobody wants to fix it right now (I don't) the best thing you could do is file a bug report or feature request
[02:07:06] <jepler> if you can test the change I suggested and mention in the feature request that it works, that's even better
[02:07:11] <Skullworks-PGAB> well - strictly speaking it follows the NGC definition
[02:07:27] <Skullworks-PGAB> but not RS 274
[02:08:39] <Skullworks-PGAB> and it isn't a killer issue - it just makes headaches because of how many post processors are defined
[02:09:21] <Skullworks-PGAB> its an all values or only changed value type choice in the post
[02:09:42] <cradek> I can see how it's probably typical to write (if the XY target is the same as the current position, don't output XY words), and that means this case is broken
[02:10:08] <Skullworks-PGAB> exactly
[02:11:48] <skunkworks> crap - keyboard still acting up.
[02:11:52] <cradek> great, will you file it? I think it is a feature request - I checked the docs and they do say at least one X/Y word is required
[02:12:45] <Skullworks-PGAB> sure - I guess I can do that - I'm about to head out the door now though.
[02:13:11] <cradek> ok, whenever you want, I just don't want it to be forgotten
[02:14:33] <Skullworks-PGAB> trust me - I won't forget - it makes my $2200 engraving software useless, and my macro library too.
[02:15:15] <cradek> I'm surprised we haven't heard about this before
[02:15:41] <Skullworks-PGAB> I hope to port that library and once proven to be fully functional/compatable offer it up as an option
[02:16:00] <skunkworks> normally - all the cheap post-processors allow you to persist or not the coordinates.
[02:17:24] <Skullworks-PGAB> the NPT thread milling macro would be a huge help to some people
[02:25:56] <Ziegler> its got my vote.... I cant code C, but I would be willing to take some active effort if possible
[02:27:43] <dmessier> sup??
[02:28:09] <dmessier> bodies to hide???
[02:32:09] <Skullworks-PGAB> bbl - must fetch that pws
[02:47:40] <a-l-p-h-a> omg, dmessier is a live
[03:19:34] <tomp> Ziegler: i think the simplest ball screw backlash test is to mount an indicator to the nut and put tip onto flank of a screw groove. then move the nut fwd & bwd ( not rotation) to show any backlash. This only shows lash between the nut and screw.
[03:35:53] <toastydeath> actually dudes usually measure from the spindle
[03:36:06] <toastydeath> putting an indicator on the spindle, and pointing it, in line, at a parallel
[03:36:28] <toastydeath> take the backlash out, set zero, then move an inch
[03:36:33] <toastydeath> record
[03:36:35] <toastydeath> move back an inch
[03:36:39] <toastydeath> deviation from zero is the backlash
[03:36:55] <toastydeath> if you have an interferometer you can do it for all three axes at once.
[03:40:57] <DanielFalck> I've done something similar to what tomp describes, only I used a lathe and fixed everything so that nothing could rotate. Then I mounted a dial indicator with the plunger touching the nut. At that point, I pushed and pulled on the nut
[03:41:13] <DanielFalck> this was when I was reloading balls into ballscrews
[03:41:30] <DanielFalck> trying different value balls in .0001" increments
[03:41:39] <toastydeath> the problem with that is it doesn't show you the actual effect on the machine, and also doesn't reproduce the forces the machine will generate
[03:41:55] <DanielFalck> I was looking at the screws themselves
[03:42:01] <toastydeath> yeah, but you don't use the screws by themselves
[03:42:10] <DanielFalck> then we looked at the screws in the slides later
[03:42:23] <DanielFalck> checking the thrust bearings
[03:42:53] <DanielFalck> this was for a bunch of screws and slides
[03:43:04] <toastydeath> fair enough
[03:43:41] <DanielFalck> I do the indicator against the spindle trick on my machines here at home though
[03:44:40] <toastydeath> that's the ASPE standardized test for machine backlash
[03:44:53] <toastydeath> i need to get a copy of that document
[04:54:25] <ds2> what is the prefered way of controlling spindle speed with EMC on a lathe? (PWM? a command through the serial port, a DAC?)
[06:39:17] <toast> ff
[06:40:40] <Jymmm> fulffy fuff?
[06:45:58] <toast> no, just "fff"
[06:56:50] <Jymmm> I'll take your word for it
[07:08:01] <Jymmm> anyone have any ideas on squaring up an aluminum blick and shaving off about .015" or so?
[07:19:21] <toast> uh, like, you are saying you have .015
[07:19:23] <toast> and that's it
[07:19:28] <toast> is that per side or what
[07:20:31] <toast> Jymmm:
[07:20:39] <toast> to true something up, you pick a side
[07:20:53] <toast> put that side face up in a vise against the hard jaw
[07:20:59] <toast> er fixed jaw
[07:21:14] <toast> put a good sized bar next to it and clamp the part through the bar
[07:21:22] <toast> this is side one
[07:21:27] <toast> mill side one
[07:21:45] <toast> flip it 90 degrees so side 1 is on the fixed jaw, repeat clamping with the bar
[07:21:55] <toast> now side 1 should be perpendicular to side 2
[07:22:09] <toast> flip it 90 again, still with the bar
[07:22:40] <toast> so side 1 rests on the bottom of the vise and side 2 is resting on the fixed jaw
[07:22:54] <toast> machine this side, then flip it 90 again, remove the bar and clamp it
[07:22:57] <ds2> that is a much more frustrating process then you'd think
[07:23:03] <toast> it's not at all, and it work
[07:23:08] <toast> i do it for production crap at work
[07:23:12] <toast> *works
[07:23:42] <ds2> forget to just hammer down one side and you have a funny shaped block
[07:23:48] <toast> don't hammer it down!
[07:23:58] <toast> that will put warp into it
[07:24:10] <ds2> if I don't get get a parallogram shaped
[07:24:25] <toast> the vise is lifting the part then, carry on
[07:24:25] <ds2> not hammer hammer...just tap it down so the parallels no longer slide around
[07:24:40] <toast> if you use a toolmaker's vise that won't happen (or shouldn't)
[07:24:48] <ds2> toolmaker as in the screwless ones?
[07:24:51] <toast> but hammering does put extra stress into the part
[07:24:52] <toast> yeah
[07:24:58] <toast> a good one, not a cheapass HF vise
[07:25:03] <ds2> Hmmm
[07:25:10] <ds2> I was doing it on a kurt
[07:25:18] <toast> yar, any screw vise will lift
[07:25:28] <toast> kurt anglock vises do it less than other brands
[07:25:30] <toast> but they still do it
[07:25:36] <Jymmm> I dont have a mill
[07:25:43] <ds2> like I said, it is frustrating =)
[07:25:48] <ds2> jymmm: lathe?
[07:25:49] <toast> Jymmm: same proccedure on a 4 jaw chuck
[07:25:54] <toast> just keep facing it
[07:25:55] <toast> and rotating it
[07:25:55] <Jymmm> I dont have a lathe
[07:26:02] <ds2> was thinking of a face plate
[07:26:09] <toast> face plate works too
[07:26:24] <Jymmm> I dont have a granite plate
[07:26:25] <toast> two jaw chuck, four jaw chuck, faceplate
[07:26:25] <ds2> 4J is another one of those super annoying things
[07:26:26] <toast> any of the above
[07:27:00] <Jymmm> I have duct tape, bailing wire, and an angle grinder!
[07:27:17] <toast> not going to happen
[07:27:19] <ds2> you could file it
[07:27:26] <Jymmm> ds2: square?
[07:27:30] <ds2> sure
[07:27:30] <toast> yeah
[07:27:38] <ds2> got a machinist square as reference?
[07:27:45] <toast> i have serious doubts as to whether or not this will end well
[07:27:52] <toast> *as to whether
[07:27:54] <Jymmm> toast: me too
[07:27:57] <ds2> file some, hold vise to light, note high spot, repeat
[07:28:17] <ds2> not square + peice to light i mean
[07:28:20] <toast> Jymmm: you have a lack of equipment necessary
[07:28:25] <toast> to make what you want
[07:28:32] <Jymmm> toast: tell me aboout it
[07:28:37] <toast> go buy some
[07:28:46] <ds2> how big of an Al block are we talking about?
[07:28:57] <Jymmm> 2" x 2" x .5"
[07:29:03] <ds2> and what kind of squareness call tolerance needed
[07:29:35] <Jymmm> it's the ballnut mounting block
[07:29:42] <toast> looooool
[07:29:42] <ds2> Oh
[07:29:45] <toast> ending so badly
[07:29:52] <ds2> good luck
[07:30:08] <toast> Jymmm: do you have any reference angle plate
[07:30:09] <toast> that you can use
[07:30:29] <Jymmm> toast: No, but I was thinking of ordering a 1-2-3 block if need be
[07:30:36] <Jymmm> I'd never use it again.
[07:30:42] <toast> 1-2-3 blocks can be useful man
[07:30:48] <toast> i use them a lot
[07:30:53] <toast> for measurement crap
[07:31:01] <toast> but i digress
[07:31:02] <Jymmm> I dont have a mill though
[07:31:11] <toast> they're not really for mills
[07:31:12] <ds2> so it just needs to be square, no need for a hole to be bored?
[07:31:24] <toast> you aren't really supposed to set up using them, but you can if necessary
[07:31:37] <toast> also what i was thinking is if you have an angle plate and some glass
[07:32:01] <ds2> if you have time, sign up for MCNC71 at deanza and use their bridgeports
[07:32:01] <toast> set the reference 90 deg thing on the glass, put some sandpaper on the glass
[07:32:41] <toast> and you can sand it
[07:32:43] <toast> but i like ds2's idea
[07:33:11] <Jymmm> Are HF mini mills "square" ?
[07:33:16] <toast> no
[07:33:19] <toast> not at all
[07:33:37] <toast> no mill is intrinsically square
[07:33:39] <toast> you have to tram it
[07:33:44] <ds2> heheheh, your block right now is probally more square then they are as purchased
[07:33:58] <ds2> even if you tram it, the HF mills are... iffy
[07:34:08] <toast> if you change your Z height
[07:34:10] <toast> on an HF mill
[07:34:13] <toast> you will no longer be in tram
[07:34:36] <ds2> Jymmm, where did the block come from?
[07:34:53] <ds2> most extrusions are pretty decent from the mill
[07:34:54] <Jymmm> my machine
[07:35:08] <ds2> oh so it has been worked on already
[07:36:02] <Jymmm> Yeah, they fucked up the machining when they made it the 1st and 2nd time, I just never realized it was "THAT" bad
[07:36:03] <ds2> might easier if you buy a peice of 2" wide, 0.5" thick bar stock and file the ends square
[07:36:58] <Jymmm> how so?
[07:37:27] <ds2> like I said, most extrusions are pretty square from the mill.. which means you will just need to clean up the ends you hack/bandsawed
[07:37:40] <ds2> so just 2 surfaces instead of 6
[07:37:43] <Jymmm> It's not an extrusion...it was machined
[07:37:54] <ds2> so there are other features on it besides just 6 flat surfaces?
[07:38:08] <Jymmm> yes
[07:38:18] <ds2> Ohhhh that complicates things a LOT
[07:38:42] <ds2> you don't just need a square'd block, you need it squared relative to certain features?
[07:38:52] <Jymmm> I moght have to remove about .030"
[07:39:13] <Jymmm> No, just sqaure it up againes the one edge
[07:39:43] <ds2> so is square now and just the wrong size?
[07:40:05] <Jymmm> I jsut dont have anything to remove THAT much material and sqaure it up.
[07:40:35] <Jymmm> ds2: (00:36:57) Jymmm: Yeah, they fucked up the machining when they made it the 1st and 2nd time, I just never realized it was "THAT" bad
[07:40:49] <ds2> cuz if that is the case, maybe super glue it to an angle block
[07:41:01] <ds2> and use that to how against a belt sander or disc sander
[07:41:32] <ds2> you asked for square.. it could have meant they made it a parallogram prism
[07:41:46] <ds2> it sounds like you just need to shave off 0.030
[07:41:46] <Jymmm> but how do you square the sander to the material?
[07:42:11] <ds2> you square it to the rest or table
[07:42:21] <ds2> and the angle block would give you the 90deg
[07:42:30] <ds2> and use the angle block to run it into the abrasive surface
[07:42:41] <ds2> touch a bit, mic it, and repeat
[07:42:53] <Jymmm> no sander, jmkasunich made me return the one I got from HF
[07:43:01] <ds2> oh
[07:43:58] <Jymmm> damn thing is, I could probably do it on my machien, if it wasn't the part I needed to drive my machine.
[07:44:41] <ds2> if you had a mill, it'd be a easy fly cut job
[07:45:13] <ds2> know anyone at san jose city college?
[07:45:21] <Jymmm> nope
[07:45:51] <ds2> sign up at the techshop?
[07:49:11] <Jymmm> what ya think? http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=947676&PMAKA=630-4010
[07:49:33] <Jymmm> brb
[07:52:51] <Jymmm> back
[08:24:11] <toast> pew pew pew
[08:24:29] <toast> Jymmm: sure!
[08:24:43] <toast> they're probably not going to last very long
[08:25:25] <toast> i wouldn't trust them as much more than blocks of metal
[08:25:34] <toast> and i can find cheaper blocks of metal than 8 dollars
[08:28:32] <Jymmm> heh
[08:35:50] <Jymmm> http://www.use-enco.com/CGI/INPDF?PMAKA=NV625-8511&PMCTLG=01
[08:45:49] <toast> 27 bucks is still kind of cheap for 1-2-3s
[08:45:51] <toast> but whutevs
[08:46:09] <toast> brb
[09:55:25] <toast> pew pwepwe
[10:07:49] <fenn> still up eh
[10:09:35] <fenn> sandpaper+glass will only get it square in one direction
[10:10:04] <fenn> should just make it on his mill.. it does work after all
[10:10:11] <fenn> s/mill/router/
[13:41:04] <jepler> wow I hate glade more every second I use it
[13:41:16] <jepler> click the wrong thing -- hit paste -- all your work from a session is gone, because there's no "undo"
[15:03:18] <tomp> My tts was reading Cory Doctorow's "Someone Comes to Town, Someone Leaves Town" and in it they talk about mesh nets. I see that gumstik has a new wifistik that can do meshnets. The idea of a free open community network is great. http://www.gutenberg.org/etext/18224
[16:12:04] <floppy1234> hello
[16:12:13] <floppy1234> i am a litte more happy now
[16:12:35] <floppy1234> i can control with hal 0 to 5 V output ;)
[16:13:05] <awallin> on a prallel port?
[16:13:09] <floppy1234> yes
[16:13:25] <floppy1234> i used pwmgen in mode 2
[16:14:07] <floppy1234> so i can give a number between 0.0 and 1.0 for 0 to 5V on pin A and a number between -1.0 and 0.0 for 0 to 5V on Pin B
[16:14:40] <awallin> ok, and you are low-pass filtering the pwm? or driving an amp directly?
[16:14:51] <floppy1234> no, a lowpas
[16:14:55] <floppy1234> lowpass
[16:15:08] <floppy1234> but my amp gonna wrong :(
[16:15:41] <floppy1234> sometimes it let flow 120mA, sometimes 0mA....
[16:15:51] <floppy1234> so i must search the mistake
[16:17:36] <awallin> but if you close the loop with a PID some small imperfections or nonlinearities in the amp should not matter
[16:19:17] <floppy1234> yes i know
[16:19:25] <floppy1234> but i want a perfect system :)
[16:19:27] <dmessier> High all
[17:14:52] <tomp> the olpc project uses mesh net for kids in computer-challenged countries http://www.youtube.com/v/7kHIZXYJbWY&autoplay=1&rel=0
[17:23:05] <JymmmEMC> Makes it much easier for kids to IM 24/7
[17:25:19] <JymmmEMC> I was in Fry's yesterday, there was a girl (maybe 14-16yo) on her cellphone at the Mac display just talking up a storm with her friend. Was giving me a headache she was talking so fast, and had nothing to say!
[17:29:18] <fenn> weird i just read "down and out in the magic kingdom" this morning
[17:29:42] <tomp> fenn: good stuff
[17:29:55] <fenn> horribly depressing if you get to thinking about it too much tho
[17:31:49] <fenn> i was bouncing around the idea of making a free mesh network using usb 802.11 thumb-thingies and dumpster-grade pc's
[17:37:21] <tomp> wow, you're kurt from the story ;) and you're the guys EE from the olpc project ( shoes for the people! free huey, free wifi )
[17:40:17] <fenn> well, i'm on page 0, i'll tell you if you were right i guess
[17:40:40] <fenn> OLPC is great; i just wish they'd give them to american kids
[17:44:40] <tomp> fenn: that book is a lot of stories, the mesh net is 1 story. its not separate, it's weirdly threaded/knotted with the other stories, so you wont get done with one without the others
[17:45:27] <tomp> and olpc, i wish we could pay our taxes in donations of units to kids. btw you can get the os
[17:53:26] <dmessier> any one have machine set up with rigid tapping ??
[17:53:54] <jepler> I only know of the mazak that we set up during fest
[17:54:30] <dmessier> hmm.. and lathes that can thread???
[17:55:32] <jepler> only if the spindle can reverse
[17:56:54] <dmessier> so its servo/spindle control thats the biggest issue??
[17:57:02] <dmessier> for EMC2
[17:57:18] <jepler> yes
[17:57:37] <jepler> you can't rigid tap without that
[17:57:45] <JymmmEMC> fenn: were you being serious?
[17:58:17] <fenn> ya
[17:58:34] <JymmmEMC> fenn: Sorry, I meant about the free mesh network
[17:58:40] <dmessier> i have an old mazak with a fanuc 3 - available for retro... but wasnt sure i wanted to play with it... any thoughts??
[17:59:11] <fenn> i used to volunteer at a place that fixed up abandoned bikes and gave them away, we were talking about a similar idea for computers
[17:59:23] <fenn> and then the problem was how to get internet access for all these people with free computers
[17:59:35] <fenn> but if we install the software we can run mesh networking on them as well
[17:59:45] <JymmmEMC> fenn: I've been considerign the idea using linksys routers and modified OpenWRT
[17:59:49] <fenn> too expensive
[17:59:59] <fenn> usb thingies are $5
[18:00:14] <JymmmEMC> fenn: The problem is no ext antennas
[18:00:21] <fenn> run a usb cable to the roof with your thingie sealed in heatshrink tube
[18:00:38] <JymmmEMC> USB has a 12' cable length
[18:00:42] <fenn> only if you're a wuss
[18:00:46] <dmessier> sounds doable..
[18:00:51] <fenn> its 16m anyway
[18:01:08] <fenn> er, 5m bah
[18:01:42] <jepler> hm, looks like the emc script can't handle having your configuration directory named "Jeff's Mill" and your inifile named "Jeff's Mill.ini"
[18:01:48] <jepler> so much for user friendliness
[18:01:51] <JymmmEMC> either way, too short
[18:01:53] <dmessier> should work hanging out a window too
[18:02:08] <fenn> i was planning on running usb over cat5.. would that work better?
[18:02:51] <dmessier> definetly add range..
[18:03:01] <JymmmEMC> fenn: Well, the linksys has two antenns, I'm not sure if that's in a dual antenna configuration or dual radios.
[18:03:34] <JymmmEMC> fenn: The other thing is the A/B/G routers, using the A (5GHz) for control/uplink
[18:04:25] <JymmmEMC> It has to act as BOTH: an AP, and a repeater.
[18:06:39] <fenn> jymmm this may be interesting to you http://www.cuwireless.net/
[18:07:09] <fenn> i talked to these guys four or five years ago when it was just getting started
[18:09:14] <JymmmEMC> fenn But that requires pole mounted radios, no?
[18:12:31] <fenn> they put them on rooftops
[18:14:54] <fenn> i also liked the ronja
[18:15:12] <fenn> http://ronja.twibright.com/
[18:58:17] <JymmmEMC> fenn: Yeah, but commercial rooftops, not residential, right?
[18:58:48] <JymmmEMC> fenn: Meaning that city/county permits are required
[19:01:30] <fenn> its residential, i dont see why that would be a problem
[19:01:42] <JymmmEMC> What, gettign permits?
[19:01:54] <fenn> why would you need a permit to put something on your roof?
[19:02:27] <JymmmEMC> fenn: What you talked about was on commercial roof tops
[19:49:51] <LawrenceG> jmkasunich: are you near the kybd this fine afternoon?
[19:51:15] <jmkasunich> who me?
[19:51:25] <LawrenceG> hey....
[19:51:49] <LawrenceG> did you ever get a complete eagle project for your fet bridge?
[19:52:11] <jmkasunich> technically its skunkwork's project
[19:52:17] <LawrenceG> I am playing with a pwm chip to do current control...
[19:52:22] <jmkasunich> I just did some layout, to optimise stray inductance, etc
[19:52:51] <LawrenceG> I have one layout, but it seems from the very early stages
[19:53:43] <jmkasunich> so you are looking for the power board layout?
[19:54:35] <LawrenceG> yes... with a couple of added current sense resistors, I think it could be driven with the uc3638 as a torque (current mode) amp
[19:56:44] <jmkasunich> maybe... to a certain extent, an H bridge is an H bridge, you can do whatever you want with it
[19:58:19] <LawrenceG> yes... but keeping the smoke in a brdge is one of the hard parts when dealing with 100v/20a servos.... your layout seems to be surviving
[20:00:53] <jmkasunich> I'm having trouble finding it
[20:01:01] <LawrenceG> :{
[20:01:09] <jmkasunich> rather, I've found something that I think is it, but I'm having trouble invoking eagle to take a look
[20:01:19] <jmkasunich> (I haven't touched eagle since I did that layout)
[20:01:29] <jmkasunich> and its on an older computer
[20:01:45] <LawrenceG> the files I have are called amp.sch and amp.brd
[20:03:22] <jmkasunich> I have those too
[20:03:26] <jmkasunich> mine are dated....
[20:03:47] <jmkasunich> oct 7, 2006
[20:04:21] <jmkasunich> after I sent those to skunkworks, I believe he added the LED side of the optos - connectors, LED series resistors, etc
[20:04:30] <skunkworks> this is the latest I have - http://www.electronicsam.com/images/KandT/servostart/schem/
[20:04:46] <skunkworks> The one that actually cut the board I brought to the fest
[20:05:02] <skunkworks> nothing is really labeled correct though ;)
[20:05:08] <jmkasunich> I think LawrenceG should start with yours, not mine
[20:07:08] <LawrenceG> thankyou skunkworks .... I see you have the ngc files as well
[20:08:39] <LawrenceG> skunkworks: have you been running your h bridge much?
[20:09:05] <skunkworks> some testing. about 50v 10a so far
[20:09:18] <skunkworks> have not blown it up
[20:09:24] <skunkworks> yet
[20:09:43] <jmkasunich> it would be interesting to observe the FET drain-source and gate-source voltages during switching
[20:10:00] <jmkasunich> drain-source for turn-off overvoltages, and gate-source for ringing etc
[20:10:08] <skunkworks> I have been meaning to do that.. It is at the shop now where the scopes are.
[20:10:23] <skunkworks> I remember you mentioning that before
[20:10:26] <LawrenceG> what fets are you using at the moment?
[20:12:03] <LawrenceG> and the drivers? ir2111?
[20:12:42] <skunkworks> yes - looking for the list
[20:13:34] <skunkworks> I had the list on cnczone - but I think it is down right now. give me a second.
[20:14:11] <jepler> oh neat -- http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Koppi's_Toy
[20:14:36] <jepler> looks like "g0" doesn't work :-P
[20:15:27] <jmkasunich> ?
[20:15:29] <skunkworks> looks like the pen doesn't lift
[20:15:30] <skunkworks> yet
[20:15:40] <jmkasunich> right, which he says (Z not working)
[20:15:41] <jepler> skunkworks: right, that's what I meant
[20:16:26] <LawrenceG> ... lloking, but just get an emptywiki page
[20:17:09] <jepler> may need to write %27 instead of '? http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Koppi%27s_Toy
[20:17:31] <jepler> bbl
[20:17:38] <LawrenceG> better :}
[20:25:15] <skunkworks> LawrenceG: fdh44n50 - fairchild 44a 500v http://www.newark.com/jsp/search/productdetail.jsp?SKU=82C2497&CMP=AFC-TL10000001
[20:25:31] <skunkworks> the Rds is a bit higher than i would like..
[20:26:29] <skunkworks> for me - 200-250v mosfets would be better.
[20:32:06] <LawrenceG> Skullworks-PGAB: how about the diodes across the fets?
[20:32:15] <skunkworks> hold on :)
[20:32:31] <LawrenceG> and ic4 the opto isolator
[20:36:52] <skunkworks> finally
[20:36:58] <skunkworks> LawrenceG: http://www.cnczone.com/forums/showpost.php?p=310625&postcount=41
[20:39:10] <LawrenceG> thks... updateing the schematic...
[20:40:04] <skunkworks> That would be cool :)
[20:40:10] <skunkworks> * skunkworks hates the cleanup work
[20:57:13] <tomp> jepler: koppi's toy is hektor http://www.hektor.ch/ stepper cog belt driven polar graffitti painting
[20:58:07] <tomp> was that emc controlled? then the kins is like polar (left motor and linkage) & complimentary polar (right motor and linkage )
[20:58:46] <tomp> the macintosh path generator has complicate dlooping designed to 'steady' the swinging mass
[20:58:58] <tomp> complicated looping
[20:59:19] <bjorkBSD> http://www.instructables.com/id/EBZ3QQVF3HY3SL2/
[20:59:26] <bjorkBSD> have anyone of you tried that? ^
[21:00:42] <tomp> no, but it looks nice, and a big one could make the parts for little ones ;)
[21:01:14] <bjorkBSD> :)
[21:02:27] <jepler> it also sounds interesting to me
[21:03:25] <jepler> tomp: "
[21:03:26] <jepler> Hektor's software is based on Scriptographer, a scripting plugin for Adobe Illustrator"
[21:04:37] <tomp> regards, the wide table there's always the possibility of a wide table twisting during motion. i just imagined a band type motion where the band was as wide as the table, and in the band were diagonal slits that went over a driven worm... no twist, force along entire edge...
[21:04:54] <tomp> jepler: yeah, the scriptographer demo movies show the weird looping
[21:05:34] <jepler> a script running in an interpreted language in a proprietary application on windows is about as far away from emc as you could get
[21:06:17] <tomp> i saw chinese guys painting with water on concrete, the painting only lasts a while... maybe hektor/koppi could do same for local townships, to advert stuff.
[21:07:44] <tomp> no ones done anything but gcode in emc so far, but the innards allow for line/arc primitives. only got a gcode interp so far ( i know ... lazy me ;)
[21:08:05] <tomp> tho hal could stream ..
[21:27:55] <floppy1234> hello
[21:36:25] <floppy1234> how fast is the parport pwm?
[21:36:32] <floppy1234> in Hz
[21:49:26] <lerneaen_hydra> floppy1234: afaik it can change state once per base period
[21:49:38] <tomp> for the wide band positioner, the worm is unneccesary, the band keeps the wide table from crabbing. it can just be driven by the axle
[21:51:58] <floppy1234> lerneaen_hydra i want to calculate a lowpass... so i must know the maximum frequency
[21:52:52] <lerneaen_hydra> floppy1234: that depends on your base period
[21:53:00] <floppy1234> well okay
[21:53:14] <lerneaen_hydra> the max stepping rate will be 1/base_period
[21:53:31] <lerneaen_hydra> (again, IIRC ;) )
[21:53:50] <lerneaen_hydra> should be somewhere in the 10-59khz range
[21:53:56] <lerneaen_hydra> s/59/50
[21:54:41] <floppy1234> BASE_PERIOD = 20000
[21:55:09] <floppy1234> 20khz?
[21:55:45] <skunkworks> 20000ns
[21:55:54] <skunkworks> 1/.00002
[21:56:34] <floppy1234> also 50 kHz
[21:56:54] <skunkworks> But I don't remember - I think you need to divide that by 2. You need 1 period for off and one for on..
[21:57:13] <lerneaen_hydra> yeah that's true
[21:57:20] <floppy1234> yes yes....
[21:57:37] <floppy1234> and the value?
[21:57:50] <floppy1234> i mean this is much slower
[21:57:54] <skunkworks> 25khz then I would think..
[21:57:55] <floppy1234> between 3 and 10 khz
[21:57:56] <JymmmEMC> spreadsheet at the Bottom of page: http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?TweakingSoftwareStepGeneration
[21:57:56] <floppy1234> or so
[21:58:17] <JymmmEMC> floppy1234: ^^^^
[21:58:25] <floppy1234> yes
[21:58:29] <floppy1234> i gonna read
[21:59:12] <floppy1234> i'm downloading
[21:59:14] <skunkworks> JymmmEMC: that is for steppers - floppy1234 is working on pwm.
[21:59:25] <floppy1234> m
[21:59:26] <floppy1234> okay
[21:59:43] <JymmmEMC> skunkworks: no idea, jmkasunich write it up
[21:59:46] <JymmmEMC> says it's for step gen
[21:59:52] <skunkworks> floppy1234: I would man pwmgen.. I think it tells you everything you need.
[22:00:01] <floppy1234> well
[22:00:02] <floppy1234> okay
[22:01:20] <floppy1234> http://linuxcnc.org/docs/2.1/html/man/man9/pwmgen.9.html
[22:01:23] <floppy1234> ;)
[22:01:26] <floppy1234> i gonna read
[22:04:20] <floppy1234> i cant find something about
[22:39:53] <tomp> floppy1234: here's a vid of smooth motion with similar rodless cylinder from Bimba
[22:44:24] <tomp> http://www.bimba.com/bandsvideo/
[23:18:35] <fenn> tomp: yeah i can identify with kurt
[23:27:45] <JymmmEMC> WOOHOO! Got the mobo mounted in the case... only needed to use an angle grinder and the drill press for the cpu fans!
[23:28:47] <JymmmEMC> Will take pics =)