#emc | Logs for 2009-03-06

[04:03:44] <|dareposte|> hi all
[04:03:59] <|dareposte|> anybody got some sort of idea for how much spindle encoder resolution is necessary to do rigid tapping?
[04:04:14] <|dareposte|> i'm about to order a 100ppr, but not sure if that will be enough or not
[04:05:33] <|dareposte|> for a m10x1.0 thread, it would be 1.0mm per revolution, so the accuracy should be good for .01mm, which seems like it should be adequate
[04:07:07] <|dareposte|> as long as there's no weirdness that happens with acceleration
[04:08:45] <cradek> is that 400 edges or 100 edges per rev?
[04:09:29] <|dareposte|> umm
[04:09:35] <cradek> what will be counting it?
[04:09:45] <|dareposte|> parallel port
[04:09:49] <cradek> ah
[04:09:50] <|dareposte|> servo thread i presume
[04:10:21] <cradek> the quadrature-reading part of the software encoder module runs in the base thread
[04:11:17] <|dareposte|> software encoder? is that what reads phases from the parport
[04:11:25] <|dareposte|> it says "100 pulses per revolution"
[04:11:40] <|dareposte|> so i guess it would be 400 edges like you said
[04:11:45] <|dareposte|> a rising and a falling on each
[04:11:47] <cradek> http://www.linuxcnc.org/docs/devel/html/man/man9/encoder.9.html
[04:12:25] <|dareposte|> hey 10 khz isn't bad for software
[04:12:55] <cradek> almost all modern machines can do 50kHz
[04:13:02] <|dareposte|> well thats good then
[04:13:14] <|dareposte|> because my spindle goes faster than 500 rpm
[04:13:43] <cradek> it only has to keep count when tapping - who cares the rest of the time
[04:14:01] <cradek> (unless you want to use it for an rpm readout or at-speed sensing)
[04:14:15] <|dareposte|> yeah
[04:14:29] <|dareposte|> i would like to use it to make sure i get to the right speed to
[04:14:31] <|dareposte|> too
[04:14:41] <|dareposte|> but an index pulse may be good enough for that
[04:14:50] <cradek> that definitely limits your resolution
[04:15:08] <cradek> you will miss the index pulse just as easily as you miss the other counts, if it's going too fast - nothing is there to 'stretch' it
[04:15:23] <|dareposte|> odd
[04:15:33] <cradek> why odd?
[04:15:35] <|dareposte|> all i have on there is an index pulse right now
[04:15:59] <|dareposte|> i was threading at 500rpm with it, but it was pretty jerky
[04:16:37] <|dareposte|> i wonder if some of that might be it missing an index pulse
[04:16:54] <cradek> that would sure mess it up
[04:16:57] <|dareposte|> i take 10 passes to get the thread to full depth, and about two out of every pass winds up being nasty
[04:17:13] <|dareposte|> if i'm lucky its one of the first ones, and the later ones cover it up
[04:17:29] <cradek> yuck
[04:17:30] <|dareposte|> if i'm unlucky then it tears up the thread and happens on one of the later passes
[04:17:36] <|dareposte|> i.e. scrap part
[04:17:48] <|dareposte|> so i've just been running them to about half depth, and finishing with a die
[04:18:24] <|dareposte|> but i'm still curious why its so jerky
[04:18:59] <|dareposte|> running slower didn't seem to help it any, and faster gets the accelerations too high to clear the blind corner at the end
[04:19:04] <cradek> I bet with a little study halscope will tell you
[04:21:13] <|dareposte|> probably
[04:21:32] <|dareposte|> at first i thought my spindle belt was maybe slipping
[04:22:08] <cradek> the index is directly on the spindle right?
[04:22:10] <|dareposte|> yeah
[04:22:23] <|dareposte|> but if the belt slipped, then the axis wouldn't know it until it was already too far along
[04:22:30] <cradek> ok, heh, I was picturing it on the other end of a V belt or something
[04:22:34] <|dareposte|> but that's not the behavior i'm seeing... its like the axis falls behind some how
[04:22:58] <cradek> does seem like that could be a missing pulse
[04:23:24] <|dareposte|> if it missed a pulse, the axis would get ahead though right
[04:23:52] <cradek> no, it would thought the spindle just slowed WAY down, so it would slow the axis WAY down
[04:23:59] <cradek> would think
[04:24:04] <|dareposte|> oh
[04:24:12] <cradek> setp hm2_5i20.0.encoder.03.scale -400
[04:24:20] <cradek> looks like my spindle encoder is 400 edges (100 lines)
[04:24:43] <|dareposte|> what are you reading it with?
[04:24:50] <cradek> mesa 5i20
[04:25:08] <cradek> lathe only goes to 3000ish rpm
[04:39:23] <|dareposte|> mine runs to 2000
[04:40:00] <|dareposte|> single belt drive, vfd into a cheap 3 phase motor
[04:40:06] <|dareposte|> not inverter duty, but it hasn't overheated yet
[04:40:22] <|dareposte|> also not drip proof or tefc, but it doesn't seem to mind getting coolant on it for whatever reason
[04:43:47] <|dareposte|> well maybe tomorrow i can fire up halscope and get this thing to thread better
[04:44:07] <|dareposte|> maybe i need a wider trigger on the spindle
[04:44:33] <|dareposte|> i have a lot of trouble with halscope getting it to trigger right though
[04:44:41] <|dareposte|> i get more done with my real scope
[05:25:41] <|dareposte|> wow that mesa 5i20 is something else
[05:26:16] <|dareposte|> i didn't realize how advanced fpga's had come on that type of hardware
[07:01:08] <Odd> Odd is now known as tim__
[07:42:57] <ChanServ> [#emc] "This is the #emc channel - talk related to the Enhanced Machine Controller and general machining. Website: http://www.linuxcnc.org/, wiki at http://wiki.linuxcnc.org/"
[11:18:08] <MrSunshine_> humm, is there any page with sample files in gcode? ... that i could try out :)
[11:21:00] <archivist> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Example_G-Code_Programs
[11:26:23] <alex_joni> lmgtfy.com/?q=linuxcnc+sample+g-code+programs
[11:26:44] <alex_joni> * alex_joni loves that page :D
[11:27:18] <archivist> * archivist misses the http part because xchat does not see it as a link
[11:27:57] <MrSunshine_> wtf, can i set scale in axis ?
[11:28:06] <MrSunshine_> cause i found a "half ball" sample, but its 0.9mm big :P
[11:28:36] <MrSunshine_> haha :)
[11:28:39] <MrSunshine_> thanks for that one alex_joni:)
[11:28:43] <archivist> alex_joni, my bot uses that page !g nick words
[11:37:23] <MrSunshine_> so any way to set the scale in emc ? ... as the stuff i load becomes like 5mm big ... everything :/
[11:42:25] <alex_joni> MrSunshine_: you can use G20/G21 to scale it by 25.4 ;)
[11:43:22] <MrSunshine_> hah :P
[11:43:26] <MrSunshine_> 2.54 isnt it ?
[11:45:11] <archivist> number challenged are we?
[11:45:41] <MrSunshine_> aparently :P
[11:45:47] <alex_joni> MrSunshine_: http://lmgtfy.com/?q=inch+mm
[11:46:11] <MrSunshine_> ahh i was thinking cm :)
[11:46:45] <MrSunshine_> i dont get it, why does 2 engines become so hot i cant touch them while the 3rd stays cool :/
[11:47:07] <alex_joni> do you mean motors?
[11:47:14] <MrSunshine_> yes :P
[11:47:15] <MrSunshine_> haha :)
[11:47:24] <alex_joni> I suspect different current limit
[11:47:39] <archivist> and different heat sinking
[11:48:19] <MrSunshine_> no heat sinks on them .. exactly the same driver (no current limitations on the drivers so :P )
[11:48:42] <archivist> frame and machine constitute heatsink
[11:55:17] <MrSunshine_> could make it a casting project =)
[11:55:35] <MrSunshine_> tho thin fens arent to easy to cast :/
[11:55:39] <alex_joni> starting a movie business?
[11:56:42] <MrSunshine_> casting as in metal casting =)
[11:59:05] <alex_joni> a new robocop movie perhaps?
[15:55:44] <BJT-Work_> BJT-Work_ is now known as BJT-Work
[17:54:30] <skunkworks_> LawrenceG: http://www.cnczone.com/forums/showthread.php?t=74532
[17:54:59] <skunkworks_> I think it is a bad idea.... but I guess that is what the mach people need. ;)
[18:23:08] <LawrenceG> skunkworks, interesting... I still dont understand why people use step/dir when quadrature is so much better.... never could convince Mariss to offer quad drives
[18:29:37] <skunkworks_> wonder why that is?
[18:40:28] <LawrenceG> skunkworks, his new cpld drives would make it easy
[18:48:10] <JymmmEMC> LawrenceG: supply and demand?
[18:50:57] <LawrenceG> I demand!
[18:51:17] <LawrenceG> JymmmEMC, how is the wx down south?
[18:51:29] <JymmmEMC> bites, cold and damp
[18:52:24] <LawrenceG> its cool here, but the sun is shining..... nice day.... supposed to snow on Sunday WTF? its march
[18:52:24] <JymmmEMC> LawrenceG: Take a number (4,345,213,596) and get in line... Now serving # 23
[18:53:00] <JymmmEMC> Early sun was out and had blue skies, now damper and grey skies.
[18:57:34] <LawrenceG> JymmmEMC, fixed my HF radio this week.... it had leaky caps --- stinky
[18:58:01] <JymmmEMC> did you use baking soda?
[18:59:03] <LawrenceG> no.... turns out leaky stuff is also basic.... but I didnt really want to put vinegar on the pcb.....
[18:59:22] <JymmmEMC> I never said vinegar, just baking soda
[18:59:32] <JymmmEMC> and clean up with denatured alcohol
[18:59:51] <JymmmEMC> well baking soda and a dab of water
[19:00:49] <LawrenceG> baking soda would have worked as an abrasive, but not neutralize the corrosive gunk
[19:01:04] <JymmmEMC> why not?
[19:01:21] <JymmmEMC> it does on car batteries =)
[19:02:04] <LawrenceG> baking soda is basic, leaky stuff is basic and vinegar and sulphuric acid are acidic
[19:02:51] <fenn> The electrolyte is usually boric acid or sodium borate in aqueous solution together with various sugars or ethylene glycol
[19:03:37] <fenn> so i'd just use water
[19:04:32] <JymmmEMC> k
[19:04:42] <LawrenceG> thanks fenn.... I just used 95% ethyl alcohol and a lot of scrubbing with qtips
[19:05:28] <LawrenceG> the board was still wired into the radio, so hard to do a full cleaning and flush
[21:04:29] <JymmmEMC> LawrenceG: You coulda just tossed it in the dishwasher or washing machine, then tumble dry. Eeeeesh.
[21:11:44] <Guest457> heloo go afthernon
[21:11:51] <Guest457> my name is rafa
[21:12:05] <Guest457> iam from brazil
[21:12:11] <Guest457> i have one doubt
[21:12:34] <Guest457> is possible on a Frequency Inverter in emc
[21:13:00] <Guest457> is possible emc control this?
[21:15:39] <Guest457> i
[21:17:00] <Guest457> heloo
[21:17:02] <rob__> of cource, but depends on input to it how you need to talk to it
[21:17:15] <Guest457> heloo rob
[21:17:22] <rob__> hi
[21:17:37] <Guest457> you have a idea about this?
[21:18:40] <rob__> how do you need to command it
[21:21:58] <Guest457> i want on this in my spindle
[21:21:59] <rob__> when i try to load the calibration window in axis i have this problem. if i set setp hm2_[HOSTMOT2](BOARD).0.encoder.00.scale [AXIS_0]INPUT_SCALE in the hal file, i get this error > http://pastebin.ca/1354743 if i set it to a value say 1000 loads fine
[21:24:51] <alex_joni> rob__: are you sure it's INPUT_SCALE in the ini? not SCALE ?
[21:25:48] <alex_joni> hmm.. it seems to be INPUT_SCALE, n/m me :)
[21:26:45] <rob__> i was just checkin, yea input_scale set to 1000 and it counts incoder fine in proper scale and axis loads no errors only when i go to calibration
[21:26:46] <jepler> rob__: it looks like emccalib can't handle the case where the thing being set has a substitution
[21:27:10] <jepler> if you write a literal number like 1000 then emccalib doesn't try to do anything with that line (I think)
[21:27:41] <rob__> when i change it to number yea it does not complaine about it
[21:28:45] <rob__> oh well no biggie ill put in my proper values in hal, throught be nice to leave it in ini file so if i ever changed them id not forget
[21:28:47] <jepler> I am pretty sure there's not an easy fix to emccalib for this
[21:29:12] <jepler> your other choice, it seems to me, is to replace [HOSTMOT2](BOARD) with the name of your board
[21:29:54] <jepler> in your hal file
[21:30:21] <jepler> hi seb_kuzminsky
[21:30:23] <rob__> ok
[21:30:28] <seb_kuzminsky> hey!
[21:30:34] <rob__> ill see if tht works thx
[21:30:42] <jepler> seb_kuzminsky: no good deed goes unpunished. your clever hal files foil emccalib, as rob__ just discovered. http://pastebin.ca/1354743
[21:30:52] <seb_kuzminsky> jepler: i got my little lathe running :-D
[21:31:01] <jepler> rob__: oh, and for posting the error message right away, you get a cookie
[21:31:12] <seb_kuzminsky> two cookies
[21:31:16] <rob__> haha
[21:31:24] <rob__> no milk
[21:32:11] <jepler> seb_kuzminsky: cool
[21:32:15] <jepler> (about your lathe)
[21:32:44] <seb_kuzminsky> yeah, "great, now i have TWO machines i need to convert to cnc/emc2"
[21:33:07] <cradek> what lathe is this?
[21:33:40] <seb_kuzminsky> nothing that would excite anyone here :-/
[21:33:43] <seb_kuzminsky> a little 7x12
[21:33:50] <seb_kuzminsky> all manual, partly rusty ;-)
[21:35:12] <cradek> neat
[21:35:19] <cradek> now you can make round things
[21:35:29] <seb_kuzminsky> heh
[21:35:30] <jepler> have any parts you're itching to make?
[21:35:55] <jepler> rob__: I'll put a bug on sf about this, so at least it's not forgotten
[21:36:05] <jepler> and maybe somebody will come up with a good solution for it that I don't imagine right away
[21:36:13] <seb_kuzminsky> i just scratched my first itch and turned replacement feets for some backyard furniture that got knocked around in a wind storm a few months back
[21:36:19] <seb_kuzminsky> now my table is level again :-)
[21:36:34] <seb_kuzminsky> next up is a pair of pulleys for the never-ending belt-drive conversion for the mini-mill
[21:36:38] <rob__> jepler, setting setp hm2_5i20.0.encoder.02.scale [AXIS_2]INPUT_SCALE works ok it seems as u said
[21:36:44] <cradek> is it threadcutting?
[21:37:09] <seb_kuzminsky> it's got a carriage leadscrew geared to the spindle, so yes in theory though i havent tried it yet
[21:37:27] <seb_kuzminsky> i got a baggie of gears when i bought it
[21:37:36] <cradek> ah, then yes
[21:37:41] <cradek> if you're lucky and have all of them anyway
[21:37:49] <seb_kuzminsky> but i hope to not turn any threads until the cnc conversion is done ;-)
[21:38:02] <cradek> it builds character
[21:38:07] <seb_kuzminsky> heh
[21:38:32] <seb_kuzminsky> hm so i dont think i understand what's up with the bug rob reported
[21:38:37] <seb_kuzminsky> what's emccalib?
[21:38:51] <jepler> rob__: ok, thanks for the report and I'm glad you could verify the workaround. I mentioned it in the bug report. https://sourceforge.net/tracker/index.php?func=detail&aid=2669566&group_id=6744&atid=106744
[21:38:57] <cradek> a gui that lets you change pid settings and then rewrites them "where they came from"
[21:39:16] <cradek> so it parses and rewrites the ini and/or hal file (I think)
[21:39:24] <seb_kuzminsky> i see
[21:39:29] <jepler> I think it figures out what can be calibrated by regular-expression-based parsing of the hal file
[21:40:00] <jepler> but it interfaces to halcmd in a way that doesn't do the expansion of inifile stuff into parameter names
[21:40:21] <seb_kuzminsky> and i imagine it'd have a hard time emitting the un-expanded thing back to "where it came from"
[21:40:33] <seb_kuzminsky> or maybe not, i dont know
[21:44:28] <seb_kuzminsky> i think our config system belongs on the "needs work for 3.0" list
[21:51:10] <geo01005> So I just got my Maxim SPI thermocouple chips. I think that I'm going to try to use the Hostmot2 RAW commands to read the chip for now.
[21:51:20] <seb_kuzminsky> cool geo01005
[21:51:53] <geo01005> Then maybe after I have figured that out I can add support to hm2
[22:18:57] <alex_joni> this is a very cool idea: http://www.datron.de/typo3temp/pics/f138d388ea.jpg
[22:19:37] <alex_joni> on the side of the spindle there's a probe which can be rotated in place to probe for the material position
[22:20:09] <alex_joni> after that it just swivels away, and it doesn't interfere with milling
[22:22:19] <fenn> yes that's cute
[22:22:52] <fenn> what's even cooler is the software it comes with to compensate for warped surfaces
[22:51:07] <rob__> datron, nice machines, rather have a matsuura ;)
[23:05:52] <alex_joni> good night all
[23:20:18] <MrSunshine__> MrSunshine__ is now known as sys2