#emc | Logs for 2006-03-04

[02:06:22] <robin_z> evening
[02:34:26] <skunkworks> hey robin - did you get your nitrogen generator running?
[02:35:38] <giacus> night
[02:41:14] <A-L-P-H-A> wuzzupy?
[03:54:43] <lilo> [Global Notice] Hi all. If you've been affected by the DCC exploit, which just surfaced in the last day or so, the problem is with your netgear router. The symptom is that you get knocked off line; it may require a router reset to recover. Please message me if this has happened to you and let me know what model router you're using. Thanks!
[04:02:50] <lilo> [Global Notice] This is what we have so far on that new exploit: http://tinyurl.com/qah9z .... thanks
[04:06:23] <lilo> [Global Notice] To summarize, since my blog is now overloaded, if you are running a Netgear WGR614 or WGT624, and probably other models, and probably Netgear routers relabeled by ISP's, you are vulnerable to a new exploit which can be used to knock you off IRC, and probably other places. Thanks.
[07:41:57] <Jymmm> anyone awake?
[07:43:17] <Jymmm> Contactless Tachometer $40, worth it? http://search.ebay.com/7595863278
[07:49:38] <Jymmm> Ah.... Use reflective tape on object to be measured and point the integral light beam or laser.
[08:16:36] <lilo> [Global Notice] Hi all. It appears likely that you can prevent the DCC exploit from working by connecting to us via port 8001 rather than port 6667 .... please try it if you've been getting caught by the DCC exploit .... please try it and let me or freenode first level support ( http://freenode.net/faq.shtml#gettinghelp ) know how it works.
[08:18:02] <lilo> [Global Notice] Also, to those of you who have been using the keylogger or DCC exploits: it's extremely annoying to the people on the channels you do it on. This is freenode, folks, we really do expect better from you. Please remember.
[08:56:13] <ValarQ> i'm quite awake
[10:34:39] <Bo-Dick> Could anyone guide me how to implement sleep mode for my stepper motor driver?
[12:00:16] <robin_sz> meep?
[17:12:07] <NickServ> This nickname is owned by someone else
[17:12:07] <NickServ> If this is your nickname, type /msg NickServ IDENTIFY <password>
[17:12:16] <Jymmm> ah, lol
[17:12:22] <alex_joni> Jymmm: too early?
[17:12:51] <Jymmm> I've heard of rice burners (japanese motorcycles), but rice powered cnc - that's a new one.
[17:13:00] <alex_joni> lol
[17:13:01] <Jymmm> alex_joni Hey, you are the one that said it, not me.
[17:13:10] <alex_joni> 19:12 < skunkworks> where is your logger?
[17:13:11] <alex_joni> 19:12 < alex_joni> it dies, power went dead. let me restart it
[17:13:17] <alex_joni> s/dies/died/
[17:13:24] <Jymmm> [09:11:19] <alex_joni> chinese brown rice
[17:13:24] <Jymmm> [09:11:32] <alex_joni> it dies, power went dead. let me restart it
[17:13:43] <alex_joni> 19:12 < skunkworks> Hi alex - today is brown rice day ;)
[17:13:43] <alex_joni> 19:12 < alex_joni> just had some
[17:13:43] <alex_joni> 19:12 < alex_joni> chinese brown rice
[17:13:43] <alex_joni> 19:12 < skunkworks> where is your logger?
[17:13:43] <alex_joni> 19:12 < alex_joni> it dies, power went dead. let me restart it
[17:13:50] <alex_joni> Jymmm: you must be missing some bits
[17:14:00] <skunkworks> ;)
[17:14:02] <Jymmm> alex_joni bullshit... you're editing out the line
[17:14:29] <Bo-Dick> * Bo-Dick is gonna eat some dinner
[17:14:33] <alex_joni> Jymmm: caffeine helps (I heard)
[17:14:34] <Jymmm> alex_joni: dont be having 42 conversations at once now!
[17:40:15] <Bo-Dick> Is this statement true? PWM stepper drivers are a method of controlling the current in the stepper motor windings and thus an alternative way perhaps slightly more responsive than linear current limiting but still aiming at the same principle.
[17:40:35] <skunkworks> yes
[17:40:54] <skunkworks> that is why good drives are pwm
[17:41:16] <skunkworks> they perform better
[17:41:25] <SWPadnos> PWM drives can use a higher voltage than linear drives, so they can get better performance at high speeds
[17:42:06] <Bo-Dick> I'm gonna aim at 60 volts. Is that enough?
[17:42:16] <SWPadnos> what voltage steppers, and what drives?
[17:42:44] <Bo-Dick> I don't know their rated voltage but I think it is 24 volts bipolar.
[17:42:56] <Bo-Dick> The coils are 120 ohms
[17:42:59] <SWPadnos> that's very high
[17:43:16] <SWPadnos> most steppers used in CNC applications are in the 3V or less range
[17:43:33] <Bo-Dick> Yeah but I got small steppers from 5.25" floppy drives.
[17:43:38] <SWPadnos> heh
[17:43:55] <Bo-Dick> Theyre weak as hell but I want to take the most out of them.
[17:44:06] <SWPadnos> they should be 12V then
[17:44:15] <Bo-Dick> Well if I current control them I should keep them from burnin'?
[17:44:22] <SWPadnos> unless they're from the original 5.25" full height drives
[17:44:53] <SWPadnos> yes, I don't think you'll be able to get very high speeds (or torque) out of them
[17:45:36] <SWPadnos> also, it depends on how you do the current control. a series resistor would be almost the same as jus tusing a lower voltage supply
[17:46:01] <Bo-Dick> No the motors are to small and their coils have wire gauge in the size of a hair straw.
[17:46:25] <Bo-Dick> But I wanna make a stepper driver that can handle more powerful steppers.
[17:46:30] <SWPadnos> yeah - you need a lot of wire, or very thin wire, to get a 120 ohm coil
[17:47:17] <Bo-Dick> I'm gonna supply 60 VDC and then let the current limiter keep the current in cortrol in order not to burn the motors. That should work shouldn't it?
[17:47:24] <SWPadnos> consider this: if the motors are 24V, 120ohm, then the max current is 24/120 = 200 mA
[17:48:24] <SWPadnos> power waste is then 200mA * 24V, or 4.8W (of heat)
[17:48:43] <SWPadnos> you can't reliably put more heat into them than this, or they'll burn up
[17:49:18] <SWPadnos> in fact, a floppy motor is probably not rated for continuous use either, so you may not be able to use them with that amount of power for long either
[17:49:25] <Bo-Dick> Of course. I'll have to current limit them for 200mA since they can't handle more.
[17:50:04] <SWPadnos> yes, but there are (at least) two things to look at. first is current, which will fry the wires
[17:50:12] <Bo-Dick> I'm gonna implement a sleep mode for them since I don't need full holding torque.
[17:50:17] <SWPadnos> second is total power dissipation, which will melt them into a blob
[17:50:39] <SWPadnos> (third is voltage limit, the instulation may arc at 60V, though that's not too likely)
[17:50:44] <SWPadnos> insulation
[17:51:11] <SWPadnos> you have to look at the total amount of power that will be dissipated in the motor as well as current
[17:51:21] <SWPadnos> I'd help you with that, but I've run out of coffee ;)
[17:51:49] <SWPadnos> brb
[17:52:45] <Bo-Dick> So the best thing would be to regulate the power through the motors?
[17:52:55] <SWPadnos> in a sense, yes
[17:53:08] <Bo-Dick> Not a voltage regulator, nor a current regulator but rather a power regulator :P
[17:53:11] <SWPadnos> have you read Mariss Friemanis' "Stepper Motor White Paper"?
[17:53:40] <SWPadnos> He's the designer of the GeckoDrives, considered by many to be the best low-cost stepper driver
[17:55:14] <Bo-Dick> awsome! :P
[17:55:21] <SWPadnos> you found it?
[17:56:10] <Bo-Dick> Yeah I've seen the site before but not realized the potential
[17:56:35] <SWPadnos> ok. there's a file on the Yahoo group . I just looked at the Geckodrive site and didn't notice it
[17:57:44] <SWPadnos> http://f6.grp.yahoofs.com/v1/kMcJRNNltFlU3Fwg1B7U1UTOnAE3G_thTPOsj3N_haOiMo_R5I3KeCclfDnABu8vTjTlTPPdXKYbWAgXs7HD2qDsIDpRjw/Gecko%20white%20papers.pdf
[17:57:53] <SWPadnos> that probably won't work, but what the heck ;)
[17:58:05] <Bo-Dick> What do they cost?
[17:58:20] <SWPadnos> $114 each, I think (per axis)
[17:58:29] <SWPadnos> more than a floppy drive motor :)
[17:59:05] <SWPadnos> I'm not suggesting that you buy the Geckodrives, since you mentioned that you're trying to do this on the cheap
[17:59:18] <SWPadnos> but the white paper is very informative
[17:59:57] <SWPadnos> also, if you join the Yahoo group, you can search for some design discussions he had recently with Nicolas Benezan
[18:00:18] <SWPadnos> (and others - I just remember that one)
[18:00:35] <Jymmm> http://www.geckodrive.com/photos/Step_motor_basics.pdf
[18:00:53] <SWPadnos> ah, under phjotos, that makes sense ;)
[18:01:09] <Jymmm> it's not linked, just store there.
[18:01:20] <Jymmm> stored
[18:01:21] <SWPadnos> yep
[18:01:26] <SWPadnos> photos, too ;)
[18:02:15] <Bo-Dick> One question. Assume my small motor would stand about 4 watts of power. Then I could feed them with 100mA and 40 volts or 200mA 20 volts. Which alternative would be most efficient?
[18:03:03] <alex_joni> Bo-Dick: the more voltage you have the faster it will go
[18:03:18] <alex_joni> but usually they have a voltage / winding
[18:03:29] <Bo-Dick> Is there a tradeoff in speed vs. torque?
[18:03:33] <alex_joni> and you should use 5-20 times that voltage to drive it
[18:04:05] <alex_joni> Bo-Dick: read Mariss' doc, that explains a lot, better than I can do..
[18:04:46] <SWPadnos> steppers are constant power once they get to their "corner frequency"
[18:04:57] <SWPadnos> so as you increase speed, torque will drop proportionally
[18:05:04] <alex_joni> in that case it's RTFM (Read The Fine Manual)
[18:05:21] <SWPadnos> higher supply voltage will increase the corner frequency, I think
[18:06:39] <Bo-Dick> Well the message is simple. The higher the voltage the better... ...assuming the coils are insulated enough!
[18:06:56] <alex_joni> Bo-Dick: don't go too high though, it will fry the motor
[18:07:30] <alex_joni> you also need a drive that can limit current properly
[18:07:36] <Bo-Dick> So 10mA and 400 volts would fry a 4 watt motor?
[18:07:54] <alex_joni> probably so..
[18:08:15] <SWPadnos> it would likely arc, and you'd get more than 10 mA for a little while (in part of the coil) ;)
[18:08:50] <SWPadnos> remember that torque is proportional to current, so limiting a motor that would normally allow 200 mA to 10mA will give you 1/20 the torque output
[18:09:22] <Bo-Dick> That confirmes my theory that torque and speed are tradeoffs.
[18:09:35] <SWPadnos> with steppers, they are almost tradeoffs
[18:09:51] <Bo-Dick> The choice is strong and slow or fast and weak.
[18:10:06] <SWPadnos> steppers are both
[18:10:22] <SWPadnos> they're higher torque at low speeds, and lower torque at high speeds
[18:10:33] <SWPadnos> the higher the voltage, the higher the "usable" speed
[18:10:50] <SWPadnos> but you always have to take total power dissipation into account, or the motor will melt
[18:10:51] <Bo-Dick> The the absolute best would be to change the voltage according to the speed of the motor?
[18:11:21] <SWPadnos> in a sense, voltage determines usable speed
[18:11:46] <Bo-Dick> Now I'm starting to realize why PWM stepper drivers are superior. They take this into account?
[18:11:58] <SWPadnos> "usable" is determined by how much torque you need from the motor
[18:12:34] <SWPadnos> PWM drives allow you to use higher voltage, which will give you the appropriate current faster (since current increase in an inductor depends on aplpied voltage)
[18:12:41] <SWPadnos> appl;ised
[18:12:44] <SWPadnos> agrarg
[18:12:46] <SWPadnos> applied
[18:12:56] <Bo-Dick> :)
[18:14:01] <SWPadnos> basically, the higher the voltaege, the better the performance will be, until you go too high for either the total power dissipation, or the insulation resistance
[18:14:34] <SWPadnos> but, at a certain point, you end up with lots more heat, for no real gain. those kinds of limits are explained much better in the white paper
[18:14:59] <Bo-Dick> Depends for the definition of performance. Is performance speed _or_ torque?
[18:15:19] <SWPadnos> you'll never get more torque out of the motor if you limit current
[18:15:38] <SWPadnos> but you can get the same torque at higher speeds, so more power, with a higher voltage supply
[18:16:53] <Bo-Dick> What I'm trying to say is that if I've got a 4 watt motor for example I can choose the following: 10 volts and 4 amps and have a slow but strong motor. I can also have 40 volts and 1 amp and have a weak but fast motor. Is this corrent?
[18:17:20] <SWPadnos> sort of ;)
[18:17:34] <SWPadnos> if you have a 4W motor, that carries with it a rated current
[18:17:52] <SWPadnos> you should always limit your drive to the rated current, regardless of voltage
[18:19:29] <Bo-Dick> Wouldn't this design be very smart then for a universal stepper driver? A potentiometer that determines the maximum voltage and a potentiomenter that determines the current and then let the system current limit so maximum performace will be achieved at all times!
[18:19:30] <SWPadnos> it's hard to describe, because it's a dynamic thing - the static ratings make no sense when the thing's running
[18:20:02] <Bo-Dick> But I think I've got it at this point.
[18:20:17] <SWPadnos> you have essentially that with the Geckos, except that the voltage is determined by the supply, not a pot
[18:20:37] <SWPadnos> cool. there's a lot of info to digest. It's easier if you're an electrical engineer
[18:20:38] <Bo-Dick> This limits the Gecko for certain motors then...
[18:21:02] <SWPadnos> the Gecko can run from any supply from 18V to 80V, and the current is set by an external resistor
[18:21:10] <SWPadnos> so they can run a lot of different motors
[18:21:46] <Bo-Dick> I thought you said theyre voltage were factory set.
[18:21:59] <SWPadnos> no, set by the power supply
[18:22:05] <Bo-Dick> Well in that case they can be considered universal.
[18:22:19] <SWPadnos> they are pretty universal, subject to the 80V / 7A limits
[18:22:39] <Bo-Dick> Powerful stuff that is!
[18:23:25] <SWPadnos> it is
[18:23:34] <SWPadnos> the servo drives are even better, 80V, 20A
[18:23:45] <SWPadnos> 1600W in a tiny package
[18:23:50] <SWPadnos> very impressive
[18:24:14] <Bo-Dick> I think thats more than enough for my little clockworkers lathe :P
[18:24:26] <SWPadnos> heh, probably
[18:24:34] <SWPadnos> they should work nicely on my Bridgeport ;)
[18:24:35] <staggerlytom> alex: wiki image uploads works now, thanks
[18:24:56] <Bo-Dick> unless I wanna snap my small ballscrews in the crossslide :P
[18:25:10] <SWPadnos> I'm not sure tha ta floppy motor could do that
[18:26:02] <Bo-Dick> Well for such a powerful driver one can assume a powerful motor would be needed
[18:26:27] <SWPadnos> they can run fairly small motors as well, but would definitely be overkill in your situation
[18:27:15] <Bo-Dick> My wallet doesn't like them though even though the performance is superior.
[18:27:36] <staggerlytom> hmm, add up the mass of your lead screw and compare to flop stepper capability
[18:27:40] <SWPadnos> I'm not so sure the performance would be very superior with those motors, but the drives would allow for future upgrades ;)
[18:27:45] <staggerlytom> you may be askin too much of that motor
[18:28:34] <staggerlytom> it was not overkill and only spun a palstic disk
[18:28:38] <staggerlytom> plastic
[18:29:39] <SWPadnos> if it's from an old full-hieght drive, then it'll actually have a bit of power, but pretty low speed
[18:30:24] <Bo-Dick> I'm afraid it isn't
[18:30:27] <SWPadnos> what you need is the motor from an old RL-05 disk pack ;)
[18:30:31] <staggerlytom> plastic disk vs leadscrew table and cutting forces... dunno
[18:31:16] <staggerlytom> grains vs oz
[18:31:23] <SWPadnos> heh, true
[18:31:56] <staggerlytom> look for another motor and save your money for now
[18:32:13] <staggerlytom> find a motor that did simliar work
[18:32:19] <staggerlytom> similar
[18:33:07] <staggerlytom> or just do it and have fun ;-)
[18:34:12] <alex_joni> staggerlytom: glad it works
[18:36:54] <Bo-Dick> I'm most concerned about the "mid-band instability". The motor seems to have zero torque at a specific speed!
[18:37:15] <SWPadnos> that happens to be another thing that the Geckos do away with
[18:37:24] <cradek> Bo-Dick: does your driver halfstep?
[18:38:22] <Bo-Dick> No
[18:38:36] <Bo-Dick> only full step
[18:39:08] <cradek> full stepping is kind of unpredictable, lots of resonance problems
[18:41:57] <Bo-Dick> It seems like parallel connection is more powerful than have the coils in series for bipolar mode! :S
[18:42:18] <cradek> yes parallel gives lower inductance, so is what you want
[18:42:39] <Bo-Dick> Oops. My motors are centertapped and not bifilar! :S
[18:44:01] <SWPadnos> 6-wire?
[18:44:05] <Bo-Dick> yepp
[18:44:16] <SWPadnos> insulate the center taps, and use it like a 4-wire
[18:44:37] <Bo-Dick> But that'll make a series connection wouldn't it?
[18:44:52] <Bo-Dick> Thus weaker than parallel?
[18:45:02] <SWPadnos> I'd have to look that up
[18:45:26] <SWPadnos> (I'm an EE, but motors and power aren't my specialty)
[18:45:47] <cradek> if it's 6 wire, you have no choice, so don't worry!
[18:46:51] <Bo-Dick> holy crap :S The more I research on this the more I realize I've underestimated the difficulty level.
[18:47:50] <cradek> I think often people go through several types of stepper drivers before they are happy
[18:48:05] <cradek> I am on my second, and I sometimes wonder how much better geckos would be.
[18:48:27] <SWPadnos> one thing I can add. take your budget and multiply it by 6-10 ;)
[18:48:35] <cradek> I've heard that whether or not you buy geckos first, they'll be the last drivers you buy...
[18:48:58] <cradek> yeah I also don't really want to spend that kind of money for stepper drivers.
[18:49:21] <cradek> I made my three axis drive for <$100 but I have a well stocked junkbox and pcb manufacturing capabilities
[18:50:08] <Bo-Dick> Do the CNC software run the stepper at constant speed?
[18:50:31] <Bo-Dick> In that case one could avoid the resonant frequency!
[18:50:39] <cradek> well the job of CNC software is to follow a programmed path
[18:50:42] <SWPadnos> only during the "cruise phase" of a linear move
[18:51:02] <SWPadnos> otherwise, it's accelerating or decelerating to either get to/from speed, or to follow a curved path at speed
[18:51:23] <cradek> Bo-Dick: because you have to accelerate from a stop, you must pass through every speed
[18:52:20] <Bo-Dick> Yeah of course. Due to the mass of the load.
[18:52:38] <cradek> right (including the motor armature)
[18:52:47] <Bo-Dick> Every speed up to the maximum speed that is.
[18:52:51] <cradek> right
[18:53:07] <Bo-Dick> If the maximum is below the resonant frequency one could be happy!
[18:53:34] <cradek> yeah a very simple driver is possible if you don't want high speed.
[18:53:44] <cradek> like what was probably in your floppy drives.
[18:53:58] <Bo-Dick> High speeds are dedicated for servos.
[18:54:33] <cradek> yes and no. lots of people are happy enough with steppers.
[18:55:00] <Bo-Dick> Well I believe the gecko could compete with servo systems.
[18:55:32] <SWPadnos> they also makle servo drives ;)
[18:55:35] <SWPadnos> make
[18:55:55] <Bo-Dick> Stepper are cheaper than servos right?`
[18:56:15] <SWPadnos> Mariss' rule of thumb is that if you need <200W of output power, use steppers, >300, use servos, and between 200-300, you need to look at the application in detail
[18:56:57] <SWPadnos> steppers are generally less expensive for a given power rating, and they require feedback, which is an additional cost
[18:57:06] <SWPadnos> oops - serovs require feedback
[18:57:23] <SWPadnos> so servos tend to be more expensive
[18:57:38] <SWPadnos> gotta run for a bit. bbl
[18:57:42] <SWPadnos> SWPadnos is now known as SWP_Away
[18:58:53] <Bo-Dick> Hmmm. Wonder if it could be an idea to have a couple of preset voltage levels to choose from together with current limiting for my stepper driver? That would make the construction somewhat universal.
[19:00:02] <Bo-Dick> My transformer allows 24, 31 and 58 volts DC.
[19:15:40] <Bo-Dick> Why isn't the sleep mode feature instresting for current controlled stepper drivers?
[19:45:49] <alex_joni> latest TESTING as tarball (http://solaris.cs.utt.ro/~emc/emc2-testing-2006-03-02.tar.gz)
[20:55:52] <K4ts> hello
[20:56:17] <Jymmm> Hi K4ts, Jacky isn't here so come run away with me! =)
[20:56:45] <K4ts> Jymmm: ah ah
[20:56:49] <Jymmm> lol
[20:58:34] <K4ts> giacus: is busy
[21:01:30] <giacus> * giacus working ..
[21:01:49] <Jymmm> giacus: I'm stealing your girlfriend, do you mind?
[21:02:00] <giacus> K
[21:02:07] <Jymmm> thanks
[21:02:14] <giacus> ]:)
[21:02:29] <giacus> hehe
[21:03:58] <Jymmm> * Jymmm waits for giacus to get slapped!
[21:04:11] <Jymmm> *SMACK*
[21:04:17] <giacus> :*
[21:04:18] <giacus> lol
[21:04:44] <giacus> cant find any hammer here around
[21:05:10] <Jymmm> giacus: Keep lending out K4ts, and she'll find a hammer alright.
[21:05:18] <K4ts> ah ahhhhh
[21:20:03] <lilo> [Global Notice] Hi all. If you're having problems with the Netgear/Linksys router exploit, please try connecting to freenode on port 8001 instead of port 6667 .... more info: http://tinyurl.com/op26n (bandwidth limited, apologies in advance)
[21:56:37] <CIA-8> 03cradek 07stp_trap_blend * 10emc2/src/emc/kinematics/ (tc.c tc.h tp.c):
[21:56:37] <CIA-8> implement path-following tolerance: in continuous mode, motion will stay
[21:56:37] <CIA-8> within this tolerance of the programmed path while blending. When this
[21:56:37] <CIA-8> is moved to HEAD, that tolerance will come from G64 Px.xxx so it can be
[21:56:38] <CIA-8> changed during the program just like continuous/exact stop.
[22:08:47] <Jymmm> has anyone used the mirco endmills in wood?
[22:11:56] <asdfqwega> I have, sorta
[22:12:18] <Jymmm> asdfqwega how was the results?
[22:12:24] <asdfqwega> Are you talking the metal-cutting variety?
[22:13:34] <Jymmm> like these --> http://drillbitcity.com/catalogue/special_tools.asp
[22:13:39] <CIA-8> 03cradek * 10emc2/src/emc/kinematics/ (tc.c tc.h tp.c tp.h):
[22:13:39] <CIA-8> new trajectory planner from the stp_trap_blend branch. Checked in early
[22:13:39] <CIA-8> for collaboration on necessary related interpreter work.
[22:16:15] <asdfqwega> Working with my cue-maker friend, we make inlays...0.0002 repeatable...but we have router bits with optimized geometry
[22:16:56] <asdfqwega> I haven't tried the rasp-style router bits like the picture
[22:17:18] <Jymmm> cue inlays... veneer?
[22:18:12] <asdfqwega> he uses that sometimes...but that's not what we cut
[22:18:38] <Jymmm> ok, what do you cut? =)
[22:18:50] <asdfqwega> hard wood
[22:19:08] <asdfqwega> veneers (from what I've seen) are usually soft
[22:19:10] <Jymmm> asdfqwega: whats the thickness of your raw stock?
[22:19:32] <asdfqwega> it varies
[22:19:36] <Jymmm> avg
[22:20:06] <Jymmm> ?
[22:20:40] <Jymmm> 1/4" ? 1/8" ? 4" ?
[22:20:44] <asdfqwega> The common size of cutter we use - 0.0313 dia., with 0.160 max depth of cut
[22:21:04] <Jymmm> are you making or buying the raw stock?
[22:21:28] <asdfqwega> You'd have to ask him that
[22:21:41] <Jymmm> I have a hard time finding thin stock
[22:22:00] <asdfqwega> but our cutters are two-flute upward spiral router bits
[22:22:05] <Jymmm> it's either veneer or 1/2"
[22:22:22] <Jymmm> asdfqwega where are you getting hte cutters from?
[22:24:15] <asdfqwega> can't remember the website
[22:24:53] <Jymmm> asdfqwega could you look it up and let me know when you find it please?
[22:24:54] <asdfqwega> For tiny cutters for wood, you can also give Atlas Fiber a call
[22:25:22] <asdfqwega> They deal with materials for cue makers, and they've also started carrying cutters
[22:25:23] <CIA-8> 03cradek * 10emc2/src/emc/kinematics/ (tc.h tp.c tp.h): get path-following tolerance from the interpreter
[22:27:39] <Jymmm> asdfqwega: I found cuestick, but that dont say if their bits are spiral upcut
[22:27:55] <Jymmm> err cuestik.com
[22:34:50] <CIA-8> 03alex_joni * 10emc2/src/emc/ (8 files in 4 dirs):
[22:34:50] <CIA-8> added the possibility to specify G64 Pxx the Pxx will specify the tolerance to
[22:34:50] <CIA-8> deviate from the programmed path. Default is 0, which will behave as it always
[22:34:50] <CIA-8> did (no restriction in deviation, just keeping speed as constant as possible)
[22:36:54] <staggerlytom> cradek: what happens when path-following becomes one unit of measure (not 0)? how is different than exact_stop mode?
[22:37:34] <cradek> very different - exact stop will stop at all endpoints, even colinear lines
[22:38:21] <staggerlytom> ok, thats what exact stop does, but what does this new method do?
[22:38:21] <cradek> now we will have the option of something like the old exact path mode (g61.1) in the specification, which never was implemented
[22:38:27] <staggerlytom> sorry
[22:39:05] <staggerlytom> where is this spec so i can read?
[22:39:07] <cradek> the new method lets you specify a tolerance, and the tp will keep the feed rate as high as possible, while staying within that tolerance of the programmed path (and machine constraints like accel).
[22:39:19] <staggerlytom> sorry aain
[22:39:32] <cradek> search google for rs274ngc - first hit
[22:39:47] <cradek> look at g61, g61.1, g64
[22:40:22] <staggerlytom> ok, as fast as possible, gotcha, and i got the old rs274 archives to read, thanks
[22:40:50] <cradek> the old spec is very handwavy - now we can specify the exact behavior we want by tolerance
[22:42:38] <asdfqwega> Is anyone here familiar with old encoder tech?
[22:42:50] <alex_joni> asdfqwega: how old?
[22:43:07] <asdfqwega> Danged if I know
[22:43:15] <asdfqwega> I have a couple pictures
[22:43:17] <giacus> :)
[22:43:28] <CIA-8> 03cradek * 10emc2/src/emc/kinematics/tp.h: forgot the prototype
[22:43:32] <asdfqwega> www.bright.net/~janfritz/rotor.jpg
[22:43:38] <asdfqwega> www.bright.net/~janfritz/stator.jpg
[22:44:29] <asdfqwega> I can't tell if it's simply a tachometer or encoder
[22:44:41] <dave-e> ouch...that looks resistive
[22:45:00] <staggerlytom> yeah, this is like an RC servo
[22:45:02] <asdfqwega> It seems to uses a coil in the center to energize the rotor
[22:45:35] <staggerlytom> then i dunno
[22:45:36] <asdfqwega> Non-contact - it's all done by induction
[22:45:42] <dave-e> those center thingies are wipers aren't they
[22:45:49] <asdfqwega> Nope
[22:46:11] <staggerlytom> inductosyn?
[22:46:19] <asdfqwega> No numbers, no names or plates
[22:46:26] <CIA-8> 03alex_joni * 10emc2/src/emc/ (5 files in 3 dirs): final bits to the puzzle of getting the PATH following tolerance from the interpreter to the trajectory planner
[22:46:40] <dave-e> what does the output signal look like?
[22:49:27] <dave-e> anyone know how to quantitate following error in emc2?
[22:51:48] <asdfqwega> I haven't tried anything with it yet...I don't know where to start
[22:51:50] <alex_joni> asdfqwega: at first glance I'd say it's a resolver
[22:51:51] <alex_joni> feed it with a sine-wave, get an induced one back..
[22:51:51] <alex_joni> otoh, are you sure it's a feedback of some kind? .. might be a motor too..
[22:51:51] <cradek> dave-e: it's a linear equation based on those two FERROR terms and the velocity, I'm looking in the wiki for it...
[22:51:52] <cradek> dave-e: or is that what you're asking?
[22:51:52] <cradek> dave-e: http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Following_Error
[22:51:52] <cradek> haha The second reason I didn't assign units to the graph is that I am not completely certain what the units of Ferror and Min_Ferror.
[22:51:52] <cradek> * cradek waves his hands wildly
[22:51:56] <dave-e> well back to work...have X decently tuned now on to Y.
[22:52:07] <jepler> Anybody know why halscope says "Realtime function not linked" in the title of the window where you choose the thread, multipler, and # channels?
[22:52:30] <cradek> jepler: do you have loadrt halscope_rt in a halfile?
[22:52:36] <cradek> or however it's spelled
[22:52:47] <jepler> cradek: yes, I think so anyway
[22:52:56] <alex_joni_> 00:48 < alex_joni> asdfqwega: at first glance I'd say it's a resolver
[22:52:56] <alex_joni_> 00:48 < alex_joni> feed it with a sine-wave, get an induced one back..
[22:52:56] <alex_joni_> 00:49 < alex_joni> otoh, are you sure it's a feedback of some kind? .. might be
[22:52:56] <alex_joni_> a motor too..
[22:53:06] <cradek> check dmesg?
[22:54:28] <dave-e> no...I'm plotting ferror on halscope for tuning and kinda wanted to know how close I was getting
[22:55:49] <dave-e> the stuff happens too fast to read on halmeter
[22:58:04] <staggerlytom> ferror must be in units of measure, I suggest degrees or um. the graph hides thats the spec is simply a +/- tolerance.
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