#emc | Logs for 2009-04-30

[00:39:43] <skunkworks> http://imagebin.ca/img/ACn6i5t7.jpg
[00:41:54] <mozmck> I'd like to get inkscape to export dxf files with arcs.
[00:42:26] <mozmck> I found a script to export dxfs, but it converts all splines and curves to line segments
[00:45:57] <mozmck> I have a file "biarc.py" that puts out gcode, written by jepler it says...
[01:01:19] <eric_unterhausen> skunkworks: that last 1/10 of a wall is just really holding out on you
[01:01:59] <skunkworks> about 60 inches :)
[01:16:28] <JymmmEMC> mozmck: Don't trust InkScape to do perfect math.
[01:23:40] <mozmck> math for what?
[01:23:51] <Valen1> eeewwww math
[01:24:01] <mozmck> converting the splines to biarcs?
[01:24:30] <mozmck> I think the math would be done in the extension...
[03:03:24] <cradek> emc2 trunk has gcodes for splines and nurbs
[03:03:45] <cradek> it is extremely new and lightly tested
[03:04:07] <mozmck> I saw that! I'd like to play with it as well.
[03:04:48] <mozmck> right now I would like to get something out of inkscape that I can use a cam program (probably sheetcam) to convert to gcode.
[03:06:18] <cradek> I think sheetcam only loads dxfs?
[03:06:34] <mozmck> yes, and gerber i think
[03:06:46] <cradek> dxfs (like gcode) are lines and arcs - not sure how to get that out of inkscape.
[03:07:20] <mozmck> I found an extension for inkscape to export dxf, but it converts splines to line segments
[03:07:52] <mozmck> I'd like to at least update that to convert the splines to biarcs.
[03:08:04] <cradek> yeah
[03:08:29] <cradek> or the spline gcodes!
[03:08:35] <mozmck> I'm trying to learn python first...
[03:08:49] <cradek> if you want to be on the bleeding edge, that is
[03:09:07] <mozmck> That would probably be next.
[03:09:55] <mozmck> There are quite a few people using Corel Draw and sheetcam in windows for making designs to cut with plasma or on router tables.
[03:10:56] <mozmck> corel has the same problem with dxf export (lots of line segments), so there is an extension for corel that you can buy to export dxf files with arcs
[03:11:20] <mozmck> it would be quite handy to a lot of folks if inkscape could do the same thing
[03:11:58] <cradek> yes sounds like...
[03:12:55] <cradek> unfortunately it will probably be at least a year before the version of emc2 with splines/nurbs is release quality.
[03:13:11] <cradek> if not for that, I'd suggest that's the way to approach it.
[03:13:51] <mozmck> yeah, and I'd really like to play with that too. but it's one thing at a time for me. I'm *way* too busy!
[03:14:54] <cradek> always short on time - story of our lives.
[03:15:03] <cradek> with that in mind, I should go to bed! goodnight.
[03:15:33] <mozmck> yup, and too much to learn. nite
[04:47:52] <MrSunshine_> if you have current limiting with pwm .. at 20kHz, how does that work with stepping frequency of 350KHz ? .. then theres no time for any current limiting is it? :P
[07:39:38] <archivist> MrSunshine_, you will never step at that speed, stepper motors have a maximum step rate
[07:39:42] <ds3> p
[07:40:14] <archivist> MrSunshine_, read some specification data
[07:55:17] <MrSunshine_> ahh ok :)
[07:55:28] <MrSunshine_> i was looking at the gecko drives they can step up to 350khz some of them
[07:59:12] <archivist> no thats microstepping not the real rrate the motor sees
[08:00:07] <MrSunshine_> oh
[08:00:21] <MrSunshine_> hm.. roller screws why do you never hear about them anywhere? :)
[08:00:27] <MrSunshine_> are they good ? .. bad? .. etc? :=)
[08:00:31] <MrSunshine_> expensive?
[09:15:48] <piasdom> g'mornin all
[10:33:43] <cncxman> hello, i have a cnc that the x axis and the y axis is not perfectly 90 degrees, i have calculated a transform matrix to compensate this, and i don't know if it is possible to assign it directly to emc instead of aplying the filter to every gcode file
[10:34:58] <archivist> yes the machine can compensate to an extent
[10:35:21] <cncxman> and where must i put this matrix in emc?
[10:36:54] <cncxman> is a 3x3 matrix to multiply to the 3 target coordinates
[10:37:49] <cncxman> so x=a*x' + b*y' + c*z' -- y=d*x'+e*y'+f*z' , etc
[10:38:03] <cncxman> so i have a,b,c,d,e,f,g,h,i
[10:38:17] <archivist> I was thinking of the screw compensation.
[10:38:34] <cncxman> no, is for compensate in software
[10:38:46] <cncxman> because i cannot calibrate the machine
[10:38:52] <archivist> you need to add something to the kins to suit your machine
[10:39:51] <archivist> see the stuff stuart did for his 5 axis to correct it
[10:40:06] <cncxman> has he a webpage?
[10:40:48] <archivist> he posted details to the mailing lists
[10:41:26] <cncxman> upss, i didn't know there is a mailing list for emc, i'm going to subscribe, thx
[10:46:13] <archivist> search for equations in kinematics in the mailing lists
[10:48:50] <archivist> http://article.gmane.org/gmane.linux.distributions.emc.user/11322/match=stuart
[11:15:18] <bogie> hello all. did anyone used image-to-gcode from timeguy?
[11:16:18] <archivist> a few have I believe, just ask the real question
[11:18:00] <bogie> i always get a mistake. the [FILTER] part is from the integrator manual. other python scripts from examples work fine
[11:18:55] <archivist> "mistake" is not enough to go on
[11:18:59] <bogie> i made a gif from a word arial and tried to run image-to-gcode
[11:19:16] <bogie> yes, yes, 5 secs, i'll post what it says
[11:19:25] <bogie> Traceback (most recent call last):
[11:19:25] <bogie> File "/usr/share/emc/ncfiles/image-to-gcode.py", line 17, in <module>
[11:19:25] <bogie> im = Image.open("arial.gif")
[11:19:25] <bogie> File "/usr/lib/python2.5/site-packages/PIL/Image.py", line 1889, in open
[11:19:25] <bogie> fp = __builtin__.open(fp, "rb")
[11:19:26] <bogie> IOError: [Errno 2] No such file or directory: 'arial.gif'
[11:19:55] <bogie> this files lies in the same directory as a script
[11:20:44] <archivist> try a full path and make sure case in correct
[11:23:27] <bogie> yep, it does something, but not an image, i see a raster. like in a tv from left to right from down to up many cuts
[11:23:53] <bogie> oh no, sorry
[11:24:02] <bogie> it does fine in 3D
[11:25:34] <bogie> erhhhh it makes milling while i need foam cutting...
[11:28:15] <archivist> ah you need another then probably http://timeguy.com/cradek/truetype
[11:31:06] <Valen1> How would you work out/measure how out of square a 3 axis mill is?
[11:32:25] <archivist> there are some standard methods in machine specs type books
[11:32:47] <bogie> nono, that for letters works perfect.
[11:33:41] <bogie> i want to cut a circle for a example, couldn't make it gimp
[11:34:00] <archivist> I got my cheapo s/h barcode thingies this morning Valen1 symbol ppt 2742
[11:34:19] <Valen1> symbol make some good (if stupidly expensive) stuff
[11:34:49] <archivist> £10 trying to get some charge in the batts to see if good
[11:35:08] <Valen1> at least odds are you can probably get new ones for them
[11:35:48] <archivist> one has 0 volts!, othe r has 3.4 so seems better
[11:36:04] <Valen1> yeah lithiums do rather badly under about 2V
[11:36:34] <archivist> I suppose 1 out of two will be ok at the price
[11:37:00] <Valen1> for ~$140 you can probably get a new battery for it ;->
[11:37:08] <Valen1> what version of windows is on it?
[11:38:03] <Valen1> gonna order mah electronics bits tonight i thinks
[11:39:29] <archivist> not got them fired up yet so dunno whats on them
[11:39:44] <Valen1> probably not loads of porn :-<
[11:40:24] <archivist> hopefully the explorer will be there and I can use that as my interface
[11:40:30] <Valen1> it will be
[11:40:38] <Valen1> 2d barcode reader nice
[11:40:59] <Valen1> oh wait a minute
[11:41:06] <Valen1> 16mb ram 12mb rom ouch
[11:41:38] <Valen1> i think python is like 6mb or so ;->
[11:42:31] <archivist> I only need an ajax type app ane use the power back at the server
[11:42:46] <Valen1> dunno if it'd have the herbs for ajax
[11:42:58] <Valen1> well not a "traditional" ajax
[11:43:04] <archivist> I dunno either
[11:43:25] <archivist> just got these to try the technology
[11:43:42] <Valen1> flat HTML with the barcode scan thing set to "enter" and a default button is probably the way to go
[11:44:00] <Valen1> it'd probably run python ok
[11:44:17] <Valen1> most of them you can stick a flash card in for some extra storage
[11:44:57] <archivist> * archivist sees no flash hole
[11:45:19] <Valen1> it might well be inside the case or behind a screw in panel
[11:48:00] <Valen1> The problem the client i am making the stocktake thing was having is the wireless drops out from time to time (as wireless does) and that causes problems with stocktaking
[11:48:17] <archivist> heh it could
[11:48:52] <archivist> you need to buffer a bit in the handset
[11:48:57] <Valen1> especially in their larger stores
[11:49:10] <Valen1> this one I'm running the whole thing inside each handset
[11:49:52] <Valen1> the handset will just transmit the results when they have completed a location, then get more locations for the counter to go scan
[11:50:44] <archivist> Im intending main stuff is central, but maybe fetch a shelfs stock to handset
[11:53:07] <Valen1> might be able to do some little java thing for that
[11:53:15] <Valen1> just a set of listboxes or something
[11:53:26] <Valen1> dunno, the performance gap is pretty striking
[11:53:52] <Valen1> on my PC that lookup thing does ~6000 lookups a second, on the PDA its doing ~12 or so
[11:54:21] <Valen1> Think i could get mesa to ship the stuff to me via USPS rather than any of those couriers they mention
[11:54:47] <Valen1> its just all those couriers stick like $150 worth of "customs" crap on that USPS doesn't
[11:54:48] <archivist> USPS is slow boat to china isnt it
[11:55:08] <Valen1> I got stuff from usa via their express thing in 4 days over a weekend
[11:55:26] <Valen1> and no $150 customs fee
[12:29:59] <archivist> bogie, lots to play with on http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Cam
[12:33:25] <bogie> i played almost everuthing from there
[12:34:09] <bogie> just want a good tool to convert image to gcode as good as it does ttf convertor
[12:34:50] <bogie> TrueType tracer works perfect i was amazed when saw it in work
[12:34:56] <archivist> better to work from a drawing not an image if you are doing circles etc
[12:35:12] <bogie> drawing you mean dxf?
[12:35:30] <archivist> thats one way yes
[12:36:07] <bogie> i want to do rather difficult decorations
[12:36:48] <archivist> like hand engraving
[12:37:00] <archivist> or carving
[12:37:51] <bogie> yep for house fronts etc
[12:39:30] <bogie> software e.g. from www.coner.com.pl cuts it on the fly without need to make formulas by hands coz they are too difficult to describe with maths
[12:40:08] <archivist> you could try http://www.vectric.com/ vcarve
[12:40:40] <bogie> i did formulas for gear wheel, it took too much work, but the formula is perfect. but it's too much work for so simple figure :(
[12:41:16] <archivist> I cut gears
[12:41:29] <archivist> but use hand crafted gcode
[12:43:10] <archivist> * archivist of out to look at a mill
[12:43:17] <archivist> off out
[12:43:27] <bogie> errhhh i need 2 hours
[12:57:12] <Optic> moo
[12:57:35] <Valen1> can one use the mesa brushless cards with EMC
[12:57:52] <Valen1> it looks like they need to run with softDMC
[12:58:27] <SWPadnos> at the moment, there's no specific support for them in EMC
[12:59:12] <Valen1> dang, cos i were thinkin these might be nice http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5142&Product_Name=HXT_80-100-B_130Kv_Brushless_Outrunner_(eq:_70-55)
[12:59:15] <SWPadnos> I think the phase currents need to be updated more often than the 1KHz servo period, so it's likely that it would take a significant amount of work to use them with EMC
[12:59:26] <SWPadnos> if it can be done at all
[12:59:39] <Valen1> softDMC supports it *sob*
[13:00:27] <SWPadnos> well, it could be possible to put the right signal generator into the FPGA, with a velocity register being the only thing that EMC has to update
[13:00:30] <Valen1> I believe they are around an 8 pole motor so at top speed its commutating at 800Hz
[13:00:39] <SWPadnos> or even to make emc work with SoftDMC in some dumb mode
[13:00:54] <Valen1> those both sound rather non trivial though
[13:00:59] <SWPadnos> yep, quite
[13:01:13] <Valen1> I do like the idea of EMC + softDMC though
[13:01:23] <Valen1> just in general
[13:01:24] <SWPadnos> 800 Hz commutation for a sine wave means much higher than 800 Hz waveform updates
[13:01:31] <Valen1> yup
[13:01:33] <SWPadnos> more like 80 kHz or more
[13:01:40] <Valen1> nah nothing like that
[13:01:50] <SWPadnos> 100 updates per full cycle seems reasonable
[13:01:59] <SWPadnos> maybe less would work. I don't know
[13:02:00] <Valen1> you only need 4 or 5
[13:02:11] <SWPadnos> that's doable with EMC
[13:02:27] <SWPadnos> you can go to around 8-10 kHz updates I believe, depending on the PC
[13:02:37] <SWPadnos> and the PCI chipset - some of them are dogs
[13:02:45] <Valen1> 80Khz is much much faster than the actual PWM frequency they use so your not going to see much benifit to that
[13:03:00] <Valen1> most of the available controllers run ~3khz PWM freq
[13:03:11] <SWPadnos> I'd be surprised at that
[13:03:18] <SWPadnos> gecko drives are 20 kHz
[13:03:18] <Valen1> I have them and use them
[13:03:23] <Valen1> these are hobby things
[13:03:34] <Valen1> you can hear it and its 3khz
[13:03:50] <Valen1> same pitch as the other motor controller boards i repair
[13:03:53] <SWPadnos> the geckos are industrial drives, they just sell to hobbyists also
[13:04:04] <SWPadnos> are you saying that Geckos are 3KHz?
[13:04:09] <Valen1> no the hobby ones
[13:04:32] <SWPadnos> ok, so you're talking about hobby boards when you say "available controlllers" ??
[13:04:55] <Valen1> nfi what geckos are other than its probably an inaudible frequency because a 1Kw motor with 3Khz PWM would wine like a bitch
[13:05:11] <SWPadnos> http://www.geckodrive.com/
[13:05:17] <Valen1> mesa have a controller for it that runs like the other ones at whatever you want it to
[13:05:19] <Valen1> up to 50
[13:05:41] <Valen1> the controllers i have used on those motors are 3khz hobby controllers
[13:06:24] <Valen1> I am somewhat suprised that the mesa card actually is using the host to provide the PWM but i guess if they have the FPGA there it makes sense to
[13:06:36] <SWPadnos> the host doesn't do the PWm
[13:06:39] <SWPadnos> PWM
[13:06:40] <Valen1> and just pass the comutation signals back to the host (or perhaps use the encoder)
[13:06:45] <SWPadnos> it sets the PWM duty cycle
[13:07:01] <Valen1> sorry the mesa driver card uses the controller card in the computer to do the PWM
[13:07:04] <SWPadnos> and the SoftDMC controller (in the FPGA) does the commutation work
[13:07:19] <Valen1> from the driver cards POV its "host" is the controller card ;->
[13:07:24] <SWPadnos> heh
[13:07:39] <SWPadnos> well, it makes sense when you consider that the driver is a peripheral for the FPGA card
[13:07:57] <SWPadnos> it's not intended to be a standalone driver, it's meant to be a form of I/O for the FPGA
[13:08:16] <Valen1> like i said "but i guess if they have the FPGA there it makes sense to"
[13:10:35] <Valen1> needs to be rewound for a higher voltage to really work for a servo system
[13:11:48] <Valen1> the current limit on controllers for this stuff, is that the supply current limit or the motor current limit/
[13:12:02] <SWPadnos> should be motor limit
[13:12:13] <Valen1> dang :-<
[13:12:50] <Valen1> I like the price for those http://kelinginc.net/ServoMotors.html motors but i cant find a 40A controller for them
[13:15:09] <skunkworks> you don't need a 40a controller. Didn't we discuss that before? ;)
[13:15:30] <skunkworks> that is probably like a 2 second peak current.
[13:15:44] <skunkworks> before the thing demagnetizes
[13:17:13] <skunkworks> its continuous current is 7.8A
[13:17:55] <Valen1> right so i can put 40A through a 20A controller and still get the peak torqe
[13:18:14] <Valen1> and no smoke
[13:18:50] <Valen1> If you are never sposed to use the motor beyond the continious ratings what is the point of the peak rating?
[13:19:56] <SWPadnos> the continuous rating is just that - the max you can use for ever and ever without the motor overheating
[13:20:08] <SWPadnos> continuous ratings are usually heat based
[13:20:50] <SWPadnos> maximum ratings are the most you can ever do to the motor, and may be based on heat in addition to other factors, such as wire gauge or demagnetization
[13:20:57] <Valen1> yep
[13:21:14] <Valen1> so why should i get a controller that cant use all of the motor?
[13:21:23] <SWPadnos> ok, so the continuous rating is useful, in case you're making an escalator or somethng, right
[13:21:48] <SWPadnos> the motor will run and run and run, as long as you don't go over that continuous rating
[13:22:08] <Valen1> I have actually built several electric motors, so i am somewhat aware of peak and continuous ratings.
[13:22:22] <SWPadnos> in the CNC world, motors are rarely used at their peak performance, but it is sometimes desirable to use them above the continuous ratings
[13:22:47] <Valen1> like say when you wish to accelerate the table in a paticular direction
[13:22:49] <skunkworks> http://www.a-m-c.com/download/datasheet/100a40.pdf
[13:22:56] <SWPadnos> sure
[13:23:19] <Valen1> skunkworks do i want to know the price on these?
[13:23:33] <SWPadnos> they're a couple hundred dollars each I think
[13:23:38] <SWPadnos> and sometimes available on eBay
[13:23:39] <skunkworks> I would guess around 300-500
[13:23:49] <skunkworks> new
[13:23:51] <SWPadnos> I have 6 of the 80V/30A units (from ebay)
[13:24:06] <Valen1> I was liking the mesa 2 channel 20A 150 volt controlers
[13:24:24] <Valen1> Valen1 is now known as Valen2
[13:24:29] <Valen2> Valen2 is now known as Valen1
[13:24:43] <Valen1> for $300 a pop
[13:24:48] <Valen1> so ~$150 a chan
[13:25:28] <Valen1> they seem to provide alot of bang for your buck
[13:26:22] <SWPadnos> look here as well: http://pico-systems.com/motion.html
[13:26:31] <SWPadnos> similar power ratings though, 160V/20A
[13:27:00] <SWPadnos> and he's got a brushless drive with the same ratings, both are $150 or less
[13:27:13] <Valen1> yeah i just noticed that one
[13:28:10] <Valen1> I like the mesa keeping it digital thing
[13:28:11] <skunkworks> For a cnc machine... lets say you set your accelleration to take 20a. (of the 40a peak) - now you when you are running the table it accellerates for a second and run at your feedrate for a while then de-accelerates for a second. (not a problem) now lets say you are contouring a part? You are constantly acc/decel - much more than 1 or 2 seconds.
[13:28:55] <Valen1> skunkworks: yes but when you are contouring you will also typically be running at a much lower speed
[13:29:14] <SWPadnos> speed and accel are mostly indepedent variables
[13:29:22] <SWPadnos> that's why servos are so great
[13:30:11] <Valen1> if the speed is lower then you need less acceleration to get to that speed
[13:30:40] <SWPadnos> if you're always changing speed, then the accel will be high all the time
[13:31:03] <Valen1> it depends on how fast you need to change speed
[13:31:15] <Valen1> if the average speed is low then the average acceleration will be low
[13:31:26] <jepler> Valen1: pico-systems are also pwm input
[13:31:31] <Valen1> (in comparison to doing the same profile at a max traverse speed)
[13:31:41] <SWPadnos> so a raster-like milling process will be bad for Z (since it's got to move up and down all the time), not bad for Y (since it just goes at one speed all the time), and very lightweight on X (since it just moves over every once in a while)
[13:31:44] <Valen1> yes i was noticing that
[13:31:48] <SWPadnos> assuming an X-Y raster :)
[13:32:10] <Valen1> yes and the acceleration you see on Z is dependant on the speed of Y
[13:32:18] <SWPadnos> no, it's not
[13:32:36] <Valen1> if you run Y slowly then the acceleration you need to follow the profile is less than if you run y fast
[13:33:13] <Valen1> lets say i want to machine a sine wave on your raster machine
[13:33:16] <SWPadnos> if you set a max accel (in EMC), then that accel will be used all the time, unless there is another joint being accelerated which limits the accel on "this" joint (to follow the correct contour)
[13:33:35] <cradek> the acceleration used to go from 0 to 1 inch/sec is the same as the acceleration used to go from 0 to 2 inch/sec; it just doesn't accelerate for as long.
[13:33:58] <Valen1> yes but if your cutting metal then you are going to be moving slower than if you moving the head around
[13:34:00] <cradek> acceleration is NOT proportional to velocity
[13:34:21] <SWPadnos> Valen1, sure. are you trying to get max current so you can accelerate to rapid speed twice as fast?
[13:34:34] <Valen1> basically
[13:34:48] <SWPadnos> if you're not going to be using max during cutting (most of the time), then the only use is rapid accel (not rapid speed, just accel)
[13:35:00] <Valen1> correct
[13:35:07] <SWPadnos> ok. if that's so important to you, knock yourself out :)
[13:35:25] <Valen1> it just bugs me to have really mismatched components
[13:35:40] <SWPadnos> I would argue that they're not mismatched
[13:36:08] <SWPadnos> if the servo drive is capable of outputting more than the continuous current, and up to the max current, then they are a good match
[13:36:16] <Valen1> the controller maxes out before reaching half of the motor capabilities
[13:36:43] <SWPadnos> if your application requires a higher percentage of max than the driver will provide, then the driver is a bad match for your application, but not for the motor
[13:37:06] <Valen1> thats the thing, most servo drives seem to be able to do 20A, and even the controllers on the site they sell don't do 40
[13:37:29] <Valen1> It seems to me odd to sell a 40A max motor and a 20A max drive for it
[13:37:46] <SWPadnos> you'll never smoke a motor with their drive :)
[13:37:54] <BJT-Work> BJT-Work is now known as BJT-GoneFishing
[13:37:55] <SWPadnos> s/a/their/
[13:37:58] <Valen1> smoking a motor holds no fear to me ;->
[13:38:16] <Valen1> I have rewound several with good results lol
[13:38:26] <Valen1> some under fairly intense time pressure lol
[13:38:39] <Valen1> although the requirements on those was greatly diminished
[13:38:40] <SWPadnos> well, have fun with it
[13:39:02] <Valen1> Is there a wiki or something with all these suppliers on it?
[13:39:20] <SWPadnos> yes, the emc wiki has a list of compatible hardware
[13:39:27] <Valen1> the EMC wiki seems to be a little light or at least the suppliers sites seem to be weak
[13:39:32] <SWPadnos> I think there's a partial list of motor drives too, but it's certainly not complete
[13:39:36] <jepler> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?EMC2_Supported_Hardware
[13:40:37] <Valen1> yeah that doesent mention an of the suppliers that have been mentioned here lol
[13:40:43] <Valen1> in their step and direction drives
[13:40:44] <jepler> that page is probably complete with respect to the smart I/O boards, and less complete with respect to anything else
[13:41:11] <skunkworks> step and direction drives are yecky.
[13:41:32] <skunkworks> (servo)
[13:41:33] <Valen1> they lump servo drives into the same category
[13:42:05] <Valen1> bastards
[13:42:43] <Valen1> http://www.granitedevices.fi/index.php?q=brushless-servomotors isn't looking too bad
[13:42:49] <Valen1> $315 australian per motor
[13:43:16] <Valen1> ahh, rather low on the peak torque
[13:43:30] <Valen1> not too bad on the cont torque though
[13:49:20] <skunkworks> Steve!
[13:49:32] <jepler> Valen1: based on vsd-e_manual.pdf sections 8.7 and 12.4, their amps will probably work well with pwm or analog outputs of mesa or pico I/O cards
[13:49:37] <Servos4ever> G'mornin
[13:49:55] <jepler> http://www.granitedevices.fi/assets/files/vsd-e_manual.pdf
[13:53:16] <jepler> vsd running motors in torque or velocity mode
[13:54:31] <jepler> interesting, the datasheet says they can run "stepper" motors in servo mode
[13:54:46] <Valen1> theres no real difference between the 2 really
[13:56:44] <skunkworks> it is what gecko is trying to build (stepper servo)
[13:56:49] <skunkworks> also
[13:57:13] <Valen1> shouldn't be too hard to do, you just need to run at a decent speed and have feedback on rotor position
[13:57:27] <cradek> seems like everyone tries it but nobody is using it
[13:57:27] <Valen1> I wonder if they can use the encoder to do that without too much hassle
[13:57:44] <SWPadnos> I think Mariss opted to redo the servo drives with CPLDs first, and he'll be back on the "unstallable stepper" drive once the G380 is done
[13:58:07] <Valen1> its the feedback thats the hard part, because the rotor position is a variable, you need to know it for commutation
[13:58:12] <SWPadnos> well, all the flavors of the G380 that is
[14:02:47] <Valen1> mesa doesn't seem to have a price on their 8I20 2200W 3 Phase Amplifier
[14:02:56] <jepler> with mach, I don't see how it can do better than his step-servo drives in the case of a following error -- i.e., just fault, and you've still lost position
[14:03:46] <SWPadnos> I agree - it's only really useful if you havea controller that can reduce speed on all joints when one is load-limited
[14:03:47] <jepler> Valen1: I agree, I don't see it on the pricelist either. I recommend e-mail
[14:04:16] <Valen1> I probably don't want to know lol
[14:04:26] <Valen1> cant run it with EMC anyway probably
[14:04:34] <jepler> (I am not sure whether the 8i20 will work with hostmot2 today; I see it requires input of reference angle, and I don't think that's any of the current hostmot2 modes)
[14:05:12] <Valen1> it has hall sensor inputs
[14:05:28] <Valen1> and i think i see a micro or 2 on it
[14:05:44] <Valen1> "The host controller may be a PC with a fast serial interface and quadrature counters or a Mesa FPGA card running SoftDMC or HostMot2 firmware."
[14:06:29] <Valen1> oh i see what you mean
[14:06:49] <Valen1> it wants torque inputs
[14:07:27] <Valen1> they mention an 8C20 to make it into a "smart" controller but that also isn't mentionend anywhere else on that page
[14:07:32] <jepler> pcw or seb are who you want to talk to, but it looks like neither of them are here right now
[14:07:48] <Valen1> its probably a mega $ product
[14:07:58] <Valen1> and then you need motors to attach to it
[14:23:23] <the__goat> the__goat is now known as the_goat
[14:38:56] <skunkworks> LawrenceG: come on now - any smoke?
[14:41:10] <LawrenceG> no smoke, but I broke off a bypass cap, drilling the heatsink
[14:42:01] <skunkworks> yeck
[14:46:41] <skunkworks> http://spaceweather.com/ space station video is pretty cool :)
[15:10:24] <Jon_geo01005> anybody know of a good, opensource c++ matrix library?
[15:10:53] <cradek> Jon_geo01005: is this for embedding in python? (I forget if you are the guy working on that problem)
[15:11:58] <Jon_geo01005> Yeah, I'm that guy. For python I have used numpy, but I'm working on a c++ version. I need some simple matrix operations functions for the optimization routine.
[15:12:16] <eric_unterhausen> boost should be a good library, but I understand it's a little slow in the matrix department
[15:12:18] <cradek> numarray/numpy do all their dirty work at C speed
[15:12:19] <SWPadnos> Jon_geo01005, they're complex to look at, but I bet the boost libraries are about the best you can get
[15:12:28] <SWPadnos> in terms of correctness and documentation at least
[15:14:05] <pcw> Too late for Valen but:
[15:14:07] <pcw> 8I20 price should be on website...
[15:14:08] <pcw> 8I20 by itself is dumb
[15:14:10] <pcw> ( well it uses a DSP for the 3 phase current DI,QI PI loops)
[15:14:11] <pcw> It needs reference angle and desired torque from host
[15:14:13] <pcw> basically a serially connected 3 phase torque amplifier
[15:14:14] <pcw> 1KHz sample rate is OK 4 KHz better
[15:15:04] <Jon_geo01005> pcw: spi right?
[15:15:29] <pcw> No, RS-485 serial
[15:15:57] <Jon_geo01005> Oh, ok.
[15:17:42] <pcw> I've got some preliminary hardware support in HostMot2
[15:17:44] <pcw> Been thinking of ways to hide the serial protocol
[15:17:45] <pcw> in the FPGA so it looks like a normal PWM/ENCODER servo setup
[15:23:10] <skunkworks> Cool :)
[15:25:44] <pcw> I'm amazed we didn't blow up any IGBT modules when testing
[15:25:46] <pcw> ( we did hide behind a chair when we first cranked the voltage up to 360V)
[15:26:42] <LawrenceG> pcw, sounds like fun!
[15:27:20] <skunkworks> http://www.cnczone.com/forums/showthread.php?p=606337#post606337
[15:27:35] <skunkworks> I have only liquified some mosfets - no bang yet.
[15:27:56] <pcw> It was fun, though I hate high voltages (too many bad memories from tube days)
[15:30:53] <pcw> At low voltages MOSFETS are almost unkillable
[15:30:54] <pcw> once you get above 100V they are a lot more fragile
[15:30:56] <pcw> you dont have the luxury of the extremely high peak
[15:30:58] <pcw> current capability of low voltage -low on resistance
[15:30:59] <pcw> MOSFETS
[15:43:01] <skunkworks> the metal back of the mosfet oozed around the heatsink
[15:43:24] <skunkworks> looked like someone tried to solder the mosfet to the heatsink ;)
[15:44:15] <LawrenceG> ah... dont need any heatsink compound... mold them right on
[15:45:22] <skunkworks> I have been having very good luck with the igbt's I am playing with.
[15:46:04] <skunkworks> very little heat and they switch fast enough for me.
[15:47:42] <skunkworks> plus they just feel solid. :) They should - they are made by irf - the experts ;)
[15:51:10] <pcw> MOSFETS are still more efficient around 200V (lower on voltage and switching time)
[15:51:11] <pcw> but above that IGBTs are often a better choice, especially if you have relatively low switching speeds
[15:51:45] <skunkworks> these seem to handle 20khz just fine
[15:52:12] <skunkworks> The mosfets I started with just had too high of Rds. (.12 iirc)
[15:53:46] <pcw> 20 KHz is a close to the limit for small IGBTs, (the 8I20 module runs at 20KHz)
[15:53:48] <pcw> On our 7I29 we use 26 mOhm Rds MOSFETS
[15:53:57] <skunkworks> Yes - .12ohms. The igbt's I am using are these. http://www.irf.com/product-info/datasheets/data/irg4pf50wd.pdf
[15:54:30] <skunkworks> (got a really good deal on them)
[15:56:01] <pcw> Thats a very fast IGBT, but still at 20A you have 40W per transisitor to dissipate
[15:57:42] <pcw> One nice thing about IGBTs is the low reverse transfer capacitance
[15:57:44] <pcw> avoids the more and more exotic MOSFET gate drive circuitry
[15:57:45] <pcw> to avoid DVDT turnon
[16:01:44] <skunkworks> yes
[16:04:35] <BJT-GoneFishing> BJT-GoneFishing is now known as BJT-Work
[16:05:08] <skunkworks> pcw: http://imagebin.ca/img/z0vrLSPy.jpg :)
[16:06:29] <eric_unterhausen> there ain't no machine hooked up to that computer
[16:07:24] <pcw> Is that one of those 945mumble dual core Atom Motherboards?
[16:07:55] <skunkworks> yes
[16:08:29] <SWPadnos> D945GCLF2
[16:08:51] <skunkworks> pcw: at 20a the seem to get a little warm http://www.electronicsam.com/images/KandT/servostart/schem/latestcurrentlimit/right.JPG
[16:09:06] <eric_unterhausen> you could get a single core and save 20 bucks
[16:09:06] <pcw> Did you see the other Erics dual core latencies with his SMP kernel?
[16:09:23] <eric_unterhausen> is it on the wiki?
[16:09:40] <pcw> No, but it was < 5 usec
[16:10:14] <skunkworks> wow - this thing runing a single core kernel runs around 17us
[16:10:31] <eric_unterhausen> he probably didn't stress test it too well :)
[16:10:41] <SWPadnos> there were some general improvements with cradeks experimental SMP kernel
[16:10:59] <SWPadnos> I think it's limited to 2 cores though, so disable HT if you want to try it on the atom
[16:11:11] <eric_unterhausen> I find a custom kernel gives you some small speedups
[16:11:27] <SWPadnos> that's the kernel that I got sub-2000 numbers on after optimizing startup scripts
[16:11:30] <eric_unterhausen> HT doesn't work well anyway, unless they've fixed it
[16:11:55] <SWPadnos> eric_unterhausen, that's my impression as well, though it appears it works pretty well in the Atom
[16:12:04] <eric_unterhausen> how do you optimize startup scripts?
[16:12:17] <eric_unterhausen> just delete a batch of daemons?
[16:12:18] <SWPadnos> I get rid of everything I don't need, like X ;)
[16:12:24] <SWPadnos> yeah, more or less
[16:12:33] <eric_unterhausen> I prefer having X available
[16:12:50] <SWPadnos> I had to make runlevel 2 more like normal Unix/Linux vs. the Debian way
[16:13:05] <SWPadnos> X is still available via the network, just not on a local head
[16:13:48] <eric_unterhausen> running the latency test over the network doesn't seem to slow it down much at all
[16:14:20] <SWPadnos> actually, I would see spikes to 16000 or so when running halscope over an ssh connection
[16:14:32] <SWPadnos> vs. <2000 without the traffic
[16:14:40] <SWPadnos> (on a local text console)
[16:15:03] <eric_unterhausen> too bad there isn't an ascii art version of Axis
[16:15:16] <archivist> ew
[16:15:17] <SWPadnos> keystick
[16:15:39] <archivist> been to see http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=180348961816
[16:15:55] <pcw> I wonder if that 16 uSec is PCI bus blockage from Ethernet DMA
[16:16:13] <eric_unterhausen> probably
[16:16:37] <eric_unterhausen> archivist, if you showed me a pic of that thing, I would have guessed it was a Deckel
[16:16:37] <SWPadnos> pcw, dunno. this is the same machine that I did the custom 5i22 thing on a year or so ago
[16:16:47] <pcw> A chipset with Enet in northbridge or PCIE Enet should fix that
[16:16:54] <SWPadnos> the chipset is particularly crappy for reads - it doesn't combine reads ever
[16:17:17] <archivist> eric_unterhausen, knee handle is nearly unusable
[16:17:19] <SWPadnos> this is the Intel ICH7 (same one used for just about all atom boards)
[16:17:43] <SWPadnos> I think it has integrated ethernet
[16:18:02] <pcw> If you enable read-ahead in PLX9030, you may be able to do better
[16:18:04] <eric_unterhausen> archivist: is that a really tiny motor on the coolant pump, or is the mill larger than it looks
[16:18:22] <archivist> small coolant motor
[16:18:30] <pcw> (watch out for things with read-side effects)
[16:18:43] <SWPadnos> did that, didn't help :)
[16:19:00] <SWPadnos> the chipset docs actually say that the chipset will not do read combining
[16:19:15] <SWPadnos> write combining maybe, reads no
[16:20:13] <pcw> Well then use DMA...
[16:21:04] <pcw> 9054 has nice DMA controller
[16:21:05] <pcw> Eventually HostMot2 should support DMA
[16:21:40] <SWPadnos> yeah. I just never got to that point with that project
[16:21:49] <SWPadnos> and it works, so I'm not changing it :)
[16:22:47] <pcw> Its actually pretty easy
[16:22:49] <pcw> I think its takes about 6 setup writes
[16:22:50] <pcw> and the blam
[16:23:07] <pcw> (then blam)
[16:23:33] <pcw> maybe 2 more writes to repeat
[16:29:40] <skunkworks> blam?
[16:31:06] <SWPadnos> blam - your data is transferred at the PCI bus clock rate
[16:31:14] <SWPadnos> or something like that
[16:33:26] <skunkworks> I thought there was an issue with emc2 using dma
[16:33:39] <skunkworks> like a big re-write or something
[16:39:08] <JymmmEMC> I thought it was BAM!
[16:40:07] <archivist> caboom crash oops another milling cutter goes boing
[16:40:36] <JymmmEMC> archivist: http://codepad.org/nxouaEMz
[16:41:50] <archivist> * archivist hits JymmmEMC with a normalisation bat or a tree bat
[16:42:05] <archivist> Trees and hierarchical data in SQL: http://hashmysql.org/index.php?title=Trees_and_hierarchical_data_in_SQL & http://dev.mysql.com/tech-resources/articles/hierarchical-data.html
[16:43:22] <archivist> if I catch you exploding data from fields the next pain will be far larger
[16:43:50] <JymmmEMC> archivist: And how do you distinguish between a folder and a document?
[16:44:09] <archivist> a status flag
[16:45:34] <JymmmEMC> archivist: That's not any different from recursion
[16:47:04] <archivist> its a recursive structure .....
[16:53:14] <archivist> remember you can build strings for display with group_concat()
[17:01:55] <eric_unterhausen> I'm giving up on Cricket
[17:03:03] <JymmmEMC> eric_unterhausen: Take up female mud wrestling instead
[17:03:26] <eric_unterhausen> well, the Indian Mafia talked me into playing their fantasy league
[17:03:29] <JymmmEMC> It's a dirty job, but someone has to do it
[17:04:18] <JymmmEMC> Indian Mafia? Isn't that a contradiction in terms
[17:04:23] <eric_unterhausen> every time I pick someone to be on my team, they have a bad day
[17:04:37] <eric_unterhausen> is Russian Mafia a contradiction in terms?
[17:05:00] <JymmmEMC> No, but most Indians I know wouldn't hurt a fly
[17:05:21] <eric_unterhausen> I think the reason there was never an actual Indian mafia was that the people that would have been in it were running the place
[17:05:41] <eric_unterhausen> you don't know enough Indians
[17:06:00] <JymmmEMC> Or you are hanging out in the wrong places =)
[17:06:12] <eric_unterhausen> http://fantasy.cricinfo.com/fantasy/fantasyleague/user/league_home.html?game_id=51;league_id=71472
[17:06:20] <eric_unterhausen> check out the name of our league :)
[17:06:44] <JymmmEMC> Ah
[17:07:53] <JymmmEMC> archivist: Alright, so how do you add an element between two other ones?
[17:08:00] <eric_unterhausen> I'm TerryMcKee, which is an Americanization for tere ma ki, which is the Hindi equivalent of "your mama"
[17:08:30] <JymmmEMC> lol
[17:10:04] <archivist> JymmmEMC, define between, that of course depends on your application
[17:11:17] <JymmmEMC> I have /Apples/ and /Bannanas/ now I want to add /Apricots/
[17:11:18] <archivist> JymmmEMC, database tables have no defined order internally its up to you (except a few odd cases)
[17:11:43] <archivist> order by fruit
[17:12:08] <JymmmEMC> No, there is no fruit.
[17:12:31] <JymmmEMC> note those are at the webroot
[17:12:35] <archivist> whatever that fields name is silly
[17:13:16] <JymmmEMC> It's not alphabetical,
[17:13:57] <JymmmEMC> Take /Products/, /Services/ and now I want to add /downloads/ between those
[17:14:11] <archivist> an order field
[17:14:21] <JymmmEMC> order by what?
[17:14:41] <archivist> chuck a number in
[17:15:09] <JymmmEMC> Can't, using that transversal thing, the numbers are sequencial, unless I use a decimal
[20:22:50] <skunkworks> http://www.cnczone.com/forums/showthread.php?t=79761
[20:35:59] <roh> i just have set up http://planetcnc.hyte.de/ please comment /advise more/better feeds
[20:36:18] <roh> or propose nicer webdesign ;)
[20:37:01] <BJT-Work> wonder what he paid Roland for it...
[20:37:30] <SWPadnos> heh
[20:37:31] <skunkworks> heh - I don't know. I think I remember that being loaded.
[20:38:17] <SWPadnos> $6k is a lot to pay for a few servos/drives (maybe $1200 each axis, for new Yaskawa), a PC ($500 max), and controller software (should be free :) )
[20:38:21] <SWPadnos> oh, and a $300 VFD
[20:38:34] <SWPadnos> $6k is also a lot to pay for a used Bridgeport
[20:38:42] <cradek> I was just typing that.
[20:38:50] <cradek> series 2 is a big machine though.
[20:39:13] <SWPadnos> lots of steel, but still a manual machine with a retrofit
[20:40:44] <BJT-Work> for 8-10k you can get a cnc BP that is in good shape
[20:40:51] <BJT-Work> ready to run
[20:41:12] <SWPadnos> or a Tormach (new), which can actually cut about as well as a series 1 BP
[20:41:19] <BJT-Work> and the price is falling on machines
[20:41:42] <BJT-Work> you can get 25-30% off on a new Haas
[20:41:52] <SWPadnos> so they're down to $25k? :)
[20:41:57] <SWPadnos> or is it 35k
[20:42:12] <BJT-Work> I had an offer for a Haas that is 2 years old for 14k
[20:42:24] <SWPadnos> oh, that's "not bad"
[20:42:30] <SWPadnos> (for some values of bad)
[20:42:34] <BJT-Work> 24x 16y 16z
[20:42:41] <skunkworks> ebay and get some hmc or vmc that is in need of a new controller. <10k
[20:43:19] <BJT-Work> I'd like to find a lathe that needs a new controller...
[20:43:24] <skunkworks> that is acutally a production machine. maybe even tool changer and pallets
[20:43:25] <cradek> SWPadnos: I really doubt the tormach can cut as well as my series 1 bp
[20:43:33] <SWPadnos> series 1 manual
[20:43:42] <SWPadnos> not necessarily the CNCs
[20:43:48] <cradek> oh ok, mayyybe
[20:44:07] <SWPadnos> they're pretty rigid for their size
[20:44:36] <SWPadnos> you couldn't cut as large a piece as quickly as a BP, but for smaller workpieces, you can remove just about the same amount of metal per hout
[20:44:38] <SWPadnos> r
[20:45:14] <cradek> maybe (1.5hp vs 2hp)
[20:45:25] <SWPadnos> actually, my series 1 is 1.5 HP
[20:45:26] <cradek> don't know if they're the same ... hp
[20:45:30] <SWPadnos> and they made 1HP as well
[20:45:55] <cradek> huh, 500lb workpiece, they say
[20:46:00] <SWPadnos> most people will tell you that it's the rigidity of the machine though, even at those relatively low spindle powers
[20:46:08] <SWPadnos> I think it's 1000 for a BP
[20:46:15] <SWPadnos> if you have strong arms for the knee ;)
[20:46:50] <cradek> ok, I sit somewhat-corrected, it's more machine than I thought.
[20:47:04] <BJT-Work> Dewalt Knee Adjustment kit
[20:47:18] <SWPadnos> it's pretty surprising to see it cutting at high load
[20:47:31] <BJT-Work> this came out nice http://imagebin.ca/view/UMi_sm.html
[20:47:33] <SWPadnos> when I was there, they were testing their super-duper insert cutter
[20:47:51] <skunkworks> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160329874392&ru=http%3A%2F%2Fshop.ebay.com%3A80%2F%3F_from%3DR40%26_trksid%3Dm38%26_nkw%3D160329874392%26_fvi%3D1&_rdc=1
[20:48:00] <SWPadnos> doing 50IPM passes with 0.1" depth and 1.5" width, IIRC
[20:48:25] <skunkworks> BJT-Work: what machine is that? (mill)
[20:48:29] <skunkworks> (nice work)
[20:48:36] <BJT-Work> BP series 1
[20:48:43] <cradek> looks like a terrific finish
[20:48:50] <SWPadnos> hmmm. that must be wrong. maybe it was 0.2" depth or something. my brain is failing
[20:49:00] <BJT-Work> I had to stop in the middle and sharpen the cutter :/
[20:50:10] <archivist> ew your lucky those puny clamps dont come loose and spoil the show
[20:50:39] <BJT-Work> only took 0.025" DOC
[20:50:43] <BJT-Work> per pass
[20:51:36] <cradek> pretty sure I would have used a boring head... how round does it have to be?
[20:51:45] <cradek> or will you finish it up that way?
[20:51:52] <BJT-Work> it is finished
[20:51:57] <skunkworks> wow - this is relitivly close. http://cgi.ebay.com/1987-Matsuura-MC-510V-CNC-Machining-Center_W0QQitemZ260401650240QQcmdZViewItemQQptZBI_Mills?hash=item260401650240&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A0%7C293%3A1%7C294%3A50
[20:52:20] <BJT-Work> tractor part not that precise
[20:53:03] <BJT-Work> just a bronze bearing pressed in and the axle part you saw yesterday fits in there
[20:53:27] <cradek> ah
[20:53:42] <BJT-Work> for sure on a roller bearing I would use the boring head
[20:54:20] <BJT-Work> talk to you guys later time to put parts back on the tractor :)
[20:54:53] <archivist> we await the assembled fergy pic
[20:55:55] <BJT-Work> I'm tired of waiting LOL
[20:57:50] <BJT-Work> I should take a pic of it scattered out on the garage floor :)
[20:58:01] <archivist> kit
[20:58:15] <BJT-Work> kit with many spare parts now
[20:58:33] <archivist> thats how some clocks get delivered here...more fun
[20:58:59] <BJT-Work> talk to you guys later
[22:01:22] <ds3> what are people doing to sheild monitors from chips in the shop?
[22:03:36] <cradek> put them high
[22:04:14] <ds3> Hmm
[22:04:31] <ds3> not sure if I trust myself to rig up a monitor stand for a CRT display
[22:04:48] <cradek> heh
[22:04:51] <cradek> bbl
[22:06:32] <alex_joni> good night all
[22:13:39] <A4ndy> http://en.wikipedia.org/wiki/GTK%2B
[22:14:24] <A4ndy> i found this, this one interrest me
[22:14:47] <A4ndy> i would like to learn it more
[22:14:49] <A4ndy> :)
[22:15:15] <A4ndy> Pyton ok
[22:15:33] <A4ndy> (python pro)
[22:17:26] <A4ndy> http://library.gnome.org/devel/gtk-faq/stable/x81.html http://library.gnome.org/devel/gtk-faq/stable/
[22:18:05] <A4ndy> just info
[22:30:04] <A4ndy> thxs
[22:30:09] <A4ndy> :)
[22:37:52] <JymmmEMC> ds3: duct tape & bailing wire