#emc | Logs for 2008-09-12

[00:47:11] <jepler> my machine does something that makes me uncomfortable (pluto_step). my stepper drivers take an active-low signal as amplifier enable. between the time that the pluto_step firmware is successfully loaded and the first execution of pluto-write, the amplifier enable pins are at the startup value, which is LOW. you can easily notice the amps coming on for a second or two during startup if you listen
[00:51:50] <jepler> maybe I should change the power-on value to be HIGH, because that's the unpowered state as well due to weak pull-ups in the FPGA...
[00:53:36] <cradek> that sounds like the right fix to me
[00:53:38] <jepler> on the other hand, right now you can override the pull-up with a stronger pull-down if the safe state on your machine is low, and this would put those people in the same boat I am now
[00:55:44] <jepler> * jepler continues pondering
[01:16:49] <SWPadnos> HIGH is more normal for a disconnected pin, so it's better as a default
[01:16:59] <SWPadnos> unless it's a low inpedance current-sourcing kind of HIGH :)
[01:17:03] <SWPadnos> impedance
[01:19:56] <SWPadnos> ideally, there would be (at least) an "enable outputs" bit in a control register, and the pins would be tristated until that's tickled at least once
[01:31:02] <jepler> yeah that'd be nice but I don't have the protocol or the gates for it
[01:31:20] <jepler> (and to even try I'd have to dig out the vmware image with the altera tools installed :-P)
[01:35:03] <SWPadnos> heh
[02:28:21] <scutsxg> hi,is there anyone who are interested in small linux based emc2?
[02:28:44] <scutsxg> such as cncuser 's coolcnc
[02:31:01] <stustev> I have an interest. I would like to see it embedded and very small.
[02:31:07] <SWPadnos> me three
[02:31:16] <scutsxg> yeah
[02:31:36] <stustev> do you have it done yet? :)
[02:32:02] <scutsxg> i found cncuser website failed
[02:32:51] <ehj> Sebastian, you there?
[02:33:31] <scutsxg> i also just begin this job,and i got ubuntu8.04+emc2 in a cf cad,it is very easy,but it is too heavy for embedded system
[02:34:23] <scutsxg> so some light linux distribution maybe be better,somebody has done some job on puppy
[02:34:23] <SWPadnos> unfortunately, he just left (the devel channel)
[02:34:55] <SWPadnos> puppy was a nice demo, but I'm not sure it's good for something that you want to keep up to date
[02:35:05] <SWPadnos> if you want to install and then leave it for eternity, it may be fin
[02:35:06] <SWPadnos> e
[02:35:44] <JymmmEMC> SWPadnos: did you see that board I linked you to?
[02:35:50] <JymmmEMC> twice
[02:36:01] <SWPadnos> hmmm - no, I think I didn't look at it
[02:36:02] <scutsxg> and more worse,the early puppy linux distribution cannt be found any more.
[02:36:23] <SWPadnos> how small a flash and memory footprint are you looking for?
[02:36:44] <SWPadnos> woohoo - he's back :)
[02:36:55] <seb_kuzminsky> and buggier than ever
[02:37:01] <SWPadnos> ehj meet seb_kuzminsky, seb_kuzminsky meet ehj
[02:37:04] <scutsxg> maybe 128M ram ,and 586 cpu is also ok.
[02:37:13] <seb_kuzminsky> hi eric :-)
[02:37:19] <SWPadnos> how big a CF/flash disk?
[02:37:26] <ehj> Hi Sebastian.
[02:37:45] <seb_kuzminsky> i looked at the dmesg output you pastbinned, and it ends before hostmot2 is loaded
[02:37:50] <SWPadnos> you two may want to go to #emc-devel, if yer gonna get all technical and stuff :)
[02:38:00] <scutsxg> i think it is not a big problem,you see,the cf card is very cheap now
[02:38:03] <seb_kuzminsky> sure, sounds good
[02:38:09] <ehj> See you there.
[02:38:16] <scutsxg> ok
[02:38:23] <SWPadnos> scutsxg, I was thinking the same thing. even an 8G SSD is relatively reasonable
[02:38:37] <SWPadnos> and CF is almost free these days
[02:38:41] <scutsxg> yeah,
[02:39:08] <SWPadnos> are you thinking of a PC-type controller, or something like an ARM/PPC/something else
[02:39:21] <stustev> so embedded is a relative term - today's desktop is tomorrow's embedded system
[02:39:32] <SWPadnos> actually, the PC is nearly free these days too: http://www.newegg.com/Product/Product.aspx?Item=N82E16813135091
[02:39:37] <SWPadnos> see above ;)
[02:39:38] <scutsxg> hahah,but you also have to know how to intergrate a linux system yourself
[02:39:59] <SWPadnos> the way a lot of people use the term "embedded" is "specific-purpose"
[02:40:07] <stustev> I want < 3 second boot
[02:40:11] <SWPadnos> I pointed out to some of the guys at ESC that Google is an embedded system
[02:40:18] <SWPadnos> but it's far from small ;)
[02:40:34] <SWPadnos> database systems are also often considered embedded
[02:41:04] <SWPadnos> the big thing is that the ideal system is one that just manages to meet its performance requirements (and will continue to do so for whatever lifespan is desired)
[02:41:33] <SWPadnos> so embedded is always about fitting as much functionality as possible into as little resources as possible
[02:41:44] <stustev> also, I like discreet components rather than all-in-one boards.
[02:42:39] <stustev> I may be able to get most of what I want with the Linux bios.
[02:42:41] <SWPadnos> I'm a component stereo kind of guy, myself ;)
[02:42:59] <SWPadnos> Linux Bios is cool, but last I saw they didn't support a lot of chipsets
[02:43:08] <stustev> one thing dies - the whole system does not have to be replaced
[02:43:36] <stustev> yes - it should get better though - and one chipset is enough if it is the correct chipset
[02:43:37] <SWPadnos> Linux does that for you in many ways, since more or less all drivers get installed with every system
[02:43:49] <SWPadnos> last I knew, it was mostly server-type chipsets
[02:43:56] <SWPadnos> it's used in cluster computing a lot
[02:44:11] <stustev> I haven't looked for a while either
[02:44:34] <stustev> I do like the idea of serving the image remotely
[02:44:48] <scutsxg> where can find cncuser,his website also down
[02:44:53] <SWPadnos> dunno
[02:45:09] <SWPadnos> I think the european mirror has the puppy ISO on it
[02:45:33] <scutsxg> ok,could you give me a website?
[02:45:38] <SWPadnos> uh -one sec
[02:46:26] <scutsxg> i search all the puppy site,it seems that they dont support early puppy distribution
[02:46:31] <SWPadnos> http://dsplabs.utt.ro/%7Ejuve/emc/
[02:46:35] <SWPadnos> http://dsplabs.utt.ro/%7Ejuve/emc/get.php?file=coolcncb05.iso
[02:46:50] <SWPadnos> I should stick that on linuxcnc.org
[02:47:05] <scutsxg> oh,thanks
[02:50:04] <SWPadnos> I'm just going to make sure it's "backed up" - you can download it from dsplabs.ro right now
[02:50:14] <SWPadnos> err - dsplabs.utt.ro
[03:15:49] <jmkasunich> OT: http://jmkasunich.com/pics/heron-takeoff-2622.jpg
[03:16:14] <SWPadnos> cool
[03:16:19] <seb_kuzminsky> nice :-)
[03:16:35] <seb_kuzminsky> i have a friend who named his son heron, i think it's a pretty cool name
[03:17:17] <jmkasunich> I have some other heron pics in that directory, but this one was taken this evening
[03:17:50] <jmkasunich> went sailing with a friend - the heron was hanging out along the river that we take from dock to lake
[06:23:28] <lonnieh> anyone in here have a few minutes of emc2 expertise to lend?
[06:31:26] <micges> Ionnieh: what's the problem?
[06:37:32] <lonnieh> when I'm jogging my steppers, the movement is very inconsistent
[06:40:09] <lonnieh> I can't seem to figure out the timings to get everything running smooth
[06:44:21] <micges> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Stepper_Drive_Timing
[06:45:10] <micges> you have board or use software step generators ?
[06:45:47] <lonnieh> all software
[06:47:22] <micges> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?TweakingSoftwareStepGeneration
[06:48:11] <micges> look at those two pages and if you didn't find any help you must wait for others to wake up to help you
[06:48:51] <lonnieh> I think I have exhausted those pages :-( . Thank you for the help, I'll hang around for a while
[06:49:09] <micges> and this too ?? http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Stepper_Formulas
[06:49:39] <lonnieh> not yet, I'll give that a read
[07:46:05] <alex_joni> lonnieh: can you rule out an electrical problem?
[07:46:10] <alex_joni> motors/drivers?
[07:48:05] <lonnieh> well
[07:49:54] <lonnieh> yeah, I think that the wiring is OK, not 100% sure about the driver but I get the same results from all 3 axises
[10:22:21] <archivist_ub> logger_emc, bookmark
[10:22:21] <archivist_ub> Just this once .. here's the log: http://www.linuxcnc.org/irc/irc.freenode.net:6667/emc/2008-09-12.txt
[12:16:03] <skunkworks> I think the news was supriesed when the weather service used "face certain death," in warnings of ike.
[12:18:07] <archivist_ub> http://news.bbc.co.uk/1/hi/world/americas/default.stm seems UK hasnt suppressed it
[12:20:00] <skunkworks> I think most americans need the 'shock' of it to get thier a$$'s moving.
[12:23:50] <skunkworks> SWPLinux: I bought 4 of those http://www.newegg.com/Product/Product.aspx?Item=N82E16813135091 for work. these will fill some empty cases we have.
[12:24:24] <skunkworks> I just hope ecs has solved thier exploding capasitor issues ;)
[12:28:01] <jepler> yeah, they solved it by dumping boards with the bad caps at a real good price :-P
[12:28:08] <skunkworks> heh :)
[12:28:09] <jepler> well, time to get going to the office..
[12:28:14] <skunkworks> drive safe
[12:28:34] <jepler> see you later
[12:31:25] <archivist_emc> * archivist_emc pokes the doc keepers, http://www.linuxcnc.org/docview/html//gcode_main.html#sub:G17,-G18,-G19: empty section links
[12:41:43] <pjm_> afternoon
[12:42:59] <archivist_ub> got a nice ballscrew yesterday, new with its test cert
[12:43:20] <pjm_> ohh nice ;-)
[12:43:53] <pjm_> i made a scalar feed on my mill last night: http://pjm.dyndns.org/feed1.jpg its for 8.4GHz
[12:44:14] <pjm_> each of the rings is 0.5mm in width
[12:45:29] <archivist_ub> epay item number 200248881852
[12:45:58] <archivist_ub> trying to knibble dinner and a customer has turned up!!!
[12:46:27] <pjm_> yeah that is a nice leadscrew!
[12:46:42] <archivist_ub> heh cnc make the microwave easier
[12:46:52] <pjm_> certainly does
[12:47:34] <archivist_ub> I must make another 10ghz discone
[12:47:44] <archivist_ub> bbl
[13:23:48] <Jymm> pwd
[13:47:15] <jepler> pjm_: neat
[13:48:33] <jepler> pjm_: I'm not familiar with a "scalar feed"; is the distance from one ring to the next related to the wavelength?
[13:49:27] <pjm_> jepler yep thats it, i scaled common Ku and C band 'chaparral feeds' and made an excel spreadsheet to calculate them for other frequencies
[13:49:53] <alex_joni> http://www.quinstar.com/antenna_scalar_horn_33ghz.html
[13:50:23] <pjm_> the EMC2 is really excellent with the on-screen rendering of the gcode, its great to be able to see what the program will do
[13:50:24] <pjm_> ah i have a question,,, this might be silly but
[13:51:06] <pjm_> last night when i was machining that feed, i dropped a file on the floor and as i went to pick it up my head hit the estop button which is at waist height
[13:51:14] <pjm_> i didnt know if it was possible to resume the program
[13:51:21] <pjm_> so i started it again from the start
[13:51:26] <pjm_> beginning i mean
[13:51:39] <pjm_> so is there a simple way to resume after an estop?
[13:51:47] <alex_joni> you should at least be able to set the enxt run line
[13:51:54] <alex_joni> it's in the menu..
[13:52:00] <pjm_> ahh
[13:52:07] <pjm_> ok i need to rtfm again
[13:52:07] <alex_joni> select the line where you want to start from, select run from line from the menu
[13:52:08] <jepler> pjm_: there is "run from line", but it has a fair number of gotchas
[13:52:11] <fenn> probably the most practical way is to edit the g-code
[13:52:19] <alex_joni> then when you start the program it will run that line
[13:52:23] <jepler> for instance, the spindle won't actually start turning if you skip over the M3 line
[13:52:35] <alex_joni> best thing is to position yourself at the end of the previous move
[13:52:49] <alex_joni> and check spindle, mist, lube, whatnot
[13:52:59] <pjm_> yeah i thought about editing the program, but i was concerned about the offsets in the circles etc, since cam-bam seems to generate 4 arcs per circle
[13:53:11] <pjm_> but yep i'll try editing the program next time
[13:53:15] <pjm_> thanks ;-)
[13:53:17] <jepler> restarting on an arc has its own set of gotchas
[13:53:38] <pjm_> yeah this is what i thought... and not being a gcode expert it was simpler to just redo from start
[13:53:38] <fenn> might want to move the estop button
[13:53:47] <pjm_> yes that is on my list ;-)
[13:53:56] <alex_joni> or the head
[13:54:06] <pjm_> although i put it there so if i'm getting mangled by the spindle i can 'knee' the button
[13:54:39] <alex_joni> you need a scream-activated-estop
[13:54:58] <fenn> sphincter activated
[13:55:06] <pjm_> hehh
[13:55:07] <fenn> wireless of course
[13:55:10] <pjm_> of course
[13:55:12] <jepler> hah I saw this and thought "dalek!"
[13:55:24] <jepler> fenn: unfortunately, microsoft holds a patent on that..
[13:56:21] <skunkworks> 'exterminaaaaiite'
[13:56:50] <pjm_> alex_joni that feed for 33GHz is pretty neat. I have to build a similar one for 25GHz for my 'lunar recon orbiter' receive project
[13:58:10] <fenn> that looks like an advanced machining project..
[13:58:18] <pjm_> yeah its pretty neat..
[13:58:55] <pjm_> i'm well pleased with the 8.4GHz feed i made... the previous one was made with bits of copper 1mm flat bar bent into circles and soldered down to a backplate
[13:59:10] <pjm_> but one milled out of solid is a lot nicer
[13:59:33] <fenn> how precise do these have to be?
[14:01:25] <stuste1> Jepler: two comments - the restart has an 'unfair' amount of gotchas - and - no one in his right mind will try to restart in the middle of an arc - :)
[14:03:10] <alex_joni> stuste1: oh, you haven't met them all yet
[14:03:23] <stuste1> if you are using tool diameter compensation the restart is much more complicated also - the restart is a special case and extra steps to restart are warranted
[14:04:01] <stuste1> alex_joni: probably not
[14:04:19] <pjm_> fenn the positions of the scalar rings have to be within something like 0.1 wavelength
[14:04:25] <pjm_> fenn so fairly precise
[14:12:45] <BigJohnT> stuste 1 some people are in their left mind
[14:16:13] <archivist_ub> stuste1, or restart and rotate A axis :)
[14:16:53] <archivist_ub> up till today I have not needed arcs
[14:17:24] <archivist_ub> BigJohnT, , http://www.linuxcnc.org/docview/html//gcode_main.html#sub:G17,-G18,-G19: empty section links
[14:19:36] <archivist_ub> pjm_, 25ghz I can generate that but not measure :((
[14:21:38] <BigJohnT> thanks archivist_ub
[14:22:21] <archivist_ub> BigJohnT, trying to learn arcs today, so might find a few other comments
[14:23:08] <BigJohnT> ok that seems to be something to do with the building of the html's the links work but don't have the numbers in the brackets
[16:33:25] <SWPadnos> heh - here's a great quote "He told the paper he could walk or kayak out if necessary. "It's just water, man.''"
[16:33:42] <SWPadnos> from a guy who plans to stay in Galveston during hurricane Ike :)
[16:35:29] <skunkworks> sounds like they are going to get hammered
[16:36:23] <SWPadnos> yep. my sister said that the water was already over the seawall this morning
[16:36:44] <SWPadnos> luckily, she was in the car, on her way to Austin
[16:37:13] <skunkworks> That is good :)
[16:37:43] <SWPadnos> yes :)
[16:37:58] <SWPadnos> I wonder if her house will survive
[16:39:54] <skunkworks> yeck - where abouts is it?
[16:40:49] <SWPadnos> a few blocks from the water. near the corner of Ball and 12th (street I think)
[16:42:47] <skunkworks> yikes
[16:43:53] <SWPadnos> yep
[17:58:36] <issy> to sym umoren i sled malko si lqgam
[18:50:22] <Dmess> hi all
[18:51:01] <micges> hi
[19:22:53] <skunkworks> http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=66052
[19:23:12] <skunkworks> http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=66051
[19:23:13] <alex_joni> IT'S A LIE
[19:23:50] <skunkworks> I am sure it is ;)
[19:25:13] <jepler> I'm sure it's every yuan it costs to produce
[19:26:30] <SWPadnos> http://www.siegind.com/CNC_MACHINE/KX1_MACH.html
[19:26:45] <SWPadnos> heh - they'll even provide a PCMCIA parallel port card if you don't have one
[19:27:31] <SWPadnos> that machine weighs about the same amount as my rotary table
[19:28:29] <dushantch> what is a direct drive stepper listed there? I'm not into steppers :)
[19:29:00] <jepler> dushantch: it means there is no gearing or pulley between the stepper and the leadscrew
[19:29:01] <dushantch> and what's a hybrid stepper?
[19:29:43] <dushantch> jepler: thanks
[19:29:44] <jepler> I'm not sure what "hybrid" means in that sense
[19:30:33] <dushantch> jepler: probably same as those "multimedia" PC cases :) just adding words for nothing :)
[19:30:35] <jepler> "Modern steppers are of hybrid design, having both permanent magnets and soft iron cores." -- wikipedia
[19:30:57] <jepler> so in this case it just means they're the common type used today, not some older worse type
[19:32:02] <dushantch> pffft, like saying some modern AC motors are of hybrid design, having both copper wires and soft iron core :)
[19:33:35] <dushantch> btw don't laugh at chinas CNC's just look at all the plastic you bought, those tools make them by milions :)
[19:33:49] <dushantch> and those cnc's make those tools :)
[19:34:06] <jepler> heh
[19:35:27] <dushantch> my friend tried once to buy some china CNC's but they sell on minimum of 10 units directly from factory :)
[19:36:28] <jepler> sounds like he only needs you and 8 other friends for that to work out nicely
[19:38:00] <dushantch> well 10 same lathes :), but he got some nice guaranteed planparallelism machine vices i think 120mm's for 200eu
[19:38:50] <dushantch> he said that plane transport and import taxes costed as much as vice :)
[19:48:32] <skunkworks> http://www.cnczone.com/forums/showthread.php?t=64357
[21:06:39] <alex_joni> good night all
[21:08:20] <pjm_> gn
[21:15:45] <archivist_ub> heh that kx1 is £2195.00 over here
[22:03:38] <Roguish> hey all. is anyone using a CNC4PC pendant? if so, what's the opinion? good, bad, or ho hum?
[22:10:36] <jepler> Roguish: I think that is the one that Jon Elson had at CNC Workshop. It seemed solid and heavy, but I don't have any experience with real commercial pendants so take that with a grain of salt.
[22:11:31] <Roguish> thanks. i am going to replace a Flashcut setup and need a pendant. it's a big gantry style machine. about 30' x 15' x 8'
[22:11:58] <Roguish> and i don't want to make something that i can purchase for less.
[22:12:35] <Roguish> what's Elson's irc nick?
[22:13:15] <jepler> he isn't here very often .. when he is, he's jelson or elson, I think
[22:15:09] <Roguish> ok, thanks. i'll ask via email list.
[22:16:44] <SWPadnos> I think BigJohnT or someone like him got a pendant and created a config for it
[22:17:57] <SWPadnos> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Hooking_Up_A_MPG_Pendant
[22:18:27] <Roguish> yeah, already been there.
[23:29:47] <dareposte> Anybody know how long a spindle pulse EMC2 needs for syncing?
[23:30:19] <dareposte> threading on a lathe is the intended purpose, and constant surface speed machining if that's possible
[23:30:23] <SWPadnos> it depends on your BASE_PERIOD and latency
[23:30:55] <SWPadnos> to be sure the transition is seen, the pulse duration should be BASE_PERIOD + 2*max_latency (I think)
[23:31:04] <SWPadnos> maybe only 1*max_latency
[23:31:53] <SWPadnos> you need to decide how accurate you want the spindle orientation to be, because your spindle speed will be limited by that as well
[23:32:46] <SWPadnos> so fir example, if you want the orientation to be accurate to 1 degree, then the spindle can't be turning faster than 1 degree per (BASE_PERIOD+max_latency)
[23:33:32] <dareposte> hmm
[23:33:35] <SWPadnos> if your BASE_PERIOD is 25000 and max_latency 10000, then 1 degree / 35 us is the highest spindle speed you can use
[23:34:14] <dareposte> that makes sense, but i hadn't thought of it
[23:34:17] <dareposte> not that way
[23:34:45] <dareposte> my circuit has a rise time of about 35us
[23:34:51] <SWPadnos> that's probably an upper limit too
[23:35:11] <dareposte> but that should be constant for each cycle, so it may not matter
[23:35:22] <dareposte> or maybe wouldn't affect accuracy as much
[23:35:31] <SWPadnos> what should be constant, and what cycle are you talking about?
[23:35:42] <SWPadnos> are you talking about revolutions of the spindle?
[23:36:13] <SWPadnos> I haven't mentioned slot size either :)
[23:36:45] <SWPadnos> of course, if you want the index accuracy to be 1 degree, then you can't have a slot any larger than 1 degree
[23:37:13] <SWPadnos> actually, I guess it's a minimum - if you have a very fast base_period and very low latency, you can have a slot as big as you want
[23:37:37] <dareposte> it shouldn't matter what size slot you have as long as it triggers at the same point each time
[23:37:38] <SWPadnos> but you need a slot big enough to be seen in one base period+latency
[23:38:11] <SWPadnos> there's no such thing as "the same point" - there will always be some variation, which is what the max_latency figure is
[23:38:25] <dareposte> for sampling by emc2
[23:38:31] <dareposte> yeah i understand that
[23:39:06] <dareposte> but as long as the signal gets to emc2 at the same point in spindle rotation, then it would be governed by max_latency right
[23:39:14] <SWPadnos> that's why I thought of the timing aspects first I guess
[23:39:23] <SWPadnos> and base_period
[23:39:35] <dareposte> if the circuit has a consistent rise time of .010 seconds then it really wouldn't matter as long as it was consistent
[23:39:38] <SWPadnos> it could have changed just barely after the last sample was taken, or just before this one
[23:40:00] <dareposte> yeah i see what you mean
[23:40:15] <dareposte> i'm trying to run latency-test now but it's giving me an error and wanting to see a library
[23:40:27] <SWPadnos> which latency test?
[23:40:36] <SWPadnos> the HAL one that pops up a window?
[23:40:47] <dareposte> scripts/latency-test
[23:40:50] <SWPadnos> ok
[23:41:05] <SWPadnos> is this a compiled version of EMC2?
[23:41:09] <SWPadnos> or installed
[23:41:09] <dareposte> i probably forgot to load that variable list like you told me to before :)
[23:41:14] <SWPadnos> heh
[23:41:20] <SWPadnos> emc-environment is your friend ;)
[23:41:28] <dareposte> yep that did it
[23:41:51] <dareposte> base thread 10,752ns
[23:42:04] <dareposte> for max jitter
[23:42:04] <SWPadnos> latency, that is
[23:42:06] <SWPadnos> ok
[23:42:27] <dareposte> max interval 35000 ns
[23:42:59] <SWPadnos> yep - it's set for 25000, so 35000 is around the max jitter plus the requested period
[23:43:26] <SWPadnos> well, set for something close to 25000 anyway
[23:43:54] <dareposte> so to get 1 degree of accuracy (assuming constant rotation speed) then i can't have the spindle going any faster than 1 degree per 35u
[23:43:56] <dareposte> us
[23:44:12] <SWPadnos> if you set your BASE_PERIOD to 25000, yes
[23:44:37] <SWPadnos> I think stepconf chooses a number that's on the large end of the range, to reduce CPU load
[23:44:44] <dareposte> i see
[23:44:50] <dareposte> i can check my config hang on
[23:44:53] <SWPadnos> when you pick the resolutions and speeds for the axes, it calculates the BASE_PERIOD you need
[23:44:56] <SWPadnos> ok
[23:45:56] <dareposte> 35500 is what it says the "minimum base period" is
[23:46:34] <dareposte> thats what I guess it set it as, but there's nowhere to modify it. I just type in the max jitter and it sets that up
[23:46:35] <SWPadnos> ok, so you'll have 35000+10752, which is very close to 46000
[23:46:41] <SWPadnos> right
[23:47:00] <dareposte> so 1 degree per 45us
[23:47:04] <dareposte> 46us
[23:47:10] <SWPadnos> you can change it later, but you have to edit the ini file and any of those edits will be lost if you re-run stepconf
[23:47:13] <SWPadnos> yes
[23:47:39] <dareposte> so that's about 60 rpm
[23:47:41] <SWPadnos> so you get about 23 degrees/sec
[23:47:47] <SWPadnos> no
[23:47:55] <SWPadnos> err - 23000 maybe ;)
[23:48:21] <dareposte> so if i do any threading then i'll need to slow 'er down
[23:48:35] <SWPadnos> that's 60 RPS, not 60 RPM
[23:48:37] <SWPadnos> 3600 RPM
[23:48:40] <dareposte> oh yeah
[23:48:44] <dareposte> damn thats fast for threading
[23:48:47] <SWPadnos> heh
[23:48:53] <dareposte> my machine tops out at 1818 rpm
[23:49:03] <dareposte> (as i just found with my newly constructed beer-can-interrupter-circuit)
[23:49:12] <SWPadnos> in that case, you'll have better than 1 degree accuracy in detecting the index pulse ;)
[23:49:19] <dareposte> so i can thread at full speed!
[23:49:20] <SWPadnos> closer to 0.5 degree
[23:49:38] <SWPadnos> EMC can thread at full speed, but who knows about the axis drives or the spindle ;)
[23:49:46] <dareposte> i wonder how acceleration works then
[23:49:53] <dareposte> rather deceleration
[23:50:02] <SWPadnos> of the spindle or the axes?
[23:50:07] <dareposte> the z axis
[23:50:27] <dareposte> to cut a 1mm pitch thread at 1818rpm it would have to be movin pretty good
[23:51:10] <dareposte> i guess about 30mm/sec
[23:51:15] <SWPadnos> well, you'll just have to experiment to see what the bottleneck is
[23:51:24] <dareposte> yeah
[23:51:35] <SWPadnos> 1mm pitch at 30mm/sec limits you to 30 RPM, which may be a bit slow to regulate
[23:52:18] <dareposte> how do you figure it limits?
[23:52:29] <SWPadnos> ?
[23:52:51] <SWPadnos> you mean if you try to thread faster than Z can move?
[23:53:03] <dareposte> 30mm/sec at 1mm pitch should limit it to 30 rps right?
[23:53:06] <dareposte> not 30 rpm
[23:53:11] <dareposte> or 1800 rpm
[23:53:15] <SWPadnos> oh, mm/sec - no problem :)
[23:53:27] <SWPadnos> that darned min/sec thing again
[23:53:58] <dareposte> i puzzled over my oscope for about 15 minutes trying to figure out why it was telling me my lathe was only moving 30rpm when it was supposedly at 1800rpm
[23:54:11] <SWPadnos> heh
[23:54:26] <dareposte> checked every time setting, recalibrated it, set the trigger over and over
[23:54:48] <dareposte> finally figured out that a second is not the same as a minute, and then it all made a lot more sense
[23:55:23] <dareposte> :)
[23:55:55] <dareposte> well i got another question for you... can emc2 do constant surface speed machining with only an index pulse?
[23:56:09] <dareposte> or is that something i'll have to look at adding
[23:56:22] <dareposte> (attempting to add)