#emc | Logs for 2007-06-30

[01:16:16] <jmkasunich_> jmkasunich_ is now known as jmkasunich
[03:06:34] <Skullworks-PGAB> Cradek - that homing method - is simular to the process used currently (on FANUC) to reset the homing soft limits when the backup battery goes dead.
[03:06:49] <cradek> interesting to know
[03:07:12] <cradek> it seems there are also some machines where this process is done at every startup
[03:12:18] <Skullworks-PGAB> so on initial program power up in EMC you manually "home" - then all future G28 or G30 moves are rapids to the point defined in the INI file in the homing parameters?
[03:12:41] <Skullworks-PGAB> but not re-reading the index channel
[03:13:41] <cradek> g28/g30 go to particular machine coordinates - these are defined by gcode variables
[03:13:49] <cradek> g28 and g30 have nothing to do with homing the machine
[03:17:23] <Skullworks-PGAB> last question for awhile - is there a variable in the interpreter to extact the axis positon?
[03:17:55] <cradek> ummmmm
[03:18:10] <cradek> something like #1 = [current position in world coordinates]?
[03:18:16] <Skullworks-PGAB> yep
[03:18:17] <cradek> X position
[03:18:38] <cradek> I think the only time you can do that is right after a probe G38.2
[03:19:52] <cradek> g0x0y0 / x1 / #1=[x position] / y1 / m2
[03:19:54] <cradek> imagine this program
[03:20:09] <cradek> what would you expect to see in #1?
[03:20:37] <cradek> I can imagine several numbers...
[03:20:51] <Skullworks-PGAB> I use it in FANUC macros to store the starting position before doing a multi move sub and have the machine reutrn to the exact starting point befor exiting the sub.
[03:20:52] <cradek> the big problem is that the interpreter reads ahead so it can get the moves queued up
[03:21:37] <cradek> yeah for some macros I suspect you would need a lot of kinds of introspection that we don't have
[03:21:39] <Skullworks-PGAB> maybe interp is not the right place
[03:22:31] <cradek> well it all depends on what the goals are
[03:22:59] <Skullworks-PGAB> think as if it were running in single block
[03:23:42] <Skullworks-PGAB> at a certain point we record position before moving to the next command
[03:24:01] <toastydeath> macros a+
[03:24:15] <Skullworks-PGAB> it would only be valid while machine is stationary
[03:24:18] <cradek> well you avoided my trick question :-)
[03:24:58] <Skullworks-PGAB> simple divide by zero and take the sqr root
[03:25:06] <jmkasunich> ;-)
[03:25:30] <cradek> for macros that go away from the part and do a machine-specific (not part-specific) thing, I think the whole interpreter state should be saved and restored - the programmer shouldn't have to worry about it
[03:25:51] <cradek> heck you might want to switch units, or go to relative mode, or who knows what
[03:26:22] <cradek> divide by zero, negate it, THEN take the sqrt
[03:26:54] <Skullworks-PGAB> I was thinking like a #5xxx like where the G54-G59.3 tables are stored - but in a range that is not saved to disk.
[03:28:09] <Skullworks-PGAB> answer FANUC 0i control - moving to irrational coordinates as programmed.
[03:28:16] <cradek> that's the problem - any "current location" has many coordinates - there are 2 or 10 coordinate systems that it's in, depending how you count
[03:30:16] <Skullworks-PGAB> so make 2 sets of variables - one based on G53 the other base on the current work offset in effect (perhaps as modified by a G92 series command).
[03:30:28] <jmkasunich> that way lies madness
[03:30:40] <cradek> ok, 3 or 19? coordinate systems, depending on how you count
[03:30:53] <cradek> see, I can't even count them
[03:31:05] <cradek> I forgot about g92
[03:31:16] <cradek> now add tool length, maybe you can get to 40 systems
[03:32:03] <cradek> and cutter comp (nominal or actual position?)
[03:32:43] <cradek> I'm being a little silly, but it probably means this is a wrong approach
[03:32:48] <Skullworks-PGAB> no - this would not include tool lenth just position as commanded X/Y/Z/A/B
[03:32:48] <cradek> (what problem are we trying to solve again?)
[03:33:00] <Skullworks-PGAB> not solve
[03:33:34] <Skullworks-PGAB> was just wondering if the data was accessable from within a macro
[03:34:20] <Skullworks-PGAB> I'm trying to update/make a custom Post processor that is optimised for EMC2
[03:35:05] <cradek> right, but I'm asking what machining operation you are doing where you think this would be helpful to have
[03:35:18] <cradek> machining or machine operation
[03:36:03] <Skullworks-PGAB> like a rectangular pocket milling cycle - with the pocket at an angle
[03:37:01] <toastydeath> techincally there are only 3 work coordinate systems
[03:37:30] <toastydeath> most controls adhere to that "environment"
[03:37:37] <Skullworks-PGAB> lots of calc in the macro (incramental moves) - but when its finished it would return to the reference starting point
[03:37:46] <toastydeath> then you just get stuff that modifies the work coordinate, like tool length offset
[03:39:01] <toastydeath> but since that's still something that the control needs to do, i'm not sure if emc jumps on the bandwagon and treats it that way, but it's kind of irrelevent
[03:39:10] <Skullworks-PGAB> * Skullworks-PGAB is plotting to wrap Toasty in 1000 meters of old mylar punched tape...
[03:39:25] <cradek> why not pass the coordinates where you want the pocket into the pocket subroutine?
[03:40:09] <cradek> and why return to the old location - what you want instead is to go to a safe height, then over to the next pocket you want to cut
[03:40:21] <toastydeath> not really
[03:40:31] <toastydeath> g-code is meant to be flexible, not to babysit you
[03:40:43] <toastydeath> macros especially so
[03:41:04] <toastydeath> which is why you can read and write to just about every part of the control when you make macros on commercial controls
[03:41:30] <toastydeath> to do any possible task that could ever come up, no matter what the control programmers envision or think is proper
[03:41:51] <toastydeath> you might want to finish detais in a pocket, for instance
[03:42:06] <toastydeath> where the macro only roughs a pocket out but leaves it devoid of certain features
[03:42:17] <Skullworks-PGAB> (finish options are a sub within the sub)
[03:43:37] <Skullworks-PGAB> most of my macros are FANUC style or Okuma (bastard Fortran/Pascal type format)
[03:45:30] <Skullworks-PGAB> but I'm trying to find what is"port_able" to EMC vrs what will require a whole new approach - vrs what should just be left up to the bulk CAM output.
[03:46:58] <toastydeath> yeah
[03:47:08] <toastydeath> i am a firm believer that you should have access to everything
[03:49:35] <danielbr> hello guys, i'm trying add gif buttons in the pyvcp http://pastebin.ca/596682 and http://imagebin.org/9143 but something(or all?) is wrong
[03:54:33] <CIA-8> 03cradek 07TRUNK * 10emc2/docs/src/config/ini_homing.lyx: new homing method: only search for index
[03:56:41] <danielbr> also, i think will be good if we can add labels in a pyvcp as a gif image
[04:00:43] <danielbr> if tomp, jepler or awallin can add this feature i think this will be great
[04:00:51] <danielbr> gn
[04:01:07] <Skullworks-PGAB> sounds like a ? for Jeff or Chris ( I don't know snake talk - Python )
[04:09:08] <Skullworks-PGAB> cradek: I just thought of something
[04:10:02] <Skullworks-PGAB> that homing method for use on a lathe would allow a moveable pointer to be clamped on the bed ways
[04:10:40] <Skullworks-PGAB> allows for different homing when using the tailstock
[04:49:02] <maddash> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Trapezoidal_Velocity_Profile_Trajectory_Planner <--- is that page of the wiki still accurate?
[05:30:56] <ohiopctechDOTcom> ohiopctechDOTcom is now known as chr0n1c
[06:41:54] <toastydeath> hey guys, do you think one could use HAL, and a set of encoders
[06:42:12] <toastydeath> to turn speakers and amplifiers into a closed loop audio servo
[06:52:48] <robin_sz> toastydeath, no.
[06:52:56] <toastydeath> why not?
[06:53:45] <robin_sz> bandwidth of the feedback loop
[06:53:54] <toastydeath> good point
[06:54:08] <toastydeath> even for an analog encoder?
[06:54:09] <robin_sz> and its utterly pointless in the first place anyway ;)
[06:54:20] <robin_sz> no, not the encoder ...
[06:54:38] <robin_sz> the rate at which EMC performs PID calcs
[06:54:43] <toastydeath> so there's no close loop stuff that will do 20-30 khz
[06:55:02] <robin_sz> analogue closed loop stuff probably
[06:55:10] <toastydeath> hmm
[06:55:33] <SWPadnos> or a DSP or FPGA
[06:55:38] <SWPadnos> good night! :)
[06:55:40] <toastydeath> nighty
[06:55:54] <robin_sz> to be sure, you need to have about 10 * the rate on the PID than the thing you are trying to control
[06:56:01] <toastydeath> well this isn't a machine tool
[06:56:13] <toastydeath> but i do see your point
[06:56:14] <robin_sz> so a PID loop with say, 200khz bandwidth would be a good start
[06:56:31] <toastydeath> hmm
[06:56:38] <toastydeath> that is up there
[06:56:38] <robin_sz> otherwise, you are going to have too much fun with the poles and zeroes
[06:56:59] <toastydeath> why?
[06:57:07] <robin_sz> why what?
[06:57:12] <toastydeath> with zeroes and poles
[06:57:22] <robin_sz> basic control theory
[06:57:23] <toastydeath> zero on the sine wave is zero on the speaker
[06:57:38] <toastydeath> could you detail that for me
[07:00:01] <toastydeath> maybe i will just look this stuff up =)
[07:00:06] <toastydeath> ty sir
[07:00:11] <robin_sz> mmm
[07:00:39] <robin_sz> you familiar with Laplace transforms?
[07:00:50] <toastydeath> no
[07:00:56] <robin_sz> hmm,
[07:00:57] <robin_sz> ok,
[07:01:03] <robin_sz> simple version then :)
[07:01:07] <toastydeath> yeah, that's all i'm asking for
[07:01:19] <toastydeath> i can do the harder reasearch on my own, i'd like the overview though
[07:01:44] <robin_sz> ok, imagine this high bandwidth control:
[07:02:10] <robin_sz> a lead weight on a brass rod
[07:02:21] <robin_sz> you want to control the position of the lead weight
[07:02:35] <robin_sz> you have some sort of servo trying to move the brass rod
[07:03:15] <robin_sz> the bandwidth of the loop is high ... any movement of the servo is coupled efficiently to the lead weight
[07:03:17] <robin_sz> OK?
[07:03:23] <toastydeath> with you.
[07:03:27] <robin_sz> right ...
[07:03:39] <robin_sz> no ... lets replace that with a low banwidth coupling ...
[07:03:43] <robin_sz> a spring
[07:04:31] <robin_sz> lead weight out of position ... servo moves a lot ... spring/mass combo has low bandwidth ....
[07:04:35] <toastydeath> so any movement has a signifigant delay factor.
[07:04:41] <robin_sz> result ... instability
[07:04:43] <toastydeath> right
[07:04:50] <robin_sz> so .. in the control loop ...
[07:06:05] <robin_sz> the lack of bandwidth leads to instablity ... basically, you ended up with a phase shift as the badwidth tailed off
[07:06:18] <robin_sz> but had more than enough gain in the system to get it to oscillate
[07:06:39] <ds2> how does a laplace transform relate to this?
[07:06:52] <robin_sz> think about poles and zeros ... and how you plot them
[07:07:19] <ds2> I just know the hard way - hours and hours of algebra :(
[07:07:30] <toastydeath> i guess my question sort of is this
[07:07:33] <toastydeath> the driver, and the amp
[07:07:35] <robin_sz> although it is some time since I did this
[07:07:37] <toastydeath> are very high bandwidth
[07:07:40] <robin_sz> yes
[07:08:03] <toastydeath> you are saying the control itself will make it act more in tune with low bandwith shenananigans
[07:08:58] <robin_sz> unless you can come up with a control loop that has no significant pahse shift in the range that you are trying to control then you will have trouble
[07:09:09] <toastydeath> hmm
[07:09:22] <toastydeath> that's no good.
[07:09:27] <robin_sz> if the feedback loop has a significant phase shift whilst the system still has gain .. then it will oscillate
[07:10:33] <toastydeath> and finding something that high bandwidth is going to be trouble
[07:10:42] <robin_sz> and pointless
[07:10:47] <toastydeath> i don't quite see the pointless part
[07:10:55] <ds2> sounds like an op amp
[07:11:15] <robin_sz> ds2, exactly, an analogue solution would be best
[07:11:59] <toastydeath> hmm
[07:12:14] <toastydeath> so if i hooked up the audio input to one side, the encoder to the other
[07:12:24] <toastydeath> that would be sufficient to drive the amplifier accurately?
[07:12:27] <robin_sz> for encoder, try "microphone"
[07:12:39] <toastydeath> no, i'm talking about linear movement matching the electronic input
[07:12:47] <toastydeath> scaled by some factor for volume control
[07:13:04] <robin_sz> this is for some other application than audio right?
[07:13:07] <toastydeath> nope
[07:13:23] <robin_sz> linear movement of what ?
[07:13:26] <ds2> is this some sort of piezo positioning ?
[07:13:28] <toastydeath> the motor
[07:13:37] <robin_sz> "the motor" ?
[07:13:38] <toastydeath> nope, regular speakers
[07:13:50] <toastydeath> the linear motors in the speakers
[07:14:26] <robin_sz> and that will achieve what exactly?
[07:14:28] <ds2> sounds like something best simulated in matlab for stability
[07:14:38] <toastydeath> eliminating error in the driver and amplifier
[07:14:53] <toastydeath> removing "color" from those items
[07:15:00] <robin_sz> if you think it will give you anything like a flat frequency response, you are several shades of crazy
[07:15:28] <toastydeath> i am more interested to see what would happen rather than actually doing it
[07:15:34] <robin_sz> wait, do you want to buy some gold plated mains plugs?
[07:15:44] <toastydeath> uh, no?
[07:15:48] <robin_sz> hmm
[07:16:03] <robin_sz> some 8 ohm transmission line for speaker cable?
[07:16:20] <toastydeath> shouldn't you throw your homebuilt machine tools away and buy REAL equipment?
[07:16:32] <toastydeath> can we stop insulting each other now?
[07:16:45] <toastydeath> i don't actually care about sound quality.
[07:17:04] <toastydeath> i certainly wouldn't use it, even if it worked
[07:17:20] <robin_sz> well, lets waste no more time on it then
[07:17:28] <toastydeath> uh, right
[07:17:48] <toastydeath> thanks for being an ass, i guess
[07:18:00] <robin_sz> fwiw, the linear motor introduces almost no distortion into the speaker, its the cone and box that do most of that
[07:18:28] <toastydeath> the motor is what you use to fix i t
[07:18:30] <toastydeath> it
[07:18:43] <toastydeath> just like the ways and kinematic design of a mill affect the accuracy
[07:18:52] <toastydeath> the servo is what you use to fix that
[07:19:22] <robin_sz> it is?
[07:19:27] <toastydeath> yes
[07:19:35] <toastydeath> that's why we have equalizers and signal processors
[07:19:56] <toastydeath> to change what the motor does to help offset environmental factors that may be harder to change
[07:20:13] <robin_sz> well, im sure you are right
[07:20:14] <toastydeath> except it's open loop, and the amplifer and motor themselves are thus part of that environment
[07:20:40] <toastydeath> i am just wondering what it would take to do closed loop stuff
[07:20:59] <robin_sz> so to close the loop ... you need to close it at the end, not part way along
[07:21:00] <toastydeath> because i've got tons of audio gear lying around from my competition days
[07:21:10] <robin_sz> audio competition?
[07:21:12] <robin_sz> weird
[07:21:13] <toastydeath> and this is where we get back to that whole bandwidth discussion
[07:21:31] <toastydeath> the motor, while not the absolute reference, is a good relative reference for corrections
[07:21:44] <robin_sz> where as the cone is a better reference ..
[07:21:48] <toastydeath> whereas the absolute measurement, in this case, would be incredibly slow
[07:21:54] <robin_sz> and the actual air movement is even better
[07:22:00] <toastydeath> the part of the motor i'd be measuring is actually attached to the cone
[07:22:13] <toastydeath> air movment = absolute, but low bandwidth measurement
[07:22:37] <toastydeath> and the box you put the speaker in is going to really mess with the air movement
[07:22:42] <robin_sz> well, I must return to reallity now and go and do some work
[07:22:44] <toastydeath> as that what it's designed to do
[07:22:50] <robin_sz> later
[07:22:51] <toastydeath> cya
[08:00:32] <kwajstabo> hello
[08:02:39] <kwajstabo> i have one comment about emergency stop switch...i think it skould also stop the program execution. Now when i hit the emergency stop and relese it afterwards, the porogram continues its execution.
[08:03:53] <The_Ball_MS> kwajstabo, im fairly sure you can wire that in HAL to pause the program
[08:04:03] <alex_joni> that's correct
[08:04:16] <alex_joni> kwajstabo: I suspect you're talking about an external e-stop switch?
[08:05:03] <alex_joni> kwajstabo: there are 2 ways to do it.. the "easy" way is to use an estop_latch component
[08:05:16] <alex_joni> and the other one is to use classicladder
[08:05:24] <alex_joni> there's a fairly good description here: http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Sample_HAL_And_ClassicLadder
[08:05:57] <alex_joni> you want estop type 4
[08:06:56] <kwajstabo> i see, will do that
[08:06:56] <kwajstabo> thank you
[08:07:33] <JymmmmEMC> Can an opto drive an opto? [PC]------[Breakout board - OPTO_OUT]---------[Driver - OPTO_IN]-------[Motor]
[08:09:32] <JymmmmEMC> I noticed that some breakout boards don't have optos when they are specifically mentioned to be used with Geckos, since geckos already have the opto, but I was wondering if it can still be used in needed.
[08:10:02] <alex_joni> sure
[08:10:22] <alex_joni> you just need an additional PSU
[08:10:32] <JymmmmEMC> ?
[08:10:44] <alex_joni> you have a separation in the breakout board
[08:10:50] <alex_joni> PC PSU, and external PSU
[08:10:57] <alex_joni> that's what the first opto is for.. right?
[08:11:25] <alex_joni> then you have a separation on the input of the gecko (external PSU input opto, internal PSU + output opto)
[08:11:39] <JymmmmEMC> Ok, my drives have optos already, and they are driven by the 48V PS already (no other PS is needed for the drives).
[08:11:49] <alex_joni> so you actually have 3 separated things: PC, intermediary stuff, and the PSU for the drives
[08:12:12] <alex_joni> you could in theory use either the PC or the drives PSU for driving the intermediary stage
[08:12:40] <alex_joni> that basicly turns one of the optos useless (working, but not separating anything, as you have the same voltage)
[08:13:16] <alex_joni> JymmmmEMC: am I making any sense ?
[08:13:35] <JymmmmEMC> I sorta forgot that aspect, needing seperate PS. Yeah, you are, it just slipped my mind.
[08:14:01] <alex_joni> for what you need this I would probably use the PC PSU for the secodn stage too
[08:14:16] <JymmmmEMC> alex_joni: I WAS looking at this one, but it too needs two PS, and comes with a USB to draw power from the PC http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=48
[08:14:31] <JymmmmEMC> s/USB/USB cable/
[08:14:40] <alex_joni> anything with optos will need 2 PS's
[08:15:28] <alex_joni> seems a bit pricey
[08:15:59] <JymmmmEMC> You think so? with the charge pump, relays, and SSR (Triac)?
[08:16:04] <alex_joni> you're getting geckos?
[08:16:15] <JymmmmEMC> I have Parker drives.
[08:16:52] <alex_joni> maybe I'm wrong about the price..
[08:17:02] <alex_joni> I would get this one for geckos: http://www.pmdx.com/PMDX-131/index.html
[08:17:06] <JymmmmEMC> it also has a analog thingy for speed control too
[08:17:12] <alex_joni> yeah, saw that
[08:17:27] <alex_joni> gotta run... bbl
[08:17:57] <JymmmmEMC> alex_joni: Heh, I saw that pdmx board, and ironically one thing turned me off about it.... the centronix connector
[08:19:40] <JymmmmEMC> And the lack of physical support - seems like it might crack the traces in the middle.
[08:20:45] <alex_joni> well.. usually you mount the geckos on heatsinks
[08:21:03] <alex_joni> so you get support from there..
[08:21:38] <alex_joni> anyways, since you don't have geckos it shouldn't matter :)
[08:21:40] <alex_joni> later
[08:21:42] <The_Ball_MS> a centronix cable is still very easy to find, but a dsub would be better
[08:22:18] <JymmmmEMC> So is a monochrome monitor, doens't mena I'd want to use one though =)
[08:22:46] <The_Ball_MS> i wouldn't say a monocrome monitor is easy to come by.. .;)
[08:23:19] <JymmmmEMC> The_Ball actually they really are.
[08:25:10] <The_Ball_MS> on that note, i have a 17" crt that will not fit in the garbage bin ;(\
[08:26:20] <JymmmmEMC> I just thought of something.... PC's have switching power supplys that usually have GND tied to EARTH ground, dont they?
[08:26:38] <The_Ball_MS> i believe so
[08:27:06] <JymmmmEMC> Isn't that why you can't chain multiple PC PS together to get 24V (as example), as they're not isolated?
[08:28:07] <The_Ball_MS> are you talking about earth or gnd? on the connectors you have gnd
[08:28:28] <The_Ball_MS> gnd might very well be floating compared to earth
[08:29:27] <JymmmmEMC> Let me grab a PC PS real quick...
[08:37:00] <JymmmmEMC> GND (like from hdd power connector is common with chassis and Earth ground
[08:38:21] <JymmmmEMC> Ok, so my question is... when you need "isolation", do all the grounds need to be isolated too, or just the signals?
[08:42:35] <JymmmmEMC> I emailed Art, the guy that makes/sells that breakoutboard, his reply in CAPS, Not the last line of his reply:
[08:43:06] <JymmmmEMC> 3) "A power supply with 5vdc@ 2 amps and 12vdc@ 0.3 amps for operation. It also requires a connection to your PC power supply" Does this mean that two separate power sources are required? One being +5vdc/+12VDC and another for +5VDC; I ask because I more than likely will use some switching PSU's that I have and I'm not sure if that would provide enough isolation as the grounds would be common with chassis. Can the second PSU (+5VDC) be common with the driv
[08:43:20] <JymmmmEMC> s/Not the/Note the/
[08:44:54] <JymmmmEMC> If the PC PS is common to the chassis and earth. And I ground the control box to earth (for safety reasons), they kind breaks what he's saying here if I'm reading that correctly.
[08:52:51] <The_Ball_MS> yes, you need to separate supplies. two pc supplies will not cut it if earth and gnd is common
[08:54:03] <The_Ball_MS> define "enough isolation", running common ground through a opto isolator gives some protection
[08:54:26] <The_Ball_MS> but does not provide a galvanic
[08:54:34] <The_Ball_MS> but does not provide galvanic seperation
[08:54:55] <JymmmmEMC> It's not that specifically... It' s db25 cable itself. Most of the good ones have the shield drain wire connected to the netal shell of the DB25 connector itself. So while the all the 25 wires inside the cable are "isolated" the shield itseld (the 26th wire) is actually conducting from the PC chassis to the Controller Chassis.
[08:55:53] <JymmmmEMC> s/netal/metal/
[08:59:31] <The_Ball_MS> you can have a little double isolated wall wart that delivers 5V as the second power supply, these do not have a earth cable and the gnd from these are floating
[09:00:38] <The_Ball_MS> also one or your above statements are false, either the gnd is not common with earth, or you can't use two pc powersupplies to get 24v
[09:01:30] <JymmmmEMC> I siad you CAN"T use two two PC PS to get 24V, because the grounds are not isolated.
[09:01:42] <The_Ball_MS> oh, i read that you could
[09:01:52] <JymmmmEMC> np
[09:02:24] <JymmmmEMC> I had wanted to do that long ago for another project, Alex was kind enough to explain to me why you can't.
[09:02:28] <The_Ball_MS> i some times read what i think should be written instead of what is written
[09:02:38] <JymmmmEMC> it's all good.
[09:03:39] <JymmmmEMC> But, even without the db25 cable in place, it still seems to me that EARTH ground is still common between both chassis.
[09:05:14] <The_Ball_MS> yes, it should be, but there is possibilities of small voltage differences, so do not use this a reference for signals, bring your own gnd
[09:06:02] <JymmmmEMC> No, no, I mena that because of this that I've lost isolation as the PC chassis is common with NEG
[09:07:08] <The_Ball_MS> yes, with two pc power supplies at both ends that will happen
[09:07:21] <The_Ball_MS> (one at each end)
[09:09:16] <JymmmmEMC> Well, let me check... it's a switching PS open frame, not PC.
[09:11:05] <JymmmmEMC> Ok, the frame itself is tied to EARTH (good thing), and the NEG is *NOT* common with Earth, Chassis, Hot, or neutral.
[09:11:28] <The_Ball_MS> then you are in the clear
[09:12:20] <JymmmmEMC> both will be tied to earth.
[09:14:13] <The_Ball_MS> what cnc control box are we talking about?
[09:14:24] <JymmmmEMC> The one I'm building
[09:14:26] <The_Ball_MS> the box should not be connected to any electronics, as in gnd
[09:14:41] <JymmmmEMC> Not NEG ground, just EARTH gnd
[09:14:52] <The_Ball_MS> as long as the box does not have any potential you can earth it, that's fine
[09:15:51] <The_Ball_MS> hmm, which pizza should i order
[09:17:04] <JymmmmEMC> Also, the DB25 in the controller will be mounted to the controllers chassis, which is also connected to EARTH gnd.
[09:17:15] <JymmmmEMC> garlic, lots of garlic
[09:18:55] <The_Ball_MS> with shielded cables it is common to only connect one side of the shield, this prevents ground loops, where two different earth potentials create current through the shield, this is common where long distances is involved
[09:19:41] <The_Ball_MS> the end of the cable which does not have the shield connected is of course earthed normaly
[09:20:29] <JymmmmEMC> Well, I just tested your theory on the DB25 cable I have right here, and the shield's are common.
[09:21:15] <JymmmmEMC> In a PC, the DB25 connector for the paraport is usually mounted in such a way that it's metal housing is common with the rest of the PC's chassis.
[09:21:23] <The_Ball_MS> <15m is not considered long distance
[09:22:00] <JymmmmEMC> iirc paraport length specs out to 33ft
[10:50:28] <lerneaen_hydra> 'lo
[11:46:04] <The_Ball_MS> almost finished with the front sliding screen now: http://wigen.net/workshop/cnc/IMG_0289.JPG
[11:53:27] <martin_lundstrom> cool mashine!
[13:00:48] <The_Ball> martin_lundstrom, :) now i need to learn how make it do something useful though
[13:11:06] <chr0n1c> is it in your living room?
[13:14:21] <martin_lundstrom> The_Ball: where do you live?
[13:14:31] <The_Ball> Brisbane, Australia
[13:14:48] <martin_lundstrom> cool, far away grom me in france
[13:15:27] <The_Ball> yes a fair distance, been there a couple of times
[13:15:59] <martin_lundstrom> I never been to australia yet, but I want to go some day
[13:16:18] <The_Ball> are you french? your surname sounds swedish?
[13:16:41] <martin_lundstrom> The surf shuold be great in many places I hear. I am swedish
[13:16:48] <martin_lundstrom> but I live here in nice
[13:17:07] <The_Ball> ok, i'm norwegian, but i live here in brissbane
[13:17:19] <The_Ball> i visited nice, it's a nice place
[13:17:33] <martin_lundstrom> cool, do you speak norwedgian?
[13:17:43] <The_Ball> better than english, hehe
[13:17:57] <martin_lundstrom> rixkringkastning ;)
[13:17:59] <chr0n1c> martin_lundstrom: hey that mill of yours looks like a nice machine
[13:18:18] <The_Ball> martin_lundstrom, nrk ja
[13:18:29] <martin_lundstrom> funny word
[13:18:42] <The_Ball> martin_lundstrom, what mill do you have/
[13:18:58] <martin_lundstrom> chr0n1c: the link is The_Ball:s mill :)
[13:19:02] <chr0n1c> i jsut figured that out
[13:19:09] <martin_lundstrom> :)
[13:19:10] <chr0n1c> <- jsut woke up
[13:19:11] <chr0n1c> just*
[13:19:33] <The_Ball> martin_lundstrom, how did you end up in nice, and are you doing any cnc projects there?
[13:19:37] <chr0n1c> do-over.... The_Ball: hey that mill of yours looks like a nice machine
[13:19:57] <martin_lundstrom> I have one crappy small chinese mill, and a 3,5*1,9 m plasma cutting table
[13:20:01] <The_Ball> chr0n1c, thanks it looks ok, but it's a cheap asian mill of course
[13:20:44] <chr0n1c> ... i'm still working with my homebrew-rigged-upghetto-mini-drillpress-frankenstien cnc
[13:20:49] <martin_lundstrom> The_Ball: my parents live here to
[13:20:52] <chr0n1c> so you got me beat at home anyways.. ;)
[13:21:24] <martin_lundstrom> chr0n1c: Where do you live?
[13:21:25] <The_Ball> ah, a plasma table is on my long list of upcoming projects, but far down from the top
[13:22:06] <chr0n1c> would a laser machine be more useful than a plasma?
[13:22:11] <martin_lundstrom> The_Ball: cool, when you are ready I can come with adwise
[13:22:19] <chr0n1c> wouldn't it be**
[13:22:29] <The_Ball> chr0n1c, cut's nicer, but it's extremely expensive
[13:22:37] <The_Ball> "cut's" / cuts
[13:22:44] <chr0n1c> ya...
[13:22:48] <martin_lundstrom> chr0n1c: yes but much more expensive
[13:23:06] <martin_lundstrom> the eco :)
[13:23:16] <chr0n1c> this place that does laser work for us at the shop just bought a brand spanking neww laser it was like $500,000(USD)
[13:23:19] <The_Ball> martin_lundstrom, are you using a fairly cheap plasma machine, if so are the results good?
[13:23:43] <martin_lundstrom> yes
[13:24:12] <The_Ball> i see some cheap asian plasma cutters, they have high frequency starting, so that could be a big noise problem
[13:24:27] <martin_lundstrom> my current one i bought as a develop machine, around 700 euro from the factory
[13:24:43] <The_Ball> that's about the right price range
[13:25:26] <martin_lundstrom> mine is from INE in italy, its a nice machine up to 7-10 mm thick cuts in steel
[13:26:03] <The_Ball> high frequency start?
[13:26:27] <martin_lundstrom> it has HF start, but my table has alot of protection for that
[13:26:48] <martin_lundstrom> HF is the best I think
[13:27:04] <martin_lundstrom> gets threw most stuff
[13:27:22] <The_Ball> does it do alu as well?
[13:27:37] <martin_lundstrom> yep, slighty less thick cuts
[13:28:04] <martin_lundstrom> Im going to get a 100 amp cutter for it
[13:28:20] <martin_lundstrom> then I can cut 30 mm
[13:29:11] <martin_lundstrom> The_Ball: what is more on your list?
[13:29:38] <The_Ball> my lathe will be converted
[13:29:55] <The_Ball> also a small asian one, but good starting point for me
[13:30:35] <martin_lundstrom> nice, lerneaen_hydra has a really nice mini lathe
[13:30:48] <martin_lundstrom> did you see the movies?
[13:30:53] <The_Ball> looks something like this http://wigen.net/hobby/lathe/CQ6123B.jpg
[13:31:02] <The_Ball> i don't think so no
[13:31:15] <martin_lundstrom> ok
[13:31:28] <martin_lundstrom> lerneaen_hydra: are you there?
[13:33:06] <The_Ball> do you have pictures of your plasma on the web?
[13:33:15] <martin_lundstrom> not yet
[13:33:43] <martin_lundstrom> Heres a picture of Dallurs plasa table http://www.dallur.com/index.php?id=130
[13:33:59] <martin_lundstrom> mine look diferent
[13:34:58] <The_Ball> hehe, that's a big one
[13:35:17] <martin_lundstrom> Dallur has written a nice beta for a simple voltage sensing torch height control
[13:35:26] <martin_lundstrom> for emc
[13:36:14] <The_Ball> cool, does torch height change during the job?
[13:37:12] <martin_lundstrom> yep, its floating
[13:37:58] <martin_lundstrom> I adjust to the voltage I want and then emc moves Z up and down to adjust
[13:37:58] <chr0n1c> chr0n1c is now known as ohiopctechDOTcom
[13:41:31] <The_Ball> very nice, i can't see from the picture, but is the x axis driven by a sprocket?
[13:44:13] <ohiopctechDOTcom> 93 unique ip addresses came to my website from wiki.linuxcnc.org .. sweet i guess i should put some metter pics and some details about my machine there
[13:44:21] <ohiopctechDOTcom> some better pics*
[13:44:48] <ohiopctechDOTcom> ***in the month on june
[13:45:47] <lerneaen_hydra> martin_lundstrom: here now
[13:46:21] <lerneaen_hydra> The_Ball: thats about the same size as min
[13:46:23] <lerneaen_hydra> mine
[13:46:43] <lerneaen_hydra> http://lerneaenhydra.shacknet.nu/index.php?option=com_rsgallery2&Itemid=32&catid=4
[13:47:12] <martin_lundstrom> lerneaen_hydra: is that the link to your lathe?
[13:47:23] <lerneaen_hydra> yeah some images
[13:47:34] <The_Ball> ah, looks good
[13:47:36] <martin_lundstrom> The_Ball you should have a look
[13:48:05] <lerneaen_hydra> http://www.youtube.com/v/MX4SWe8WFA4 a video of it cutting
[13:48:07] <The_Ball> * The_Ball is looking ;)
[13:48:31] <lerneaen_hydra> first part so rather conservative speed
[13:49:10] <lerneaen_hydra> http://www.youtube.com/v/tFWmeG-2uVo and some threading
[13:49:34] <The_Ball> did you convert it to a dc motor or was this from the factory?
[13:49:54] <lerneaen_hydra> the spindle? it was dc from the factory
[13:50:12] <lerneaen_hydra> it was CNC to begin with, although with an absolutly horrid control system
[13:50:28] <lerneaen_hydra> 7 LEDs and a 4 digit number display
[13:50:29] <The_Ball> i see, mdi?
[13:50:41] <lerneaen_hydra> yeah, tape based storage
[13:50:48] <ohiopctechDOTcom> * ohiopctechDOTcom dreams about owning his own cnc lathe
[13:51:05] <lerneaen_hydra> you can find them for not too much
[13:51:12] <lerneaen_hydra> 2k or thereabouts
[13:52:17] <ohiopctechDOTcom> so i just signed your guestbook, lerneaen_hydra
[13:52:21] <ohiopctechDOTcom> word up
[13:52:38] <ohiopctechDOTcom> that page is nice.. is it a cms?
[13:52:45] <lerneaen_hydra> yeah same as linuxcnc.org
[13:52:46] <lerneaen_hydra> joomla
[13:52:57] <lerneaen_hydra> http://cgi.ebay.com/Emco-Compact-5-CNC-Lathe-w-Welturn-Upgrade_W0QQitemZ320132463221QQihZ011QQcategoryZ97230QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
[13:53:02] <lerneaen_hydra> http://cgi.ebay.com/Emco-Compact-5-CNC-Lathe_W0QQitemZ180134162896QQihZ008QQcategoryZ97230QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
[13:53:23] <ohiopctechDOTcom> ahhh... i was going to use joomla... but i found drupal and fell in love
[13:53:37] <lerneaen_hydra> heh ok
[13:53:49] <ohiopctechDOTcom> i'm working on adding a store to my site now for the stuff i was selling on ebay... we'll see how it holds up
[13:57:14] <lerneaen_hydra> btw, how do you find maximum speed / accel values for a stepper system?
[13:57:21] <lerneaen_hydra> experiment, see where it looses steps
[13:57:27] <The_Ball> lerneaen_hydra, very nice, im look forward to doing threading
[13:57:47] <The_Ball> use servos... ;)
[13:58:39] <lerneaen_hydra> The_Ball: :p
[13:59:27] <ohiopctechDOTcom> i just cut air and played with my speeds n feed until i found a spot where it didn't lose steps and then put those values in the ini.. now that is my max feed
[13:59:43] <ohiopctechDOTcom> **on steppers
[14:00:03] <lerneaen_hydra> doesn't sound like the best way of doing it
[14:00:18] <lerneaen_hydra> it sounds rather crude
[14:00:27] <ohiopctechDOTcom> well, have you seen my machine? lol
[14:00:35] <lerneaen_hydra> say you have a cutter force that causes it to loose steps
[14:00:48] <lerneaen_hydra> or some chatter that increases the force needed to drive
[14:00:57] <ohiopctechDOTcom> i'm with you there.. but i am only vutting plastic and wood...
[14:01:04] <ohiopctechDOTcom> cutting*
[14:01:09] <lerneaen_hydra> oh ok
[14:01:24] <ohiopctechDOTcom> i am gonna have to come up with a more stable machine base before i go cutting steel
[14:01:57] <ohiopctechDOTcom> i tried to cut a die for work on it.. no enough ballz for it...
[14:03:44] <lerneaen_hydra> too weak, lots of deflection?
[14:04:36] <ohiopctechDOTcom> deflection in the dremel spindle and my y axis slide has about 20 thou play for some reason
[14:04:54] <ohiopctechDOTcom> it's not meant to be on a machine like this
[14:04:56] <lerneaen_hydra> dremel spindle?
[14:04:57] <lerneaen_hydra> oh my
[14:05:03] <ohiopctechDOTcom> it was a slide from an old pick n place robot cell
[14:05:07] <lerneaen_hydra> I think I see your problem
[14:05:07] <ohiopctechDOTcom> :))
[14:05:09] <lerneaen_hydra> ah, right
[14:05:34] <lerneaen_hydra> btw, why use an electic motor for high speed spindles instead of pneumatic ones?
[14:05:49] <ohiopctechDOTcom> less noise?
[14:05:54] <ohiopctechDOTcom> no air comp needed?
[14:06:33] <ohiopctechDOTcom> i know my air drill that i use at work is a loud sonofabitch
[14:06:43] <lerneaen_hydra> oh ok
[14:06:49] <lerneaen_hydra> hmm that it true
[14:07:02] <lerneaen_hydra> air is cheaper and it would seem that it can last longer
[14:07:13] <lerneaen_hydra> no brushes, though there are vanes instead
[14:07:31] <ohiopctechDOTcom> you can't use air at low speeds really
[14:07:50] <ohiopctechDOTcom> not for cutting... i may be wrong.. just my experience
[14:08:24] <ohiopctechDOTcom> if the air line drops below a certain psi.. the air drill won't even spin
[14:10:00] <ohiopctechDOTcom> lol, wtf is you be doin inside a cnc lathe yo?
[14:10:52] <lerneaen_hydra> I was thinking air for 20k+ spindles
[14:11:24] <lerneaen_hydra> and this system would be installed where there is limitless air
[14:11:41] <ohiopctechDOTcom> if only air was free :|
[14:11:43] <ohiopctechDOTcom> lol
[14:11:49] <lerneaen_hydra> haha
[14:13:18] <martin_lundstrom> bbl
[14:13:24] <SWPadnos> air is inefficient
[14:13:46] <The_Ball> lerneaen_hydra, since we are youtubing, here is one i made http://www.youtube.com/watch?v=s6avL3ZYTIQ
[14:14:12] <lerneaen_hydra> SWPadnos: very true, but in my case good enough
[14:14:20] <ohiopctechDOTcom> ha, you peck drill video links to mine
[14:14:23] <ohiopctechDOTcom> your*
[14:14:26] <ohiopctechDOTcom> on youtube
[14:14:30] <ohiopctechDOTcom> 1sy on the list
[14:14:33] <ohiopctechDOTcom> ist
[14:14:33] <ohiopctechDOTcom> damn typos
[14:14:37] <ohiopctechDOTcom> 1st*
[14:14:53] <lerneaen_hydra> ohiopctechDOTcom: what type of rpm control do dremels have?
[14:14:56] <lerneaen_hydra> open loop?
[14:15:22] <The_Ball> some have closed loop i have heard, but badly made, mine is open
[14:15:30] <ohiopctechDOTcom> i'd say open loop... i never took it apart... it's a wheel in the handle with 1-10 markings
[14:15:33] <The_Ball> ohiopctechDOTcom, no emc creditation in yours
[14:15:47] <The_Ball> oh there it is
[14:15:57] <ohiopctechDOTcom> ya.. in the more description
[14:17:07] <ohiopctechDOTcom> if my webcam wasn't so lame i'd put up some better vids
[14:19:27] <SWPadnos> my dremel has closed loop, but it isn't a very fast response loop
[14:20:17] <SWPadnos> at least it seems to be closed loop - there's a digital display of the krpm setting, and it doens't sound as though it changes much
[14:21:16] <ohiopctechDOTcom> you can tell when mine takes a bigger-ish cut.. it bogs down a bit.. or in corners sometimes
[14:21:59] <The_Ball> in that video i had to constantly adjust the slider
[14:22:01] <SWPadnos> ok - I just turned it on - it wobbles all over the place when it's unloaded (and at low speed)
[14:22:11] <SWPadnos> loaded, it sounds a lot more consistent
[14:22:37] <ohiopctechDOTcom> the spindle in mine has very little slop...
[14:22:53] <SWPadnos> I didn't put a big load on it - just squeezing a cutting wheel post with my finger :)
[14:34:56] <ohiopctechDOTcom> http://www.youtube.com/watch?v=oga_4uoCvnA&mode=related&search= <-- video of cnc toast graphics (not mine)
[14:39:13] <The_Ball> haha!!! that's awsome
[14:46:07] <robin_sz> meep?
[14:46:20] <ohiopctechDOTcom> um yo robin_sz
[14:46:51] <robin_sz> wet here ...
[14:46:56] <robin_sz> lots of rain
[14:47:05] <ohiopctechDOTcom> it's dry and like 68 degrees here
[14:47:12] <ohiopctechDOTcom> sorry to hear about your rain
[14:48:09] <robin_sz> its cuased a few problems
[14:48:17] <robin_sz> wetteset month on record
[14:49:18] <SWPadnos> lots of flooding in Sheffield
[14:50:00] <ohiopctechDOTcom> it's rained so little here recently i haven't vut my grass in two weeks
[14:50:05] <ohiopctechDOTcom> *almost 3 weeks
[14:50:13] <ohiopctechDOTcom> cut*
[14:50:43] <SWPadnos> yeah. nice, isn't it?
[14:52:30] <robin_sz> yeah, sheffield is bad
[14:52:36] <robin_sz> on the bright side ...
[14:52:49] <robin_sz> it might wash some of the grime off the place
[14:52:54] <SWPadnos> d'oh!
[14:52:57] <robin_sz> brightside, geddit?
[14:53:25] <ohiopctechDOTcom> it aint easy bein greasy/grimey.. in the hood is where you'll find me...
[14:53:43] <robin_sz> brightside is an area of sheffield
[14:53:44] <ohiopctechDOTcom> sorry.. i had a rhyme stuck in my head... had to get it out
[14:56:28] <ohiopctechDOTcom> um cya later, gangsters... time for the my day to begin
[14:58:05] <lerneaen_hydra> later
[15:11:46] <lerneaen_hydra> SWPadnos: have you done stepper based systems?
[16:15:39] <awallin_Guest154> hi
[16:16:03] <awallin_Guest154> anyone here that knows about transformers?
[16:16:16] <awallin_Guest154> I'm load testing the 1.8kva thing I talked about a few days ago
[16:17:14] <lerneaen_hydra> nice and big
[16:18:29] <awallin_Guest154> so far it looks like this http://imagebin.org/9150
[16:18:49] <awallin_Guest154> I don't have any more resistors or stuff that I can load it up with...
[16:19:01] <awallin_Guest154> does the voltage drop when loading it up look normal??
[16:19:23] <awallin_Guest154> this is an unregulated supply. just transformer, diode bridge, and caps
[16:19:47] <lerneaen_hydra> is this voltage after the rectifier?
[16:20:00] <awallin_Guest154> yes, this is the DC voltage after rectifier and caps
[16:20:07] <awallin_Guest154> and DC amps too
[16:20:09] <lerneaen_hydra> how much delta V do you have?
[16:20:26] <awallin_Guest154> can I mesure that with the multimeter in the AC setting?
[16:20:27] <lerneaen_hydra> between the sinus tops
[16:20:35] <awallin_Guest154> I haven't looked at it with a scope...
[16:20:41] <lerneaen_hydra> I think you'll need a scope
[16:20:52] <awallin_Guest154> let me try that...
[16:21:19] <lerneaen_hydra> could be that the cap is too small and the large variations are more noticable and lead to a lower RMS value
[16:26:22] <awallin_Guest154> the scope shows about 1.4V of ripple at 7.7A current
[16:27:26] <awallin_Guest154> the transformer has 2x30V secondaries, so the 85V at no load seems about right
[16:27:47] <awallin_Guest154> but I'm wondering if the drop in voltage when loading it is normal or if I've done something wrong
[16:27:55] <lerneaen_hydra> ok so the ripple isn't causing the lower voltage
[16:28:10] <lerneaen_hydra> there will be a drop in voltage, but I can't say if that's more than usual
[16:28:23] <awallin_Guest154> ok.
[16:28:29] <lerneaen_hydra> it could be that the transformer has a relatively high inductance/resistance
[16:28:59] <awallin_Guest154> I might post a message to cad_cam_edm_dro or something...
[16:29:15] <lerneaen_hydra> try asking in ##electronics
[16:29:22] <lerneaen_hydra> I'm sure someone there knows
[16:29:33] <lerneaen_hydra> I'd like to hear their answer too
[16:29:42] <lerneaen_hydra> (on freenode)
[16:31:02] <awallin_Guest154> asking now...
[16:32:03] <awallin_Guest154> bah. nobody there.
[16:35:01] <lerneaen_hydra> apparently not :(
[16:35:18] <The_Ball> is there a easy way to convert vector graphics into toolpaths?
[16:36:19] <lerneaen_hydra> there's an ugly way but then you'll have to rasterise it, and thereby loose the vector clean-ness
[16:36:24] <lerneaen_hydra> and then using image to gcode
[16:37:10] <The_Ball> yes, i know that route, but i do need to follow the outlines of the vectors
[16:37:16] <lerneaen_hydra> hmm
[16:37:26] <lerneaen_hydra> maybe you could hack cradek's ttf tracer program
[16:37:44] <lerneaen_hydra> the one used to make the axis default gcode file
[16:38:02] <The_Ball> hmm, possably
[16:49:58] <awallin_Guest154> gotta go, be back later maybe.
[18:29:15] <awallin> anyone have a good link that explains what's so different with GPL v3 ?
[18:34:28] <SWPadnos> awallin, try starting here: http://gplv3.fsf.org/
[18:35:01] <lerneaen_hydra> anyone here done a stepper based setup?
[18:35:33] <SWPadnos> probably :)
[18:35:44] <SWPadnos> (not me though, to answer your earlier question)
[18:35:58] <awallin> lerneaen_hydra: yes, our current mill uses geckodrives
[18:36:09] <SWPadnos> well, unless you count the Shoptask with Ah-Ha controls
[18:36:22] <lerneaen_hydra> awallin: how did you find good values for maxvel and maxaccel?
[18:36:42] <JymmmmEMC> SWPadnos: at least you said shoptask and not shopbot
[18:36:48] <SWPadnos> heh
[18:36:50] <lerneaen_hydra> awallin: didn't you refit the opti to servodrives?
[18:37:10] <lerneaen_hydra> SWPadnos: ah-ha?
[18:37:37] <SWPadnos> yes, they're oiut of business, as of this January I think
[18:37:41] <awallin> lerneaen_hydra: we are still in the process of fitting servos...
[18:37:50] <lerneaen_hydra> ah ok
[18:38:42] <awallin> basically we set maxvel and maxacc as high as possible while trying to avoid stalling the motors. knowing when they stall is a matter of experience only (at the ends of travel the table is harder to move, motors get weaker when they are hot, etc etc)...
[18:40:17] <lerneaen_hydra> ah, so there's no easy way to figure it out?
[18:41:19] <JymmmmEMC> Is there a way to tell/confirm that the pc and controller is isolated and there are no ground loops?
[18:41:52] <awallin> from a software point of view there's probably a way of setting what is maximally possible. but with our mill the mechanics and the dynamics of the motors is the limiting factor.
[18:42:29] <JymmmmEMC> awallin: LOL, that last statment of yours sounds like it came from a politician
[18:43:07] <lerneaen_hydra> awallin: hmm, you had an opti bf 20, right? how strong are your motors?
[18:46:35] <awallin> hmm... theyre the nema size that has a 100mm bolt circle. is that NEMA23? I seem to recall a value of 280 Ncm for the holding torque, not sure.
[18:47:59] <lerneaen_hydra> hmm ok, I have some 3.3 Nm drives, what values do you have for maxvel and maxaccel?
[18:48:23] <lerneaen_hydra> they would probably work as a baseline
[18:48:48] <awallin> don't know ;) maxvel is around 1000mm/min with 2.5mm/rev ballscrews
[18:48:53] <lerneaen_hydra> 100mm bolt circle?
[18:48:58] <lerneaen_hydra> that big?
[18:49:02] <lerneaen_hydra> oh, ballscrews
[18:49:09] <lerneaen_hydra> I've only got acme
[18:51:30] <awallin> so the bolts are 100/sqrt(2) apart, something like 76 or 74 mm I think
[18:51:45] <awallin> direct drive. no pulleys or gears.
[18:52:11] <lerneaen_hydra> oh, ok, quite big
[18:52:18] <lerneaen_hydra> are they only 280 Ncm?
[18:54:13] <awallin> I think so
[18:54:35] <awallin> MAE-something, I can see if I find the pdf datasheet
[18:55:59] <lerneaen_hydra> strange, the ones I have are far smaller and rated to 3.3Nm
[18:59:08] <awallin> powersupply stuff just posted on my blog http://www.anderswallin.net/2007/06/1800-w-80-v-psu-for-servos/
[19:00:32] <lerneaen_hydra> 1.8kVA for servos?
[19:00:43] <lerneaen_hydra> isn't that a bit excessive for an 800W spindle?
[19:02:36] <awallin> lerneaen_hydra: MAE HN3451 series on pages 17/22 and 18/22 of this pdf http://www.oem.fi/pienmoottoriosasto/Mechanics2004pdf/Askelmoottorit_ja_ohjaimet.pdf (sorry it's in Finnish)
[19:02:57] <lerneaen_hydra> and won't you really really mess up the power grid when pulling 1kW with that type of psu?
[19:04:10] <awallin> hm, might be HN3426 series after all. they're 280 Ncm with bipolar drive
[19:05:26] <awallin> 1.8kVA was just a secondhand transformer I got sheaply. The stall current of the motors is something like 6-7 A, so if you plan on stalling all X/Y/Z motors then you need something like this.
[19:06:04] <awallin> I don't think the power grid will be messed up at all. It would be much worse if I were to design an amateur switched-mode psu I think.
[19:06:43] <awallin> it's the switched-mode stuff that needs PFC etc etc to play nice
[19:06:51] <lerneaen_hydra> heh, well you do pull all your power from the tops
[19:09:55] <awallin> anyone know if I need to add a bleeder-resistor over the caps, or will the pico-systems servo-drives empty the caps in reasonable time?
[19:10:20] <awallin> Now I measured about 30V on the caps a day after switching off ;)
[19:11:11] <JymmmmEMC> sorta kinda sounds like it, or add a ESTOP with dump circuit
[19:11:14] <lerneaen_hydra> attach a cooling fan :) that's what I did (and a high-power resistor to lower the voltage)
[19:12:39] <awallin> JymmmmEMC: now it was only the psu, no servordives or any load hooked up
[19:13:17] <JymmmmEMC> awallin: Ok, lets say you have the servos hooked up, if you need to stop NOW, where's it gonna go?
[19:14:41] <JymmmmEMC> awallin: Might be totally overkill, but I see it like this... What if your 8yo niece was about to touch something, or get hair/clothing caught.
[19:14:56] <awallin> the E-stop switch from pico-systems will hopefully disconnect the DC-rail from the servodrives
[19:15:15] <awallin> JymmmmEMC: I totally agree that safety is important
[19:15:20] <JymmmmEMC> awallin: is that a electronic switch or eletro-mechanical
[19:16:30] <awallin> it's electronic (FETs)
[19:16:53] <JymmmmEMC> awallin: have you seen Mariss' servo estop circuit?
[19:17:34] <awallin> no. URL?
[19:18:52] <JymmmmEMC> I just uploaded it to here http://www.zshare.net/download/25017868923ace/
[19:20:12] <JymmmmEMC> awallin: it uses a DPDT relay in a latching configuration.
[19:20:57] <JymmmmEMC> awallin: I plan on using a modified variant of that in mine.
[19:21:16] <awallin> thanks.
[19:21:53] <JymmmmEMC> awallin: Alex was telling me that in EU it's required to have dual safety systems, but I'm not quite sure how that goes, I didn't get all the details.
[19:22:39] <awallin> in Finland I can't tell difference btw. the hot and neutral lines... (wall plug goes in both ways). There's a dump resistor on Jon Elsons E-stop board... need to look closer at this next
[19:22:52] <JymmmmEMC> awallin: Also, be aware that *IF* the START button was held down or got stuck for some reason the circuit fails in an UNSAFE manner.
[19:23:54] <JymmmmEMC> awallin: It's a great circuit, I've used it many times and I've played around alot with it (mostly for Q&D alarm systems)
[19:24:09] <awallin> yeah, having the coil of a relay witch its own current seems like an invitation for feedback relatede weirdness
[19:25:34] <JymmmmEMC> awallin: Don't let that one item I mention prevent you from using it though. I just wanted you to be aware of that just so that you use quality switches is all.
[19:26:03] <awallin> ok, I'll think about it.
[19:26:27] <JymmmmEMC> awallin: you could easily add in a lightbulb to verify the START button isn't stuck.
[19:27:17] <JymmmmEMC> awallin: besides, something is better than nothing at all.
[19:31:38] <JymmmmEMC> awallin: but if you hit estop, the circuit will open, even if the START button is stuck, I just looked at the ciruit again. I didn't notice where the coil was in respect to the ESTOP button
[19:33:17] <JymmmmEMC> Oooops, I take that back, the ciruit will be completed thru the stuck START button instead of the contacts.
[19:33:56] <Skullworks-PGAB> need the specs in english - I have a link...
[19:40:07] <robin_sz> awallin, don't forget, in Finland there are special safety requirements for machinery
[19:42:21] <JymmmmEMC> http://www.bannerengineering.com/training/subtopic.php?topicID=P8_01
[19:42:41] <awallin> robin_sz: this is mostly hobby, I'm not selling anything, so I'm not expecting an official control of regulations anytime soon
[19:43:19] <robin_sz> well, still, its worth rememberign the special arrangements that apply for machinery in Finland
[19:43:18] <JymmmmEMC> I love it... The "best" e-stop circuit I ever saw was a maintained mushroom head switch, with the contacts directly across the source voltage. Hit the switch, kill the power. They went thru a lot of fuses, eventual replaced fuse with circuit breaker. As far as I know, that switch is still across the supply line. Leagal??? Sure It Is. Effective? OH YEAH!
[19:44:16] <awallin> I bet those ISO standards are not available freely on the web...
[19:44:24] <JymmmmEMC> http://www.plctalk.net/qanda/showthread.php?t=9174
[19:44:39] <robin_sz> awallin, you are supposed to fit them with an alcohol detector, to prevent operation while drunk. as an alternative, its permissible to simply not allwo them to be switched on a week either side of midsummer.
[19:44:45] <robin_sz> or most of the winter
[19:46:19] <awallin> haha
[19:46:31] <robin_sz> * robin_sz has seen finns at midsummer
[19:49:20] <JymmmmEMC> awallin: search in this page for "October 24th, 2004, 11:44 AM" http://www.plctalk.net/qanda/showthread.php?s=b6b9e7b70072ee2a5df275da71879685&t=10917
[19:51:49] <JymmmmEMC> I like this concept... http://www.pilz.com.au/pulse.htm
[19:51:52] <awallin> I wonder if the FET E-STOP can fail in a mode that leaves the FETs conducting ? (in other words, do I need an additional mechanical E-stop relay for the DC-rail?)
[19:53:25] <JymmmmEMC> awallin: read that link where I mention search the page, regulations REQUIRE it to be electro-mechanical, not electronic (in most cases)
[19:54:07] <JymmmmEMC> And in EU, it's even worse
[19:56:07] <JymmmmEMC> IMNSHO... Folks consider E-STOP as the PAUSE button, not EMERGENCY STOP. If you want a PAUSE button, add one, but let the E-STOP do what it's suppose to do.
[20:20:35] <JymmmmEMC> Yeow! http://video.yahoo.com/video/play?vid=370258&fr=&cache=1
[20:28:08] <JymmmmEMC> robin_sz:
[20:28:54] <robin_sz> what?
[20:29:15] <JymmmmEMC> robin_sz: I want you thoughts on something...
[20:29:18] <JymmmmEMC> http://www.zshare.net/download/25017868923ace/
[20:30:03] <robin_sz> pissing awful site
[20:30:13] <robin_sz> why so many crap adverts?
[20:30:29] <JymmmmEMC> in that ciruit, if the START gets stuck, the E-STOP fails. But, what if the START button was tied to the NC side of the relay instead of the common side? Would it work?
[20:30:41] <robin_sz> is this servos or steppers?
[20:30:50] <JymmmmEMC> either.
[20:31:11] <robin_sz> not an answer
[20:31:29] <JymmmmEMC> robin_sz: You're missing the point.... it could be a lightbulb.
[20:31:48] <JymmmmEMC> If the START button got stuck closed, the circuit fails.
[20:32:54] <JymmmmEMC> because the ciruit would be completed thru the START button instead of the relay contacts.
[20:33:10] <robin_sz> the estop should NOT be momentary
[20:33:23] <JymmmmEMC> The START button, not the STOP
[20:33:27] <robin_sz> it should be a physical latching switch
[20:33:41] <JymmmmEMC> are you looking at the circuit?
[20:33:44] <robin_sz> if the ESTOP was of the correct type, the it will work
[20:34:11] <JymmmmEMC> It *IS* a latching circuit
[20:34:37] <robin_sz> just use a latching estop switch, as required by law
[20:34:46] <JymmmmEMC> Come on robin, I'm trying to aks your thoughts on something here, not go off on a tangent.
[20:35:33] <robin_sz> ffs, read what I wrote. the circuit is fine and fulfills one of the two requirements, it needs a mechanically latching estop, thats all
[20:35:49] <robin_sz> then it will fulfil both requiremements
[20:36:00] <JymmmmEMC> robin_sz: Hold down the START button, and the circuit fails if the STOP is hit.
[20:36:05] <robin_sz> no it doesnt
[20:36:09] <JymmmmEMC> Yes, it does.
[20:36:39] <robin_sz> replace the estop with a mechanically latching estop switch .. as required by law
[20:36:55] <robin_sz> hit the estopm .. it remains open until reset
[20:37:13] <robin_sz> wait ...
[20:37:37] <JymmmmEMC> In THIS circuit, if the START button is held down, it completes the circuit thru the START button instead of the relay contacts.
[20:37:52] <JymmmmEMC> if if you hit and held down the STOP button
[20:37:56] <JymmmmEMC> Even if you hit and held down the STOP button
[20:38:02] <robin_sz> break that link from the top of the relayt coil to the top of the txfmr winding
[20:38:27] <JymmmmEMC> That's where the latching of the realy comes into play.
[20:38:33] <JymmmmEMC> relay
[20:38:35] <robin_sz> wait .. thats still fucked up
[20:39:01] <JymmmmEMC> But... what if you connected the top of the START to the NC of relay?
[20:39:15] <JymmmmEMC> instead of the fused side
[20:39:23] <robin_sz> nope
[20:39:35] <JymmmmEMC> Then, when the relay is latched, it would disable the START
[20:39:48] <JymmmmEMC> but it's that timing thimg
[20:39:53] <robin_sz> yep
[20:40:33] <JymmmmEMC> So, could something like a cap be placed in there just long enough to keep it energized for a few mS?
[20:40:39] <robin_sz> the contacts which latch the coilnope
[20:40:42] <robin_sz> nope
[20:40:46] <robin_sz> its AC
[20:40:59] <robin_sz> cap on an AC circuit?
[20:41:33] <JymmmmEMC> Just a thought, just need the tinest delay in holding the circuit closed. Not like relays are make before break.
[20:41:56] <robin_sz> wouldn;t work ...
[20:42:04] <robin_sz> you need an estop relay :)
[20:42:36] <JymmmmEMC> There's gotta be SOME thing to add a slight delay.
[20:42:46] <robin_sz> there are two basic requirements
[20:43:12] <robin_sz> 1) go off and not come back on again if the power is removed
[20:43:41] <robin_sz> 2) if the estop is pressed, not be able to be switched back on again by pressing start
[20:44:08] <robin_sz> a latching mushroom head pushbutton does 2)
[20:44:09] <JymmmmEMC> Right, and this circuit as it stands fails on #2
[20:44:48] <robin_sz> you will need another set of contacts
[20:45:34] <robin_sz> you'd be better off with a DC relay, and use dioded to isolate the logic a little
[20:45:50] <robin_sz> no .. wait .. thats crazy too :)
[20:46:15] <robin_sz> that works ...
[20:46:27] <JymmmmEMC> what, that you're crazy? lol
[20:46:47] <robin_sz> so ... DC relay powered by the secondary side
[20:47:11] <maddash> meep
[20:47:28] <JymmmmEMC> robin_sz: and use that relay to disable the START button?
[20:47:49] <robin_sz> hmmm
[20:48:03] <robin_sz> woulndt it just be easier to buy an estop relay?
[20:49:18] <JymmmmEMC> robin_sz: it be easier, but I'd actually like to figure this out somehow. It's SO somplistic, just missing the solution. But I do like the idea of relay on the secondary side.
[20:50:22] <robin_sz> well, to do it right, its going to be trickier ...
[20:50:35] <robin_sz> you dont want mains going through your estop chain
[20:50:49] <robin_sz> and you do want the estop to function before the supply comes up
[20:51:04] <robin_sz> so you probably need a second supply for estop logic
[20:51:32] <JymmmmEMC> It'll function, just that the START button defeats it, and needs to be disconnected (somehow).
[20:51:44] <robin_sz> ok
[20:51:47] <robin_sz> good luck
[20:52:15] <JymmmmEMC> thanks, I might play around a bit with the relays I have here.
[21:22:58] <robin_sz> where is my pizza?
[21:23:09] <robin_sz> * robin_sz wants hsi beer and pizza
[21:40:18] <maddash> where's my spartan 3?
[21:46:36] <robin_sz> tonight, I am not drinking Marstons Pedigree
[21:46:39] <robin_sz> oh no ...
[21:46:51] <robin_sz> tonight it's Theakstons :)
[22:04:47] <Sapote_reloaded> Sapote_reloaded is now known as Sapote
[22:15:21] <robin_sz> well, thats the theakstons dealt with, time to start on the next beer
[22:26:15] <JymmmmEMC> Saw this in the store, kinda cool actually... http://www.miogps.com/US/products_h610_features.htm