#emc | Logs for 2009-09-16

[01:02:37] <MarkusBec> MarkusBec is now known as MarkusBec_away
[02:38:56] <toastydeath> thundercats, ho
[02:42:41] <Valen> you didnt do the intro to that
[02:43:06] <toastydeath> that's because i was deprived as a child and saw very little thundercats
[02:45:32] <Valen> ahh
[02:45:37] <Valen> sucks to be you
[02:46:25] <toastydeath> yes.
[02:46:37] <Valen> of course that can e good at times
[02:50:22] <Valen> be
[02:51:47] <Valen> oh yeah ran the servo thread at 10khz last night too, seemed to make things a little smoother
[06:07:58] <Skullworks> Valen : If you happen to read back the bookmark - PM me your email.
[07:15:23] <pjm> good morning
[07:15:55] <micges_work> good morning
[08:03:01] <MarkusBec_away> MarkusBec_away is now known as MarkusBec
[08:18:43] <MarkusBec> MarkusBec is now known as MarkusBec_away
[08:24:37] <MarkusBec_away> MarkusBec_away is now known as MarkusBec
[09:16:43] <piasdom> g'mornin all
[12:31:05] <Valen> Think I voided my warranty ;->
[12:31:20] <Valen> bypassed the current limit on the 7i40 and the mill runs nicley now ;->
[12:32:17] <Valen> Going to run some bussbars so we can run 2 axis simultaneously, without frying the PCB, and put 20-25A fuses in the motor leads
[12:32:44] <Valen> combine that with some forced air and possibly some heat sinking and I am hoping all will be well
[12:33:51] <maximilian_h> Hey Valen
[12:33:56] <Valen> howdy
[12:34:18] <maximilian_h> did you find out what was missing the last time with the debug hal script ?
[12:35:01] <Valen> no, I found the problem on the control cards and have just been using it through axis
[12:35:45] <maximilian_h> too bad, I was quite curious ....
[12:36:08] <Valen> how hard is it to give a step input to the PID through HAL?
[12:36:08] <maximilian_h> but you've got a working setup now, don't you ?
[12:36:16] <Valen> getting there
[12:36:53] <SWPadnos> Valen, if you ever blow a fuse, you will probably see an explosion on the driver card
[12:36:55] <maximilian_h> if the pid controller is connected to the axis module, then you can't input a setup there
[12:37:04] <maximilian_h> but there is an offset module
[12:37:12] <SWPadnos> most motor drivers really don't like to be disconnected from the motor while they're running
[12:38:30] <Valen> I want to tune the PID but its a little difficult when its getting the position updates through a G1
[12:38:59] <Valen> SWpadnos, disconnecting from the motor should be ok, its pulling the power supply that will normally blow stuff up
[12:39:06] <SWPadnos> use a siggen, which has square, triangle, and sine wabe input
[12:39:20] <SWPadnos> no, disconnecting the motor is usually a recipe for disaster
[12:39:33] <Valen> what is the mechanism for that?
[12:39:45] <SWPadnos> at least with steppers. it may not be a problem with servos, but I don't see why it wouldn't be
[12:39:46] <Valen> I can see some arcing past the fuse perhaps
[12:40:01] <SWPadnos> no current sense, so something goes over-voltage (or something like that)
[12:40:20] <SWPadnos> actually, I don't know, so don't listen to my explanation :)
[12:40:26] <Valen> yeah a stepper might do it because the energy in the active coil might dump through an inactive coil
[12:40:50] <SWPadnos> no, it's something to do with current sense
[12:40:53] <Valen> a servo (DC at least) when the motor is disconnected the energy is hopefully just going to go into melting the arc
[12:41:01] <SWPadnos> or lack thereof
[12:41:17] <SWPadnos> it's a drive thing, not a returned energy thing
[12:41:20] <SWPadnos> AFAIK
[12:41:23] <Valen> again if its just open circuit it shouldn't be able to destroy itself
[12:41:33] <SWPadnos> ok. you can try it
[12:41:41] <Valen> lol probably will
[12:41:53] <Valen> one of my "day jobs" is repairing speed controllers
[12:42:04] <SWPadnos> AC, DC, or both?
[12:42:12] <Valen> DC mainly
[12:42:36] <Valen> generally bigger brothers to the layout of the 7i40
[12:42:38] <SWPadnos> ok
[12:43:04] <Valen> 2-4 FET's per leg of the bridge, 50A cont or so
[12:43:38] <Valen> the only way I can see damage happening is arcing as the fuse breaks, It might cause some high voltage spikes into the line
[12:43:50] <Valen> thats a good call, I'll put some TVS diodes in there
[12:44:10] <Valen> which I notice the 7i40 is missing now that I look at it closer
[12:44:33] <SWPadnos> I suspect most drivers are missing that
[12:44:48] <Valen> its pretty common on most motor controllers actually
[12:44:57] <Valen> ones using discrete FETs anyway,
[12:45:11] <Valen> well all the ones I've seen for DC brushed motors have them
[12:45:28] <Valen> it helps protect the driver from brush arcing and the like
[12:45:45] <Valen> Probably more of an issue with a 300A controller
[12:46:40] <archivist> reminds me of how well blown up audio amps can be
[12:47:08] <Valen> I wasn't trying to sound "smart" in that i "know" that it wont blow, Just saying when it does I have a chance of putting the smoke back in ;->
[12:47:25] <Valen> yeah I hear they can cook good
[12:48:24] <Valen> Oh yeah, speaking of which, how hard would it be to get EMC to talk serial (at a high speed presumably) to a controller?
[12:49:03] <Valen> thinking 1 byte address 2 bytes of PWM (probably chopped to 10 bits or so in the controller) then receive 2 bytes of encoder position.
[12:50:31] <Valen> hey archivist have you in your travels seen a glass clock?
[12:50:50] <Valen> as in mechanical ticking clock type dealy with glass gears etc?
[12:53:15] <archivist> no
[12:53:22] <Valen> hmm interesting
[12:53:57] <archivist> one could make one
[12:54:06] <Valen> thats what I was thinking
[12:54:35] <Valen> Might need to plate the edges with some sort of metal to lower the friction somewhat
[12:54:52] <archivist> nah glass will be ok
[12:55:11] <Valen> glass on glass? thought it might be too sticky
[12:55:37] <archivist> but it wont like the shock loads of a typical clock
[12:56:07] <Valen> hmm I was thinking a pendulum style grandfather clock too
[12:56:27] <Valen> It'd only be the early parts that would see the big loads no?
[12:56:39] <Valen> the what is it? "release"?
[12:57:05] <archivist> no, the escapement has shock, and the other end has high static load
[12:57:23] <Valen> glass should be good with the static load
[12:57:48] <Valen> I was thinking of making it out of fairly large peices
[12:58:34] <Valen> ahh there would be the problem with glass on glass, it'll grind itself pretty fast I'd think, and if you got a moderate sized flake of crud in it, it'd make a massive point load
[12:59:50] <archivist> clocks run dry for that reason, so dirt does not stick
[13:00:08] <Valen> I was thinking the crud would come from the gear itself
[13:00:21] <Valen> if you flaked a corner off
[13:00:35] <Valen> be interesting to try anyway
[13:01:52] <Valen> Have you read any terry pratched archivist? specifically "thief of time"?
[13:02:19] <archivist> no, dont read fiction
[13:03:03] <Valen> oh :-< he is pretty good
[13:03:42] <archivist> I have a book habit, but its technical books :)
[13:03:46] <Valen> anyway, must say big thankyou's to everybody here for helping getting the mill running
[13:10:18] <Valen> what escapement would you think would suit such a clock archivist?
[13:10:45] <archivist> grass hopper maybe
[13:12:34] <archivist> http://www.bhi.co.uk/museum.html wooden clock has one iirc but website sux
[13:13:37] <Valen> http://www.geocities.com/mvhw/bpinwhl.html might work ok for it
[13:13:53] <Valen> there are a whole bunch of animated ones there
[13:14:36] <Valen> I was thinking of cheating and governing the pendulum with an electromagnet
[13:17:09] <Valen> (it'd also help with the added friction in that escapement)
[13:35:04] <grmlgrml> i wonder if it's possible to drive small stepper motors directly vai
[13:36:02] <grmlgrml> oops, ...directly via the parallelport (plus small drivers like uml2003)
[13:36:27] <SWPadnos> yes, with an external power supply
[13:36:30] <grmlgrml> with emc2?
[13:36:32] <Valen> could be, would need some hacking though I'd imagine?
[13:36:39] <archivist> not alot of power that way
[13:36:46] <SWPadnos> the parallel port is unlikely to be able to source enough current to move anything
[13:36:55] <SWPadnos> also, you're limited to unipolar motors, I think
[13:37:14] <SWPadnos> stepgen can generate 4-phase outputs, with either full or half-stepping
[13:37:21] <Valen> handy
[13:37:32] <grmlgrml> stepgen?
[13:37:43] <SWPadnos> that's the software step generator in EMC2
[13:38:11] <grmlgrml> ah, ok.
[13:38:14] <SWPadnos> read all about it here http://www.linuxcnc.org/docs/2.3/html/
[13:39:16] <grmlgrml> ok, that helps. thanks.
[13:39:20] <SWPadnos> sure
[13:39:21] <Valen> SWPadnos so what did you think of the possibility of serialing in and out PWM and encoder positions?
[13:39:37] <SWPadnos> not going to be too fast without hardware assist
[13:39:49] <pcw_home> valen: if you disable the current limit, and overvoltage event will turn on all the MOSFETS (with no current limit)
[13:39:51] <pcw_home> This is likely undesireable
[13:39:54] <SWPadnos> bit-banging takes a lot of time
[13:40:16] <SWPadnos> bbiab
[13:40:39] <Jymm> Good morning Mr SWPadnos. yor mission, if you choose to accept it... This irc server will self destruct in five seconds. Good Luck SWPadnos.
[13:42:24] <Valen> pcw_home: just looking at the PCB now, the current sensor seems to be on the low side of the bridge, if the over-voltage turns on the high and low side fets simultaniously, how does the current sensor know what the current is?
[13:44:05] <Valen> SWPadnos, I was meaning to have an external module that would run the actual PWM out, IE you send it a value of 50% and it will run a 50% duty cycle at whatever frequency you wanted. Then you could poll it for the encoder positions
[13:45:00] <Valen> if you had a 2 byte payload you could hit around 7200 updates a second from a standard serial port
[13:45:34] <Valen> probably be more like 5000 by the time you add some error checking and synchronysation gumf
[13:45:45] <pcw_home> It has to go through the low side,,,
[13:46:14] <Valen> oh yeah, duh
[13:46:58] <pcw_home> Without current limit you can easily get 1000A peak
[13:47:08] <Valen> for a short period of time ;->
[13:47:32] <pcw_home> Long enough...
[13:47:35] <Valen> it would be limited by the RDSon of the fets somewhat but not much
[13:48:12] <Valen> I meant the period of time would be short before they became "flame emiting transistors"
[13:50:50] <pcw_home> At low voltages (40 or so) MOSFETS are really tough, so a direct short with 100o or so amps is survivable
[13:50:51] <pcw_home> but watch out for induced voltages elsewhere
[13:51:00] <Valen> we will be keeping the power supply voltage down, 24v seems sufficent to run things
[13:51:16] <Valen> I'
[13:51:27] <Valen> I'll also be adding some TVS diodes to the motor leads
[13:51:41] <Valen> you see any problem with moving the fuse out to the motor leads directly?
[13:53:06] <pcw_home> The Primary fuse see much lower current then motor current in normal servo applications, plus protect PCB
[13:53:08] <pcw_home> in case of MOSFET failure
[13:53:54] <Valen> yeah, We will be bypassing the PCB with bussbars (aka wires) to protect that
[13:54:08] <Valen> i meant wrt what happens if the fuse blows whilst in operation
[13:55:16] <Valen> I dropped the PWM freq to 20Khz and we are seeing mosfet temps of ~50c uncooled after a series of 500mm G0 with a max velocity of 6000mm
[13:55:39] <Valen> running only one channel to keep the currents down somewhat until we get the busbars and forced air cooling in place
[13:57:47] <Valen> was sitting at 60C or so at 60khz
[13:58:02] <Valen> that was doing G1s at 100mm/minute
[13:58:19] <pcw_home> Motor fuse blowing should be OK, It may trigger the overvoltage protection circuit however
[13:58:34] <Valen> from the power supply over shooting?
[13:59:15] <pcw_home> 20 KHz is better, no need for high PWM frequencies unless you have ironless core motors
[13:59:42] <pcw_home> Also slow decay mode is better for efficiency
[13:59:48] <Valen> I tried 5 but the whine was a bit irritating and i figured the ripple current might warm the motors up too much
[14:00:03] <Valen> what is the fedault do you know?
[14:00:22] <pcw_home> Not sure. look at manual
[14:00:28] <Valen> will do
[14:05:06] <pcw_home> Note the the current limit is desiigned so that full 15A current will not cause a rate of MOSFET temperature rise faster
[14:05:08] <pcw_home> than the Overtemp circuit can catch. If you increase or disable the current, you can lose MOSFETS
[14:05:29] <Valen> heh what do I win if i get the mill to play a jaunty tune with the PWM freq ;->
[14:06:10] <Valen> I am fully aware that the warranty is well and truly voided by doing this ;->
[14:07:13] <Valen> where are the temperature sensors on the board anyway? I only see gate drive kinda stuff around the fets?
[14:09:38] <pcw_home> There are some SOT23 dual diodes that are used as temperature sensors
[14:11:18] <Valen> ahh I think i see them, nice hack, very analogue, were you not able to get termistors in surface mount or some such?
[14:12:26] <Valen> I was planning on putting a polyfuse or similar that tripped at 100C onto the fets and have it take out the power supply relay
[14:12:44] <pcw_home> diodes are much cheaper (and linear for those cases where we can xmit the temperature)
[14:12:54] <Valen> It wont save it from driving a short but the power supply should trip if that happens
[14:13:14] <Valen> but it should protect it from overwork type over heating
[14:13:29] <Valen> power supply or motor fuses
[14:14:48] <pcw_home> I think the shutdown temp is 120C
[14:14:52] <Valen> I just figured the signal variation from the temperature of the diode would be low, but then you have those nice opamps floating about the place so analog design holds no fear for you ;-> I prefer digital
[14:15:34] <Valen> yeah thats what the manual says
[14:15:34] <Valen> I was figuring some margin would be an idea as polyfuses are slow and somewhat crappy
[14:20:03] <ChanServ> [#emc] "This is the #emc channel - talk related to the Enhanced Machine Controller and general machining. Website: http://www.linuxcnc.org/, wiki at http://wiki.linuxcnc.org/"
[14:41:18] <Valen> pcw_home: I think ford would not be so helpful If i were to talk to them about putting a turbo on my car, thanks for your help, I really appreciate it
[15:17:57] <pcw_home> NP The MOSFETs are rated 65A at 100C case, the current limit is all about thermal management
[15:18:48] <skunkworks_> I was schooled on that a while ago. (and liqified a few mosfets in the process)
[15:18:54] <pcw_home> (with no heatsink)
[15:21:29] <Valen> they will be package limited less than that I think
[15:21:40] <Valen> TO220 package limit is 75A
[15:21:45] <Valen> more than that you melt the legs
[15:21:46] <Valen> off
[15:23:10] <pcw_home> Yes 42A DC package rating
[15:23:23] <Valen> yeah thats the real killer
[15:23:43] <archivist> fused legs
[15:23:53] <Valen> IRF seemed to be trying to keep the package limit a bit quiet for a while, it was a foot note on the 2nd to last page of their datasheets for a while
[15:43:08] <steve_stallings> steve_stallings is now known as steves_logging
[16:18:41] <skunkworks_> LawrenceG: how is the drive coming?
[16:29:44] <archivist> * archivist just been exploring inside an inverter looking at the mosfwts
[16:30:56] <skunkworks_> pc power supplies?
[16:31:08] <skunkworks_> I would think you cold get some decent ones from there..
[16:31:34] <archivist> IRFZ46N in this one
[16:31:43] <archivist> 37A at 50v
[16:32:31] <archivist> has 16 devices in it
[16:44:30] <LawrenceG> skunkworks, good day.... http://imagebin.ca/view/xQCommQo.html
[16:47:15] <LawrenceG> Skullworks, http://imagebin.ca/view/ufZBtg.html
[16:47:39] <LawrenceG> opps.. ment for skunkworks http://imagebin.ca/view/ufZBtg.html
[17:02:07] <skunkworks_> cool!
[19:19:49] <ZeroFlex1> sjieskebab
[19:19:54] <ZeroFlex1> ZeroFlex1 is now known as ZeroFlex
[19:20:41] <archivist> ¿ qɐqǝʞsǝıɾs
[19:20:59] <ZeroFlex> :)
[19:22:34] <ZeroFlex> archivist do u know how servos and servo drives work ? i'm reading and i'm trying to find it out but keep bumping into things i cant comprehent
[19:22:57] <archivist> just ask and anyone can answer
[19:23:34] <ZeroFlex> well, on ebay (and sort of ebay sitez) i find lots of 3phase servo's (more then normal dc or so)
[19:24:25] <ZeroFlex> but, the motor specifications are so wide spread from motor to motor
[19:25:06] <archivist> because the work they do varies too
[19:25:19] <ZeroFlex> i can find drives (i have read about and people say they are very good and powerfull) but when i look @ the specs on the servo motor they exceed it easely
[19:25:27] <ZeroFlex> the drives can do to 160volts
[19:25:38] <ZeroFlex> but the servomotors need often much more
[19:26:09] <ZeroFlex> yha i know that there are various types of servo's for various types of work
[19:26:24] <ZeroFlex> but why do many of them need such high voltages
[19:27:10] <EbiDK|AWAY> http://www.dailystar.co.uk/news/view/98918/Guinness-is-250-years-old/ Cheers :P
[19:27:17] <SWPadnos> in very general terms, voltage = speed
[19:27:35] <archivist> higher voltage means a faster rate of change of the current though the motor
[19:27:37] <SWPadnos> servos need high torque, since they are expected to change speed and direction often
[19:28:02] <SWPadnos> so they need a lot of current, or a lot of turns of wire (it's amp-turns that generate torque)
[19:28:14] <SWPadnos> more turns means you need higher voltage for a given speed
[19:28:36] <SWPadnos> more amps means you need thicker wire, which increases the moment of inertia, which is not desirable
[19:29:03] <ZeroFlex> ok
[19:29:16] <ZeroFlex> but i thought, that voltage and amps go up together
[19:29:20] <ZeroFlex> when more voltage
[19:29:22] <archivist> more turns mean higher inductance and slower rate of current change
[19:29:23] <ZeroFlex> more amps needed
[19:29:25] <SWPadnos> I think that's the answer, in very broad terms
[19:29:38] <SWPadnos> for a static load, that's true
[19:29:53] <SWPadnos> ie, if you sick a DC supply across the motor terminals, the current will go up as you increase voltage
[19:29:56] <SWPadnos> stick
[19:30:23] <SWPadnos> but, since most servos are driven with more complex controls than a simple switch, that
[19:30:29] <SWPadnos> that's not really applicable
[19:30:54] <SWPadnos> most drives have current limiting, which prevents the (average) current from going past a certain point
[19:30:55] <ZeroFlex> hmm ok
[19:31:17] <SWPadnos> peak current too - they shut off the source if the current gets too high
[19:31:25] <archivist> if your are pwm driving the average the peak current is achieved faster with high voltage
[19:31:50] <SWPadnos> yes, which also improves response to changing speed requirements
[19:32:03] <SWPadnos> ie, acceleration :)
[19:32:24] <ZeroFlex> owkeej
[19:32:42] <ZeroFlex> http://vincent-w.demon.nl/download/servo/100_4641.JPG <<-- thats a servo i was looking for
[19:32:49] <ZeroFlex> 3 phase 370 volts
[19:33:41] <archivist> ac servo
[19:34:07] <ZeroFlex> will it be usefull behind this drive then ? http://www.granitedevices.fi/index.php?q=servo-drive-vsd-e
[19:34:30] <ZeroFlex> or wil it just run @ 40% of its power
[19:34:55] <SWPadnos> it will either run or it will not run. I'd ask Granite Devices if that motor will work with their drive
[19:35:13] <ZeroFlex> they say it will
[19:35:20] <SWPadnos> then it probably will :)
[19:35:23] <ZeroFlex> but how i cant tell
[19:35:49] <archivist> dunno if you get full torque or just a bit slower
[19:35:59] <SWPadnos> their drive is an AC or DC drive. I don't know how that works
[19:36:09] <ZeroFlex> yha thats what i mean archivist
[19:36:25] <archivist> prolly good enough
[19:36:36] <archivist> depends on machine
[19:36:58] <SWPadnos> I didn't notice the current rating of the motor
[19:37:13] <SWPadnos> you won't get more than 40% of the rated speed
[19:37:17] <SWPadnos> (160 / 370)
[19:38:08] <ZeroFlex> hmmm
[19:38:31] <archivist> motor has A 60 on it and drive is 20A peak
[19:38:35] <ZeroFlex> so will be better for me too look for more suitable servo's for the driver, or find more suitable drivers for the servo
[19:39:00] <archivist> dunno...what torque /speed do you need
[19:39:18] <SWPadnos> unless 1/6 torque and 0.4x speed is sufficient for your machine
[19:39:38] <ZeroFlex> hmmm
[19:39:56] <ZeroFlex> nope, want a quik machine
[19:40:11] <SWPadnos> then it's time to find a different motor/drive combination
[19:40:17] <ZeroFlex> k
[19:40:17] <archivist> heh, time for some thinking
[19:40:46] <ZeroFlex> * ZeroFlex is getting a bigger headache and a feeling of a red account book .... :)
[19:40:56] <ZeroFlex> hmm
[19:41:11] <ZeroFlex> what are good alternative drives ?
[19:41:57] <ZeroFlex> 70% of the servo's on ebay (ebay sitez nearby the netherlands) is of an higher voltage
[19:46:51] <PCW> ZeroFlex: Most larger motors use ~360V as thats what you get from a direct line operated supply (from 220V)
[19:49:35] <ZeroFlex> hmmm
[19:51:54] <PCW> A 60A 360V motor is pretty damn big for a servo, is this 60A peak or continuous?
[19:56:27] <ZeroFlex> thats another prob, cant get my hands on a spec sheet of siemens
[19:56:31] <archivist> hence the need to size motors correctly so you dont throw the machine out the door on a traverse
[19:56:48] <ZeroFlex> contacted them but they (i think) wont give me the data sheet
[19:57:42] <ZeroFlex> want to know where i got the motor from etc
[19:59:18] <cradek> the motors on my not-huge but very fast VMC are 6.5A continuous 32A instantaneous
[19:59:31] <ZeroFlex> hmm
[19:59:42] <ZeroFlex> how big is that vmc cradek ?
[19:59:47] <cradek> it is this motor http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190108618319
[20:00:46] <cradek> small for a vmc - about 24x18x18 travel
[20:00:53] <ZeroFlex> hmm
[20:00:59] <cradek> extremely fast, rated 780 inch/minute rapids
[20:01:10] <ZeroFlex> owhz yha
[20:01:32] <PCW> 320V motors?
[20:02:20] <cradek> the amps take 320V in, but the motors say 113v 6.5A continuous
[20:02:34] <cradek> strangely, there is no max V rating on the motor label
[20:02:49] <BJT-Work> * BJT-Work heads home to play with a giant Hilti hammer drill and some concrete
[20:03:02] <ZeroFlex> lol
[20:03:10] <PCW> Probably high voltage but low current for rapids
[20:03:54] <PCW> So about 1HP continuous
[20:04:15] <cradek> anyway I agree it seems like 60A is a huge servo and would belong on a very large machine
[20:05:10] <ZeroFlex> ok
[20:05:19] <PCW> We have a 45A peak 360V motor here we use for testing its about 4 HP
[20:05:34] <ZeroFlex> i dont have a little machine but neither a big one
[20:05:51] <PCW> (4HP continuous)
[20:06:00] <archivist> about bridgeport size
[20:06:17] <ZeroFlex> its in industrial conventional machine with NC on it of heidenhain but driven only with one motor on 3 axes with sort of gearbox in it
[20:06:29] <ZeroFlex> i would say a smaller
[20:06:36] <ZeroFlex> deckel fp2 alike
[20:06:46] <ZeroFlex> maho mh300
[20:06:54] <skunkworks_> http://www.electronicsam.com/images/KandT/servotag.JPG
[20:07:32] <ZeroFlex> hmmm
[20:07:43] <ZeroFlex> also big peak amp
[20:10:33] <PCW> skunkworks: how big a machine is that from?
[20:10:54] <skunkworks_> I don't know - never saw it. it was blue ;)
[20:11:16] <skunkworks_> it direct drived a 2tpi ball screw
[20:11:58] <PCW> Probably a lot bigger the ZeroFlexs' machine
[20:12:51] <skunkworks_> :)
[20:12:53] <cradek> ZeroFlex: do you have belt reduction between servo and screw?
[20:13:11] <cradek> oh one motor + gearbox, hmm
[20:13:15] <cradek> WILL you have belt reduction? :-)
[20:13:56] <ZeroFlex> yha, the servomotor's must be mounted on the outsite of the machine but will use a belt drive for it not direct on the axis
[20:14:09] <ZeroFlex> axis - spindel
[20:19:04] <skunkworks_> http://www.electronicsam.com/images/KandT/conversion/yservomaybe.JPG
[20:20:22] <skunkworks_> cradek: get your pannel done?
[20:20:51] <cradek> cut and installed yes - wired no
[20:21:27] <cradek> I don't have enough IO so I'm faced with adding another 5i20 and opto22 board [which I have, but hate to use just for a front panel] or figuring something else out
[20:21:28] <skunkworks_> nice :)
[20:21:42] <skunkworks_> printer port?
[20:21:56] <cradek> yes that's possible - not sure if it's quite enough though
[20:22:07] <cradek> combined with the few opto IO left over, yes (but ick)
[20:22:11] <skunkworks_> heh
[20:22:15] <skunkworks_> so hackish
[20:22:48] <cradek> I could also make a USB thingy to read the panel switches etc in userland
[20:22:53] <cradek> but, also ick
[20:23:13] <cradek> so that's why I'm not further along
[20:24:10] <cradek> hm it's even worse - when I hook up the spindle encoder I have to lose two more IO for the jogwheel
[20:25:51] <skunkworks_> jepler has a 72 i/o pci board that just need to be debugged.. ;)
[20:25:58] <cradek> ugh
[20:26:21] <cradek> iirc it is just defective hardware
[20:26:32] <skunkworks_> yes - most likely
[20:30:47] <skunkworks_> isn't there a 4 header mesa card?
[20:31:04] <cradek> yes but it's expensive
[20:31:06] <skunkworks_> ah
[20:31:31] <cradek> more than two 5i20 (6 connectors) iirc
[20:31:47] <cradek> (... which does not make sense to me)
[20:31:50] <skunkworks_> so - does anyone know what they use in cheap oilless air compressors? piston/cylinder so they last?
[20:32:03] <skunkworks_> cradek: odd
[20:32:03] <cradek> what makes you think they last?
[20:32:17] <skunkworks_> well - last for more than a few hours anyways... ;)
[20:32:29] <EbiDK> EbiDK is now known as EbiDK|AWAY
[20:32:38] <cradek> they use extreme volume to make you turn them off as fast as possible - this leads to longer life
[20:32:45] <cradek> (sorry I have no idea)
[20:32:47] <skunkworks_> heh
[20:33:02] <cradek> I assumed they were a rubber thing and reeds like an aquarium pump, not a piston at all
[20:33:15] <skunkworks_> a lot of the pancake style ones contrators use for trim nailing are that style.
[20:33:18] <SWPadnos> the 5i22-1 is only $369
[20:33:30] <SWPadnos> it's only the -1.5 that's >2x the 5i20
[20:33:37] <cradek> SWPadnos: oh ok, thanks
[20:33:45] <cradek> * cradek distributes much misinformation
[20:33:48] <SWPadnos> heh
[20:33:48] <skunkworks_> heh
[20:33:55] <skunkworks_> hater!
[20:34:02] <SWPadnos> for the extra $60, I'd probably just get the extra .5M gates
[20:34:04] <SWPadnos> (but that's me)
[20:34:33] <cradek> I have no use for more gates than emc needs
[20:34:48] <cradek> (or may reasonably need in the future)
[20:34:50] <SWPadnos> I suppose that depends on how many gates might be useful in the long term
[20:34:52] <SWPadnos> yep
[20:35:43] <cradek> a couple pins for spi-to-a-bunch-of-not-quite-as-realtime-IO would solve my front panel problem neatly
[20:36:12] <cradek> wouldn't even have to be isolated - the IO card could run LEDs and power the switches itself
[20:44:35] <SWPadnos> isn't there a 7i64 or some such for that?
[20:44:59] <cradek> but our firmware can't run it, right?
[20:45:04] <SWPadnos> well, there is that
[20:45:12] <SWPadnos> plus, it's about as expensive as another 5i20
[20:46:11] <cradek> ok, that's not a win for me then
[20:53:43] <SWPadnos> if you didn't have the 5i20 already, a 5i22 would be a win
[21:06:06] <jepler> cradek: somewhere around here I have a usb avr board with 17 I/Os in a mesa-like "alternating grounds" configuration. (mesa-like because it's only 36 pins instead of 50, and because I put grounds on odd numbered pins, not even).
[21:06:31] <jepler> with the right firmware it should be able to count an axis of quadrature at 1kHz+, read the other inputs, and act like a USB HID device..
[21:14:06] <PCW> We haev a SPI thingy coming out (7I50) that gives 24 I/O Open drain TTL (I/O module dirve capable) from one SPI port Its $45
[21:17:48] <PCW> Actually 5I20 firmware supports 7I64, driver does not
[21:17:50] <PCW> but can be hacked to work using rawread/rawwrite
[21:17:52] <PCW> maybe Ill poke at Jimbos component till it works
[21:17:55] <cradek> both of those sound great for this
[21:18:59] <cradek> I already have usb up there in the head, for the screen
[21:19:10] <cradek> would just add a hub
[21:19:49] <PCW> 7I43 with usb HostMot2 woud work as well if there were a driver (Just looks like a serial port)
[21:20:38] <cradek> wonder if seb wants to visit lincoln...
[21:24:51] <PCW> I think SPI support looks like a bottomless pit so he's been avoiding looking at it
[21:26:01] <SWPadnos> http://www.ultimarc.com/JShopServer/section.php?xSec=13
[21:26:22] <PCW> Jimbos component to access the 7I64 had these enormous case statements translating bits to u32
[21:26:24] <PCW> is there some better way to translate a bit array to u32
[21:26:34] <SWPadnos> weighted_sum
[21:26:42] <SWPadnos> or a loop
[21:26:55] <PCW> (both ways?)
[21:27:00] <SWPadnos> no
[21:27:11] <SWPadnos> but he could have used a loop instead of the case statements
[21:27:19] <PCW> I guess HAL only has bits, not bit arrays
[21:28:11] <PCW> How do you index through the bit parameters?
[22:01:21] <SWPadnos> PCW, the bits are an array of HAL_BIT types, and can be indexed like any other array
[22:02:25] <SWPadnos> in C, I'd do something like this: for (i=0,mask=1,result=0;i<32;i++,mask<<=1) { if (input[i]) result |= mask; }
[22:03:06] <SWPadnos> bbl
[22:17:32] <PCW> OK in the comp they were individual I presume non-indexable bits.
[22:17:33] <PCW> Ill change to array of bits
[22:43:38] <Guest577> question about G43 tool offset specifically G00G43Z0.7874H1 Is that offset essentially the same as a touch off on Z of .7874 ? That is every Z move from that point on is realtive to .7874?
[22:49:34] <Guest577> Anybody? Or did I explain it badly?
[23:17:28] <MarkusBec> MarkusBec is now known as MarkusBec_away
[23:21:49] <cradek> that moves Z up by the length of tool #1 (H1)
[23:22:27] <cradek> hm, impatience pays off
[23:33:17] <tomp> tomp is now known as tom3p