#emc | Logs for 2009-11-24

[22:08:59] <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/"
[22:09:18] <tom3p> tarzan: these look like collets http://shop.kress-elektrik.ch/browse.php?sid=529001259099882&pos=c136 but i spose many 'hand drill's dont
[22:09:25] <tom3p> yay! logs are back
[22:09:25] <awallin> so 1750/13= 134V
[22:09:35] <skunkworks_> might want to keep an eye on these drives also... (usually go pretty cheap for a try)
[22:09:46] <skunkworks_> http://cgi.ebay.com/Advanced-Motion-Control-Servo-Amplifier-BE25A20H-AMC_W0QQitemZ120495808484QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1c0e1c1fe4
[22:10:09] <skunkworks_> BE is brushless
[22:11:42] <tom3p> cheap... reminds me i just got 2 turkeys, and gotta make room in freezer right away. look for 'Deals' in midwest, (like a dollar store) 5$ per turkey, 10-12lbs yep, 5$!
[22:11:42] <tom3p> bbl
[22:13:22] <awallin> just worried with ebay drives that finding the pinouts for the connectors is difficult and programming the PID-loop and I-limits etc is even more difficult
[22:14:01] <skunkworks_> This drive take +/-10v
[22:17:13] <skunkworks_> BE25A20 is 25a peak 200vmax 14.5a cont.
[22:18:17] <skunkworks_> bbl
[22:19:27] <awallin> so where could I get a 1000ppr encoder for the spindle motor? cheap!
[22:23:56] <tom3p> aha, but 1000ppr at what speed ( count frequency )?
[22:24:13] <alex_joni> 2EtaHz
[22:24:31] <tom3p> thats like a kajillion, maybe more
[22:24:38] <awallin> the servo is rated for 3000rpm, and the spindle bearings for 4500 I think
[22:24:57] <alex_joni> 500kHz
[22:25:09] <alex_joni> err.. 50kHz
[22:25:23] <awallin> yes, that should be ok for the m5i20
[22:25:26] <awallin> I think
[22:25:55] <alex_joni> 5i20 counts up to 2MHz I think
[22:28:21] <fenn> 4000counts/rev * 3000 rpm = 200kHz
[22:28:40] <pjm__> awallin i have a surplus heidenhain rod620 quadrature encoder, 1250ppr if its any use
[22:29:01] <awallin> mm, the square wave is only 50kHz, but there are two of them in quadrature, and 200 edges/s
[22:29:09] <awallin> 200k
[22:29:33] <awallin> pjm__: does it have A, B, and Index output? any pics?
[22:30:35] <pjm__> it says zero pulse ref=1 on the case so i guess thats index
[22:30:39] <tom3p> is it 1v p/p or the 11ua for AB and 5ua for Z ( many pre-2000 heids are micro amp)
[22:30:58] <pjm__> all the outputs are driven by a 74hc04, its ttl as far as i can see, +5v vcc etc
[22:32:53] <pjm__> its pretty much the same as http://stronic.fr/photos/DRJ0016.jpg except without that multiway connector
[22:33:15] <tom3p> rod 260 with ttl? rod270 is ttl http://www.auto-met.com/heidenhain/angularencoders/ROD200.htm
[22:33:15] <tom3p> nm: rod 260 is ttl
[22:33:34] <pjm__> i'm only guessing due to the o/p IC
[22:33:44] <pjm__> plus everything on the case is 5v etc
[22:33:54] <tom3p> label shows sqr wave
[22:34:06] <pjm__> yeah with UA1/UA2
[22:34:11] <pjm__> and a direction arrow
[22:34:30] <pjm__> i have another heidenhain encoder, 18000 ppr
[22:34:43] <pjm__> but saving that for a rainey day
[22:34:55] <tom3p> sornau connectors, plan on soldering your favorite onto cable.
[22:35:26] <tom3p> nice stuff
[22:36:31] <tom3p> good point... awallin theres how fast you can read it and how fastthe encoder is rated to spin and how fast the encoder electronics can supply the signals ( each has a limit )
[22:38:45] <tom3p> i think heidenhain bought out anilam anorad and bei, heidenhain is devouring all the other encoder companies, like geo. fischer ate up so many of the edm companies
[22:46:52] <PCW> Ever look at the Renishaw Resolute encoders? pretty amazing 27 bit absolute encoder capable of 36000 RPM
[22:47:18] <awallin> amazing price also?
[22:47:33] <PCW> Im' sure
[22:47:51] <PCW> They work a little like an optical mouse
[22:48:07] <DaViruz> 27bit :O
[22:49:07] <PCW> Led flash takes snapshot of magic barcode, DSP processes image
[22:51:19] <PCW> (probably just linear image sensor)
[22:57:32] <andypugh> Renishae encoders are not horribly expensive, and you can buy direct at http://www.rlsdirect.com/ProductSelection.aspx
[22:58:57] <alex_joni> PCW: I'm more amazed at the older absolute encoders
[22:59:03] <alex_joni> the ones that are mostly mecanical inside
[22:59:23] <alex_joni> one big disc for current rotation, then lots of gearing and smaller discs for rotation counts
[22:59:23] <PCW> (but they dont show the "RESOLUTE" models)
[22:59:56] <andypugh> There is a design for a 13 bit absolute encoder with only one track, and the sensors cunningly placed round it.
[23:00:16] <andypugh> rswww.com
[23:00:46] <andypugh> Doh! stubid snow-leopard "upgrade" has changed the windwo selection behaviour
[23:01:42] <tom3p> awallin: take alook at this chip, http://www.rls.si/default.asp?prod=am4096
[23:01:52] <PCW> Alex: Yes, Ive taken some of those mechanical encoders apart. tiny ball bearings and anti-backlash gears
[23:01:54] <tom3p> andypugh: running an osx ?
[23:01:58] <andypugh> Aye
[23:03:08] <alex_joni> PCW: right.. wonderfull work inside them
[23:03:53] <PCW> Reminds me of some of the old mechanical flight computers
[23:04:59] <alex_joni> fly by mechanical wire?
[23:05:03] <alex_joni> :D
[23:09:28] <numen> is it possible, to build an handjog for emc2 with usb?
[23:09:48] <awallin> check the wiki
[23:09:53] <awallin> joypad or smth
[23:10:49] <cradek> emc reads the wheel in real time to give responsive jogging. you can hook a wheel to a parport or any other realtime digital input you have, or you can use any supported hardware encoder counter
[23:11:59] <numen> cradek ive just 1 parallel port
[23:12:18] <numen> no pci ports
[23:12:18] <numen> just usb
[23:13:31] <andypugh> USB joypads are easy to set up, even I managed it.
[23:13:33] <andypugh> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Simple_Remote_Pendant
[23:14:30] <awallin> with hm2, is it possible to have PWM-generators in hardware with different PWM rates, say 25kHz for Z and X axes, but 100 kHz for spindle control
[23:14:43] <awallin> that is hm2-driver on m5i20 card I am thinking about
[23:15:17] <alex_joni> awallin: probably with a special firmware, but PCW will surely set me straight if wrong
[23:15:48] <awallin> I thought hm2 was all about modular firwmare on the fpga?
[23:16:50] <alex_joni> modular things enabled from an existing firmware
[23:16:50] <andypugh> However I am thinking of making a USB jogwheel using one of these chips (which appear as HID devices, so should hook into EMC like the joypad does, but give you 16 digital bits of IO)
[23:16:51] <andypugh> http://www.delcomproducts.com/productdetails.asp?productnum=902770
[23:17:13] <alex_joni> awallin: take a 12 servo, 4 stepper firmware, then you can mix&match things
[23:17:41] <alex_joni> say you want 4 encoder counters, 3 pwm gens, 3 stepgens
[23:18:47] <ds3> how fast can emc read pulses from the serial port control lines like DCD or CTS?
[23:19:50] <awallin> alex_joni: ok, I was just thinking about driving the spindle in torque mode, so then I would know in real-time the commanded torque. But maybe I can just drive it in position-mode with step/dir and forget about monitoring spindle torque
[23:19:52] <archivist_emc> no one in there right mind used the serial port
[23:19:58] <archivist_emc> uses
[23:20:03] <numen> i dont realy want a joypad
[23:20:12] <numen> s.th like an rotary encoder
[23:20:31] <ds3> archivist_emc: why? the DCD and CTS lines are basically GPIOs
[23:20:39] <awallin> get more parallel ports, or dedicated hardware
[23:21:44] <andypugh> numen: Maybe that USB chip then, with a quadrature encoder and hardware quadrature to binary chip reporting wheel position back to EMC on some of the 16 io bits?
[23:23:26] <numen> andypugh just 1 parallelport avaible
[23:23:39] <andypugh> Yes, so use USB
[23:24:13] <andypugh> That cypress USB chip I linked to earlier.
[23:24:19] <andypugh> Then http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=4965642
[23:25:25] <andypugh> and http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2508309689
[23:26:20] <numen> this one has no usb...
[23:26:37] <andypugh> Or, at the risk of missing some quadrature counts, skip the interface chips and wire the USB IO into a soft quadrature counter in EMC
[23:27:12] <andypugh> Eh? You said you had no PCI, but did have USB.
[23:27:36] <Engineer> Hello all
[23:27:36] <andypugh> If you have no PCI, no USB, no parallel then you don't have many places to plug in a jogwheel
[23:27:38] <PCW> awallin: With current HM2 firmware, there is only one PWM reference counter so all PWM frequencies are the same
[23:27:39] <PCW> and the driver sets the resolution based on frequency, but if you really needed 25 KHz and 100 KHz and you dont mind
[23:27:41] <PCW> 12 bit resolution on 25 KHz versus 10 bit on 100 KHz its possible to hack the driver and get 2 (binary multiple) rates
[23:28:33] <micges> hi Engineer
[23:28:40] <awallin> PCW: ok, I was thinking about a setup with one analog servo axis, your 7i33 is designed for 100kHz, and the other axes would be PWM-drive at 25kHz or so.
[23:29:18] <numen> andypugh usb i have
[23:29:25] <PCW> Oh NP for 7I33, 7I33 is optimum with PDM and it has its own rate
[23:29:33] <numen> the chip, you've shown has no usb
[23:29:40] <andypugh> numen: which one?
[23:29:57] <numen> http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2508309689
[23:30:04] <awallin> not sure what the best control for a lathe spindle with C-axis capability is. for turning you want high RPMs but for C-axis very slow or standstill
[23:30:13] <Engineer> I was wondering.. I want to design my own microcontroller for my 3-axis cnc machien .. what would be the best choice of driver chip to work just fine with EMC2 software ?
[23:30:16] <awallin> PCW: what is PDM?
[23:30:40] <awallin> Engineer: what would your microcontroller do?
[23:30:43] <PCW> Pulse Density Modulation
[23:31:04] <archivist_emc> numen, you use more than one chip to build the interface
[23:31:33] <awallin> PCW: so I could run the 7i33 with 25kHz PWM from the 5i20 and the analog +-10V is still "clean"
[23:31:38] <Engineer> controlling the three step motors
[23:31:54] <Engineer> and reading a simple feed back
[23:32:01] <andypugh> I meant this one: http://www.delcomproducts.com/productdetails.asp?productnum=902770
[23:32:19] <Engineer> about the current positions of the motors
[23:32:24] <PCW> awallin: Yes optimum PDM rate ist set to 6 MHZ and PWM is independent of that
[23:32:52] <andypugh> Which is digital IO to USB, and then use the quadrature to parallel to link up the rotary switch
[23:33:24] <archivist_emc> Engineer, emc does the position control not external, you just need stepper drivers, step and direction
[23:33:33] <awallin> PCW: ok. do you have 5i20 and 7i34 and 7i33 in stock at the moment?
[23:33:40] <PCW> (optimum for 7I33 you can tradeoff ripple for linearity)
[23:33:49] <andypugh> But, as I also mentioned, it isn't too bad if EMC misses pulses on a jog wheel, so you could just wire USB input direct into an EMC encoder counter.
[23:34:20] <awallin> hm I menat 7i37TA
[23:34:26] <awallin> meant
[23:34:43] <Engineer> any recomended MC diagram ?archivist
[23:35:12] <andypugh> Mesa seem to use highly-trained carrier-snails to deliver to the UK
[23:36:26] <PCW> We are behind with 7I37TAs (maybe a week now) others in stock
[23:36:28] <PCW> (7I47 maigh be a 7I34 alternative if you want RS-422 with terminal blocks)
[23:36:42] <Engineer> ....
[23:36:56] <PCW> (better than untrained carrier snails)
[23:36:58] <awallin> I want isolation, differential encoder inputs, and the one analog output
[23:37:05] <archivist_emc> Engineer, http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl see mid page for setting up stepper systems
[23:37:09] <andypugh> Engineer: What do you mean by MC diagram?
[23:37:46] <PCW> 7I33 will give you 4 diffen enc niputs and 4 analogs sort of overkill
[23:37:57] <Engineer> mc= microcontroller
[23:38:08] <Engineer> thanks a lot friend
[23:38:25] <archivist_emc> Engineer, we dont use microcontrollers really
[23:38:26] <awallin> PCW I will need 3 of the encoder inputs. Will not do anything with 3 remaining analog outputs
[23:38:38] <PCW> that was well typed I must say...
[23:38:47] <Engineer> then what do u use ?
[23:39:01] <archivist_emc> the pc does the work
[23:39:40] <archivist_emc> and use a stepper driver bought or home made
[23:39:59] <Engineer> you connect the stepers directly to the parellel port ? or what ?
[23:40:14] <Engineer> I see
[23:40:47] <archivist_emc> very nearly, usually via an opto isolater
[23:41:24] <andypugh> You _can_ run steppers directly from the parallel port, but it is silly.
[23:41:34] <Engineer> well >> I'm still fresh to the whole CNC stuff
[23:41:44] <Engineer> it won't work
[23:41:50] <PCW> Maybe you could try the 7I47-S (new) Its got the 4 encoder inputs plus 1 analog out (unipolar 5-15V you supply reference = isolated pot replacement)
[23:42:03] <Engineer> they drain a large amount of current
[23:42:15] <awallin> steppers are silly. use servos, AC ones if you can afford them.
[23:42:39] <andypugh> It has been done with very, very, small steppers. I did say it was silly.
[23:42:47] <awallin> PCW: hm, the servo-drive wants +-10V torque command
[23:44:09] <archivist_emc> Engineer, in all cases there is an interface to increase the current
[23:44:18] <awallin> * awallin sleeps
[23:44:23] <PCW> Oh well, no 7I47-S
[23:44:28] <Engineer> that's for sure
[23:44:41] <pjm__> awallin let me know if u are interested in this encoder, we can do a deal!
[23:44:57] <Engineer> archi .. what do you think about this stepper motor : https://secure1.make-a-store.com/cgi-bin/alltronics/Make-a-Store.cgi?category=154&item=28M009&=&quantity=3&<ELEMENT>.qty.x=104&<ELEMENT>.qty.y=15&<ELEMENT>.qty=1
[23:45:05] <awallin> pjm__: where are you (shipping??)
[23:45:20] <pjm__> england
[23:45:28] <pjm__> its very light, i can send it to you if u want to muck about with it to test etc
[23:45:58] <archivist_emc> pjm__, did you get the milling head?
[23:46:05] <pjm__> ahh finland, i'm up in denmark next week which is closer so could post it then
[23:46:11] <pjm__> archivist neggy, it got a bit silly!
[23:46:19] <archivist_emc> :)
[23:46:21] <awallin> could you send me a pic: anders.e.e.wallin at gmail.com
[23:46:26] <andypugh> Engineer: Well, it's cheap enough, but a bit tiny.
[23:46:33] <andypugh> What size machine are you using?
[23:46:34] <pjm__> awallin sure i'll do it tommorow
[23:46:51] <archivist_emc> Engineer, a bit small for real work, a bipolar motor has more power
[23:46:57] <Engineer> and what would you recomend Archi .. I need a powerful one
[23:47:29] <andypugh> Are you in the US?
[23:47:34] <archivist_emc> I dont know your machine, measure the torque needed
[23:48:15] <Engineer> well I had the design in 3d-max form
[23:48:20] <andypugh> These Nema 34 steppers look like a serious bargain to me, and he has lots of them.
[23:48:22] <andypugh> http://cgi.ebay.com/G58046-Parker-VS31B-DFFLY-Motor_W0QQitemZ290371630288
[23:48:25] <archivist_emc> pjm__, I was bidding a spectrum analyser near you but that got silly too
[23:48:32] <Engineer> I designed it myself
[23:48:43] <pjm__> ah right, typical, thats the way of ebay i spose!
[23:48:55] <pjm__> although there seems to be a good run of decant priced microstepper drives lately
[23:49:03] <pjm__> i bought a couple as 'stock' for my machine
[23:50:25] <Engineer> it's quite large so I need a powerful motors .. 3-4 volts and about 4 amp current
[23:50:53] <andypugh> If you are in the US, snap up some of those I just linked to.
[23:51:56] <archivist_emc> Engineer, we use much higher voltages to get the steppers to move faster
[23:52:12] <archivist_emc> 40 volts ish
[23:52:17] <Engineer> is there a website that I can buy the stepper system with their micro-controller from ?
[23:52:44] <andypugh> Lots of them. Which country are you in?
[23:52:44] <awallin> geckodrive is popular
[23:52:51] <archivist_emc> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?EMC2_Supported_Hardware
[23:52:59] <awallin> actually I have three geckodrives and NEMA34 motors for sale
[23:53:02] <Engineer> what's the current being used with 40 volts ?
[23:53:15] <archivist_emc> the same
[23:53:19] <andypugh> You set the drive to the motor rated current
[23:53:19] <awallin> http://picasaweb.google.fi/anders.e.e.wallin/3AxisStepperDriveMotorsForSale#
[23:53:51] <archivist_emc> the drive limits the current
[23:54:01] <Engineer> thanks guys .. you're really very helpful
[23:54:21] <andypugh> But the voltage is used to overcome the motor inductance, for faster pole-switching and higher speed
[23:54:52] <Engineer> I might be the first one in Iraq to design and build a home made CNC mechien LOL
[23:55:04] <Engineer> I see
[23:55:29] <andypugh> Fastest way to get up and running would be http://www.geckodrive.com/product.aspx?c=3&i=14469
[23:55:55] <archivist_emc> see what others have done http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?EMC2_Supported_Hardware
[23:56:12] <andypugh> Though there are much cheaper 4-axis drives out there on eBay.
[23:56:56] <andypugh> http://cgi.ebay.co.uk/New-4-Axis-CNC-Stepper-Motor-TB6560-Driver-Board_W0QQitemZ130345894797
[23:56:56] <Engineer> it's hard for me to buy from ebay .. shipping costs too much!
[23:57:15] <andypugh> That one I just posted is free shipping...
[23:57:30] <awallin> well this is funny: http://www.freesteel.co.uk/wpblog/2009/11/detecting-shallow-areas-on-bad-triangulations/
[23:57:31] <andypugh> (direct from China, so you are closer)
[23:57:44] <Engineer> free only inside the US i think
[23:58:02] <Engineer> oh really ? from china
[23:58:11] <Engineer> yea much closer
[23:59:27] <andypugh> Ah, actually, not free to Iraq. But probably worth asking how much extra it is.
[23:59:59] <Engineer> I would say about 200$ extra fees