#linuxcnc | Logs for 2012-03-27

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[00:38:37] <Nick001> ssi - you there
[02:01:06] <DJ9DJ> moin
[03:33:18] <Loetmichel> mornin'
[05:27:03] <Paragon-ws> Hello Everyone. What would be a recommended resistor for interfacing the Mesa 7i43 to IL74 opto-couplers?
[05:34:14] <SolarNRG> Hi guys
[05:34:20] <SolarNRG> The microwaveable crucible arrived today
[05:34:36] <SolarNRG> Here's my very first picture of it http://i.imgur.com/Ow1yj.jpg
[05:36:37] <SolarNRG> Here's the first video of it: www.youtube.com/watch?v=6RR-LsALORY
[05:49:59] <awallin> SolarNRG: no flame/furnace needed for alu-casting then?
[05:54:42] <Paragon-ws> Could someone please point me to a homebrew circuit design for a breakout board / optocoupler board that can be used to interface the Mesa 7i43 card?
[05:56:30] <awallin> optoisolators. but the chips may not be as cheap as they were in 2006... http://www.anderswallin.net/2006/08/optoisolator-cards-for-mesa-5i20-servocard/
[05:56:31] <SolarNRG> awallin, hopefully not
[05:56:51] <SolarNRG> I'm getting a bigger microwave to fit the lid on it and a fire extinguisher to be safe then I'm doing it
[05:57:19] <awallin> Paragon-ws: and a very simple breakout-board with no optoisolation http://www.anderswallin.net/2010/01/mesa-5i20-breakout-boards/
[05:57:40] <awallin> SolarNRG: cool. keep us posted on the progress!
[05:57:59] <Paragon-ws> awallin: Thanks very much.
[05:59:01] <SolarNRG> Thanks~
[05:59:13] <awallin> Paragon-ws: although in fairness if mesa has isolator/breakout cards in stock it is probably faster and cheaper to buy from there than to DIY...
[05:59:23] <Paragon-ws> SolarNRG: One thing to note, I would suggest running it outside if you are going to melt beer / coke cans etc as the smell from the paint is quite smelly!
[06:00:11] <SolarNRG> I have an extension lead
[06:00:30] <SolarNRG> This is what I did during my first test: http://www.youtube.com/watch?v=VSKl1konZ0U
[06:00:30] <awallin> SolarNRG: I guess you need some handles etc. to pick it up and something to pivot the kettle around for pouring into a mould..
[06:00:46] <SolarNRG> But with a very primitive crucible that didn't work
[06:00:47] <Paragon-ws> awallin: I was considering that. I did make some awhile ago but on revisiting the project my mind is a little fuzzy.
[06:01:05] <SolarNRG> The airgap means the crucible can be lifted by hand wearing gloves
[06:02:56] <Paragon-ws> SolarNRG: LOL I like the way you took cover behind the door!
[06:02:58] <SolarNRG> Also I've snipped off the paint bits of the cans I'm only using the tops and bottoms
[06:03:08] <SolarNRG> The door acts as a saftey screen
[06:08:04] <Paragon-ws> I built a 3k Watt induction heater a few years ago which I managed to melt steel with. It was initially based on an LCLR tank with a schmitt trigger for self resonance. But I rebuilt it based on this design http://www.mindchallenger.com/inductionheater/
[06:11:24] <SolarNRG> Nice!
[06:12:21] <awallin> SolarNRG: where did you get that microwave furnace? and how much $ ?
[06:13:06] <SolarNRG> I had to ring up a company that made it for me
[06:13:09] <SolarNRG> It wasn't for sale
[06:13:11] <SolarNRG> It was custom made
[06:13:16] <Paragon-ws> I used a graphite crucible to melt aluminium which would melt in about 40-50 seconds! :-)
[06:13:31] <SolarNRG> But you'd burn your hands on it though
[06:13:44] <SolarNRG> This you can lift the outer ring by hand, no burns, no medical biills
[06:14:41] <Paragon-ws> Oh for sure... I used tongs to pick up the crucible and wore thick leather foundry gloves for safety.
[06:15:44] <Paragon-ws> The crucible was a small foundry type held around 3-4oz at a guess.
[06:18:18] <Paragon-ws> SolarNRG: I would still suggest that you wear leather foundry gloves. In the event that it cracks in your hands while lifting which is a distinct possibility due to thermal stresses especially over time!
[06:18:22] <SolarNRG> Your crucible only had one ring though?
[06:18:30] <SolarNRG> I have leather foundry gloves
[06:18:40] <SolarNRG> And I'm going to be wearing my oven mittens on top to give me double insulation
[06:18:55] <SolarNRG> You think the crucible will eventually die on me?
[06:20:15] <awallin> hm. when you start pouring from that, will all the molten alu end up in the air-gap?
[06:21:44] <Paragon-ws> SolarNRG: Over time I think it will. As each melt will deteriorate it. Additional moisture will inadvertently creep in due to it being hygroscopic in nature which could cause hairline cracks when heating.
[06:22:43] <Paragon-ws> This is the same shape crucible I used ... http://b2bprofessionaltools.net/GRAPHITE-CRUCIBLES-SIZE-8/M/B003F5SJX2.htm?traffic_src=GB&utm_medium=CSE&utm_source=GB&id=uk
[06:24:14] <SolarNRG> Yeah, you're right
[06:24:34] <SolarNRG> Nice, it has a little spout!
[06:25:32] <mazafaka> Do you want to create pastons for moto or auto engines?
[06:26:02] <SolarNRG> I'd like to make an alcohol engine
[06:26:11] <SolarNRG> as in one that makes alcohol for me to drink
[06:26:13] <SolarNRG> :D
[06:29:30] <mazafaka> it also shall make snacks then
[06:32:59] <Paragon-ws> Is there away to search the #emc archives? The reason I ask is that I covered a lot of the ground with regards to interfacing and protection of the 7i43 card quite sometime ago but am rusty on revisiting the topic.
[06:34:54] <psha[work]> Paragon-ws: http://psha.org.ru/irc/
[06:35:14] <psha[work]> or use google with site: tag
[06:35:29] <psha[work]> logger[mah]: .
[06:35:30] <logger[mah]> psha[work]: Log stored at http://linuxcnc.mah.priv.at/irc/%23linuxcnc/2012-03-27.html
[06:35:54] <psha[work]> Paragon-ws: same here http://linuxcnc.mah.priv.at/irc/
[06:36:06] <Paragon-ws> psha[work]: Thanks psha[work] ... Google with site: tag?
[06:36:38] <psha[work]> if you add site:something.com/path into google it will limit search to that site
[06:36:54] <psha[work]> so it's possible to search for "something site:http://linuxcnc.mah.priv.at/irc/%23linuxcnc/"
[06:36:57] <psha[work]> for example
[06:37:24] <Paragon-ws> Oh didn't know that.. That's very handy! :-)
[06:37:52] <psha[work]> don't know about mah's logs but my are indexed
[06:37:54] <psha[work]> mostly :)
[06:38:11] <psha[work]> on-site search however searches through all logs
[07:11:30] <mazafaka> psha[work]: 'logs' are being amateur users? :)
[07:31:44] <mazafaka> psha[work]: Do you like UAZ van properly but moderately modified
[07:40:27] <mazafaka> Loetmichel: would you like this vehicle: http://i.drom.ru/reviews/photos/uaz/buhanka/big_43829_9451_add_2.jpeg (4400x1850x2100 mm, 1815 kg dry weight), dimensions: http://uazbuka.ru/models/img/razm3962sx.gif
[07:43:29] <Loetmichel> hmmmm
[07:43:33] <Loetmichel> little small
[07:43:39] <mazafaka> :)
[07:44:02] <Loetmichel> but should be grat as a camping van for the "no road needed/wanted" guys ;-)
[07:44:08] <Loetmichel> great
[07:45:29] <mazafaka> for landskaper.de - yes, but not for me. I think to use gas for gasoline engine, all together for about 3000 USD, and I will need to gradually restore and renew various mechanisms, and clean some rust off the frame and the body
[07:47:05] <mazafaka> Loetmichel: I just want some volume for moto or bicycle, for some dry twigs I could find somewhere in the forest, to store it for winter.
[07:47:57] <mazafaka> I also think of some social activity - neighbours ask for transporting and welding, and roof repairing...
[07:48:19] <Loetmichel> wouldnt be my car of choice, not since we hat a gaz(elle) pickup in the company. to unreliable.
[07:48:36] <Loetmichel> but one has to work with what one has...
[07:49:02] <Loetmichel> s/hat/had
[07:49:10] <mazafaka> And UAZ is considered as needing maintenance in the garage while can turn you back from the trip even with some bearings broken
[07:49:56] <Loetmichel> ok, if you say so...
[07:53:02] <mazafaka> this is an opinion of they owners, and it's new to me.
[07:53:49] <mazafaka> Loetmichel: gazelle is a name of big russian van from the GAZ manufacturer
[07:54:42] <mazafaka> as a truck: http://auto-bazar.com.ua/images/gruzovik/2010/a46abf845e1465167be375c9d5219614.jpg
[08:15:45] <Loetmichel> mazafaka: right
[08:15:58] <Loetmichel> we had one in the company for "rugged tests"
[08:16:45] <Loetmichel> (strapped the Server/workstation under test on the loading bay, driven across a fresh plowed field ;-)
[08:17:08] <Loetmichel> ploughed
[08:20:26] <ssi> morn folks
[08:21:47] <Loetmichel> ssi: evening from here ;-)
[08:22:11] <ssi> are you some kind of time traveler?!?!
[08:22:40] <SolarNRG> Guys I want a top to wear so that if I get splashed by molten aluminium it will negate the damage enough for me to co2 myself. what do you recommend?
[08:22:56] <SolarNRG> Would a boiler suit work?
[08:23:00] <ssi> welding jacket?
[08:24:51] <mazafaka> Loetmichel: Russian car magazines has a lot of experience using Russian cars and trucks. There are many unreliable things in them. Although, current VAZ is considered to be ot bad city car.
[08:32:23] <Loetmichel> ssi: no, german ;-)
[08:33:10] <Loetmichel> ssi: just wear a motorcycle leather suit
[08:33:21] <Loetmichel> or a welding jacket/trousers ;-)
[08:33:39] <Loetmichel> should be enough for an occasional spill
[08:34:08] <Loetmichel> would not be sufficient if you plan to pour the cucible over your head, though
[08:34:19] <Loetmichel> ;-)
[08:34:52] <mazafaka> dangerous, do everything being sane and having clear mind
[08:35:50] <mazafaka> I think women around like men who do the job very technically, with necessary safety - but easily at the same time\
[08:35:57] * Loetmichel has poured aluminium wearing only a face shield and a bottom long "matrix" leatherjacket
[08:36:32] <Loetmichel> (and gloves of course)
[08:36:49] <Loetmichel> small drops of aluminium are nothing bad
[08:37:12] <Loetmichel> just be sure that you have NO opening where the molten alu can jump in
[08:37:33] <Loetmichel> just (at least 1.2mm thick) leather on the outside
[08:37:33] <mazafaka> whole another craft to know how to do this all
[08:38:06] <mazafaka> welding is a craft, too
[08:39:04] <Loetmichel> mazafaka: hmmm... so i am not really a talented artist...
[08:39:45] <Loetmichel> my last weld on saturday (stick weld inverter, 1,5mm sticks, 30A) ...-> http://www.cyrom.org/palbum/main.php?g2_itemId=12958
[08:40:35] <Loetmichel> ... have done that MUCH better, should get some exercise ;-)
[08:46:43] <mazafaka> MAG welding is very easy, sticks for stick welders must be dry (or dry enough to at least weld somehow)
[08:48:53] <Loetmichel> mazafaka: right.
[08:48:55] <mazafaka> or MIG... I do not remember the abbreviation...
[08:49:23] <Loetmichel> MIG/MAG is the one with the blank wire instide the Gas nozzle
[08:49:35] <Loetmichel> MMA is the one with sticks
[08:51:47] <Loetmichel> and you're right : mig/mag can be done by every retart, if the current and feed is adjusted by a professional at least ;-)
[08:51:55] <Loetmichel> retard
[08:54:35] <mazafaka> ha, exactly.
[08:54:54] <mazafaka> I have newer adjusted it myself
[08:58:07] <Loetmichel> mazafaka: difference mig/mag: mig= welding with 100% Ar, (for inox and aluminium for example), MAG= welding with CO2 oder mixes CO2/Ar (for mild steel
[08:59:25] <Loetmichel> but to be honest i thoight the abbreviations were german
[08:59:37] <Loetmichel> "MIG" = Metal Inert Gas"
[08:59:52] <Loetmichel> MAG "Metal Active GAS"
[09:01:08] <Loetmichel> MMA "manual metal arc welding"
[09:08:47] <mazafaka> yeah...
[09:14:05] <mazafaka> I think welding of a car body needs MAG or I can use 2 mm sticks with MMA I have bought this winter.
[09:15:37] <mazafaka> Loetmichel: Whole fun is I will have to reduce tyres pressure for this AWD van to be parked in another garage (my garage only can handle huge SUVs with soft top, maybe some middle-height SUVs)
[09:16:20] <mazafaka> Soviet Union has given us strange real estate items.
[09:18:06] <Paragon-ws> Quick question regarding ILD74 and 4n25 optocoupler input voltage. Can I feed these with 12v input?
[09:19:07] <awallin> datasheet?
[09:21:42] <Paragon-ws> awallin: I looked at the ild74 datasheet but I cannot see what the max voltage input is. The peak reverse is 3v with Forward continuous current of If= 60ma
[09:22:34] <Paragon-ws> http://www.datasheetcatalog.org/datasheet/vishay/83640.pdf
[09:23:46] <pcw_> with the right input resistor, sure so 1.1 K for ~10 mA
[09:23:49] <awallin> hm, ok. you should put a series resistor to limit the current to something suitable. that resistor will determine the voltage range that will work (or is safe)
[09:24:28] <Paragon-ws> Great, Thanks Guys!
[09:25:01] <pcw_> If you are fussy about input threshold you can put a parallel resistor across the LED as well
[09:25:34] <pcw_> you als0 need to know how much output current you need
[09:26:02] <Paragon-ws> The output is to be fed into a 7i43 io card
[09:27:14] <pcw_> those OPTOS have a 12.5% minimum CTR so 10 mA in may only give you 1.25 mA out
[09:28:03] <pcw_> I think you would want a better guaranteed CTR
[09:29:17] <Paragon-ws> Mmmm I see...
[09:31:21] <Paragon-ws> Could I use say a 250 ohm to give 40ma in and 5ma out? Would that work?
[09:31:37] <pcw_> The 7I43 uses the FPGAs built in pullups on the I/O pins. These are in the 2-10K region
[09:31:39] <pcw_> so worst case around 1.6 mA. So you could just use the OPTO output to ground the 7I43 pins
[09:31:41] <pcw_>
[09:32:08] <pcw_> Yes but thats 1/2 a watt!
[09:32:43] <Paragon-ws> True ... God it's been a while!
[09:33:56] <pcw_> I would choose a better OPTO ( or maybe 20 mA would be an OK compromise if you already have the OPTOs)
[09:34:18] <Paragon-ws> Would the opto output require a resistor to protect the 7i43. Yes already have a bunch of them.
[09:35:24] <pcw_> No if the OPTO is physically close to the 7I43 no other components are needed
[09:36:05] <pcw_> I am assuming this is for relatively slow signals
[09:36:34] <pcw_> limit switches etc
[09:36:37] <Paragon-ws> Cool. What about going the other way around. The 7i43 driving the input of the coupler? Yes it is for limit switches, Greyscale 3 pin input etc.
[09:36:50] <Paragon-ws> Estop and so on.
[09:37:38] <pcw_> for the 7I43 driving the OPTO you will need a resistor
[09:38:26] <Paragon-ws> What would be an ideal value? From memory the 7i43 is 30ma max right?
[09:38:37] <pcw_> 24 Max
[09:38:46] <Paragon-ws> Oh 24 ok.
[09:39:15] <Paragon-ws> 500ohm?
[09:39:56] <pcw_> Well would not use the maximum current unless you have to (better opto...)
[09:40:12] <Paragon-ws> 5v/500ohm = 10ma ?
[09:40:52] <awallin> there will be some voltage drop over the diode too..
[09:41:45] <pcw_> so if you connect the OPTO anode to a 390 Ohm resisitor connected to 5V
[09:41:47] <pcw_> and connect the OPTO cathode to ground, this will give about 10 mA
[09:42:31] <pcw_> you need to set the 7I43 for 5V tolerant inputs and use open drain drive to do this
[09:44:05] <Paragon-ws> I think I have already set it to 5v tolerant some months back. But I will check the documentation for the jumper settings just incase
[09:44:36] <pcw_> (set both is_opendrain and invert_output attributes for the GPIO pin that drives the LED)
[09:44:54] <pcw_> assuming OPTO on = ON
[09:46:03] <Paragon-ws> just pulling up the manual. I have the card in my hand.
[09:54:16] <ssi> I think it'd be helpful to have a document somewhere that illustrated common techniques for interfacing hardware
[09:56:57] <Paragon-ws> OK just checked the card and manual here is the configuration of the 7i43 card, W1=up (5v supplied to p3 an p4), w2=up (Bus Switch Mode 5v tolerant), w3=up (pre-config pull-ups pins in high state) , w4/w5 = down (epp comms mode), w6=up (currently set for usb power)
[09:57:36] <Paragon-ws> Does this appear to be OK?
[09:58:36] <pcw_> Yes but the open drain and invert stuff still applies
[09:59:38] <Paragon-ws> pcw_ were do I configure that, within EMC?
[09:59:59] <Paragon-ws> Sorry for my naivety!
[10:00:09] <ssi> hal parameters on the pin
[10:00:43] <pcw_> you need open drain so the LED is not slightly driven by the 5V - 3.3V = 1.7V you will have with the default P-P outputs
[10:00:55] <pcw_> when off
[10:01:13] <pcw_> man hostmot2
[10:01:54] <Paragon-ws> Oh I see, otherwise there will still be a small amount of power to the LED. Right?
[10:02:37] <pcw_> Yes
[10:03:41] <Paragon-ws> Thanks Guys! :-)
[10:05:51] <Paragon-ws> So in a nut-shell when connecting 7i43 to output of opto-coupler no resister is required but connecting it to the input of the opto in my case try a 390ohm resister.
[10:06:30] <Paragon-ws> As well as open-drain as stated.
[10:07:42] <pcw_> 5V ==> 390 Ohm R ==>OPTO LED anode ==> 7I43 output
[10:08:16] <pcw_> oops should be LED cathode ==> 7I43 output
[10:09:20] <Paragon-ws> OK great thanks pcw_.
[10:10:19] <pcw_> this 5V should come from 7I43 (pin 49)
[10:11:09] <Paragon-ws> I see.
[10:13:39] <pcw_> Though this is less important on 7I43 and other Spartan3 or 6 cards as the
[10:13:41] <pcw_> 5V tolerance bus switches make the outputs float when there is no power
[10:16:31] <Paragon-ws> And coming from a limit switch for example: switch==> 5v/12v ==> 390/1k ohm ==> OPTO LED anode ==> OPTO LED cathode ==> GND
[10:18:43] <jdhnc> is there a repository of 7i43 bitfiles other than the ones that come with the stock install?
[10:21:19] <Paragon-ws> should the output of opto come from collector or emitter into the 7i43 input?
[10:24:33] <awallin> I guess you can put a pull up/down resistor on either collector or emitter. not sure how to choose between those..
[10:25:11] <awallin> with the resistor on the collector ("high") side the logical "0" will not be exactly 0V
[10:25:37] <awallin> with the resistor on the emitter side ("low") the logical "1" will not be exactly +VCC
[10:26:59] <Paragon-ws> OK, so what would you say is more preferable high side or low side or is it arbitrary?
[10:27:00] <pcw_> jdhnc there may be a few more in the mesa 7I43 dist (there are 31 pinouts available currently in the source)
[10:27:29] <pcw_> emitter to ground, collector to 7I43 input
[10:27:54] <Paragon-ws> and no resistor required?
[10:28:00] <pcw_> (that way you use the I/O pullup thats already there)
[10:30:09] <pcw_> (31 7I43 pinouts out of 147 total pinouts ATM)
[10:31:09] <Paragon-ws> Oh that makes sense. So that is current sinking right?
[10:31:26] <pcw_> Yes
[10:31:40] <Paragon-ws> It's starting to sink in ;-)
[10:32:29] <pcw_> if you notice the bare FPGA pins are pulled up (so if you read an unconnected input it will read high)
[10:33:25] <pcw_> So if you are careful you can use the bare FPGA pins for switches just by grounding them
[10:33:41] <pcw_> with the switch closure
[10:34:08] <Paragon-ws> Right I see :-)
[10:34:20] <pcw_> but if you connect the wires to something bad (say 12V) its fryola
[10:36:07] <Paragon-ws> Hence the use of the opto to switch the state of the 7i43 pin to gnd.
[10:38:00] <jdhnc> is there any advantage to a 7i43 over a 5i25 (if you don't need the additional pins)
[10:38:41] <pcw_> Not really
[10:39:15] <Paragon-ws> Thanks for your help! Very much appreciated!
[10:40:23] <jdhnc> a 5i25+7i76 seems to have more than enough IO for any home stepper system.
[10:40:25] <pcw_> welcome
[10:40:49] <pcw_> Yeah it s probably over kill
[10:41:21] <jdhnc> $199 with cables though.
[10:41:50] <pcw_> plus you could add a 7I74 and have more than 400 I/O points :-)
[10:42:20] <ssi> I really want to try the sserial stuff
[10:42:41] <jdhnc> I have a 7i34, don't remember why.
[10:42:44] <pcw_> Andy did a nice job on the driver
[10:42:52] <ssi> I'm thinking that I'm going to get a '44 for my third port on my 5i23
[10:43:06] <jdhnc> and a 7i47
[10:43:18] <ssi> and then a '69 for my front panel, and a '73 for a pendant
[10:43:21] <ssi> that'd be a pretty hot setup
[10:43:45] <ssi> I'm gonna have a damn thousand dollars just in mesa hardware in this machine before I'm through :)
[10:43:54] <pcw_> 7I47 is good for step/dir/encoders/sserisl mixes
[10:44:21] <pcw_> the 69 and 73 are pretty cheap
[10:44:36] <ssi> oh wow they are
[10:44:38] <ssi> sweet
[10:44:53] <ssi> then I'll need a couple more breakouts for the '69 probably
[10:45:00] <ssi> well I have another '42TA on hand
[10:45:27] <jdhnc> with the 7i43, I could use the 7i47 on one port for stepgen & encoder and 7i37TA on the other for general IO?
[10:45:36] <pcw_> Sure
[10:46:01] <jdhnc> I feel better about what I bought now :)
[10:46:09] <pcw_> SVST2_4_7I47_48.vhd
[10:46:12] <ssi> pcw_: warn me before you guys are ready to ship the high-output '49, I may want to have you box in some extra stuff :)
[10:46:18] <Jymmm> pcw_: (Think we can get ssi up to $2000 before the day is over?)
[10:46:40] <Jymmm> pcw__: (and up to $32,000 before the end of the week?)
[10:47:01] <pcw_> well eveything at this point is $49 to $79 so it will be tough
[10:47:02] <ssi> would that I had $32,000
[10:47:13] <ssi> yea the '49 was the big outlay
[10:47:19] <ssi> one of the more expensive daughtercards
[10:47:34] <Jymmm> pcw__: (We'll go for the shirt and pants next week ;)
[10:47:53] <pcw_> well A-D and lots of little parts make it expensive
[10:47:58] <ssi> yep
[10:48:11] <ssi> and it's got it's own little mcu on it too, doesn't it
[10:48:22] <ssi> although I guess the sserial ones do too
[10:48:47] <pcw_> no mcu on 7I49
[10:48:54] <Loetmichel> grrr... all aluminium mill bits <=2mm broken. and mmetoolshop.de doesent deliver the last wees order of fresh ones...
[10:48:54] <ssi> oh I thought it did
[10:49:06] <Loetmichel> *wait*
[10:49:28] <pcw_> but because of all the little parts assy cost is >$30.00
[10:49:54] <ssi> yeah makes sense
[10:50:08] <pcw_> MCU is in FPGA
[10:50:09] <ssi> it's got a billion little jellybeans on it
[10:50:57] <pcw_> many of which are .1% resistors
[10:51:03] <ssi> right
[10:51:25] <Jymmm> 0.1% seriously?
[10:51:51] <ssi> got to have TEH PRECISIONZ
[10:51:57] <pcw_> its also expensive for you since you are only using 2 or 3 channels
[10:52:04] <ssi> yes, that's true
[10:52:11] <ssi> it feels wasteful :)
[10:52:24] <ssi> I need to add three more axes to the machine just for the hell of it
[10:52:33] <Loetmichel> hmmm. 0.1% resistors. whar a waste
[10:52:39] <pcw_> I may make a cheaper 3 resolver/4encoder version
[10:52:40] <Jymmm> ssi: add 12 instead, then you'l have extras
[10:52:55] <ssi> pcw_: having a mix would be really nice
[10:53:36] * Loetmichel makes his R2R networks with standard 1% 0603 on reel and match half a 10k reel just before soldering into one board ;-)
[10:54:05] <ssi> sounds tedious
[10:54:22] <ssi> especially with 0603... do you have a fixture to do that?
[10:54:27] <ssi> doing it by hand sounds like a recipe for cramps
[10:56:41] <Loetmichel> ssi: just a rig to press the Rs on 2 contacts with a tweezer
[10:56:55] <Loetmichel> and some boxes to sort them in classes.
[10:57:18] <ssi> Loetmichel: you know you can buy them presorted right?
[10:57:23] <ssi> they're called 0.1% resistors :D
[10:57:28] <pcw_> .1% are not just selected 1% they have better TCR and are less affected by stress on PCB
[10:57:30] <pcw_> definitely worth the ~$0.10
[10:57:49] <Loetmichel> i.e. a box <990R, a box 990-1000, a box 1000-1010 and so on ;-)
[10:58:19] <Loetmichel> ssi: i can, but i am to cheap for that ;-)
[10:58:23] <ssi> if they're 1%, you shouldn't have any < 990R!
[10:58:43] <Loetmichel> jeh, make that 999, 1000, 1001 and so on
[10:58:49] <ssi> :D
[10:58:58] <Loetmichel> was just an example
[11:00:01] <frysteev_> moo
[11:00:42] <ssi> I have had my control cabinet on its side on a table for the last week or so while I was wiring it
[11:00:49] <ssi> last night I cleaned up and righted it
[11:00:58] <ssi> tonight I need to re-hookup all the cables to the lathe
[11:01:03] <Loetmichel> the exact value isnt inportant in r2r, just that all Rs are identical ;-)
[11:01:13] <ssi> Loetmichel: yea I'm familiar
[11:01:31] <ssi> Loetmichel: and I guess I shouldn't be surprised.. if you're too cheap to buy a DAC, not surprising you're too cheap for 0.1% resistors :)
[11:01:42] <Loetmichel> right ;-)
[11:01:56] <ssi> k lunch bbl
[11:02:29] <Loetmichel> but at the moment i am noch cheap, i am angry to be stalled by not having any mill bits left
[11:02:54] <MattyMatt> make the r-2r out of nichrome and trim it with a dremel
[11:02:57] <Loetmichel> should have ordered some time ahead, knowing that my dealer needs sometimes more than 2 weeks...
[11:03:09] <Loetmichel> MattyMatt: BTDT ;-)
[11:03:24] <Loetmichel> (but with steel wire, not nichrome ;-)
[11:05:47] <MattyMatt> sounds sensitive, unless they were 3ft wires :)
[11:33:06] * JT-Shop wonders how many days it will take to download 80mb on dial up :?
[11:35:08] <Jymmm> JT-Shop: This has gone on for a week so far, when is your broadband suppose to be back up?
[11:40:02] <JT-Shop> never
[11:40:29] <JT-Shop> they are taking down the tower because the butt head next to the tower sued them
[11:44:50] <Loetmichel> exactly next to the tower?
[11:45:34] <Loetmichel> ... where the field is the lowes because of the "donut" charactaristics of the antennas?
[11:46:49] <Loetmichel> thats like here in germany, where (iirc) Vodafone build a gsm tower. immediatly there were "buergerinitiativen" formed and people complainig about headace and sleepless and so on...
[11:47:15] <Loetmichel> comment from vodafone: "ho bad will it get when we switch the tower ON?"
[11:47:17] <Loetmichel> ;)
[11:47:33] <cradek> wow
[11:48:51] <cradek> I guess it's nice that people are so safe and secure in daily life that they need to make up imaginary threats/enemies/hardships
[11:49:54] <JT-Shop> this nut claimed the tower caused more lightning strikes on his house...
[11:50:27] <JT-Shop> when they take the tower down he will be the highest point on the hill LOL
[11:51:01] <Loetmichel> harhar
[11:51:13] <pcw_> Maybe that will solve the problem
[11:51:15] <Loetmichel> does he know ben franklins invention?
[11:51:21] <cradek> buy him a set of golf clubs
[11:52:38] <Loetmichel> cradek: i dont think its imaginary. more like placebo: if people think something will have an impact on their health, it WILL have a measurable impact.
[11:52:56] <Loetmichel> no matter there is no source of influence
[11:54:10] <cradek> I agree the placebo effect is real
[11:54:23] <cradek> ... but I don't think that's contrary to what I said
[11:54:28] <pcw_> well they just need to say "everyday in every way I'm getting better and better"
[11:54:30] <pcw_> (from the discoverer of the placebo effect)
[11:55:46] <Loetmichel> cradek: i meant: its not because they are "safe and secure" its more because they are TOLD it will bei a thread
[11:55:50] <Loetmichel> so it IS a thread
[11:56:20] * cradek shrugs
[11:57:55] <pcw_> what I dont get is people that complain about cell phone
[11:57:57] <pcw_> towers 100 meters away then put a 3W cell phone transmitter
[11:57:59] <pcw_> inches from their brain
[11:58:25] <cradek> pcw_: maybe schools should teach the inverse square law
[11:58:39] <pcw_> sounds like a plan
[11:59:16] <archivist> very hard to stay awake during an inverse square law lecture
[11:59:19] <Loetmichel> PCW: nothing wors than a sound half-wit ;-)
[11:59:26] <Loetmichel> +e
[11:59:47] <cradek> yes shrill panicked crazy folks waving their arms around are much more exciting to listen to
[12:00:22] <archivist> JT-Shop, sue the bum for loss of internet
[12:00:47] <ssi> friend of mine works for itron, making smart power meters
[12:00:47] <Loetmichel> the only time I was afraid of microwaves wars at the navy, $me working on the radar dish and som stupid sergenant switched it on (afer removing the 50*80cm Sing saying not to and puttin in some new main fuses)
[12:01:04] <ssi> and there's a bunch of paranoid crazies that think that the smart power meters are this huge privacy threat
[12:01:28] <ssi> one of them said this:
[12:01:29] <ssi> The radio-frequency waves and electromagnetic fields emitted by the smart meters slapped on our property without our consent are harmful to our health. For those who falsely claim they are no more harmful than cell phones, why do you think we are warned to shut off our cell phones and wireless devices during aircraft take off? If cell phones can interfere with the plane's electronic gadgets, it stands to reason that a smart meter's constant pulse can in
[12:02:10] <Loetmichel> ssi: they are right. a smart power meter CAN be used to tell waht you are doing, even which TV channel you are lokking at.
[12:02:34] <pcw_> because they are smart
[12:02:37] <ssi> taken alone, perhaps
[12:02:45] <pcw_> too smart...
[12:02:51] <Loetmichel> but: who will be interested enough at "john doe" to crack the safetys and lokk at the meters 24/7?
[12:02:52] <ssi> but they're far from the biggest threat along those lines
[12:02:56] <IchGuckLive> Hi all around the world
[12:02:58] <ssi> ffs look at the "Smart TVs" that are coming out
[12:03:03] <cradek> yep that airplane thing sure proves it
[12:03:06] <ssi> cradek: right?!
[12:04:00] <cradek> airlines know best when it comes to electromagnetic fields causing health problems
[12:04:12] <Loetmichel> hmm
[12:04:23] <ssi> also
[12:04:25] <pcw_> smart meters have to be some of the more benign RF devices just because of their power budget (at least the lithium cell powered gas meters around here)
[12:04:35] <ssi> the "no cell use while airborne" thing doesn't come from the FAA
[12:04:37] <ssi> it comes from the FCC
[12:04:48] <IchGuckLive> no EM today -> http://sohowww.nascom.nasa.gov/data/realtime-images.html
[12:04:51] <Loetmichel> some iof the airlines are re-allowing cellphones and computers at the moment...
[12:04:52] <cradek> what about AM radio!!?!
[12:04:55] <ssi> because line of sight on a cellphone at altitude means they can see HUNDREDS of towers
[12:05:03] <Loetmichel> so that argument is down the drain ;-)
[12:05:29] <cradek> I know for 100% certain that AM radio programs damage people's brains
[12:05:31] <ssi> but nowadays cell towers are less omni, and they have nulls more vertically
[12:06:15] <ssi> (which sucks when you're actually trying to use a cellphone in an airplane, btw)
[12:06:36] <ssi> I usually have to get down inside 3000' AGL in order to check my email ;)
[12:06:50] <Loetmichel> ssi: harhar
[12:06:55] <ssi> serious
[12:06:59] <Loetmichel> i know
[12:07:09] <ssi> not only that, a couple times I couldn't get FSS on the radio,
[12:07:16] <ssi> so I descended and filed flight plans via iphone
[12:07:18] <ssi> super lulzy
[12:08:18] <pcw_> In other news what about the tsunamis caused b HAARP?
[12:08:36] <ssi> oh is that what did it? :P
[12:09:38] <pcw_> I saw it on the webs
[12:30:10] <IchGuckLive> Question homany steps are you calculationg for rotation axis is 1000steps per Deg egnoph ?
[12:31:44] <IchGuckLive> i want to build a high performance C-axis with Nema34 400steps 30:1 30:1 400x30x30=360000
[12:31:58] <archivist> plenty, the rotary itself wont be that good
[12:32:33] <IchGuckLive> i got parts with 2.5m diameter
[12:32:36] <archivist> gear and worm quality is your real limit
[12:33:08] <IchGuckLive> i woudt go for 2 pricise worms
[12:33:15] <IchGuckLive> http://maedler.de/Product/1643/1619/705/743/769/771.aspx
[12:33:59] <archivist> there is no quality spec there
[12:34:55] <IchGuckLive> http://smarthost.maedler.de/datenblaetter/praezischnecken_EN.pdf
[12:36:38] <archivist> those are power drive sets no angular specification
[12:39:43] <archivist> try 90:1 for best results
[12:41:31] <IchGuckLive> the 30x30 gives me a 0,0218mm at 1250mm part radius min tool displace
[12:41:59] <archivist> you need a collimator and mirror on the axis to check rotational accuracy, /me seen nearly a degree of error on "quality" rotaries
[12:42:07] <IchGuckLive> i think thats ok also it holds 80Nm
[12:42:52] <archivist> dont confuse resolution with accuracy
[12:43:06] <IchGuckLive> i see
[12:44:03] <IchGuckLive> as it is syrocut main use i think its good enoph at all
[12:45:58] <archivist> my rotaries are 90:1 and 400 steps per rev of the steppers, not fully tested these for accuracy yet but are cheap Vertex type
[12:47:19] <IchGuckLive> at 120Euros the precision ones are not expensive
[12:51:29] <IchGuckLive> example of parts that wee make 3mx2mx1meter http://www.pictureupload.de/originals/pictures/270312194056_burg.jpg Drawing
[12:53:38] <IchGuckLive> i think this year i will also go for a vertical lathe with rotation headIf i can overcome the postprocess
[12:57:58] <IchGuckLive> this is the largest part the mashine ver handeld http://www.pictureupload.de/originals/pictures/270312194734_styropor_gaul.jpg
[12:58:12] <IchGuckLive> ever has handeld
[13:18:40] <IchGuckLive> everyones dream milling 5axis 1:5
[13:18:44] <IchGuckLive> http://www.youtube.com/watch?v=vark2IBMGr0
[13:19:50] <archivist> you should make sure you control worm to gear backlash
[13:19:57] <IchGuckLive> http://www.mdaprecision.com/
[13:20:24] <IchGuckLive> Starting as low as: $24,000 B) O.o
[13:20:47] <FredrikHson> hi i was wondering if anyone here has any experience milling pcbs specifically how to clamp the boards down without getting them tilted or anything like that
[13:21:15] <IchGuckLive> FredrikHson: Vacuum
[13:21:23] <IchGuckLive> i mill that way
[13:21:30] <FredrikHson> just did one board where i cut a plane + some stops out of a mdf board and 4 screws at the sides worked... well not at all
[13:21:33] <cradek> FredrikHson: carpet tape
[13:21:50] <cradek> clamping simply doesn't work
[13:21:56] <FredrikHson> tried tape before and got 1 working board and one tilted so :\
[13:22:04] <IchGuckLive> cradek: agree
[13:22:11] <cradek> use better tape and be more careful
[13:22:19] <cradek> and/or :-)
[13:22:32] <IchGuckLive> 3M has very good stuff
[13:22:50] <cradek> a couple pics of my results using carpet tape: http://timeguy.com/cradek/cnc/pcb
[13:23:08] <FredrikHson> ok will try some tape again then
[13:23:12] <IchGuckLive> archivist: i only mill in one rotation direction no backwards
[13:23:28] <FredrikHson> that looks pretty good actually
[13:24:19] <archivist> my beef with carpet tape is bending the item getting it off!
[13:24:23] <pgf> IchGuckLive: why is that important, in this case?
[13:24:43] <IchGuckLive> pgf: what ?
[13:24:54] <pgf> milling in just one direction
[13:25:11] <pgf> oh -- sorry.
[13:25:19] <pgf> thought you were talking about pcb milling.
[13:25:39] <alex4nder> joe9: you still alive?
[13:25:41] <FredrikHson> hmm i think i need to make sure to actually check that its level before milling the next time ;)
[13:25:41] <IchGuckLive> no the rotation axis going from 0to360 no backward the mill goes up and down
[13:25:53] <FredrikHson> guess i was just to lazy to look for the dial
[13:25:54] <joe9> alex4nder: yes.
[13:26:00] <IchGuckLive> pgf: B)
[13:26:15] <alex4nder> joe9: good, just making sure
[13:26:18] <alex4nder> how's the mill?
[13:26:46] <joe9> good, opened the boxes. will have it assembled in a day or two.
[13:26:51] <FredrikHson> cradek: do you use an endmill or a vbit for those?
[13:27:06] <IchGuckLive> FredrikHson: spindel speed at 60.000rpm is the best
[13:27:19] <IchGuckLive> ok its late need to go by
[13:27:25] <cradek> V
[13:27:35] <FredrikHson> 60k... my machine only goes up to 11
[13:27:46] <FredrikHson> but i run it at max anyway
[13:48:09] <fragalot> I run mine at 28k atm, and it's a bit too slow
[13:53:17] <FredrikHson> works just fine at 10k for me the feed speed isn't that great anyway on this thing
[13:53:26] <FredrikHson> tops out at 800ish
[13:54:54] <JT-Shop> YEA! my OD roughing/finishing nggui subroutine works so much better now
[13:58:47] <ssi> JT-Shop: OMG WANT
[13:58:58] <ssi> JT-Shop: how are you handling the profile?
[14:01:54] <JT-Shop> ssi: I thought you downloaded them yesterday?
[14:02:09] <ssi> I probably did, but I haven't actually LOOKED at them yet ;)
[14:02:20] <JT-Shop> LOL
[14:02:24] <fragalot> FredrikHson: mine tops at 800 too but I rarely go over 75
[14:02:26] <ssi> I've been deep in hardware
[14:02:35] <JT-Shop> well the profile-od or what ever it is called does profiles
[14:02:43] <ssi> btw I'm still trying to figure out how to handle high/low clutch for spindle
[14:02:46] <JT-Shop> I can understand
[14:02:55] <ssi> either you or cradek have some magic that'll help me I'm sure
[14:03:21] <JT-Shop> I'm wondering if I might want have a choice of SFM for roughing and finishing???
[14:03:50] <JT-Shop> my spindle is direct drive so cradek is your man for that
[14:05:45] <ssi> is yours a servo?
[14:09:51] <JT-Shop> yes
[14:10:12] <JT-Shop> I just programed a 4 step part in seconds :) I love ngcgui
[14:15:55] <fragalot> nice
[14:27:04] <Nick001-Shop> does your program do corner rounding as it's going up the diameters?
[14:28:02] <ssi> Nick001-Shop: I cleaned my X tach yesterday
[14:28:18] <ssi> it seems to have made a bit of difference in the servo response
[14:28:24] <Nick001-Shop> I looked at it real quick yesterday on the formum but not in detail.
[14:28:26] <Nick001-Shop> Is anyone working on a program to do incremental changing in the cold table?
[14:28:38] <ssi> I did notice that I had to retune it afterward; it buzzed a bit once I cleaned it and I had to reduce the gain
[14:28:41] <Nick001-Shop> SSI-I saw that yesterday and was there much oil in their
[14:28:46] <ssi> no, not really
[14:28:55] <ssi> but there was some brush dust
[14:29:19] <Nick001-Shop> actually a thin film is all it needs to start screwing it up and dust will do it to
[14:29:42] <Nick001-Shop> are you still running those slides over 200 in./m
[14:29:51] <ssi> yea but I'll probably dial it back to 180 max
[14:30:17] <Nick001-Shop> good idea – that's what I did on my machine because of the age of the servomotors.
[14:30:49] <ssi> 4ips runs those drives at 10v
[14:30:54] <ssi> and they're supposed to be 8.5v max
[14:31:02] <Nick001-Shop> also, do you have your central lube system working
[14:31:05] <ssi> yes
[14:31:11] <ssi> it's filming the bed nicely :)
[14:31:18] <ssi> I bought a gallon of vactra even
[14:31:30] * ssi is trying to do this lathe right
[14:31:47] <ssi> vactra in the way reservoirs, mobilmet 766 neat in the coolant sump
[14:32:08] <Nick001-Shop> that's necessary especially for that carriage because of the wear bearing surfaces. They will start to heat up and cause errors
[14:32:16] <ssi> yeah
[14:32:29] <ssi> it's running nice and smoothly
[14:32:37] <Nick001-Shop> Vactra 2 i hope
[14:32:47] <ssi> yeah, vactra 2
[14:32:54] <ssi> I got lucky on that one
[14:32:58] <Nick001-Shop> expensive stuff nowadays
[14:32:59] <ssi> I think vactra 2 is all that mcmaster stocks
[14:33:33] <Nick001-Shop> there is avactra light also
[14:33:42] <ssi> i think there's like four different ones
[14:34:14] <Nick001-Shop> the number two is the important one for this machine
[14:34:17] <ssi> last night I sorted out my bad Z home signal and my turrent problem
[14:34:20] <ssi> i had those lines crossed
[14:34:35] <ssi> I still haven't worked out the homing magic in linuxcnc, so I have no homing yet
[14:34:58] <ssi> it's three part homing, so it's complex
[14:35:15] <Nick001-Shop> did you order new way wipes for the carriage. They also help hold oil in
[14:35:22] <ssi> no, I haven't been able to find them
[14:35:26] <ssi> do you have a link?
[14:36:13] <Nick001-Shop> Hardinge has them directly -
[14:36:31] <Nick001-Shop> do you want their phone number
[14:36:43] <ssi> I can get the number off their website I suppose
[14:36:49] <ssi> I was hoping they had a parts inventory online
[14:36:54] <ssi> but their site is tough to navagite
[14:37:03] <Nick001-Shop> no they still do things the hard way I believe
[14:37:34] <Nick001-Shop> what was your turret problem
[14:38:10] <ssi> had an encoder line mixed up with a home signal line, and so it would find some tools (but give me the wrong station number), and other tools it would up and spin and time out
[14:38:51] <Nick001-Shop> ouch – that sounds like a wicked mess – but it's easy to do with all the wires coming out of that machine
[14:43:20] <ssi> it's not too bad
[14:43:30] <ssi> that's one of only two significant wiring mistakes
[14:43:42] <ssi> the other one was where on the drawing there were two lines crossing
[14:43:51] <ssi> and there's an error on the drawing, they added a line segment that shouldn't have been there
[14:44:02] <ssi> and it made them look like they crossed, when actually it was supposed to be more of a near miss :)
[14:56:54] <Nick001-Shop> are you talking about the Hardinge drawings?
[15:20:52] <SolarNRG> Hi guys
[15:42:12] <ssi> Nick001-Shop: you still here?
[15:42:27] <ssi> Nick001-Shop: (and yes, I was talking about the hardinge drawings; the schematics of the limit switches specifically)
[15:42:51] <ssi> Nick001-Shop: I have the parts book open, looking for the wipers. I talked with Morris South about parts, and I'm trying to find the numbers for them
[15:43:34] <ssi> I'm trying to figure out if both wipers on the Z axis are the same part number or not
[15:43:37] <ssi> and it's not obvious
[15:56:41] <nickoe> Anyone using RTAI kernel?
[15:58:39] <PCW> anyone using LinuxCNC for controlling a machine very likely is using RTAI
[16:03:45] <ssi> they're definitely different part numbers
[16:03:50] <ssi> and the rear one is twice as much money as the front one
[16:03:51] <ssi> lovely
[16:04:32] <JT-Shop> mine are the same
[16:04:41] <ssi> http://www.bptparts.com/product_info.php/cPath/33/products_id/520
[16:04:47] <ssi> that's the front one
[16:05:01] <ssi> rear one is similar to this http://www.bptparts.com/product_info.php/products_id/519
[16:05:05] <ssi> but not the same part num
[16:23:23] <DJ9DJ> gn8
[16:44:08] <Nick001-Shop> AB machine front & rear are different
[16:44:51] <Nick001-Shop> The rear one in my hand won't fit the front of the carrage
[16:48:08] <ssi> Nick001-Shop: yea that's how mine is too
[16:48:42] <A0Sheds> JT-Shop, interested in machining a stainless piece?
[16:49:03] <Nick001-Shop> if I remember correctly they had me put a clearance radius on the bottom of it. One side measures 1.2 from the side to the bottom of an angled side for the carriage and the other side measures 1.7, so there are not symmetrical.
[16:49:06] <JT-Shop> depends
[16:51:11] <Nick001-Shop> I just happened to have this extra one because I got lazy and didn't put it on the second machine. Looking at it, I can see where it's cracked in various spots because of age so I guess I better get to it before I fire it up. That's the machine that still has a working AB control. Barely working that is, I have to slow the rapids in half otherwise it will trip out.
[16:52:26] <PCW> ssi real name so we send 7I49HV to right place
[16:59:09] <djdelorie> It cuts! http://www.youtube.com/watch?v=CsCY5vXzm_E
[17:06:01] <SolarNRG> Is that your first CNC machine?
[17:06:04] <SolarNRG> Clap clap clap
[17:06:13] <SolarNRG> You've made an engraver!
[17:06:20] <djdelorie> first machine, first anything cut, first first first!
[17:06:25] <SolarNRG> WELL DONE
[17:06:35] <SolarNRG> Now make a name tag for your door
[17:06:56] <djdelorie> I actually have useful things to make, like replacement mounts for the control boards in the cnc machines
[17:07:28] <SolarNRG> What's the total cost of your project to date?
[17:07:37] <djdelorie> I don't know, I haven't been keeping track...
[17:08:30] <djdelorie> most of it was salvage, I really only paid for the electronics
[17:09:31] <djdelorie> and those I made myself, so it was "parts cost"
[17:10:44] <SolarNRG> What driver do you use? Gecko?
[17:11:03] <Nick001-Shop> ssi if it helps , the Hardinge part # is HCB0008050 for the rear wiper
[17:12:15] <djdelorie> http://www.delorie.com/electronics/bldc/ - I designed my own to go with the surplus motors a friend offered me
[17:14:15] <SolarNRG> Did you make that board yourself?
[17:14:34] <djdelorie> yes
[17:15:20] <SolarNRG> I bet all the little pins were a pain in the ass to solder
[17:15:52] <SolarNRG> I take it you're using bipolar stepper motors on that board
[17:15:53] <djdelorie> heh, no. I used a solder paste stencil and reflowed it all on a $20 hotplate.
[17:16:23] <SolarNRG> Hotplate? What an ingenious idea
[17:16:23] <djdelorie> but I *can* solder 0.5mm pitch parts, my electronics expertese far exceeds my cnc expertese...
[17:16:54] <SolarNRG> I've made a stepper motor controller before out of a load of electrical connectors and a ULN2003
[17:16:57] <djdelorie> http://www.delorie.com/pcb/hotplate/
[17:17:02] <SolarNRG> I could only do 100 steps a second though
[17:17:12] <djdelorie> the motors are brushless DC servo motors
[17:18:38] <djdelorie> the encoders are 1000 line encoders, I can configure them for up to 4000 steps/rotation. I've got them at 2000 for now, the pc can't go much faster than that, but the boards will accept up to 1,000,000 steps per second
[17:19:12] <djdelorie> *useful* steps/sec is limited by motor top speed
[17:19:22] <SolarNRG> Its usb complient?
[17:19:38] <SolarNRG> Looks ethernetish
[17:19:52] <djdelorie> it uses USB for the configuration menus. For running the motor, it uses a standard step/direction setup - the RJ45 is for those signals.
[17:20:02] <djdelorie> It also has a CAN interface but I haven't done anything with that yet
[17:20:26] <djdelorie> the three controller boards are wired to the parallel port on the PC via the RJ45's
[17:20:46] <A0Sheds> PCW: have any boards besides the PC104 analog cards for ADC ? I'd like to use them to read temperatures from some thermistors
[17:21:54] <JT-Shop> skunkworks does that with an Ardunio or how ever it is spelled on his K&T
[17:21:56] <SolarNRG> What are those 4 fatty capacitors for?
[17:22:13] <SolarNRG> I work with arduinos,
[17:22:29] <SolarNRG> A giant leap over legacy PIC technology
[17:23:02] <djdelorie> fatty capacitors? URL?
[17:23:21] <SolarNRG> http://www.delorie.com/electronics/bldc/ps-60v-top.jpg
[17:23:26] <PCW> A0Sheds: No not at the moment we will have some sserial analog input modules but these dont make sense for a small system
[17:23:50] <A0Sheds> I have maybe 8 to read
[17:23:52] <pgf> djdelorie: congrats.
[17:24:12] <pgf> i got all my motors running today, after replacing my blown controller card.
[17:24:13] <djdelorie> ah, those. Bulk capacitors for the power supply. I'm not actually using that supply, but the linear one I"m using has the same four capacitors
[17:24:37] <PCW> Actually I like the PICs they have pretty good PWM/A-D peripherals
[17:25:00] <djdelorie> the RX/62T has all that but much faster :-) It's specificially designed for motor control
[17:25:19] <PCW> lot of the newer ARMs and AVRs look like they have peripherals from the 80s
[17:26:06] <A0Sheds> PCW: these http://www.mesanet.com/analogcardinfo.html??
[17:27:02] <PCW> No the sserial ones are not listed yet
[17:27:27] <PCW> Is this for LinuxCNC?
[17:27:34] <A0Sheds> PCW: yes
[17:27:40] <A0Sheds> well sort of
[17:27:59] <SolarNRG> PICS do boast lower cost, better spec than atmega these days, but for simplicity where I can just stick jumper pins into a board, usb it, code and off I go it's sooooo much easier than the days of ziff sockets, assembly serial pic prog and bending pins and soldering up your board wrong. I mean arduinos I can code in C. 10 years ago it all had to be done in assembly
[17:28:05] <A0Sheds> well yeah, using classic ladder
[17:29:01] <A0Sheds> PCW: monitor temps to turn on/off relays and e-stop etc
[17:29:07] <djdelorie> SolarNRG: I usually end up making breakout boards like http://www.delorie.com/electronics/rx/rx62n-breakout.html to prototype with
[17:29:41] <PCW> A0Sheds is anything real time?
[17:29:57] <A0Sheds> PCW : not for analog temp
[17:30:47] <PCW> why not just an arduino or some such if its not realtime
[17:30:47] <djdelorie> now I just need a linux-friendly CAD/CAM package to design things with... ?
[17:31:16] <A0Sheds> PCW : the only realtime is a servo motor in speed mode
[17:31:31] <mozmck> PCW: I'm curious what you mean by looking like the peripherals are from the 80s?
[17:31:58] <mozmck> djdelorie: kicad :)
[17:32:11] <djdelorie> kicad is not a cad program, it's an electronics design suite
[17:32:26] <djdelorie> and I use gEDA, not Kicad :-)
[17:32:27] <SolarNRG> DJ, that breakout board pisses all over my atmega board, I love the fact it has LOADS of input/outputs
[17:32:35] <mozmck> djdelorie: I know, and also that you use gEDA, hence the :)
[17:32:43] <A0Sheds> PCW : it could be, I was just checking to see if any of the IO boards might have some analog in
[17:32:45] <djdelorie> it has ALL the inputs and outputs, except those dedicated to bootloading and console
[17:32:55] <PCW> the current $3.00 DSPics have 4 MHz A-Ds UARTs that go to 10 MBaud, 960 MHz PWMs etc
[17:33:10] <djdelorie> here's a sillier breakout board, I was mostly just testing the concept: http://www.delorie.com/electronics/m16c-26-adapter/
[17:33:43] <mozmck> djdelorie: theres a program that's not free called synergy...
[17:34:04] * djdelorie prefers open source software
[17:34:10] <mozmck> http://www.webersys.com/
[17:34:39] <mozmck> Me too if it's available. I've heard synergy is not too expensive, but that's about all I know.
[17:35:22] <PCW> A0Sheds you can use any encoder counter (even the software one) with a simple V-F for a really simple A-D
[17:35:36] <SolarNRG> What chip is that: http://www.delorie.com/electronics/rx/rx62n-breakout-assembled.jpg
[17:35:43] <djdelorie> the RX/62N
[17:36:23] <djdelorie> same family as the 62T but more general purpose and less motor control. The 62N series has built-in ethernet, usb, and more memory
[17:36:32] <SolarNRG> Yeah, it looks way more advanced than my atmega/pic dip technology
[17:36:33] <PCW> A0Sheds: thats all our THCAD is (except 2500V isolation on signal/power)
[17:37:17] <SolarNRG> What processor power has it got?
[17:37:25] <SolarNRG> Can it be USB programmed with C?
[17:37:32] <SolarNRG> Does it have an internal clock?
[17:37:44] <SolarNRG> How many total inputs and outputs has it got?
[17:37:47] <SolarNRG> Can it do PWM?
[17:37:57] <djdelorie> the 62N or 62T ?
[17:37:58] <SolarNRG> Has it got Analog to Digital converters?
[17:38:05] <SolarNRG> This board you made: http://www.delorie.com/electronics/rx/rx62n-breakout-assembled.jpg
[17:38:22] <djdelorie> sure, make me go look things up... ;-)
[17:39:55] <djdelorie> the 62N has 8 12-bit channels or 8 10-bit channels, 1uS sample rate, plus two 10-bit DACs, up to 12 synchronized PWM outputs
[17:41:01] <djdelorie> you program it in C, C++, asm, pascal, whatever GCC supports, using either a serial port or USB.
[17:41:50] <djdelorie> internal clock on the 62N is up to 100 MHz but 96 MHz is used when you're using USB. Most instructions complete in one clock, including floating point
[17:42:18] <djdelorie> the family ranges from 64 pins (the ones I'm using in the cnc) to 176 pad BGAs
[17:43:13] <djdelorie> the controllers in my CNC are running at 80 MHz with six-phase PWM at 20 KHz, and the motor control loop happens once per PWM cycle
[17:43:16] <pgf> djdelorie: what family of chips is this?
[17:43:24] <djdelorie> the RX/62N and RX/62T family
[17:43:39] <djdelorie> www.rxmcu.com
[17:43:46] <pgf> ah. thanks.
[17:43:51] <djdelorie> the RX/62T is in my controller cards
[17:44:27] <djdelorie> the design consisted mostly of connecting pins on the RX chip with the connectors and drivers they went with, there was very little logic needed aside from the analog interfaces
[17:44:36] <SolarNRG> How much for one of these boards? Do you ship to the UK?
[17:44:54] <SolarNRG> I like it a lot
[17:44:57] <djdelorie> price and shipping info is on that page
[17:45:01] <SolarNRG> It's like 8x as fast as my atmel
[17:45:34] <djdelorie> at this point, I'd probably end up making whatever you ordered though, I'm low on assembled boards
[17:45:35] <SolarNRG> $65 for http://www.delorie.com/electronics/rx/rx62n-breakout-assembled.jpg yeah?
[17:45:40] <SolarNRG> If so, bargain
[17:45:46] <SolarNRG> For what it does
[17:45:53] <SolarNRG> It's like a super duper arduino mega
[17:45:55] <djdelorie> I don't include the headers, though
[17:46:06] <SolarNRG> The things the pins plug into?
[17:46:18] <SolarNRG> Or the C headers
[17:46:20] <djdelorie> the big 0.1" pitch connectors around the outside
[17:46:27] <SolarNRG> :(
[17:46:32] <SolarNRG> How much to add them?
[17:46:40] <djdelorie> they're expensive and everyone wants something different
[17:47:15] <djdelorie> cheaper for you to buy them locally and solder them in. I'm not trying to profit from those, just trying to help folks who don't like tqfp packages
[17:47:32] <SolarNRG> Can you make me a board that will control these 439oz/inch or 3.1NM 8 wire stepper motors: http://imgur.com/IkDzm
[17:47:33] <djdelorie> I'm not even sure if I have any here
[17:47:55] <SolarNRG> I want to do a mill to CNC conversion
[17:48:04] <SolarNRG> I'm working on casting to start off with
[17:48:11] <djdelorie> it's a lot less hassle to just buy a stepper driver
[17:48:23] <djdelorie> like a gecko or something
[17:48:35] <SolarNRG> Everyone recommends gecko
[17:48:41] <SolarNRG> They say DO NOT buy chinese
[17:48:50] <djdelorie> the only reason *I* didn't buy a pre-made driver is because I'm not using steppers
[17:48:58] <SolarNRG> Seems the Chinese don't like competing industry
[17:49:16] <SolarNRG> Yeah you said, servos are more accurate, they got feeback
[17:49:20] <SolarNRG> Steppers are assumed accuracy
[17:49:20] <pgf> i like the sparkfun quadstepper i just got.
[17:51:00] <djdelorie> servos also offer torque at high RPM, which steppers don't
[17:51:32] <djdelorie> just checked my box-o-crap, no headers. I did find some of these http://www.delorie.com/electronics/rx/rx62t-80-breakout.html though (62T breakouts)
[17:51:35] <SolarNRG> Do you think a servo approach is superior to the stepper idea?
[17:52:13] <djdelorie> it's more expensive and harder to control, but the motors run faster. These will do 3000 RPM if I can get the EMI squashed (and find a big enough power supply)
[17:52:42] <djdelorie> that's 6.5 IPS on my slowest axis
[17:53:18] <djdelorie> if I swap out the screws for 5 TPI, I could do 12 IPS on X and Y
[17:53:43] <SolarNRG> What are you using, Acme thread?
[17:53:45] <djdelorie> (that's 720 IPM)
[17:54:05] <djdelorie> I'm using whatever surplus screw rods my friend brought over
[17:54:15] <djdelorie> X is 10 TPI, Y is 4-start 12mm
[17:54:31] <djdelorie> Z is 16 TPI threaded rod from the hardware store ;-)
[17:55:08] <pgf> all three of my axes are 18tpi rod from the hardware store. i can do a whopping 30ipm. :-)
[17:56:49] <SolarNRG> Aren't you worried about using different tpis on the x and y asxis and having a "squashed" image... I can see this isn't the case so you must have coded to compensate
[17:57:04] <SolarNRG> replace image with carving
[17:57:04] <djdelorie> for my Z axis, I threaded two blocks of soft maple to match the threaded rod, works like a champ.
[17:57:26] <djdelorie> SolarNRG: LinuxCNC has places to enter all the gearing and threading info
[17:57:44] <djdelorie> each axis needed completely different configuration info, but the result is, all the units are "inch" and it works
[17:59:12] <SolarNRG> Lucky Americans, here in Britain we've got to do both for the benefit of all the Europeans who come over and then we have to use cm, kgkm
[18:00:04] <djdelorie> for you, you'd click the "metric" button, then it's all converted to cm :-)
[18:00:16] <SolarNRG> Fantastic, this is why I love open source
[18:00:49] <SolarNRG> I've got freecad running on my Ubuntu boot. Can I turn a freecad drawing into a carving?
[18:01:01] <djdelorie> what it's missing is the ability to mix inch and metric info in the dialogs, so I had to convert mm to tpi manually :-(
[18:04:11] <SolarNRG> CAn I use your board as an exoskeleton controller? I mean I need a board with LOADS of analog to digital converters
[18:04:28] <SolarNRG> ADC
[18:04:37] <SolarNRG> Seeing that board, I'm in heaven
[18:04:43] <djdelorie> If by "loads" you mean "8", perhaps ;-)
[18:05:18] <djdelorie> I did a board for my furnace that uses a single MCU to do 12 16-bit ADCs to a single I2C interface
[18:05:36] <djdelorie> but it cheated, the chip only has 10-bit ADCs so I oversampled them :-)
[18:06:22] <SolarNRG> Heh, same as arduino, anything from 0 to 1023
[18:06:43] <djdelorie> well, the RX has 12-bit ADCs but if you've got time, oversampling works too
[18:07:09] <SolarNRG> Hey it isn't accuracy I'm after, it's amount
[18:07:11] <djdelorie> the furnace board just sampled each ADC 64 times and added the numbers together. It turns out it does a pretty decent job at pretending to be a 16-bit ADC
[18:07:12] <mikebronner> Hi guys, still experimenting with EMC2/AXIS. Getting errors of the nature of Linear move on line 20 would exceed joint 0's negative limit. I thought I set up my machine parameters correctly, but you never know. Any ideas? Googling didn't provide very valuable results.
[18:07:26] <djdelorie> did you home the machine ?
[18:07:59] <mikebronner> Yes, all 3 axis are homed, the Z axis being homed to the top of the material.
[18:08:18] <djdelorie> when you ran stepconf, did you tell it the right values for the workspace and where the home switch was?
[18:08:30] <SolarNRG> Well if I want a chip that say has a few hundred analog to digital converters, even if they are only 8 or 10 bit, what do you suggest?
[18:08:38] <JT-Shop> and the preview shows where your out of bounds
[18:08:41] <djdelorie> On mine, it homes to the positive side, so for example my Y axis is range 0..26 but the "home switch location" is 26 and "home" is 25
[18:09:10] <djdelorie> SolarNRG: I think you'd need to have multiple chips for that
[18:09:49] <djdelorie> but consider - putting a tiny MCU like an avr or r8c near the sensors, you can turn 8-12 analog lines into two digital lines, and save wiring.
[18:10:10] <SolarNRG> All boils down to response time though
[18:10:37] <SolarNRG> Like if I want to run in a suitthe total system response time needs to be under 1ms
[18:10:54] <SolarNRG> Mosfets are too slow
[18:10:56] <mikebronner> djdelorie: hmmm, you may be on to something. I set the home location to 0, but when homing, I actually homed in the middle of the table (I don't have home switches set up yet). How would the machine know that it would exceed the physical boundaries when I rehome? Wouldn't it take my word for it that I'm homing in the proper spot, or does it somehow know that I'm homing in the middle of the table?
[18:11:01] <SolarNRG> CNC drivers respond VERY quickly
[18:11:19] <SolarNRG> Less rise and fall time between pulses
[18:11:31] <Valen1> SMPS use mosfets at 2Mhz switching speed
[18:11:40] <SolarNRG> Fast enough
[18:11:43] <djdelorie> mikebronner: if you "homed" while it was in the middle of the table, then 3/4 of the table is now unusable
[18:11:57] <PCW> RF amps use MOSFETS as well
[18:12:19] <SolarNRG> I meant to say mosfet transistors on their own are too slow
[18:12:27] <djdelorie> if you want to play it dangerously, go to stepconf and tell it the extents for the X and Y axes are like -100 to +100 inches, home at 0
[18:12:28] <SolarNRG> I need a mosfet driver chip, much faster
[18:13:07] <PCW> standard gate drivers are available up to 4A and more
[18:13:32] <ssi> speaking of homing
[18:13:34] <mikebronner> djdelorie: which is fine, because I'm only working on a small piece. I guess I should home to the corner of the table, and create my g-code accordingly.
[18:13:40] <djdelorie> mikebronner: safer would be to tell stepconf the *actual* extents of your table, like 0..24, and where you *actually* will be homing, like 12, so that linuxcnc won't **try* to break your table.
[18:13:43] <Valen|> I use 13 amp ones from microchip they are robust
[18:13:45] <ssi> PCW: how did we decide that I should go about gating the resolver index with my fine home switch
[18:14:21] <djdelorie> Homing just sets the *machine* home. The *part* home is completely different. Choose a suitable "home" for the part, and tell linuxcnc where it is. Don't design the part for your table
[18:14:44] <PCW> what is ssi's secret identity? we wanted to send you the 7I49HV but were not sure
[18:14:54] <ssi> PCW: Ian McMahon, Kennesaw GA
[18:15:02] <djdelorie> the machine home tells linuxcnc the physical extents of the machine itself, you want that to be correct or you break your table.
[18:15:06] <PCW> OK will send tommorow
[18:15:11] <ssi> cool
[18:15:41] <djdelorie> When you go to cut a part, you can manually jog the cutter to a known location and tell linuxcnc "the tool is now at (x,y,z) on the part" to make the cuts relative to that
[18:15:52] <Valen|> Mike look into the difference between homing and touching off
[18:15:52] <mikebronner> djdelorie: I did enter the extents of the table, but I guess having the homing location in stepconf assumes you have a homing switch in place. Oh, speaking of the different homings: that may be my issue. So lets say I home the machine first, do I then need to re-home it with the part?
[18:15:53] <djdelorie> all this, I learned today, too...
[18:16:04] <PCW> actually it works OK with 1 --> 1/2 resolvers just noisier (maybe 13 bit resolution)
[18:16:22] <mikebronner> Valen|: thanks, i think that will answer my question. :)
[18:16:22] <PCW> inputs set for 10V P-P maximum
[18:16:41] <ssi> PCW: does it still have the option for half-drive on 3-5?
[18:16:48] <PCW> Yes
[18:16:55] <ssi> ok cool
[18:17:32] <djdelorie> "homing" sets the ABSOLUTE home for the MACHINE. This is the phyical limit of the table before it breaks. "touching off" sets the RELATIVE home for the PART so that the machine cuts where you want it to
[18:17:40] <PCW> I will eventually add the AGC code when I get some free time
[18:18:01] <ssi> I'd love to get familiar enough with the code that I can contribute
[18:18:05] <ssi> but I don't know if that's likely
[18:18:13] <mikebronner> djdelorie: thanks :) I think that's where my misunderstanding stems from. :) reading up on it now, and I'll give it another shot
[18:18:16] <ssi> it's been ten years since I touched VHDL, and I was never particularly expert in it
[18:18:31] <Valen1> we ran our mill for years without homing
[18:18:45] <Valen1> its safer to use the homing lol
[18:19:06] <Valen1> hmm somebody has pinched my nick
[18:19:09] <Valen1> this will not stand
[18:19:09] <PCW> well the code is actually assy code from the embedded processor in the FPGA
[18:19:16] <ssi> ahh ok
[18:19:23] <ssi> what core is it?
[18:19:38] <PCW> my own (b32)
[18:19:58] <ssi> fancy
[18:20:13] <PCW> very simple 32 Harvard architecture bit DSP
[18:20:19] <PCW> 32 bit
[18:20:21] <Valen> better
[18:22:00] <Valen> pcw you might be one to answer this, I want to make a joystick (computer) with unreasonable precision, 65536 counts across a 40 degree range
[18:22:11] <Valen> I'm wondering if resolvers would be the way to go
[18:22:22] <Valen> it works out about 600k counts for a full revolution
[18:22:33] <PCW> all the sserial (SSLBP) resmod and twiddler code will eventually get onto the buildbot
[18:22:34] <PCW> but since its assy language for a obscure processor I doubt anyone will look at it
[18:22:46] <ssi> I'll probably look at it
[18:22:51] <ssi> shake my head and go do something else
[18:22:52] <ssi> :D
[18:23:19] <PCW> Thats what I often _want_ to do
[18:24:06] <Valen> lol
[18:25:01] <PCW> Valen there are encoders that will do that, take a look at the Avago sine/cos output optical modules
[18:25:02] <PCW> a
[18:25:19] <ssi> btw it looks like the <other company> resolver converters that have jumpers actually change the drive level rather than the inputs
[18:25:26] <Valen> I'm trying also to not cost eleventy billion dollars ;->
[18:25:49] <SolarNRG> How do the auto spindlehead changers on more advanced CNC machines work?
[18:26:06] <ssi> SolarNRG: usually a pneumatic drawbar
[18:26:07] <PCW> The modules are only a few dollars (you need a uproc interpolator)
[18:26:59] <PCW> well its a lot easier to change the drive level since no matching is needed (and exactly what I will do with the AGC)
[18:27:04] <ssi> right
[18:27:49] <ssi> so the AGC would somehow measure the nonlinearity of the returned signal and adjust drive to compensate
[18:27:50] <PCW> but i want to be in the ballpark so I use as much of the ADCs resolution as I can
[18:27:55] <ssi> ie max drive without distortion?
[18:28:28] <PCW> I think I will just check for over/underflow and adjust
[18:28:32] <ssi> aha
[18:28:37] <ssi> that sounds easier :)
[18:29:38] <SolarNRG> This guy made his own: http://www.cnccookbook.com/CCBlogMar2007.htm
[18:30:09] <Valen> pcw sorry to press, i'm having difficulty finding the parts your mentioning on the avago website, i seem to be stuck in 500cpr encoder land
[18:30:26] <PCW> the A-D is 12 channel 12 bit simultaneous sample so at the front end I will just check for over/under (FFF or 0)
[18:30:28] <ssi> SolarNRG: it's not uncommon
[18:30:54] <djdelorie> food... biab
[18:31:41] <SolarNRG> I was thinking about doing something like this for my solar project, you know one boiler for power generation, and one to vapourize water out of icy rocks on the moon
[18:37:05] <PCW> valen: aedr8320 is one possibility
[18:38:03] <Valen> hmm
[18:39:26] <Valen> and analog sample the inputs rather than digitally you think
[18:39:40] <Valen> do they have sin/cos codewheels?
[18:40:27] <PCW> no, standard striped wheel/strip
[18:42:05] <mikebronner> djdelorie, Valen|: thanks so much for the advice between the difference of homing and touching off. :) just what I needed
[18:42:17] <Valen> no worries
[18:43:00] <Valen> hmm I always imagined the outputs to be pretty square wave to be honest even in the analog domain
[18:43:56] * Valen reads some
[18:44:20] <PCW> they usually are pretty close to sine/cos before squaring
[18:44:59] <PCW> what about a good conductive plastic potentiometer and a good A-D
[18:45:22] <Valen> nah, it'll wear out, I'm trying to make the "ultimate" one
[18:45:28] <Valen> ball bearing races in gimbals
[18:45:34] <Valen> none of this plastic ball and socket junk
[18:45:54] <Valen> yeah just going through the datasheet for that part you mentined
[18:45:55] <PCW> Strain guage?
[18:46:19] <Valen> hmm would you get 40 degrees of motion out of one of those?
[18:46:31] <PCW> bend a spring
[18:46:32] <Valen> accuratley
[18:46:43] <Valen> sounds mechanically messy
[18:47:10] <Valen> your idea for the optical encoder is looking good
[18:47:13] <PCW> is this a hand operated device?
[18:47:17] <Valen> yeah
[18:47:20] <Valen> computer joystick
[18:47:26] <Valen> flying aeroplanes
[18:47:51] <PCW> just use a regular high res encoder and interpolate
[18:48:23] <Valen> i've never really understood this whole interpolating thing, so I need to look into it more
[18:49:02] <PCW> I dont have 16 bit hands, who does?
[18:49:54] <Valen> do they just (in effect) use a bunch of comparators and rather than changing output states at 0v, change at 5,4,3,2,1,0,-1,-2,-3,-4,-5
[18:50:07] <Thetawaves> <PCW> I dont have 16 bit hands, who does?
[18:50:10] <Thetawaves> thats what i was thinking
[18:50:33] <Valen> people spend $300 on power cables for their sterio that have been dunked in liquid nitrogen lol
[18:50:53] <PCW> my guess is anything above a few thousand counts over 40 degrees would be indistinguishable from continuous
[18:51:17] <PCW> ahh the Monster cable market
[18:51:31] <Valen> The other thing is 40 degrees is the full travel range, some people will prefer to have much smaller travels (5-10deg) and i still want them to have adequate resolution
[18:51:57] <PCW> re comparators yes in fact old interpolators worked that way
[18:52:28] <Valen> I'm hoping i can fake a static stick, where they use strain guages to read the force on the stick with the stick not moving (much)
[18:52:42] <Valen> I could just make a static stick, but I was hoping to be all things to all men
[18:52:46] <PCW> nowdays you would use a tracking converter or arc-tangent
[18:54:18] * Valen gives up trying to explain to a person how antivirus software on their computer wont help their website getting hacked
[18:54:27] <PCW> what about some other analog scheme (like fiber optic bending)
[18:54:57] <Valen> I was hoping to find something off the shelf to be honest, 16 bit accuracy is hard to do physically
[18:55:19] <Valen> 19 bits over a full rotation
[18:55:32] <PCW> 16 bit accuracy sure 16 bit resolution not so hard
[18:55:40] <Valen> true that lol
[18:56:37] <PCW> rubber strain gauges will get you 16 bit resolution
[18:57:14] <Valen> I was thinking of using a 12bit rotary magnetic encoder, which can be had for ~$4 all up and combining that with another one belt driven 1:10
[18:58:01] <Valen> basically take the first N bits from the fixed rotary encoder, that will give 512 counts over the range, and use the belt driven one for the "resolution" side of things
[18:58:08] <Valen> upside is it'd look cool
[18:58:13] <Valen> downside is its messy
[19:00:19] <Valen> but no, a modest optical encoder and lots of interpolation is sounding like the best option
[19:01:27] <PCW> Ive seen a 1 or 2 miilion count optical encoder made with a couple buck Avago module and a DSP
[19:02:48] <Valen> was the DSP doing more than ADC?
[19:02:52] <PCW> dsp does interpolation and probably some fixing of various non-linearities
[19:03:15] <Valen> what are they using to read the output from the encoder?
[19:04:04] <PCW> probably does arctan interpolation, interface is serial
[19:04:28] <Valen> i meant to read the analog values
[19:04:38] <PCW> ADC in DSP
[19:05:35] <Valen> wouldn't even need to be that sensitive
[19:06:02] <PCW> DSPIC would do or TI Piccolo or whatever
[19:06:20] <Valen> read in digital data to keep up with the encoder, then take an analog sample when its time to send out the data
[19:06:25] <PCW> no 8 bit A-D is probably OK
[19:06:46] <Valen> probably wouldn't even need a dsp if the frequency of readout isn't that great
[19:07:07] <PCW> dont want to lose you place
[19:08:30] <Valen> use "digital" input for that I was thinking, comparator fed to digital I/O pins, perhaps with some nice encoder stuff in hardware
[19:09:15] <PCW> yeah unless you have special hardware you cannot get high rest at high motion speeds
[19:09:29] <PCW> high res
[19:09:43] <Thetawaves> why?
[19:10:24] <Thetawaves> your encoder cables will start acting like antennas?
[19:10:28] <Valen> yeah, i wont need that, 1khz sample rate would be sufficent
[19:11:10] <Valen> so a dual sample ADC (or 2 ADC's) would do the job, read digital position and trigger ADC capture (presumably with some time offset)
[19:11:35] <Valen> lookup table to get positioning then spit it back out over SPI
[19:17:12] <PCW> Thetawaves: No at high count rates the DSP is not fast enough but fine for slow stuff and resolution goes up as speed goes down
[19:17:52] <Thetawaves> oh right, just use a faster dsp
[19:18:17] <Valen> hardware encoder module will make up for a lack of CPU speed ;->
[19:18:21] <Thetawaves> i use an asic to convert my quadrature encoders into spi
[19:18:27] <PCW> yeah with the proviso that arctan needs to be done carefully
[19:18:29] <Thetawaves> so i can read at the speed of spi
[19:19:03] <Thetawaves> (which is not as fast as the really really fast encoders)
[19:19:49] <Thetawaves> the problem is the cables
[19:19:50] <Valen> pcw what pitfalls should i be looking for (other than simultanious sample, and fast sample)
[19:20:00] <Thetawaves> 100mhz is no problem on a circuit board
[19:20:14] <Thetawaves> try to put that in a cable 10 feet long and you've got issues
[19:20:36] <PCW> I dont think its too hard a $3.00 DSPIC would do
[19:21:04] <Valen> i haven't used one of those though, and an AVR with encoder module is easy ;->
[19:21:21] <Thetawaves> DSPIC has much more reliable interrupt latency
[19:21:32] <Thetawaves> the xmega did a lot to iron out those issues though
[19:21:44] <PCW> I think the AVR and its A-D is too slow
[19:22:29] <Thetawaves> you will have to run the math to determine if it is too slow
[19:24:23] <Thetawaves> programming dspic on linux isn't the sweetest thing ever
[19:25:40] <PCW> AVRs dont have simultaneous sample ADCs AFAIK which is a showstopper
[19:27:41] <PCW> I doubt if the development environment matters much
[19:27:42] <PCW> If you cant get the ISR into 50 or so very well chosen instructions there's probably not much hope
[19:32:27] <PCW> looks like the AVR32 has simultaneous sampling
[19:36:48] <Thetawaves> what about the stm32?
[19:38:23] <Thetawaves> yeah i think it does
[19:51:21] <Valen> I was just going to put a pair of external ADCs in so i can site them right at the measurement location
[19:51:40] <Valen> and given the application interrupt latency wont be much of an issue
[19:51:52] <Valen> I'm only going for a 1khz readout rate
[19:52:49] <Valen> now to find phosphor bronze in 1mm 1.5mm and 2mm sizes
[19:53:14] <Valen> for actual machining work
[19:53:23] <Valen> any ideas
[19:56:59] <Thetawaves> avr will do 1khz
[19:57:11] <Valen> no simultanious sampling though
[19:59:26] <Thetawaves> you should get an stm32
[20:02:57] <Valen> I want to opensource the electronics in it, so I'm thinking AVR probably has the widest userbase
[20:03:19] <Thetawaves> arm is used billions more devices than avr
[20:04:01] <Thetawaves> for ~1$ you get 150mhz, 32bits, 20k ram, 40k flash
[20:04:31] <Valen> yes, but how many hobby programmers use arm?
[20:05:12] <Thetawaves> most the people in #electronics use arm
[20:05:53] <Thetawaves> and that is a pretty use cross section of hobbyist embedded
[20:06:06] <Thetawaves> huge, god damnit i can't type or something
[20:06:13] <Valen> simultanious sampling?
[20:07:58] <Thetawaves> there are two 8 channel adcs that can be sampled simultaniously
[20:09:23] <Valen> part number?
[20:09:34] <Valen> also OSS programming?
[20:09:37] <Valen> and USB stack?
[20:10:13] <Thetawaves> http://www.st.com/internet/mcu/subclass/1521.jsp
[20:10:26] <Thetawaves> linux runs on arm.
[20:12:09] <Valen> yes, but i want to do teensy embedded programming without huge amounts of pain
[20:14:41] <Thetawaves> http://search.digikey.com/scripts/DkSearch/dksus.dll?WT.z_cid=sp_497_0928_buynow&site=us&lang=en&Vendor=497&mpart=STM32F4DISCOVERY
[20:15:39] <Thetawaves> 3×12-bit, 2.4 MSPS A/D converters: up to 24 channels and 7.2 MSPS in triple interleaved mode
[20:16:17] <Thetawaves> if you want to be linux friendly, use this
[20:16:25] <Thetawaves> otherwise just use dspic
[20:17:08] <Thetawaves> good news is bare bones arm isn't that rough :)
[20:37:31] <CareBear\> Valen : NXP LPC1343 http://stuge.se/lpc1343_buttons.tar.bz2 http://cbs.stuge.se/
[22:36:35] <ssi> got my spindle abs working
[22:36:48] <jdhnc> then you can work on pecs
[22:37:05] <ssi> maybe!
[22:39:14] <Thetawaves> abs?
[22:39:28] <ssi> yea absolute value of the spindle vel-cmd sent to the pwmgen
[22:39:35] <ssi> I need 0-10v positive always
[22:39:39] <ssi> plus a fwd/rev enable signal
[22:40:24] <Thetawaves> i've got a few questions for you then
[22:40:28] <ssi> ok
[22:40:54] <Thetawaves> so linuxcnc emits a 0-10v pwm signal?
[22:41:08] <ssi> well no
[22:41:58] <ssi> I believe if you look at the raw pin of a pwmgen, what you see is 50% duty = 0, and 100% duty is +10v and 0% duty is -10v
[22:42:08] <ssi> you need some support circuitry to actually make it so
[22:42:14] <ssi> on this lathe the 7i49 does that for me
[22:42:21] <ssi> 7i48 I think also does that, and perhaps the 7i33
[22:42:45] <ssi> on my little lathe, I don't have any of those daughtercards, just a bare 7i43, and I am using a stupid little C10 board to do it
[22:43:02] <Thetawaves> ohhh your spindle driver takes +-10v
[22:43:09] <Thetawaves> linear
[22:43:13] <ssi> my spindle's driven by a VFD
[22:43:16] <ssi> which takes 0-10V
[22:43:22] <ssi> for frequency
[22:43:29] <ssi> and then fwd/reverse switch closures
[22:43:32] <ssi> which I'm driving with a transistor
[22:44:36] <Thetawaves> very cool
[22:45:25] <Thetawaves> my goal was to get a 0-5v pwm signal onto a parallel port pin to drive a custom 100vdc motor controller
[22:46:14] <Thetawaves> i nuked the manually operated power supply on my 300w spindle
[22:46:33] <Thetawaves> and after having looked on ebay for 100v stuff
[22:46:40] <Thetawaves> i'll just have to build it instead
[22:52:40] <ssi> I see
[22:52:55] <Thetawaves> i like your setup because you don't have to actually measure the motor speed
[22:52:57] <Thetawaves> you just know it
[22:53:18] <ssi> well it's not quite that simple
[22:53:33] <ssi> because there's two clutched reductions (high/low) and a varispeed screw
[22:53:43] <ssi> I'm not actually running the varispeed screw, and I may never
[22:53:49] <ssi> but I need to pick a spot for it and block it there or something
[22:54:18] <ssi> anyway, the spindle has a resolver on it
[22:54:22] <ssi> so I CAN measure spindle speed
[22:58:01] <Thetawaves> you've got some nice io cards
[23:04:08] <ssi> yea mesa's good stuff
[23:22:37] <ssi> anyone ever messed with the gearchange component?
[23:38:08] <Nick001> have you kooked at Kirk Wallaces Hardinge?
[23:38:16] <Nick001> looked
[23:41:00] <alex4nder> yoh
[23:41:20] <ssi> I've seen a bit of it
[23:43:32] <Nick001> in his io.hal, there's refence to high - low clutch. I think his machine started out as a GE deal
[23:45:02] <Nick001> his file is ported out through parport so you'd have to rearrage things for mesa
[23:46:16] <ssi> I have my clutches connected to pins
[23:46:22] <ssi> what I'm not sure about is how I want to actually control them
[23:47:15] <ssi> I'm thinking a couple of gearchange custom M codes
[23:47:19] <ssi> M103/M104 maybe
[23:47:42] <ssi> 103 selects low clutch and scales the spindle PWM to the low range, 104 selects high clutch and scales the spindle PWM to the high range
[23:48:23] <ssi> thing is, I don't actually want to run the clutch all the time... so I probably want the "selection" to set some internal signal, and then somehow have it enable and disable the appropriate clutch with the spindle enable
[23:50:18] <Nick001> you would leave it in high most of the time and switch to low for roughing with higher torque
[23:51:08] <ssi> I'd use low for threading as well
[23:51:22] <ssi> I just dunno that I want to leave the clutch enabled all of the time
[23:51:31] <ssi> I don't know if the coils in them can burn out or anything
[23:52:01] <Nick001> one or the other has to be energized to run the spindle at all
[23:52:07] <ssi> yes, I know that
[23:52:17] <ssi> but neither needs to be energized when the spindle's not running
[23:52:59] <Nick001> wouldn't m30 cover that?
[23:53:15] <ssi> how would it cover that
[23:53:48] <Nick001> just like it automatically does m9 and such
[23:54:21] <Nick001> and m5
[23:55:16] <ssi> I don't know how it would know about my custom clutch codes magicaly
[23:55:22] <ssi> and I don't know how to go about making it know about them
[23:55:36] <ssi> easier just to have the clutches come on and off automatically with the spindle enable
[23:56:28] <Nick001> cuts down the wear by leaving it engaged
[23:56:37] <ssi> wear on what
[23:57:00] <Nick001> disk plates inside
[23:57:20] <ssi> so on continuously for hours is better for it than on and off?
[23:58:38] <Nick001> if your turning the spindle on and off constally running parts - have to figure ou costs