#emc | Logs for 2006-04-14

[00:46:19] <CIA-4> 07HEAD * 10/testing/: Log message
[00:46:20] <CIA-4> 07HEAD * 10/testing/: Log message
[00:47:37] <cradek> that's me, just ignore it
[01:27:59] <A-L-P-H-A> hmmm....
[21:31:08] <|Magician|> I'm not having too much luck finding a board
[21:32:27] <jmkasunich> what kind of board?
[21:37:26] <|Magician|> I need a board to interface 3 stepper drivers and 1 pwm servo amp
[21:38:21] <jmkasunich> thats going to be tough
[21:38:37] <jmkasunich> most are aimed at one or the other, not a mix
[21:38:52] <|Magician|> yeah, I know
[21:38:57] <jmkasunich> what kind of speeds do you need (encoder count rate and stepper step rate)?
[21:39:50] <jmkasunich> using pure software generated steps, "pwm", and encoder counting, you can get to about 10K steps/counts per second
[21:39:51] <|Magician|> the servo amp is advanced motion controls......the stepper drivers are gecko g202
[21:40:18] <jmkasunich> the servo amp actually expects PWM input?
[21:40:46] <jmkasunich> I thought most servo amps were analog input
[21:41:42] <|Magician|> I'm pretty new at this, so I am still trying to figure most of it out
[21:43:34] <jmkasunich> is there any data onlne for the servo amp?
[21:44:42] <|Magician|> yes...I was just looking for the link...i've seen it several times
[21:47:57] <|Magician|> http://www.a-m-c.com/download/datasheet/50a20.pdf
[21:48:29] <|Magician|> try that one...i believe its right, but i dont think i can open a pdf on this computer
[21:48:52] <jmkasunich> that amp wants an analog input, not PWM
[23:02:25] <fenn> hum what do you think would be the minimum memory requirement to run emc
[23:02:42] <jmkasunich> emc itself, not much at all
[23:02:55] <fenn> emc and linux, not even xwindows
[23:03:04] <jmkasunich> the X windows and gui crap that goes with it, probably 64M min, 128M better
[23:03:09] <cradek> 32 meg if without X
[23:03:14] <|Magician|> the model # of the servo amp is 50A20M-DM1
[23:03:16] <fenn> ok good
[23:03:20] <cradek> it's hard to boot in less than that
[23:03:34] <fenn> supposedly this thing actually came with linux
[23:03:38] <cradek> 64 would be best. you can probably even run an X server in it.
[23:03:42] <fenn> but someone stole the disk chip
[23:04:30] <cradek> I've been meaning to bring over xemc from emc1, it works much better than tk on a light system, and is almost as functional (I used to use it)
[23:05:52] <jmkasunich> Magician: the datasheet doesn't say what the DM1 means
[23:06:10] <jmkasunich> other than that, it seems like a normal analog input servo amp
[23:06:41] <|Magician|> yes....I believe its just a code for who they made it for
[23:06:55] <|Magician|> It is on a dyna mechtronics lathe
[23:06:55] <jmkasunich> its surplus?
[23:07:11] <|Magician|> I was already on the machine
[23:07:19] <|Magician|> no...it came new on the lathe
[23:07:23] <jmkasunich> the problem with things like that is maybe they customized it a little for that customer
[23:07:32] <jmkasunich> and you don't know what they did
[23:07:43] <|Magician|> the pins look pretty standard
[23:08:32] <jmkasunich> they would be unlikely to change that
[23:08:51] <jmkasunich> custom might mean they changed the input voltage range, or the tuning, or any number of other things
[23:10:44] <|Magician|> what are your thoughts?
[23:10:54] <jmkasunich> I don't have thoughts
[23:11:09] <Jymmm> tis true!
[23:12:48] <|Magician|> i am using the same type power supply that ran the system before...so the voltages should not be an issue....or thats what I thought
[23:13:33] <jmkasunich> the original system had three stepper and one servo channel?
[23:14:09] <Jymmm> "Dont do that! You'll blow up the Y flux capacitor!"
[23:14:38] <|Magician|> the original ststem had one motherboard (power dist. board) three stepper cards, and a spindle interface card for the servo amp
[23:14:58] <jmkasunich> the servo is on the spindle?
[23:15:08] <|Magician|> the spindle also had a encoders on it
[23:15:11] <|Magician|> yes
[23:15:18] <|Magician|> dc brush
[23:15:27] <|Magician|> excuse me...brush
[23:17:24] <|Magician|> you are right it is analog input
[23:18:07] <jmkasunich> so you need one analog output, one encoder counter, and three step generators
[23:19:28] <|Magician|> I would like to make provisions for possibly adding encoders to two of the three steppers
[23:19:35] <jmkasunich> why?
[23:19:39] <|Magician|> one of the speppers controls the turret
[23:20:12] <jmkasunich> steppers don't need encoders, and unless you get very sophisticated, steppers can't effectively use encoders
[23:20:18] <jmkasunich> so adding them just wastes money
[23:20:58] <|Magician|> the x and z axis dont have them now...but the turret has an encoder that shows position
[23:21:20] <jmkasunich> precise position, or just which tool is selected?
[23:21:28] <|Magician|> which tool
[23:22:06] <jmkasunich> the actual tool position is probably determined by stops or something right?
[23:22:38] <jmkasunich> (not by the stepper, the stepper just moves from one "notch" to the next, then a stop moves into the notch and locks the tool in place?
[23:23:25] <|Magician|> yes....thats right
[23:23:57] <jmkasunich> so that encoder is probably very coarse, you could to toolchanges with classicladder
[23:24:24] <jmkasunich> unlock, start motor turning, when "encoder" says the right tool is close to the proper position, stop moving, and lock
[23:24:27] <|Magician|> yes....that was kind of what I was thinking...but I havent got that far yet
[23:24:36] <|Magician|> you have got it
[23:25:06] <jmkasunich> so that won't even be an EMC axis
[23:25:34] <jmkasunich> and unless you are trying for very fast chip-to-chip time during toolchanges, it can be controlled by a software step generator
[23:26:01] <|Magician|> I havent actually used EMC yet, so I am still unsure about its capabilities
[23:26:30] <jmkasunich> emc2 can do a lot of custom stuff like what you are looking at
[23:26:39] <jmkasunich> what is your budget?
[23:26:41] <|Magician|> ofcourse I want it as fast as possible....but I dont know how I am going to get there yet
[23:26:59] <jmkasunich> when we first started talking, I assumed you were doing a hobby class machine, and was thinking of cheap solutions
[23:27:02] <Jymmm> What defines an LED's 'angle'? Is it the die itself or the encasing?
[23:27:04] <fenn> * fenn suggests getting it working, then trying to make it quick
[23:27:13] <jmkasunich> Jymmm: both
[23:27:55] <Jymmm> jmkasunich That didn't help me in the least =)
[23:28:17] <jmkasunich> what are you trying to figure out?
[23:28:35] <jmkasunich> the angle (beam width I assume) is what it is
[23:28:41] <jmkasunich> you don't like it, use a different part
[23:28:51] <jmkasunich> so who cares what exactly determines it
[23:28:52] <|Magician|> unsure about budget
[23:28:54] <Jymmm> jmkasunich I have some 15 deg LED's, and if I can muck with the casing to get a bigger angle
[23:29:09] <Jymmm> 30 deg would be nice
[23:29:14] <giacus> G nite
[23:29:15] <jmkasunich> going wider is probably doable
[23:29:34] <fenn> jymmm why do you want a wider angle?
[23:29:56] <jmkasunich> Magician: do you know things like steps per inch, etc? do you know how fast the machine originally was (feeds and rapids)?
[23:30:04] <Jymmm> fenn why do you ask?
[23:30:04] <fenn> Jymmm: wont that cause more light leakage?
[23:30:13] <Jymmm> fenn yes it would
[23:30:15] <fenn> do you know what the critical angle is?
[23:30:16] <jmkasunich> maybe he wants to see it from a wider angle
[23:31:30] <|Magician|> I am not real familiar with the machine...but I can find out anything I need to know about the way it was
[23:31:44] <|Magician|> I still have all of the original manuals
[23:31:54] <jmkasunich> well, you can't even begin to pick out cards until you know what performance you are aiming for
[23:32:04] <fenn> jymmm you know what would be cool
[23:32:09] <jmkasunich> there is some not terribly hard math that will tell you the step rates you need
[23:32:18] <jmkasunich> but you _must_ have the data
[23:32:21] <fenn> custom lighted dashboard gauges
[23:32:24] <Jymmm> fenn solar powered EL lighting?
[23:32:46] <jmkasunich> looking at cards before you get the data and do the math is a good way to waste money on stuff that is either overkill or won't meet your needs
[23:33:02] <fenn> dunno how to make the needle glow though
[23:33:40] <Jymmm> fenn: dayglow paint
[23:37:22] <|Magician|> I would rather go overkill, and leave myself room for improvements in the future
[23:40:21] <|Magician|> you are right...I expect to make mistakes for sure
[23:45:26] <|Magician|> I have prbably already made a few mistakes
[23:50:55] <|Magician|> kinda feels like i'm pissing in the wind
[23:51:22] <fenn> * fenn knows the feeling
[23:51:37] <fenn> buy it now buy it now
[23:52:23] <fenn> this will be way cool if it works though