On Tuesday 05 May 2009, Kirk Wallace wrote: >On Mon, 2009-05-04 at 14:43 -0500, forget color wrote: >> Alexey and Kirk (and the rest), >> >> Thank you so much for your detailed answers. I have a couple followup >> questions. >> >> > Kirk said: >> > >> > If you need axes motion control for your tool change, typically, you >> > would need to create g-code subroutines, which you would insert into >> > your part g-code files as needed. For example, to change a pen in a >> > plotter, all that might be needed is to move the pen holder into and out >> > of a pen park location (toggle). Each pen unload and load would be two >> > g-code subroutines of X and Y movements. You can also set/reset pins >> > with g-code (M62-65) so if you have a solenoid activated gripper, this >> > could be used. Conditional control could be handled with g-code O (Oh) >> > commands. >> >> So if I'm using, say, a Gecko G540 as my axis control, how do I hook >> up to this solenoid? Would I add another LPT port to the machine, >> then hook up to it that way? > >It looks like the G540 has two outputs that can drive up to 1 Amp at 50 >Volts. This should be enough to drive a small solenoid directly or a >higher power relay. Parallel ports are inexpensive and can up to twelve >outputs: >http://www.linuxcnc.org/docview/html//hal_drivers.html#r1_1_1 > >Typically their outputs can only drive 20 mAmps at 5 Volts, so you will >need a breakout or driver board. Since the voltage or current needed to >drive a peripheral can vary a lot, I tend to make my own driver boards. >I have one of these: >http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=380121177989 > >which seems to be a good board for the price, but I haven't used it much >so far. It looks like it will drive 50 mAmps at 70 Volts, which could >drive small loads or a relay. > Yes, and for small to medium stuff, a nice selection of drivers at decent prices. But they lose the price edge when shipping is added. So this particular board is the only one I'd be interested in.
But aren't those opto's a little slow? Pix of them running at 1 khz aren't all that impressive considering we need microsecond response times for boards like the xylotex if the full speed potential is to be used. It looks like the fall time isn't too bad, but the rise time sucks even in those 'class c' pix. That would be a huge problem at 20 kilohertz stepping rates. More current through the opto's phototransistor might help, depending on what the added power dis might be. >> > Alexey said: >> > >> > You could use 4th driver for tool changer, but it is not good to >> > push it as 4th axis through emc/axis. I think, you can just create >> > XYZ machine and then add one more stepgen module to control >> > tool changer. >> >> In this suggestion, can the tool changer run through an axis port on a >> G540 (or other similar BOB), or does it need to run through something >> else? > >The fourth driver on your G540 just needs step and direction signals, >which can come from stepgen. You will need to write a program or script >to tell stepgen what to do, but you will most likely need a script to >control the other parts of the tool changer anyway. Using an EMC2 axis >to control a tool changer motor is possible, but then you would need to >put tool changer commands in with your part programs, which is not where >they are meant to be. > >> I understand these are partially not EMC2 questions, but I'm hoping >> someone can help. I think my main confusion is how I will get signals >> for a tool changer of any sort (whether it's something fancy or just a >> solenoid-activated gripper mechanism that is moved into place with >> axis movements) into and out of EMC2. Can it run through the 4th axis >> of a BOB since I'm only using 3 axes? Or do I need another route? If >> another route, can/should I just add another LPT card so I can hook up >> to the tool changer that way, or do I need to be thinking about using >> individual Geckos (e.g. 203v) for the axes steppers, and then >> something else for the tool changer so that it can all run into the >> same LPT? >> >> Many thanks for your help. EMC2 is fabulous and I can't wait to dig >> into it, but I'm a little stuck on this end of things before I can get >> there. >> >> fg > >Most tool changers are controlled with simple on/off outputs to control >simple movements. Unless you have an unusual machine, like a pen >plotter, you won't need to think about using an EMC2 axis for the >changer. If you can describe the basics of your machine, the tool >holders you want to use, and a rough idea of what the tool changer might >look like, we can start to give you our opinions on what the details >might be. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Caution: breathing may be hazardous to your health. ------------------------------------------------------------------------------ The NEW KODAK i700 Series Scanners deliver under ANY circumstances! Your production scanning environment may not be a perfect world - but thanks to Kodak, there's a perfect scanner to get the job done! With the NEW KODAK i700 Series Scanner you'll get full speed at 300 dpi even with all image processing features enabled. http://p.sf.net/sfu/kodak-com _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
