Sam, I also have three of these from a school (compact 5 cnc versions). One has the tool turret.
I couldn't do the web documented stepper mod because my boards were of a different revision. So I bought some chinese stepper drivers and just converted one (longs_motor 4.2A DM542A). The orig steppers were weak enough (plus I accidently let smoke out of one playing w/ it) so I converted them to modern steppers too (nema 23, 12.6Kgcm). I run out of voltage before turning them super fast but they're faster than the orig control/steppers and way more torque. Might try faster ones on the next build but the leadscrew whip will be the limiting factor. The orig *TINY* motor pulleys provide a bit of a hurdle moving over. New shafts just aren't long enough to pin the pulleys like they were before. I ended up using loctite (bearing locker.) I was skeptical at first but once you do the math of the cm^2 of wetted area the safety factor is something like 1000+. They will never come off w/ the torque those little motors can turn out;) I also didn't bother to reverse engineer the spindle drive. Just used a new KBWD-16(?) 90V drive. ~$85 wasn't worth the time of figuring out the other one. Running it all w/ a Atom board & mesa cards (which admittedly are a bit overkill.) Will probably try just a Atom next go round. Tucking everything inside the orig cabinet. Im currently cutting new faceplates to fit a ELO 15" touchscreen on the far right side (hopefully far enough away from any chips esp w/ the safety guard.) I'll provide more info when done. Stephen On Mon, Jul 8, 2013 at 8:13 AM, sam sokolik <[email protected]> wrote: > We got a few of these lathes from a local school. they are cute little > cnc lathes. > The technology is pretty old though. The steppers are 72 steps per rev. > > I found this > > http://www.maxton.com/ebay/emco/EMCO%20Compact%205PC%20Conversion%20to%20Mach3.pdf > > which talks about converting to mach. They remove the octal latch and > jump through it. > I wanted to see if I could get linuxcnc to drive the board without > hacking the latch out. > > this is what I have found/figured out > > I think this is correct.. (this is with switch 1 on the interface board > set to > 'on' which puts the board into step/dir) > > x step pin 2 > x dir pin 3 > z step pin 4 > z dir pin 5 > index pin 12 > estop pin 11 > 100 ppr sensor pin 10 > 74ls374 enable pin 14 > 74ls374 clock pin 1 > > I setup linuxcnc to send a pulse at every base period for the 'clock' > that latched the outputs of the chip. (thanks Jeff E for the idea) this > is using the > 'reset' option of the printer port that allows for a cycle within each > base period > the same feature that makes 'double step' work. This allows me to > 'latch' the > 74ls374 each base period with the current step/dir pattern. It seems to > work > > Now it took me a bit of tinkering to figure out that I didn't read the > above article > well enough to notice that you needed to set a switch to put the emco > interface > board into step/dir mode. During this time I was flipping bits on the > printer port > to try to figure out why it wasn't working. I think by default the > interface is setup > as phase drive. (4 phases per stepper) as I think I was flipping all 8 > data bits on > the printer port and was getting stepper clunking. > > Well - the performace of these drives/steppers are pretty poor. (assuming > I have the timing right - and I didn't get too much time to play with > it.) In the > above article they talk about around 20ipm is about max. That is what I > was > seeing - plus there is a weird interaction when you run both axis at once. > (they get quite a bit noisier for some reason). Now it could be that I > don't quite > have the timing correct - like maybe the step/dir needs to be inverted or > or something - I will play with it more. > > I would also like to switch it back to non-step/dir mode. (phase drive > maybe?) > because there might be a reason the original software used it.. (better > performance?) plus I think I have the original software and would like > to try > it out also. (need to setup a pure dos machine to test) > > lathe > http://www.electronicsam.com/images/emco/emcoclose.JPG > interface/drive > http://www.electronicsam.com/images/emco/interfaceanddrive.JPG > > sam > > > > > > > > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
