ok - some cool news I think. So - with the switch on the interface board set to off (non step/dir mode) the control signals are 4 phase drive. (seems to be unipolar). pins 2 through 5 control one axis - 6 through 9 control the other. I hacked a hal file to setup stepgen to output 4 phase (patterns 5 through 10).
First tried pattern 9 (Unipolar Half Step) because the scale was setup for that. the performance was the same. 20ipm max and would probably have to back that off... Second was pattern 10 (Bipolar Half Step) I know - not likely - and it wasn't. Didn't like it. Third was pattern 5 (Unipolar Full Step) I halved the axis scales also. similar performance.. 20ipm max. (and sound so far was pretty crappy) fourth was pattern 6 (Unipolar Full Step (two windings on)) Holy crap. That sounds nice. maxed out at 30ipm and didn't try any faster. Full stepping is .00054ish per step. Workable for sure. That is what the original control/software maxed out at. I will try faster when I get a chance. That is totally usable with linuxcnc - no mods to the control. I need to hook up the index and 100ppr and try some threading! One thing to try is - I think I can put the interface board back into step/dir and full step. I don't know what pattern it does though. sam (happy dancing..) On 7/8/2013 7:13 AM, sam sokolik 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 > > ------------------------------------------------------------------------------ See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. Start your free trial of AppDynamics Pro today! http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
