So - as far as I can tell - the original control did 1/2 stepping up to about 19ipm - then full stepping from there to 30ipm. Now the lathe runs fine on full stepping from 0 to 40 (maybe 45)ipm. Half stepping only works well up to 20ipm-ish. (stalls above that)
But why stop there.. I started thinking about if linuxcnc could do that.... (without coding anything) A couple advantages of halfstepping.. 1 higher resolution 0.000273403/step vs 0.000546806 per step 2 reduced resonance.. (I have not run into this with full stepping on the lathe) Then at normal cutting speeds - < 16ipm you get a higher resolution. So why not have 2 stepgens running. One that half steps (type 9) with input scale of 3657.6073152 and the other full stepping (type 6) with a scale of 1828.8036576 (lathe calculation - metric screws) Then switch between the two stepgens at a specific feed (I picked 16ipm with a hysteresis of 1ipm) All I can say is - HAL IS AWESOME I setup a Lut5 with Jeff E's help (thanks jeff!) that switches the printer port between the 2 stepgens. A offset componant was used between the 2 stepgens to better align the phasing. (not tweeked 100% yet) but we jogged it around - could not tell that it was switching between the 2 stepgens and it always came back to 0. there is a bit more than that.. (ddt for calculating the axis velocity, abs of that, comp w/hystorisis, and stuff I have forgotten already.) And here is a halscope capture. Left side is halfstepping - right side is full stepping. The trigger is the velocity threshold. http://www.electronicsam.com/images/emco/Screenshot.png I think the offset could be tweaked more scientifically to maybe get rid of the blip. But as it is running the 4 phases directly - it didn't seem to effect the motion. here is the initial configs. http://www.electronicsam.com/images/emco/linuxcnc_configs/full-half_step_test/ again - jmk and everyone that has worked on hal - Very very awesome work! sam On 07/18/2013 06:55 AM, sam sokolik wrote: > one last - I swear.. ;) > > https://www.youtube.com/watch?v=Z_LxyosF2yc > > sam > On 7/15/2013 5:42 PM, sam sokolik wrote: >> one more.. >> >> https://www.youtube.com/watch?v=_7skJhKzU7Y >> >> Dad is having too much fun... >> >> sam >> >> On 07/11/2013 08:43 PM, sam sokolik wrote: >>> quick threading video.. (yes - not the correct cutter - and the exit >>> move is a bit shallow.. but shows the spindle sync is right on...) >>> >>> https://www.youtube.com/watch?v=ERMizV-yy8U >>> >>> sam >>> >>> On 07/11/2013 02:56 PM, sam sokolik wrote: >>>> Seems to run nice at 40ipm >>>> >>>> http://electronicsam.com/images/emco/EMCOThreading.JPG >>>> >>>> video soon... >>>> >>>> >>>> On 7/9/2013 11:34 AM, sam sokolik wrote: >>>>> 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 >>>>> >>>>> >>>> ------------------------------------------------------------------------------ >>>> 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 >>>> >>> ------------------------------------------------------------------------------ >>> 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 >>> >> ------------------------------------------------------------------------------ >> 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 >> >> > > ------------------------------------------------------------------------------ > 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 > ------------------------------------------------------------------------------ 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. 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