On Tuesday, December 27, 2011 11:52:23 AM Mark Wendt did opine: > On 12/26/2011 12:34 PM, gene heskett wrote: > > I guess I've finally reached that age where everything I like is > > either illegal, fattening, or immoral. Sigh... > > Or broken... ;-) > Well, with my sugar, I'd prefer to call it "worn out". :)
> > Cheers, Gene > > mark Looking at the current integrators manual, encoder modules pages, I am wondering how hard it would be to develop a stop signal that would be a combination of the spindle not on, but getting output from the encoder indicating the spindle is still coasting at some very slow speed? I'd like to be able to sequence the following set of spindle states: 1. Spindle off, nothing from the encoder = false 2. Spindle enabled, nothing from encoder in 50ms or so = e-stop error true 3. Spindle on, pulses from encoder = false 4. Spindle off, pulses from encoder = true So that is 2 signals, one of which goes to the e-stop, the other to enable a relay that will feed maybe 2 amps dc through the motor to effect a 'suicide braking' effect on the motor for as long as its turning even if the spindle is being positioned by hand. The idea would be to achieve the quickest reversal of the spindle motor of this lathe I'll buy in the next couple of months, so the sequence in the g- code would go something like this: Hit end of fwd threading motion loop programed, stop spindle, which will make condition 4 true, back out x by .1", make interpreter wait until condition 4 above = false, the spindle has effectively stopped. enable spindle in reverse to retract to start of thread, with z following the encoder in all cases, or... It might be better if z stopped following spindle lock at the stop point, then became locked again, when the spindle has retraced to that point in the reverse direction. This would prevent digging into an adjacent, larger diameter section at the end of the loop while x is retracting and the spindle hasn't quite stopped. I have no clue just yet, if hal can actually sequence such a scenario or not, so much study of my fresh manual printout will need to be done. If it can't, no use me spinning my wheels. Or, since threading is dependent on the index pulse to synch z to spindle anyway, would it actually be better to just stop/unlock z, retract x, retract z to start, then lock on the next index pulse to start the next cut? I can't see this as workable unless the entry of the thread is at least a turn out into empty space just to let z accelerate and get in step since there will be a large following error at the start. Not having any really effective way to speed adjust this induction motor so the spindle can be effectively stopped in the last 1/4 turn to the end point, from perhaps 1000 rpm when doing small threads, may be making the problem worse in my mind than it is in practice. Discussion? Or should I spend umpty bucks for a 1.5 hp vfd & toss this 1 hp motor into the pile in the corner to run a cooling fan someday? Googling says this option starts at about $400 for 1.5hp, rising rapidly. 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) My web page: <http://coyoteden.dyndns-free.com:85/gene> Vote anarchist. ------------------------------------------------------------------------------ Write once. Port to many. Get the SDK and tools to simplify cross-platform app development. Create new or port existing apps to sell to consumers worldwide. Explore the Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join http://p.sf.net/sfu/intel-appdev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
