On Thursday, February 09, 2012 02:22:45 AM andy pugh did opine: > On 9 February 2012 01:38, gene heskett <[email protected]> wrote: > > And I know there is a debounce gizmo I have not > > studied yet, can it be made suitably slow at going back false only? > > http://www.linuxcnc.org/docview/html/man/man9/debounce.9.html > That reads like it time constant is the same going both ways, not exactly what I had in mind.
> > Or perhaps there is a re-triggerable one shot module? > > http://www.linuxcnc.org/docview/html/man/man9/oneshot.9.html Now this looks pretty good. I presume it could run at BASE_THREAD rate, or is it servo thread only? In the meantime I've added a smallish tantalum capacitor, 3.3 u-f I believe it is, across the probe to ground, which can discharge probably at 20x the BASE_THREAD rate, but will take long enough to recharge that any contact should register. That seems to have helped, I'm getting results of about +- 0.001" this way. Now my problem is solving for the offsets to apply after having measured in G54, that will result in a G55 command to go to 0,0 putting it exactly on the left front corner, and when probing the drilled hole, putting it on the right front corner when an 0,0 in G56 is done. I am within perhaps 20 thou of that, but my back pain is such that I couldn't concentrate on which fudge number needed to be adjusted which way, so I gave it up about midnight. Getting old isn't for wusses. ;-) Thanks Andy & the rest of the crew. 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> Just because everything is different doesn't mean anything has changed. -- Irene Peter ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
