On Wed, 16 Feb 2011, andy pugh wrote: > Date: Wed, 16 Feb 2011 19:21:01 +0200 > From: andy pugh <bodge...@gmail.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: [Emc-users] Encoders with no Index > > Is there any reason why it would be a bad idea to derive an index > pulse in software? I am thinking about situations where folk are short > of P-port pins but want to tap/thread etc. > You can do lathe threading with one pulse per rev and a single pin, > but I can't help feeling that multiple pulses and a software-derived > index would work better (whether is is done with modulo division > cobbled together with HAL functions, a custom component, or even a mod > to the existing encoder counter) > > Rigid tapping will always need two pins to sense direction, but unless > people do multi-pass tapping (and I guess they might, with taper, > second and plug (yikes!)) the index serves only to start the cycle so > should be perfectly safe to derive synthetically. > > -- > atp > "Torque wrenches are for the obedience of fools and the guidance of wise men" >
Seems reasonable to me, no help for spindle orient but fine for rigid tapping/threading. Your synthesized index reference position should persist until EMC is shut down, so really no different than a true index except: 1. Random relation to spindle orientation 2. Orientiation changes every EMC startup I guess the mod function could allow for encoders with non 1-1 gear/belt ratios with the spindle Peter Wallace Mesa Electronics ------------------------------------------------------------------------------ The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE: Pinpoint memory and threading errors before they happen. Find and fix more than 250 security defects in the development cycle. Locate bottlenecks in serial and parallel code that limit performance. http://p.sf.net/sfu/intel-dev2devfeb _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
