On Fri, 2 Dec 2011, andy pugh wrote: > Date: Fri, 2 Dec 2011 19:29:23 +0000 > From: andy pugh <[email protected]> > Reply-To: EMC developers <[email protected]> > To: EMC developers <[email protected]> > Subject: [Emc-developers] Single-wire encoders > > Vehicle engines generally measure crank position using a > single-channel encoder. Traditionally it worked by sensing the starter > ring-gear. The index is simply a missing (in practical terms, a little > shorter) tooth. > Many now use a magnetic code-wheel and a hall sensor. I have some, as > it happens, and they are a very attractive form factor, being 125mm OD > with a 100mm through-bore > > It seems that this scheme could be useful in EMC2, especially for > lathe-users who are short of pins, and the form factor is ideal for > this too. > > I wonder how much work it would be to add this as a mode to the encoder > module?
Sounds pretty easy theoretically since the encoder module has timestamps. You would have to have a base thread rate enough faster than the tooth rate at max speed to have enough timing resolution to reliably detect the missing tooth I guess the missing tooth detection also has to inform the position/velocity estimation stuff to hold the last velocity number and extrapolate the position Another possibility is some kind of DPLL running at the base thread rate to lock onto the input frequency (and bound the tracking acceleration so the missing pulse doesn't cause a big change in velocity estimate or position) Then the apparent large acceleration caused by the missing tooth trigger the index logic. > > -- > atp > The idea that there is no such thing as objective truth is, quite simply, > wrong. > > ------------------------------------------------------------------------------ > All the data continuously generated in your IT infrastructure > contains a definitive record of customers, application performance, > security threats, fraudulent activity, and more. Splunk takes this > data and makes sense of it. IT sense. And common sense. > http://p.sf.net/sfu/splunk-novd2d > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
