John haha yep I'll not do that. I'm thinking I'll use a 1mm cutter anyway if the sensors are good enough for that
On Mon, 28 Mar 2022, 08:23 John Dammeyer, <jo...@autoartisans.com> wrote: > Just don't do what I did which is design the plate for a 3mm cutter and > then start the LCNC G-code with a 4mm cutter. > John > > > -----Original Message----- > > From: Chris Albertson [mailto:albertson.ch...@gmail.com] > > Sent: March-27-22 11:31 AM > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] Homebuilt encoder > > > > Forgot to include a link. You can buy the bare sensor but also you can > buy > > them on PCBs with connectors attached and ready to go. > > amazon.com/Measuring-Optocoupler-Interrupter > > <https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection- > > > Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor&qid=1648405019&sr=8-17> > > > > Best to use a thin aluminum plate to make the interrupter disk. Make > the > > slots 50% duty cycle, You need three sensors for quadrature with > index. > > The above sensor should directly interface to Measa or a parallel port > or > > some microcontroler. > > > > > > On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson < > albertson.ch...@gmail.com> > > wrote: > > > > > THis goes to 10K RPM? that is 167 revolutions per second. 400 slots > > > means 70 KHz signal. > > > > > > Can you design an inductive sensor that does 70KHz but is also > sensitive > > > enough for near zero RPM? Optical sensors can work up to 1MHz with no > > > problem as they don't have any inductanve. You can buy a "C" space > > > sensor for a few dollars > > > > > > In either case, optical of inductive, you want a 50% "slot" where > there is > > > as much metal left as cut away Then the "edges" of the square wave > are the > > > same in either direction. The 50% duty cycle in effect doubles the > > > sensor resolution. > > > > > > Why? Think about the signal when the direction changes. You have > two > > > sensors in quadrature and lets say one is being blocked and one is > not, I > > > think you want the turnaround to take as long for each sensor. > > > > > > > > > On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh <bodge...@gmail.com> wrote: > > > > > >> > > >> > > >> > On 27 Mar 2022, at 08:09, andrew beck <andrewbeck0...@gmail.com> > wrote: > > >> > > > >> > And is bigger dia better for higher resolution? > > >> > > >> Probably not, as it will perhaps have more scope to oscillate at > 10,000 > > >> rpm. > > >> > > >> Don�t neglect the purely mechanical design of this fast-spinning part. > > >> > > >> Have you considered optical sensors rather than inductive? > > >> > > >> What will be counting the pulses? > > >> > > >> LinuxCNC can lathe-thread with one sensor. > > >> But rigid-tapping is different as it needs to accurately detect the > > >> reversal point. So you need three channels for index and full > quadrature. > > >> > > >> Work out what error you can accept in the reversal point detection > (as a > > >> fraction of thread pitch) and you can get a feel for how many slots > you > > >> need. > > >> > > >> > > >> > > >> > > >> _______________________________________________ > > >> Emc-users mailing list > > >> Emc-users@lists.sourceforge.net > > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > >> > > > > > > > > > -- > > > > > > Chris Albertson > > > Redondo Beach, California > > > > > > > > > -- > > > > Chris Albertson > > Redondo Beach, California > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
