Looking at the PDF, It seems I forget to ask one question about the signal: Is the sin/cos signal single-ended or differential? In other words is it referenced to ground or do we get pins with labels like sin+ and sin-
If there are even 100 pulses per revolution and the spindle runs at 100K RPM then we are talking about 10000K or 10 MHz. At that point I start thinking about hardware quadrature decoding rather than software or in the Linux CNC world they use FPGA chips. But without understanding the signal it is way to early to even think about a design solution. Let's see what's on all the wires first. On Fri, Feb 14, 2020 at 7:29 AM dave engvall <dengv...@charter.net> wrote: > a bit overdone for your app but this should give you an idea. page down > to fig 16. > > > https://www.st.com/content/ccc/resource/technical/document/application_note/group0/6a/82/83/37/61/69/4e/74/DM00497286/files/DM00497286.pdf/jcr:content/translations/en.DM00497286.pdf > > Dave > > On 2/13/20 11:01 PM, andrew beck wrote: > > Chris. I'm still learning electronics. Could you expand a bit on this > > please. > > > > Maybe draw a napkin sketch of it. Sorry to be a bit slow on the uptake > > > > On Thu, Feb 13, 2020, 5:46 AM Chris Albertson <albertson.ch...@gmail.com > > > > wrote: > > > >> A sin and cos are 90 degrees apart. All you should need to do is > threshold > >> the signal and you have A/B quadrature. Many ways to threshold it but > >> you want the one with least noise. > >> > >> A simple way to convert a sin wave to a square wave is to amplify then > clip > >> it with diodes. A comparator can also convert the signal. > >> > >> The point to remember is that sin/cos is quadrature and all that is > needed > >> is some signal conditioning. > >> > >> On Tue, Feb 11, 2020 at 10:46 PM andrew beck <andrewbeck0...@gmail.com> > >> wrote: > >> > >>> Hi guys > >>> > >>> wondering if anyone has any ideas here. > >>> > >>> I have a heidanhain spindle motor that runs up to 10000 rpm and has a > 5v > >>> sin cos encoder on it. I am currently controlling the motor with a > >>> schiender vfd. I am talking to the support engineers here in New > Zealand > >>> about buying a encoder card so I can get better low down torque. If I > >> run > >>> the card in full encoder closed loop control in the vfd I can get 200 > >>> percent of the torque right down to 0 rpm for 30 seconds or so which is > >>> pretty useful. I am currently just running the drive in Variable > >> frequency > >>> control which rapidly looses torque at low rpm. > >>> > >>> Anyway they have a bunch of cards I can use but don't have a encoder > card > >>> that is suitable for sin cos encoders. I have no trouble changing the > >>> encoder but am not sure if I can get a source of encoders that spin up > to > >>> 10k rpm. > >>> > >>> Anyone have any suggestions? > >>> > >>> regards > >>> > >>> Andrew > >>> > >>> _______________________________________________ > >>> Emc-users mailing list > >>> Emc-users@lists.sourceforge.net > >>> https://lists.sourceforge.net/lists/listinfo/emc-users > >>> > >> > >> -- > >> > >> 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 > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
