sorry there was no part number on the encoder. I figured it was the generic Omron clone that is 5 to 12 volts. But there are two kinds that other is 12 to 24. volts. See in the link below https://www.ia.omron.com/products/family/486/specification.html
Is the encoder "open collector" or voltage output. If open colector pull the outputs up to 5 volts. Placing an encoder part number of the schematic would help. Can you post a picture of "ghost pulses", if using an analog scope just use you phone camera, most digitalscopes can save the scree to USB drive. Noise like this is best eliminated at the source On Sun, Oct 10, 2021 at 1:04 PM Peter Hodgson <peterjohnhodg...@gmail.com> wrote: > Hi Chris, > > The encoder datasheet gives a voltage range of 10-30vdc so I don’t think > direct connection with 5vdc would be an option. > > Would a direct connection via voltage dividers eliminate the ‘ghost > pulses’ being picked up by the Pico board? > > The encoder won’t be running above 3,000 rpm. > > Pete > > > On 10 Oct 2021, at 19:00, Chris Albertson <albertson.ch...@gmail.com> > wrote: > > > > Is your math right? Yes, I get 83 KHz for a 500 line encoder at 10,000 > > RPM. Yes that is < 1% of the isolator's rated speed (of 10 MHz) > > > > But the schematic had an RC low pass filter in the encoder output that > > would have prevented the system from working above about 1000 RPM. I see > > this is gone now. > > > > But why are these isolators even needed? Why not simply operate the > > encoder at 5 volts? > > > > Or if you must run the encoder at 12 volts, you can do level translation > > with a resistor voltage divider. > > > > There is nothing yo isolate. The entire system runs on a common ground > and > > there is no high power devices in the schematic and I assume the entire > > system is in one building with no long (100 meter) cables > > > > If you are worried about accidents blowing up the controller, use diodes > to > > shunt any transients. But really there are no inductive loads > > > > > > > > > > > > On Sun, Oct 10, 2021 at 10:25 AM John Dammeyer <jo...@autoartisans.com> > > wrote: > > > >>> From: Gene Heskett [mailto:ghesk...@shentel.net] > >> > >> > >> > >>> If the opto's are fast enough, you should be > >>> fixed. A 500 ppr encoder s/b fine. A 1024 or 1000 requires a faster > >>> opto. > >>> > >> > >> HI Gene, > >> Comparing the cheap far east BoB optos with the HCPL2621 is apples and > >> oranges. > >> > >> A 2500 line encoder still only creates 2500 pulses. The quadrature just > >> looks at two lines and 2 edges for 10,000 edges. But the max speed of > his > >> encoder is 10,000 RPM which in RPS is 166.7 and would result in 417kHz > >> which is 4% of the opto max 10 Mbps capabilities if the encoder was > 2500 > >> line. > >> > >> But his is 500 line so at 166.7 RPS is 83kHz which is 0.8% of opto > >> capabilities. > >> > >> > >> John > >> > >> > >> > >> > >> _______________________________________________ > >> 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 > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
