On Wednesday 18 November 2020 11:50:26 Chris Albertson wrote: > Your encoder is likely just a bare phototransistor. You might need a > 10K pull-up. THat might be enough
[...] > Disconnected from the bob, it does do a > > rail to rail swing with a rise or fall time in the very low > > microsecond range. Read this last sentence again Chris, the rise time is just a microsecond when disconnected from the BoB, Connected to the BoB, fall time is unchanged, but rise time looks like it having to charge a .1uf cap. Tested now with 3 Sainsmart BoB's. I can see a change in the curve as it goes above the opto's on point at about 2 volts, the rc curve suddenly gets extended to about double. I can still see the change in the shape of the curve at the output of the encoder with a 1500 ohm pullup. It gets about 10x faster with a 1500 ohm pullup, but how much can it sink? Its nice and square just driving the scopes 10x probes. This is beginning to look as if I am going to have to pull the optos out of the sainsmart BoB's. Its a PITA, but I've done it before. And I normally install a couple 1n914's as rail snubbers to protect the gates of the HCT stuff on the card. So I may as well get to it. Thanks Chris. > > Thanks all. > > > > Cheers, Gene Heskett > > -- > > "There are four boxes to be used in defense of liberty: > > soap, ballot, jury, and ammo. Please use in that order." > > -Ed Howdershelt (Author) > > If we desire respect for the law, we must first make the law > > respectable. - Louis D. Brandeis > > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
