On Wednesday 18 November 2020 13:07:18 Chris Albertson wrote: > That is what you do, look at the shape with no load. the 10X probe > did that. > > I have to admit my experience with encoders is mostly wth directly > connecting to microcontroller pins. No need to opto-isolate if > everything is driven from the same driven power. > > IIt would seem then that those optical couplers are hard to drive and > maybe they were designed to be driven by mechanical limit switches. > In any case I don't see a reason to use an optocoupler when the device > you are connecting in an optical coupler. I think if you drive the > motor encoder from the same power and gund at the BOB you are good.
Just try to buy a bob w/o them damned things. If you don't want them you have to rip em out. > > As for removing those chips. Buy a cheap chinese hot air solder > station, then un-soldering even a 16-pin through-hole DIP chip is > easy. Before I owned one I used to clip all 16-pins from the chip > and toss the chip in the trash then un-solder each clipped off lead > pin one at a time. Of course the hot air is designed for SMT but it > make through-hole very easy. Been there, done that twice now. I am a C.E.T. And I've had an iron in one hand since about 14yo, and a scope probe in the other since I was 16 yo. > On Wed, Nov 18, 2020 at 9:38 AM Gene Heskett <[email protected]> wrote: > > 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 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
