On Monday 14 October 2019 08:14:38 Kenneth Lerman wrote: > They are actually rated from zero Hz (DC) to 100MHz. > Then they have stuff in there that not in the diagrams in the pdf. 'twon't be the first time howto's don't show proprietary stuff :)
> Ken > > Kenneth Lerman > 55 Main Street > Newtown, CT 06470 > > On Mon, Oct 14, 2019 at 5:27 AM Gene Heskett <[email protected]> wrote: > > On Sunday 13 October 2019 19:46:55 Kenneth Lerman wrote: > > > Hello All -- especially Gene, > > > > > > I've seen many posts on the lists regarding breakout boards and > > > dealing with issues regarding slow opto-isolators. I have a > > > question: > > > > > > Is anyone using: ISO776x > > > <http://www.ti.com/lit/ds/symlink/iso7760.pdf> devices? > > > > I've seen that pdf before, but in the cases where I've simply > > bypassed them, I had good solid, noise free sources to start with. > > If I use a BoB, its a Saintsmart, simply because there is not any > > opto's in their output path, and most outputs goto the input opto's > > of a stepper driver, which I've found is a bit faster than the > > average bear. A 2M542 for instance can, if the drive is good rail to > > rail stuff, be driven to about 375k steps a second before it > > miss-behaves! That will turn a nema-23 motor rated for 270 oz/in, > > to over 3000 rpms if the supply voltage is pushing the 2M542 at > > around 42 volts. Nearly 2000 revs at 28 volts. > > > > I suspect the reason they aren't used may have something to do with > > the cost, or possibly the fact that they are capacitively coupled > > and very low re-rate signals might drift back to their default > > state, without any change in the input voltage. > > > > But thats, to me, just a SWAG. > > > > The most glaring example of too slow in my stuff is the 1000 line > > encoder sitting on top of the G0704 spindle motor, an ABX encoder, > > and the resultant "scale" is over 14,000 in the .ini file, and thats > > way too fast for an opto. So I have 2, $2, rs485 convertors to make > > single ended rail to rail logic out of the encoders differential > > outputs, Those 2 single ended signals are now being fed to a > > sainsmart bob whose optos I have bypassed, and on to the 5i25. Works > > perfectly. > > > > I have switches on the gearshift knob that tell my .hal file which > > gear its in, or no gear in case its between gears, in which case I > > feed the pid just enough offset to make the motor spin maybe 25 rpm > > when its out of gear, making gear shifts slick and painless while > > its running! When its in gear by the last degree and one of the > > switches is closed, the circuit then scales the "scale" by the gear > > and restores the speed input from lcnc, and 200ms later the spindle > > is back up to the set S speed even if its 3000 revs. Thats 800 revs > > faster than OEM. > > > > The 5i25 encoders x input is still the x input from the original > > optical encoder wheel I made. And with that high a resolution, > > quantization noise is essentially gone, and I can run the spindle > > pid's PGain at 40 or so, but 20 is unconditionally stable. > > > > With 126 volts in the motor supply feeding one of Jon's pwm-servo > > amps to that 90 volt, 9.7 amp rated motor, I'm getting close to 2hp > > at the amplifiers 17 amp limit, rigid tapping in steel with a 3/8's" > > tap can be done by pecking in steel or cast, going about 1/2 turn > > per peck. No change in the speed until that 17 amps limit makes its > > iron chirp. > > > > And I'm amazed that the plastic gears in that 2 speed head are still > > working, by all rights I should have stripped the teeth off them by > > now. Tough stuff. > > > > > They are 100 MHz data rate devices, have high isolation, have six > > > in a package, and look like they would work just fine. The only > > > downside might be that they are limited to 5.5 volts on the > > > output, so you might need to add a transistor driver after them. > > > And all of the ones in a single package share a ground. > > > > > > I hadn't seen them before, so I thought I'd mention them. > > > > They look like they'd be perfectly usable in an active circuit, but > > I'd have reservations about putting one in a home or limit switch > > circuit until we find out what their dc characteristics are. > > > > > Regards, > > > > > > Ken > > > > > > Kenneth Lerman > > > 55 Main Street > > > Newtown, CT 06470 > > > > > > _______________________________________________ > > > 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 > > _______________________________________________ > 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
