On Wednesday 18 November 2020 13:56:37 Gene Heskett wrote: > 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.
I'll take that back. This particular Sainsmart board, the ST-V3 was used specifically because it doesn't have any opto's on it, but it still has 5 gawdawful bright leds to tally the inputs, and from the placement of the led's, I'd have to say they are powered by the logic 1 status of the input. And I'd assume that the output back to the 5i25 P2, is for those 5 inputs, interrupted by a 74HCT14 Schmidt trigger. So, the logic 1 would be anything over about 2.6 volts but haven't checked the data sheet for sure. So that means there is a pretty good load on that encoders logic 1 state if it lighting up a grain of sand led blindingly bright. Thinking a bit outside the box, I am tempted to put those 1500 ohm resistors in series with the inputs. I cannot find it, but every input reads 97.5 nf if I give the meter enough time to settle. leads open its 0.17nf. And I just found the 97.5nf caps that I think are the real problem. I bought two of these and have the 2nd one in my hands right now. I have several others in service here already, bought specifically because there's no opto's on 'em. The only bob I've found, other than the discoed C1G rev 4, that doesn't have them. In the morning, set up my hot air kit and get rid of the caps on those 2 inputs. They are grain of sand monolithic types on the bottom of the board. I'm betting that will fix it. Are Mach setups normally plagued with enough noise to need that filtering? [...] 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
