On Friday 01 December 2017 22:10:42 Jon Elson wrote: > On 12/01/2017 12:33 PM, Gene Heskett wrote: > > I guess my memory was playing tricks on me. After looking up the > > 74**86, I found it wasn't whats needed. Now I'll investigate some > > rs485 to usb gizmos I bought to find out how fast they were for a > > $1.00 each, which was plenty fast enough for this, and see if I can > > find a good logic level out of them when acting as a receiver. IIRC > > as a transmitter they just barely exceeded 1 megabaud, but that may > > have been a usb side limit. Interesting experiment at hand. > > Right, if you want a quad differential line receiver, the > 26C32 is a current part, and I think is > pin-compatible with the 75ALS195. The 7486 is a quad XOR gate. > > Jon > It also appears that a max485 also works, quite well in fact. I had bypassed the usb2 stuff on that board, taking the output directly from pin 1 of the max485, and that worked well. But when I went looking for a bag of 9 left, it didn't come when I whistled. Poking around here in the coyotes den, I find a bag of about 6 teeny little boards with only the max485 on them, intended I guess as a ttl-485 translator, so I've mounted them of a couple tinned perfboard strips that I can get two of hid in one of those little diecast boxes we glue to motors for a termination box, and those are about 1/2 wired up, but one end of the boards could touch the cast into the corners of the boxes screw bosses, so they are at present sitting so a layer of Go2 will cure, insulating them from that potential short. So there will be 4 wires exiting one end of the box, power, gnd, single ended phases a, b.
With the encoder cable coming into the other end, picking up the gnd & 5 volts there, and the encoders balanced a/b's entered into the teeny little green data terminals on the board the ic is on. When set on edge into the box, the tops of the green terminals will serve as spacers, giving it as an assembly, perhaps 1/16" of rattle room. I'll add a 5v to gnd tantalum bypass to help control the crosstalk. Should work just fine in the middle of the cable from the encoder to the encoder plugin I put on the end of the big box 2+ years ago so I could unplug everything. With all those toroids for the motor psu, its small block and tackle to put it up on that shelf, or to get it down in case I have to do a truly major rebuild. I'll order another of those pwm-servo amps, and swap this one out when it gets here, and send that one in then. That way I'll have a spare on the shelf when it comes back. Thanks Jon. > ---------------------------------------------------------------------- >-------- Check out the vibrant tech community on one of the world's > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
