Greetings all; Those gizmo's you can buy that purport to be usb-rs485 translators?
They have a row of 4 flea clips in the middle of the board that let you modify them. Pull the clips from the 5 volt, rx and tx posts. Hook the terminal labeled ground on the 3 terminal end of the board, to a ground on the bob. Hook one channel of the encoder to the other two terminals as the balanced input to it. Put a scope probe on the rx pin vacated by the flea clip, on the little 8 pin side of the row. Turn motor a degree or so, see couple of pulses on the scope. Fire up lcnc, enable the machine, which in my case enables the soft start spindle power. Click on clockwise button when my pyvcp button turns green and add couple clicks on the + button. spindle spins up to full song, 126 volts on a 90 volt motor. Pulse on scope has a period that translates to around 84.9 kilohertz, is full 5 volt rail to rail swing with rise and fall times in the 10ns area. So 2 of those solves my diff to single ended signal problems with bandwidth to throw away. Almost dc to light. And the duty cycle is 50%, plus or minus 2% worst case due to the motors wibblies at nearly 8500 rpms. So thats one problem solved at junk box cost. The 8 pin, I think tsop, style chip, is a max485, just what the doctor ordered. Now to build 2 of them in a box of some sort and hook it all back up. Then, recalibrate the scale factors, I'm sure I mucked that up. Oldtimers maybe? 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
