On Friday 08 May 2020 13:34:36 Gene Heskett wrote: > On Friday 08 May 2020 12:09:45 Dan Henderson wrote: > > Thanks Andy/Jon/Gene. To enable Quadrature do I merely turn on > > phase-A/B/index inputs and remove “encoder-counter-mode = True”? > > Sounds good. > > > Here’s a pic of the reverse circuit I’m making to enable M4 polarity > > reversal of the DC motor. > > We all know this stuff runs on smoke and mirrors. > > That controller probably will NOT like being reversed without first > stopping the motor, then reverse that relay and restart the motor. > > Doing otherwise will probably break the mirror and let all the smoke > out. Typically they don't work anymore. > > Ideally, two relays. I have used the P&B ice cubes with 20 amp > contacts for this. One to apply a braking resistor to absorb the > motors energy as its stopping and a second to do the reversal. Its > wired closest to the motor with the moving contacts to the armature.
Thats ambiguous, the braking relay is closest to the motor. > A calrod coil out of an electric cookstove makes a good braking load. > Somewhat overkill but 100% serviceable forever. > > The reversal sequence would be: > 1. hold the reversal from motion, blocking it from the controller > > 2. use that to reduce the drive to zero useing a rate limiter like a > limit3, switching its input with a mux2. > > 3. When the drive is off, switch on the load R relay to stop the motor > much quicker. > > 4. when, according to the encoder, the motor has stopped, release the > braking relay, > > 5. enable the reversal relay AND restore the speed input to the limit3 > and let it ramp the motor back up to set speed > > Do the same thing in reverse at the top of the backout move. > > hint, an xor2 is used to detect the change in state of the rev signal > from motion. A miss-match is the trigger for the stop sequence. > > I ran my 7x12 that way for about 2 years without letting the smoke > out. But with a heavy 5" chuck, the overshoot at the bottom of the > hole was terrible. So I eventually threw more money at it. > > Cheers, Gene Heskett 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
