Stuart Stevenson wrote: > During this I learned something. I have been trying to "fix" the servo > amps so when I hit a hard limit they just disable the direction the table > was moving when the limit switch was contacted. I found the servo amps are > working correct. It is EMC2 that is shutting the servos off when I hit the > limit switches. Are you using the individual amp enables? I think if you use the E-stop relay to enable the amps, they will stay on after a limit switch is hit. A limit switch normally does the same as hitting F2, which goes from "Machine On" to "Machine Off", but it doesn't cause an E-stop. > I much prefer the servos to remain on. This is not a problem > on the X, Y or Z axes. The problem is the A and B axes. Given the weight of > the head and the reality that there are no brakes on the motors: > if the head is tilted enough to hit the limit > switch > and > the servos turn off > then > the weight of the head will cause the head to > coast (fall) until the pinion gear disengages from the rack. > This is not a huge problem and should be almost nonexistent. I will know > and do not feel comfortable with this as a possibility. > I have disengaged the limit feedback for each axis. I am just using one > limit hooked to the home feedback. This allows homing. > My question is this (and maybe I have just overlooked it in the manual). > Is there a pin out of EMC2 that will disable the > motion in the direction of motion instead of shutting down all the servos? > Well, EMC by default doesn't produce separate amp enables for + and - direction. it depends on additional limit switches to control those direction enable inputs on the amps. But, of course, you could rig the regular limit inputs in HAL directly to digital outputs to drive the amp's limit inputs. Given enough digitial outputs, that would be no biggie, and you shouldn't even need any hal component for it. Just use the invert parameter of the output pin to select the desired polarity. Of course, on a 5-axis machine, this will eat up 10 more digital outputs.
I hope this helps. Jon ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
