> > Brushless servos have a permanent magnet rotor. The coils that make > up the stator ( the stationary coils) are up against the outside walls > of the motor so any heat from the coils can be transferred out of the > motor rather easily. On a brush servo motor, the rotor has a wound > rotor with a set of brushes and a commutator. Permanent magnets are > usually on the inside of the motor shell which surrounds the rotor. Due > to this arrangement it is usually harder to keep the rotor cool - so the > motor has to be larger than an equivalent power rated brushless motor. > Because the brushless motor has no brushes - which eventually wear out, > a brushless servo motor is simpler and usually more reliable. > > Brushless motors can be very accurate. Brushless motors are generally > superior from a technology and performance standpoint. > Thanks for the info on how the brushless motors work. I am going to read up more on how they are controlled so see if I can understand them better.
> EMC2 can run either way - closing the servo loop on PC inside emc2, or > letting the servo controller do it. > > Mesa cards (and other similar hardware) expose the servo encoder to > emc2; emc2 does the PID calculation and computes a signed-magnitude > motor control value; this gets fed to the motor amps. This is nice > because you get full insight into what the motor is doing, and you can > easily tune the PID controller. I dont know for sure, but I suspect > that emc2's PID controller is better than most embedded solutions; it > has first- and second-order feedforward etc. > > Gecko servo controllers (and other similar hardware) consume the servo > encoder information; do their own PID calculation; and feed the motor > the proper power. In this case, emc2 communicates only "desired > position" information to the controller, usually via step/dir signals. > This is nice because it makes it very simple to get the motor up and > running. > Between your information and a post I found on CNC zone at http://www.cnczone.com/forums/showthread.php?t=91306 I think I got a handle on how things are supposed to work together. Is the mesa 7I43 card the recommended card for EMC out of the mesa products? ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
