On Wed, Mar 01, 2017 at 07:46:24AM -0600, dragon wrote: > better to run the servo amplifiers in velocity mode or torque mode. I
I think the benefits of velocity mode are that it better tolerates (still gives smooth motion with) low encoder resolution and low servo cycle update rates, and it's much easier to tune the position loop (the part in linuxcnc/hal). Some old CNCs had 100Hz servo cycles and fairly rough position feedback. If you didn't want to see stair steps on the taper you were cutting on your lathe, you really wanted velocity mode so it would keep moving in about the same direction between updates. The drawback of velocity mode is the amp is much more complicated, and you have to tune the velocity loop in the amp, and you might even need extra parts, such as tachs, to give velocity feedback in hardware. Today with millisecond or faster servo cycles, and really fine encoders, I bet you can get similar results with both setups. If you can select with a switch, why not try tuning up an axis both ways and see what works best? I'd love to see your results if you do this. Chris ------------------------------------------------------------------------------ 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
