On Mon, Oct 20, 2008 at 10:56:12AM -0500, Jeff Epler wrote: > On Mon, Oct 20, 2008 at 04:50:11PM +0200, Sasa Vilic wrote: > > This mean than, that I cannot use two servo motors for the same axis, > > because each motor has its own encoder. Is it than possible to use two axis, > > to control same joint? > > In the case of two servo motors, you would have two pid instances. each > pid would get feedback from its associated servo motor, and have a > different velocity command for each amplifier. > > However, you can still only hook one signal to axis.0.motor-pos-fb for > the purpose of detecting following errors.
You could do your own following error detection though. Subtract commanded from feedback for each motor (sum2), take the absolute value (abs), compare it to a threshold (comp), or them both together (or2), and hook that to axis.0.amp-fault-in. Or more directly, you could detect the difference between the two motors' positions and use that as an additional fault condition. On my system I use amp-fault-in for "the PID has been saturated for a while" (probably indicating a failed encoder - runaway condition) but you can use it for any error condition you want. ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
