Chris Radek wrote: > On Tue, Sep 22, 2009 at 11:43:30PM +0200, Sven Wesley wrote: > > >> BTW, I'm running servo's... :) >> Well, what servos, what interface? If you have Gecko 340 drives (that's a 320 with a pulse multiplier) it can be messed up by the direction signal changing too soon after tha last step pulse. It continues to generate the multiplier setting of encoder-scale moves which SHOULD have all been made in the same direction, as the computer intended them. But, the output moves immediately change direction when the direction signal is changed. So, each time you change direction, some number of encoder counts are made in the wrong direction, and the error can accumulate. There are hold time settings in stepgen that can prevent this.
This is only one particular sort of error that can develop in step-servo systems. Interference between motor drive signals and the encoder signals are another, and of course a bad encoder is another possibility. Also simple mechanical slippage between the motor and leadscrew has tripped up more than one person. 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
