Dave wrote: >> >> I suggested it earlier as a way to check that two slaved axes were >> acceptably in-synch. >> One unpleasant scenario in the machine described is the failure of one >> home-switch, but not the other. I suggested a component that would >> panic if one axis was still searching more than a few mS after the >> other had started latching, >> >> I might just put the home switch on the "master" side of the gantry. >> >> > I think index homing on a gantry would only be worthwhile if home > offsets could be applied after the index/marker pulse was found. > On a big servo system, you aren't going to want to rotate the motors to > get the index/marker pulses aligned so the gantry is square. It just > isn't practical. > But, the first side to find the index marker will stop there, the second side will have to travel to the index mark, thereby racking the gantry. that is unacceptable. So, the two encoders MUST have the index marks aligned. Depending on how the machine is built, it may not be that hard. It may be possible to lift the pinion off the rack to get close. if the motor drives a gearbox or timing belt drive, the couplings or pulleys can be readjusted on the shafts. if the encoder has servo mount, it can be rotated to adjust the timing.
Jon ------------------------------------------------------------------------------ Try New Relic Now & We'll Send You this Cool Shirt New Relic is the only SaaS-based application performance monitoring service that delivers powerful full stack analytics. Optimize and monitor your browser, app, & servers with just a few lines of code. Try New Relic and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_may _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
