Igor Chudov wrote: > I am working on getting 4th axis to work. While it does move as commanded, > it does so in a visibly jerky way. > > At first I thought that it was mechanical issue inside the rotary table, > such as rust, poor gear meshing, eccentricity etc. > > I took off the motor and even the lovejoy coupling. The motor, with the > attached resolver etc, is now completely alone, lying on a foam pad on the > floor. > > The way this system works is that the motor has a little tiny toothed belt > going to the resolver, wires from resolver go into "Resolver to Quadrature > Encoder Converter", and from there into PPMC as an input. > > The bad news is that even without anything on the shaft, it still moves in a > jerky way. > > What I mean by this is not just vibration, but the fact that it periodically > accelerates and decelerates.FASTER-slower-FASTER-slower etc. > > OK, use Halscope to look at ppmc.0.encoder.nn.delta and see if that is moving smoothly, or perhaps has jagged velocity changes. I am thinking that there is something wrong with the reading of resolver position. Unlike an optical encoder, which can just lose pulses, the resolver converter will always "catch up" at some time, so it can give an uneven conversion of velocity while never losing long-term position.
If you are still using the old cables with the common point between the two stator windings, that could be the cause, by mixing she sin and cos signals. Otherwise, definitely disconnect the stator signals and hook to an oscilloscope. Turn the motor until the signal on one of the stator windings reaches a maximum and then see if it is close to 3.6 V P-P. If not, then adjust the jumpers on the resolver converter board to get as close to 3.6 V P-P as you can get. Jon ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
