I found I had problems with the US Digital Encoders. Changing to CUI was an amazing improvement. The motors were DC Brushed servos run with the UHU Servo Boards and the upgraded processor in a piggyback board. I finally changed over to AC Servos from Bergerda after I found that the X axis motor was probably a 180V rather than 90V motor and was constantly losing position. A replacement motor from Automation Technologies with shipping and exchange was more expensive than the AC Servo c/w controller. Now I have Bergerda drives and motors on the whole mill.
John > -----Original Message----- > From: Sam Sokolik [mailto:samco...@gmail.com] > Sent: March 7, 2025 5:29 PM > To: Enhanced Machine Controller (EMC) > Subject: [Emc-users] Another reason why I don't like CUI encoders. > > I had bought a few and thought I would play with them. Figured out pretty > quickly that they have way too much noise for closed loop servo control. I > demoted them to rpm sensors. I put one on the monarch spindle motor. > Tuning for spindle speed was acting goofy. I finally broke out halscope > and look at the velocity from the mesa encoder counter (this is > velocity-rpm) > > https://photos.app.goo.gl/WyDxavoi2NBNPG797 > > IF I did the math correctly - every rotation of the motor - the rpm varies > 250rpm. (about 1700rpm and 3 cycles every 100ms) > > I might swap it out. I don't know yet. I don't know how well I can tune > this motor with field weakening.. Here is after I lowpassed the rpm at a > gain of .01. > > https://photos.app.goo.gl/1icRGaFH2AVTSS4i8 > > that is an overshoot of about 150 rpm. (totally usable - for me it is > pretty great) > > sam > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
