2012/1/31 Viesturs Lācis <[email protected]> > 2012/1/31 Peter C. Wallace <[email protected]>: > > > > The three phase PWM is a fair noise source. Not just capacitively coupled > > noise from the three motor wires but inductively coupled noise due to > > current spikes from the 28V PWM driving into the motors winding/frame > > capacitance. This can be mitigated by putting a common mode choke (Big > > ferrite bead) over the three motor leads (DO NOT include the ground lead) > > > > Please try the encoder sample rate lowering example I provided. This will > > quickly help to see if there is a noise problem. Noise piked up by the > > encoder wires either inductively or capacitively tends to be short > pulses. > > By lowering the input bandwidth a lot of this kind of noise can be > filtered > > out. > > > > Thank You, Peter and guys! > I am really starting to think that I should do some additional > testing, before spending any additional funds. > > Viesturs > > I'm jumping in here, without reading the entire discussion, but you need to ground the encoder housing as well. The Ethernet ground is not connected to the chassi of the encoder. I have been using AMT's for years with great success but had a tiny but very irritating lost-step-syndrome that a Ukrainian guy (Balazs at CNCDrive) solved in a split second: Add another ground cable to the encoder chassi. I did, know I'm leaving the machine for hours without a doubt.
Diff.line driver's GND terminal --- Machine metal frame Machine metal frame --- PE (Protective earth grounding point) I could take a picture if you need to see what I mean. Regards, Sven ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
