I wanted to have a real motor/encoder system for my office EMC instead of using a simulated configuration. So, ruined a surplus printer to get the motor/encoder assembly, which I connected to an L298 and a +12 Volt motor supply. When I got to testing it, I had a hard time with tuning. On occasion, the motor would not move. I connected a voltmeter to the motor leads and found around a Volt going to the motor. Then I increased P until I got about 2.5 Volts and still no movement, so I helped it rotate, at which, it jumped to the commanded position and started oscillating. So, my thinking is, the the commutator configuration does not allow for a constant torque vs. voltage at every angle and the system friction is high enough to cause a stall at reasonable P values at certain start points. This seems like it might be a common problem for small systems where a torque/friction ratio might be fairly low. Or, is this more of a problem with inexpensive DC motors. This motor was designed to position paper to within a few thousandths of an inch plus traverse the length of the paper in about a second, so from my experience, the printer designers must have spent a fair amount of time with tuning. Do Etch-Servo setups have the same problem?
-- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe Bridgeport mill conversion pending Zubal lathe conversion pending) ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
