On Wed, 2007-10-17 at 23:02 -0500, Jon Elson wrote: > Kirk Wallace wrote: > > Thanks again Jon and Chris. What should have been obvious turns out to ... snip > >trouble shooting for a while. > Check the grounding carefully. The best is to not have the > encoder grounded to the machine frame, but grounded through the > board reading the encoder signals.
I have the shield of encoder cable tied to a central ground on the backplate that mounts all the left side electronics. > Shielding of the encoder > cables is almost always required. I used the existing shielded four pair. > Check the lay of probable > interference sources like motor-VFD cables and any other that > might have 120 or 240 VAC on them. I have a differential driver mounted next to the encoder, then the shielded cable to the receiver next to the UPC. About six inches away from the UPC are the two 100 Volt PWM amps. A little farther away are a bank of AC SSR's. I'll post some pictures soon. When I was getting index pulses without an encoder disk installed, I decided to disconnect the index connections to see when the noise stopped. The noise stopped as soon as I disconnected the encoder sensor. So either the noise is coming from the sensor, or having the sensor connected promotes the noise. I am going to have to give this some thought in order to plan the next move. > > Jon -- 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
