On Sat, 20 Oct 2007, Peter C. Wallace wrote: > Date: Sat, 20 Oct 2007 07:36:35 -0700 (PDT) > From: Peter C. Wallace <[EMAIL PROTECTED]> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Threading Hickups > > SNIP------------------------------------------------------------------> >> Using an oscilloscope, when I probed the power supplies with the spindle >> running, I got about .5 Volts of ripple that had a three stair step up >> and down appearance. Probing the +5 Volt differential signals I got a >> very short 10 Volt spike on the rising edge of each pulse, but otherwise >> they looked well formed. Without the differential boards, the +5 Volt >> encoder pulses had a more drawn out spike on the rising edge and the >> tops varied about a Volt above +5. >> >> The whole idea of the differential boards where to reduce the >> susceptibility of the system to noise, but the boards themselves seem to >> make the effect of the noise worse. >> > > Are your differential inputs terminated? If not, that would account for the > spike... > > CAT5 has 100 Ohm charateristic impedance, so you need a 100 Ohm resistor > across each A /A, B /B, X /X pair. >
Forgot to say that these resistors are on the _receiver_ end of the CAT5 cable... Peter Wallace ------------------------------------------------------------------------- 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
