Intermittent digital signal when PWMs are used

[michael714]

Hey Folks,
We're having a strange issue where we get intermittent true and false on our digital I/O port, but only when PWM cables are plugged in (to the same digital sidecar). When we unplug the PWM cables, the intermittency goes away. And we get the intermittency whether the line sensors are plugged in or not, so it's not the line sensor causing the problem. Also, we've tried to different digital side cars and we get the same results.

We noticed this PowerPoint (http://www.google.com/url?sa=t&sourc...urig& cad=rja) That seems to indicate that we should use one sidecar for digital I/O and another for PWM. Is anyone else doing that?

Any thoughts would be appreciated.