Thread: "No Comms"
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Unread 08-03-2009, 22:38
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AKA: Paul Fleming
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Re: "No Comms"

We experienced no comms during competition and tracked it down to one Fisher Price motor being driven by a Jaguar. The WGA was mounted high and well away from the motor however the Jaguar was only a few inches off the CRio near the ethernet port. We kept getting comms drop outs even when tethered. When we disabled the motor, problem went away. We then also ran the motor but at lower PWM levels and the problem went away. At high PWM values the dropouts came back. We swapped the Jaguar for another without any impact. We swapped the Jaguar for a Victor without any impact. We are implementing a rerouting of all wiring to keep all power lines away from the CRio. Putting EMI suppression cap on the FP motor to the extent legal. The problem did not crop up until elimination rounds, so perhaps brush wear or contamination had an impact. The above troubleshooting strategy seems to have pretty definitively pointed the FP motor's brush noise out as the source. Better electrical board layout may have helped to prevent the failure. Hope this can help someone else. Thanks to Eric of 1511 for his help.
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