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Unread 31-03-2011, 13:39
Unsung FIRST Hero
Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
FRC #0111 (WildStang)
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Rookie Year: 1996
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Re: servo jitter when running Jaguar on RS-775

I am going to throw a guess on this one where the Jag breaker isolates it and switching PWM servo outputs moves the problem. The Jag is capable of very high rise times and therefore is likely to put some wild RF signals on the motor leads. If the 775 has a case short, caps across the motor leads will not help. I have experienced noise currents traveling on wire and then crossing over to another wire and causing problems. Sometimes, RF ferrite beads around the conductors can shunt the noise. My suspicion on the 775 problem is that you will find it to be a greater problem when driving in one direction vs. the other. If that is indeed the case, then there are significant currents driving through the case to the common electrical lead on the Jag and back out to anything connected to the Jag with the same common terminal.
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Good Luck All. Learn something new, everyday!
Al
WB9UVJ
www.wildstang.org
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Storming the Tower since 1996.