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Unread 02-03-2012, 15:44
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Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
FRC #0111 (WildStang)
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Re: Wiring a limit switch.

Quote:
Originally Posted by andreboos View Post
Why would an unconnected pin report random values? Or do you just mean it would be a noisy zero?
The open input to the analog board is capable of receiving electrical noise interference from the environment, sparks generated in motors or other electronic signals within the robot. Best practice is to somehow limit analog inputs to prevent this noise intrusion. A limit switch between +5 and power common provides a very low impedance source in either case that minimizes noise pickup. Yes, noise can be picked up of sufficient amplitude that it could be interpreted as a valid signal.
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Al
WB9UVJ
www.wildstang.org
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Storming the Tower since 1996.