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Unread 13-12-2013, 09:20
Unsung FIRST Hero
Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
FRC #0111 (WildStang)
Team Role: Engineer
 
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Rookie Year: 1996
Location: Wheeling, IL
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Re: MicroControllers at competitions

As Ether has pointed out above, wire is a known resistance for length and can be easily monitored in much the same way as you propose for your shunt. A 1 foot piece of #10 wire will drop 0.1 volts at 100 amps. Inserting a shunt resistor in the pathway (wiring) feeding a speed controller does violate the rules as Eric pointed out above. The Jaguar has a resistor built into the input side of the controller to generate the current reading available on the CAN buss.
The clamp on ammeters may give you a false reading do to the switching load of an operating controller. Look at frequency response for the device you are considering or using. For most applications the switching frequency of the Victor is within spec while the Jaguar is not. Your mileage will vary.
Magnets, it would help if we knew what your team number is when you refer to team history.
A good method for diagnosing shorted device problems is simply to pull all the breakers except for the the DSC and then add them back one at a time until you find the offending device.
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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.