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Re: 12V Voltage on Robot Frame (Perhaps because of a BaneBot)
Quote:
Originally Posted by artdutra04
Removing the breakers probably won't work in this situation. The breakers are single-pole on (AFAIK) the high side of the circuit. If a RS775 is case shorted, removing the breaker won't show the problem.
I would check first to make sure cRIO is isolated, then check to make sure the camera is isolated, then physically disconnect both wires leading to every RS775 (one at a time) from the M+/M- side of the speed controller, then check any custom sensors (such as Sharp IR sensors), as these in that order are the most likely causes of grounded frames.
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You are correct that only the positive of the PDB board is fused and the negative terminals still have continuity even when the breaker is pulled.
However, correct me if I am wrong but unless powered and driving, if I recall correctly, the motor terminals of the motor controller should be isolated from 12V positive or negative side of the motor controller. So if the suspected shorted motor was wired correctly, pulling power by removing the breakers to the motor controller, I believe should remove the short to the frame.
Also, if the motor is shorted to its case, the actual short to the frame would change depending on which direction the motor was driven, and the voltage differential being provided to it.
If the short still exists, then its not a motor, and running though the circuits as I mentioned should help narrow it down. I would agree if they are reading a delta 12v between battery positive terminal and frame, when the robot is disabled, it means the robot chassis is shorted to battery negative terminal somewhere on the PD/CRIO/Dlink/Camera side of the system.
-Kevin
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Last edited by NotInControl : 25-02-2014 at 11:58.
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