As promised previously, here's the Q&A so that when someone reads this in 2020 they can see the content:
Quote:
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Originally Posted by Q646
- Q. In this post: http://www.chiefdelphi.com/forums/sh...81&postcount=3 and following, it is suggested that the brake/coast pin of a PWM-controlled motor controller may be wired to a control signal from the RoboRIO's DIO port. I read this as a violation of R68, and as a modification beyond the wording of R66, especially bullet I. Others there see it as legal. Is this practice permitted? If allowed, I suggest providing clarification in the rules as to how to wire this safely.
- A. You are correct, this practice is a violation of R68. We acknowledge that this has been a common practice, and we will review this with Inspectors.
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As for a simple way to do this safely (but not currently legally), an
optoisolator could be used to act as a virtual jumper. Assuming the outputs of the isolator can handle the current that passes through the jumpers, this should only need a ballast resistor for the LEDs to be enough. If more current is needed, a few transistors and resistors would be necessary to supplement. One could even do the double isolation and use a totally COTS
relay module. Repeat: this would be safe, but not (currently) FRC legal.