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Unread 15-03-2016, 13:14
GreyingJay GreyingJay is offline
Robonut
AKA: Mr. Lam
FRC #2706 (Merge Robotics)
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Join Date: Mar 2015
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Re: Standard Motor Driver Schematic for FRC

The Talon SRX is only slightly more expensive than the Victor SP and has many nice things under the hood including full software control over the CAN bus and the built-in ability to interface with encoders, limit switches, and do PID control.

From a value proposition - and taking into account the typical skill level of high school students - this is hard to beat.

While you are correct that, at heart, a basic FRC motor controller could just be a PWM-controlled H-Bridge, I think there's a lot to like about buying a COTS part versus making our own. The fact that it's COTS, already, gives a lot of advantages when playing by FRC rules in terms of being able to swap them out easily for repair, replacement, or upgrade. I would hate to be in a competition situation, with 15 minutes until our next match, combing over a half dozen custom-made motor control circuits trying to figure out why our robot doesn't move. Plus they're sealed, packaged robustly and compactly, made to interface with standard components and connectors, and offer quick easy tools for changing brake/coast modes, recalibrating, etc.

And to top it off, they can be free for FRC teams through the rookie kit and through yearly product donation vouchers such as FIRST Choice. My team ordered four Victor 888 controllers through FIRST Choice and had the choice of either 2 Talon SRX's or 3 Victor SP's from the PDV, all "free". In addition, we got another two Victor SP's in our rookie kit. That's plenty for a robot drivetrain and mechanisms.

FRC is an expensive competition, but motor controllers are not where I'd peg most of the cost.

Last edited by GreyingJay : 15-03-2016 at 13:25.
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