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Re: PID on Jaguars is Illegal
To all reading this thread,
I think we should probably try to coordinate the inevitable Q&A submissions asking for clarification and/or modification of this ruling. Bombarding the GDC with 50 followups on this isn't going to help.
So, first and foremost, if you're reading this and have already sent a followup Q&A, please reply below to let us know, along with a copy or summary of what you posted.
Second, lets all wait about 2-3 hours to see if anyone's already posted followups.
Third, I'll nominate myself to post a followup on the Q&A at around 2PM CST addressing these issues. My proposed post follows, any suggestions or edits appreciated.
1. Limit switches, thermal/overload limiting, and voltage ramping. Do limit switches count as command signals coming from the Jaguar? What about the intrinsic current and thermal overload limiting? Does the programmable acceleration/deceleration function count as the Jaguar modifying or interfering with the command signal from the cRIO?
2. The Jaguar purports to implement an FRC specific trusted communication protocol with the cRIO to ensure proper shutdown when communications are lost. As such, a properly programmed and operating cRIO should have constant control of a properly programmed Jaguar at all times, regardless of the operating mode of the Jaguar. The Jaguar is then simply operating as a standard servo controller that will shut down when host communications are lost. Reasonable interpretation would read this as the cRIO sending a position/velocity COMMAND to the Jaguar, and the Jaguar translating this into an appropriate voltage command to the motor. In fact, this would appear to be absolutely identical to the functioning of the perfectly legal RC servos, which implement closed loop position control of a DC motor based on potentiometer feedback and a cRIO position command.
So we're curious is <R62> outlaws RC servos as well. And if not, what the distinction between the RC servo controller and a closed-loop Jaguar might be.
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The difficult we do today; the impossible we do tomorrow. Miracles by appointment only.
Lone Star Regional Troubleshooter
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