Help with Falcon 500 brake mode

Hi - we have a falcon that is in brake mode (set in the code and the mode button lights up red), but the falcon will not stop instantaneously and has little resistance on the shaft (the shaft can be rotated fairly easily). We tried putting the motor in coast mode to see the difference, and we are definitely setting the motor to brake as there is more resistance and the shaft stops spinning much quicker than the coast mode setting. We took a self-test snapshot in Phoenix Tuner while the motor was slowing down, and continually received sticky faults on stator current. We need this motor to stop quickly and resist rotation, but we are unsure as to what is going on – we would appreciate some advice.

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Brake mode does not stop the motor instantaneously and the resistance on the shaft is relative to the speed the motor is spinning.

The brake feature on a motor controller relies on the electrical resistance inside of the motor to slow it down. It cannot prevent motion, only lightly resist it.

If you need a motor to stop quickly and resist motion, you might consider adding a mechanical brake, or applying power in the direction of rotation opposite to the motor’s current direction of rotation using something like a PID loop.

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The Talon’s mode is a NeutralMode not a brake mode.

As the requested output goes to zero (neutral) the talon will either supply a small amount of electrical help to slow the motor down, or not.

There are some other threads around here that talk about how to configure the talon in a way that changes the amount of current that is applied with Neutralmode, but you’ll want to heavily read their documentation about it before you go doing things that may not be optimal for what you’re trying to do.

The relative configurations have to do with changing the output stator current settings.

I DID NOT know this could be changed! Can you reference some good links?

The CTRE javadocs mention it.

I’m not sure what you’re talking about here; “neutral mode” is just the name of the setting, which is indeed either brake or coast, the same as on all the other motor controllers we’ve used for years. The amount of current that goes towards braking is determined by the velocity of the motor; the motor controller does not affect it at all.

Neither the Talon nor the NEO offer an active braking mode in the sense of “supplying a holding current without commutating the motor,” because the torques you get are small considering the amount of current you can safely maintain through a single coil for any length of time.

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I agree with you. I would add that according to the CTRE docs, the motor controller config does indeed affect it.

If you’re braking hard enough to get anywhere near the current limit, the motor’s spinning awfully fast. The OP described a situation where they don’t have enough braking force to begin with, so I don’t think this is relevant.

It’s possible that maybe I don’t understand what that stator current setting does.

I read the request from the OP (in part) as wanting to have the Falcon brake mode stop the motor more quickly than they are experiencing.

I read the CTRE documentation saying that the stator config setting adjusts how strong the brake is.

Those feel pretty related to me, again, assuming that I’m not misreading either of those things. Whether or not that is the totality of the solution to their problem (it’s objectively not in my mind) is a different question altogether.

Brake mode has a standardish power across any motor (not just falcons). AFAIK, Falcons offer the ability to decrease that power, not increase it.

However, as @Oblarg said, you’d have to be moving extremely fast for that limit to matter unless you set the limit absurdly low