Hello, our team is getting the kraken motors for our swerve drive this year. Are the encoders absolute or relative. Also links to the encoders documentation would be appreciate. Thanks in advance.
Any encoder inside a motor is going to be relative, and the kraken shares the Talon FX controller with the falcon, so the software should be the same.
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My small Design devision in our team is also looking at getting the Kraken motors. Since this is also a Talon FX motor, the same as the Falcon 500, which is a 2048 relative encoder. I’m assuming it’s the same thing, since motors tend to only have relative encoders.
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Beat me to it.
You are not wrong that the documentation for the Kraken is a bit lacking in detail about the encoder, especially compared to the Falcon.
Although the additional Docs don’t list it, the main Kraken page says it is 0.18degree precision.
This (kinda) aligns with an encoder that has a resolution of 2048 CPR (counts per revolution):
(360deg/rev) / (2048 counts / rev) = 0.1757…deg / rev
Honestly it should explicitly list 2048 CPR because that is the number you / the Talon firmware is using in it’s code.
It is not impossible that a motor COULD have an absolute encoder in it. Multiturn absolute encoders do exist but they are much more expensive and not needed for the safety or packaging requirements of FRC applications.
Honestly, you’d probably still want an external encoder on your swerve azimuth or whatever anyways so you can directly measure the thing you care about with no backlash in the powertrain, etc.
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Better explanation. Thank you
This means my encoder should always return a reading of 0 units when I turn on the robot right?
Yes, as long as it doesn’t move
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In Phoenix 6, the Talon FX encoder is always initialized to its absolute position on boot: Feature Replacements. In Phoenix 5, the initialization strategy was available as a config with options of booting to zero and booting to the absolute position.
The Talon FX rotor sensor position is absolute within one rotation. That is, a position of 12.6 rotations is an absolute position of 0.6 (unless you call setPosition(0) to zero the sensor). However, since it is absolute at the rotor (i.e. before any gear reductions), there are not many applications for its use as an absolute sensor.
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3 Kraken Swerve!
- Drive motor
- Steer motor
- Steer encoder
Throw people for a loop at competition