Motor speed sensing with the Jaguar motor controller?

[BradFerg]

Digging into the LabVIEW code, it appears that the Set Speed and Get Speed VIs just end up setting and retrieving the PWM output value (0..255) by way of a speed value (-1..1). By default, the VIs assume the motor's speed is linear from 0 to 255. If it isn't linear, you can specify your own VI to do the transformation.

So, there is no speed feedback from the Jaguar at this time. It is possible that speed will be available over the CAN bus in the future, but I don't know.

[RyanCahoon]

The Jaguars have the capability to report the amount of electric current being drawn by the motors (but this does not give you direct information about the actual speed of the motors) over their CAN bus interface; this interface is illegal for FRC this year. If you want to know the motor speed, try using the US Digital encoders included in the KoP. These have an API in LabVIEW that will automatically track speed, as well as distance traveled and direction of movement if both sides of the quadrature encoder are wired. The encoders get connected to two digital inputs on the Sidecar: Wire the Brown, Red, and Blue wires to the Ground (black), +5 (red), and Signal (white/yellow) wires of one PWM cable, respectively, and the Yellow wire to the Signal wire of a second PWM cable.

--Ryan

[JohnLocke]

Originally Posted by RyanCahoon

The Jaguars have the capability to report the amount of electric current being drawn by the motors (but this does not give you direct information about the actual speed of the motors) over their CAN bus interface; this interface is illegal for FRC this year.

Which rule states that we can't get use the Jaguars interface? I am under the impression you are able to use it...

[jgannon]

Originally Posted by JohnLocke

Which rule states that we can't get use the Jaguars interface? I am under the impression you are able to use it...

That would be <R62-A>.

Originally Posted by R62-A

Support for the CAN bus port on the Jaguar speed controllers is prohibited for this competition, and the port is not to be used. Nothing shall be connected to the CAN bus port. It is recommended that the port be protected with a piece of tape to prevent debris from entering the port.