Jaguar brake/coast behavior / ramp mode question

[MrRoboSteve]

1. Our team is interested in how the brake/coast setting on the Jaguars work.

We removed the brake/coast jumpers from the two Jaguars controlling our drive train and there wasn't a noticeable difference in behavior. The Jags are controlled via PWM.

The documentation we found isn't very specific about what the brake/coast setting actually does. Can anyone point us to a specific discussion on how the Jag's behavior changes in these two modes?

2. Is there a reason why a team would select the ramp mode on the Jag when controlling drive train motors?

Steve

[Ether]

Originally Posted by stevep001

1. Our team is interested in how the brake/coast setting on the Jaguars work.

We removed the brake/coast jumpers from the two Jaguars controlling our drive train and there wasn't a noticeable difference in behavior.

You don't remove the jumpers. You move them. From brake to coast, or vice versa.

See attached diagram.

[Al Skierkiewicz]

Steve,
With simple DC motors of the type used on the robot, the momentum of the moving robot actually causes the motors to become generators. The "brake" mode on either type of speed controller, essentially causes a shorted resistance to be placed across this generator. The result is that the current flowing in the short produces a force which opposes the motor rotation. When the motor is not moving, the brake mode has no effect.

[ehochstein]

Is it the same way with Victors? At our last competition we switched out our jags with victors and after switching the programming we now coast instead of brake. Is there a jumper on the victor that we need to move?

[Mark McLeod]

The Victors have the same jumper on the lower left