NXT Motor in float mode with encoder enabled

I am trying to implement a new NXTMotor class for the Java variant of the brickpi. I would like to use the encode only of the NXTmotor. I have read the codes of other project but it seems that the motor is always powered or did i miss something? When the motor is in float mode the encoder can be used as a rotary sensor. I say the timeout for the runaway robot problem, but is it possible to float motor separately? All help is welcome.

Kind regards,
Maarten Storm