check out the documentation on the REV web site. Not familiar with the SPARK MAX in any detail, but these are some of the features of the talon SRX:
It can run in traditional PWM [pulse width modulated, aka SERVO signal] mode, though in this mode all you can control is the duty cycle because this is all PWM supports.
It can also be operated through the CAN (Controller Area Network, a protocol apparently created so that automobile sensors and actuators and the central computer could all talk to each other) in a wide variety of modes. Here are some of the most commonly used ones:
- Duty Cycle: equivalently to PWM but with the control over a different protocol
- Voltage Compensated: Duty cycle which runs longer when the battery voltage is low
- Current Limited: the controller has an internal current meter and limits the duty cycle so that the controller does not draw more than a specified current from the battery
- Positional/distance feedback: requires an encoder or potentiometer, and allows the RIO to tell the controller to drive a certain distance or put an arm or elevator in a specific position
- Velocity feedback: requires an encoder or potentiometer, and allows the RIO to tell the controller to move the robot or manipulator at a certain speed and direction
- Motion Magic: Enables “motion profiling”, which requires an encoder or potentiometer and combines several of the above; the RIO can (for example) tell the robot to drive forward 35 feet at no more than 6 ft/s and no more than 5 ft/s/s acceleration.
- Follower: enables a Talon SRX or Victor SPX (and, I believe a MAX) to mimic the duty cycle of another CAN motor controller. That other controller may be using one of the more complex modes, meaning that that one sensor feedback may effectively control two or more motors.