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• This function is used to check if the incoming serial message is continuously updating
• Last byte of the serial message changes with each message. If that is the case for receiver, a continuous stream is happening
• If any match is detected, the commCheck changed to be 'false' to inform the program that high level controller is always sending the same message which is an error

For example, in 3rd axis the minimum value to send is -999 which correspond to 0999 in serial message. In case of encoder casing slipping, the data we send becomes 01005 for -1005. This results in making the encoder feedback 27 bytes instead of 26 bytes.

Talon SRXs support a mode whereby the robot controller can stream a sequence of trajectory points to express a motion. If we use this mode, we can pass the trajectory points to the HERO continuously and Talons make sure that the desired points are reached. This way we can achieve a smoother movement.

ALSO, using this mode increases repeatability and saves us from adding a higher level motion control mechanism (like a queue in the hardware interface).

From https://docs.ctre-phoenix.com/en/stable/ch16_ClosedLoop.html#motion-profile-control-mode

Each trajectory point holds the desired velocity, position, arbitrary feedforward, and time duration to honor said point until moving on to the next point. The point also holds targets for both the primary and auxiliary PID controller, allowing for differential control (drivetrain, differential mechanisms).

Alternatively, the trajectory points can be streamed into the motor controller as the motor controller is executing the profile, so long as the robot controller sends the trajectory points faster than the Talon consumes them. This also means that there is no practical limit to how long a profile can be.

What is the benefit? Leveraging the Motion Profile Control Mode in the Talon SRX has the following benefits:
Direct control of the mechanism throughout the entire motion (as opposed to a single PID closed-loop which directly servos to the end target position).
Accurate scheduling of the trajectory points that is not affected by the performance of the primary robot controller.
Improved repeatability despite changes in battery voltage.
Improved repeatability despite changes in motor load.
Provides a method to synchronously gain-schedule.

Talon SRX Motion Profile Reference Manual.pdf

As far as I have observed, there is no need for such a thing for the 2nd axis, but doing this for the 3rd axis is necessary.