Using MX 106R with Arduino and Dynamixel Shield to control position of a ball on table platform

Issue:
I am trying to receive angles (in a string) from a python code to control the position of dynamixel mx 106 motors using arduino uno and dynamixel shield. I have implemented the code on arduino to receive the angles through the serial port of arduino and pass them into the setgoalPosition functions, but the motors do not respond at all. It seem the motors are not receiving the angles commands through the serial port. Need help.

Servocommands2.ino (2.5 KB)
Im sending the desired angles from python using :

arduino.write(f"{motorA1},{motorB1},{motorC1}\n".encode())


DYNAMIXEL Servo:

DYNAMIXEL MX-106R with protocol version 1.0.
using RS485 communication port.
I am using 3 motors per platform.


DYNAMIXEL Controller:

DynamixelShield


Software Interface:

Arduino IDE and Python