Dynamixel MX28 with DynamixelShield not responding

Hi,
I’m currently working on a robotic gripper project and I am using a Dynamixel MX-28 with and Arduino Yun.
This worked fine with standard libraries but I wanted to get feedback from the motor so purchased a Dynamixel Shield.
Currently have it hooked up to a 12V power supply, motor flashed its led so I know it’s powered, and the Yun is powered through a USB connection to the computer.

I installed both suggested libraries found on the e-manual page,
http://emanual.robotis.com/docs/en/parts/interface/dynamixel_shield/

But when I try to run one of the basic programs, such as ping or led nothing happens with my motor, I get absolutely no response.
I have checked that my Dynamixel version matches the one in the code and the baudrate, but still nothing.

Does anyone have any suggestions? I feel like I may have just wasted money on the shield.

Cheers in advance!