Instructions for the SparkFun TB6612FNG indicate that the ground connections for the voltage driving the motors and the logic voltage must be connected together. For motor voltage, I am using a model TE-5305 bench power supply as shown, with a green middle post for GND:
I am assuming that I would make the ground connection for the power supply at that post. What I am confused about is the ground connection for the Arduino board. Connecting the grounds of a device like the power supply and the tiny Arduino board seem "disproportionate" in some way. Am I OK?
Also, should I connect the black negative post of the power supply to its own ground post, as suggested by some sources online? If I don't connect them together, where would I connect the negative post in the circuit?
PS: I did read about ground loops in this answer here: https://electronics.stackexchange.com/a/56130/27163
However, I am still lost with the specifics for the case at hand.