I would assume it is covered in IMAQ help, but details like this have been missed before.
Since you want two parameters (or more), you need the array input for parameters. Stretch it so it has two entries showing. Select "Center of Mass X" for the first one, and "Center of Mass Y" for the second one.
Since you will have multiple regions, you will get a 2D array output. If you loop through this array, value 0 is the X and value 1 is the Y (inside the loop).
Bruce
Bruce Ammons
Ammons Engineering