Elovia, Suite doesn't have a "Center" snap setting, but it does have an "Object Snaps" setting. This is apparently checked by default in Pro and Architectural, but not in Suite. After checking that, I could locate dimension lines to the center of a circle. They would remain attached and update dynamically as I moved the object. The problem is that it is very difficult to position the device by reading the dynamically changing dim values while moving the object. Even with grid and all other snaps turned off, as well as big magnification, the dimension readouts jump all over the place. Setting the dimension manually is a solution, but that is very klunky when attempting to read relative distances from walls and other objects dynamically.
Thanks for your suggestion. It put me on the right track. And thanks to all the others who chimed in.
Frank