Okay. I see what you're talking about. I'm including the text here so I don't have to look it up again. It appears that the difference between closing the torque (current) loop and the velocity loop on the motor drive itself is that the parameters used for PID control of velocity set up in MAX for the motion controller wouldn't be able to be utilized. If you want to have that nice velocity control through the software on your PC rather than through whatever interface you might have through the motor drive, the velocity loop needs to be closed back on the controller and not externally on the drive.
Hopefully this is helpful to you. Best of luck.
Jim
"National Instruments recommends that when you use the UMI-7774/7772 with a servo mo
tor drive, you use the torque (current) mode option on the drive instead of the velocity mode to simplify the system setup and tuning. In torque mode, only the current loop is closed on the drive. Both the position and velocity loops are closed on the motion controller using encoder feedback. When you use torque mode, you can set all of the control gains with the National Instruments motion controller software. Using torque mode on the drive also reduces noise and enables you to achieve high position repeatability in the motion system."
