[HomeCNC]

Jim, If you are going to use the G320/G340 drive then you will need a DC BRUSHED motor with a 5V encoder on it like the E2 from USdigital. This is the encoder I use on my servo motors.

Tom, The servo system is closed loop back to the drive because the drive has a buffer built into it and will keep the step commands processing. If you are pushing the limits of the machine and the step command fill the buffer and the computer is still sending more the drive will fault and stop. The PC will not know this has happened so you will then need to stop the controller software. The benifit to me is the fact that if you do overload the system and the drive faults you will know about it. If you do this with a stepper system and you skip a few steps you my not know about it until your job is done and then find out your part is wrong!