The XR3 6-axis drive rack with field replaceable, front-mounted, 3U plug-in amplifiers support both linear and PWM topologies. The XR3 can control any combination of brushless, DC brush or stepper motors at up to 320 VDC operating voltage and 30 A peak current capability. Both the current loop and servo-loop are digitally closed to ensure the highest level of positioning accuracy and rate stability. This processing capability allows the XR3 to provide loop closure rates up to 20 kHz and to handle both digital and analog I/O processing, data collection, process control and encoder multiplication tasks in real time.