A four-axis stepper motor drive from National Instruments, Austin, is housed in a compact metal case. The MID-7604 stepper drive features LED motor-status display, front-panel axis configuration, and motor and limit-switch connections. Motor commands, motion I/O, control, and feedback signals connect through a single, shielded cable between the stepper drive and a PC-based, motion-controller plug-in board. MID-7604 features a built-in power supply and configurable microstepping for smooth, low-speed operation. It provides between 0.2 and 1.4 A/axis. Motion I/O-limit and home-switch inputs incorporate input filtering for noise immunity.