通过一个NI USB-6501 便携式数字I/O设备，控制一个步进转台的旋转。可选择旋转方向，并以5°为单位旋转。-NI USB-6501 via a portable digital I/O devices, control the rotation of a stepping turntable. Alternatively the direction of rotation, and 5 units of rotation.

USB-6501数据采集卡的开发例程，包括I/O和COUNTER。(USB-6501 data acquisition card development routines, including I/O and COUNTER.)