美国仪器NI PXI-6624 VDC 计数器/定时器模块

Buffered Operations and DMA

The National Instruments counter/timers can capture numerous data points without dead times. These types of measurements, called buffered operations, are valuable in applications that range from statistical analysis on production lines to experiments in molecular chemistry. For instance, when you configure a counter for buffered period measurement, data is moved from the counter into a buffer.

Each edge that initiates a measurement also causes a transfer of the count into the buffer. With buffered operations, data is transferred to the computer memory using DMA or interrupts. DMA offers a considerable performance advantage; if your application requires this performance simultaneously on multiple counter/timers, you must know how many DMA channels are available on a particular counter/timer device. For example, if a device contains three DMA channels and eight counter/timers, you can simultaneously perform three high-speed and five lower-speed, interrupt-based, buffered operations.