You can configure lines on parallel digital modules to detect rising or falling edges. When one or more of these lines sees the edge specified for that line, the cDAQ chassis samples all the lines in the task. The rising and falling edge lines do not necessarily have to be in the task.

Change detection acquisitions can be buffered or nonbuffered:

  • Nonbuffered Change Detection Acquisition—In a nonbuffered acquisition, data is transferred from the cDAQ chassis directly to a PC buffer.
  • Buffered Change Detection Acquisition—A buffer is a temporary storage in computer memory for acquired samples. In a buffered acquisition, data is stored in the cDAQ chassis onboard FIFO then transferred to a PC buffer. Buffered acquisitions typically allow for much faster transfer rates than nonbuffered acquisitions because data accumulates and is transferred in blocks, rather than one sample at a time.