National Instruments NI-Motion - Manual (Page 146)

Chapter 11 Acquiring Time-Sampled Position and Velocity Data
NI-Motion User Manual 11-2 ni.com
The FIFO buffer is of a fixed size that can accommodate 4,096 samples for
one axis. One sample consists of position data, in counts or steps, and
velocity data, in counts/s or steps/s. As you increase the number of axes
from which you are acquiring data, you also decrease the total number of
samples you can acquire per axis. For example, you can acquire up to
1,024 samples per axis for four axes. You also can vary the time period
between acquired samples from 3 ms to 65,535 ms.
Algorithm
Figure 11-2. Acquire Data Algorithm
Acquire Data
Specify the number of axes, sample
period, and number of samples
Wait for Time = Sample Period
Wait until at least one sample
has been achieved
Read One Sample
Wait more than the sample period
to allow the controller to fill the FIFO
Loop if Wait Period > Sample Period