With buffered position measurement (position measurement using a sample clock), the counter increments based on the encoding used after the counter is armed. The value of the counter is sampled on each active edge of a sample clock. The sampled values will be transferred to host memory using a high-speed data stream. The count values returned are the cumulative counts since the counter armed event; that is, the sample clock does not reset the counter. You can route the counter sample clock to the Gate input of the counter. You can configure the counter to sample on the rising or falling edge of the sample clock.
The figure below shows an example of a buffered X1 position measurement.