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7. AUXILIARY FUNCTION
7.12.6 Number of sampled points
By setting the number of sampled points (sampling setting No.0002), points to be sampled can be changed.
Number of data which is sampled before the trigger conditions are met (set with pre-trigger) is specified by
percentage to the number of sampled points. However, when the number of sampled points exceeds 8192, the
percentage is to 8192.
For when the number of sampled points is 8192 or less, and 8193 or more, the characteristics are shown
below.
(1) When the number of sampled points is 8192 or less
When sampling of the points set in the sampling points (sampling setting No.0002) is completed, sampling
itself is completed automatically. Since the host controller is required to read the sampling data buffer area
after the sampling is completed, the load on the host controller is light, however, on the other hand,
sampling for a long time cannot be executed.
(2) When the number of sampled points is 8193 or more
Points which are set to the sampling points (sampling setting No.0002) are sampled by the position board.
However, the host controller is required to read sampled data during the sampling, the load on the host
controller is high.
The sampling data buffer area of the position board internal memory is regarded as the ring buffer of 256
pages (8192 points), and the host controller and the position board read the sampling data read area with
executing exclusive control based on the page number.
POINT
The larger the pre-trigger setting is, the higher the load on the host controller
is since it is required to read the sampling data in a short time after the trigger
conditions are met. As an example, when pre-trigger is set to 90%, after the
trigger conditions are met, the host controller is required to complete reading
the data sampled by pre-trigger (at least 1 page) before the position board
completes the sampling of 10% left.