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Burst mode sampling - speeds
from 1kHz to 100 kHz, 13-bit
(raw data is processsed into engineering units
at the end of the burst, can take some seconds).
Up to 65,000 samples in
a burst.
Pretrigger data can be captured... trigger point can be anywhere
in the burst mode data buffer (0 to 100%).
The burst mode runs continuously,
the triggering initiates the process which freezes the data in the burst memory
for
later processing into formatted data.
At present
the DT800 burst buffer is limited to max 65535 fundamental readings.
Fundamental
readings are the various readings taken which make up a channel reading.
For
example channel type V (voltage) involves 4 fundamental readings:
+ve to -ve,
+ve to GND, -ve to GND, +ve to -ve again.
These four readings are used to
create 1 channel reading.
By contrast channel type
VNC (Voltage No Correction) involves 2 fundamental readings,
+ve to -ve and
+ve to -ve which are averaged.
Twice as many burst
readings can be taken with VNC than V
because of two fundamental readings
instead of four.
Time to clear the burst buffer after a burst.
The following bursts use 65,000 fundamental readings.
In the first two burst examples
there are 32000 samples (VNC uses 2 fundamental readings for each sample = 64000),
at 1000Hz A/D clock rate, and then at 10000Hz A/D clock rate.
RA;BURST(32000,1000)
1VNC takes approx 90 secs per burst (64 sec to take the readings, 26 sec to unload
& process the buffer)
RA;BURST(32000,10000) 1VNC takes approx 30 secs
per burst (6.4 sec to take the readings, 24 sec to unload & process the buffer)
RA;BURST(16000,1000) 1V takes approx 75 secs per burst (64 sec to take the readings,
11 sec to unload & process the buffer)
RA;BURST(16000,10000) 1V takes
approx 25 secs per burst (6.4 sec to take the readings, 19 sec to unload &
process the buffer)
Bear in mind that twice as many
readings can be taken with VNC than V
because of two fundamental readings
instead of four.
These data are for single thread
(current) firmware which strictly executes tasks serially,
and should improve
with the multi-threaded firmware when finalized which executes tasks in parallel
by time-slicing.