Section 3: Functions and features
Model 2657A High Power System SourceMeter® Instrument Reference Manual
3-12
2657A-901-01 Rev. B/December 2012
Commands to access readings:
printbuffer(
start_index, end_index,
st_1, st_2, ... st_n
)
Prints data from buffer subtables:
start_index
(starting index of
values to print).
end_index
(ending index of values to print).
st_1, st_2, ... st_n
(subtables from which to print, each
separated by a comma).
Buffer storage control attributes
The following table contains buffer storage control attributes.
Before changing the
collectsourcevalues
,
collecttimestamps
, or
timestampresolution
attributes, you must clear the buffer using the
smua.nvbuffer1.clear()
or
smua.nvbuffer2.clear()
command.
Buffer storage control attributes: Describes buffer storage attributes
Storage attribute
Description
appendmode
The append mode is either off or on. When the append mode is off, a new measurement
to this buffer overwrites the previous contents. When the append mode is on, the first new
measurement is stored at what was formerly
rb[n+1]
. This attribute is initialized to off
when the buffer is created.
cachemode
When this attribute is on, the reading buffer cache improves access speed to reading
buffer data. When running successive operations that overwrite reading buffer data
without running any commands that automatically invalidate the cache, the reading buffer
may return stale cache data. This attribute is initialized to on when the buffer is created.
collectsourcevalues
When this attribute is on, source values are stored with readings in the buffer. This value,
off or on, can be changed only when the buffer is empty. When the buffer is created, this
attribute is initialized to off.
collecttimestamps
When this attribute is on, timestamps will be stored with readings in the buffer. This value,
off or on, can be changed only when the buffer is empty. When the buffer is created, this
attribute is initialized to off.
fillcount
The reading buffer fill count sets the number of readings to store before restarting at index
1. If the value is 0, then the capacity of the buffer is used. This attribute is only used when
the
fillmode
attribute is set to
FILL_WINDOW
.
fillmode
The reading buffer fill mode controls how new data is added to the reading buffer. When
this attribute is set to
FILL_ONCE
, the reading buffer will not overwrite readings. If the
buffer fills up, new readings will be discarded.
When this attribute is set to
FILL_WINDOW
, new readings will be added after existing data
until the buffer holds
fillcount
elements. Once there are
fillcount
elements, new
data starts overwriting data starting at index 1.
timestampresolution
The timestamp resolution, in seconds. When the buffer is created, its initial resolution is
0.000001 seconds. At this resolution, the reading buffer can store unique timestamps for
up to 71 minutes. This value can be increased for very long tests. Note: The minimum
resolution setting is 1 µs (0.000001 seconds).
NOTE
Summary of Contents for 2657A
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