2600S-901-01 Rev. C / January 2008
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7-5
Series 2600 System SourceMeter® Instruments Reference Manual
Section 7: Buffer (Data Store)
Reading buffers
Readings can be obtained in multiple ways including synchronous or overlapped. Furthermore, the
routines that make single point measurements can be configured to make multiple measurements
where one would ordinarily be made. The measured value is not the only component of a reading.
The measurement status (e.g. “In Compliance” or “Overranged”) is also an element of data
associated with a particular reading.
All routines that return measurements can return them as reading buffers. Overlapped
measurements are always returned in a reading buffer. Synchronous measurements return either
a single-point measurement or a buffer reading. The more advanced user can access additional
information stored in the reading buffer.
A reading buffer is based on a Lua table. The measurements themselves are accessed by
ordinary array access. If rb is a reading buffer, the first measurement is accessed as rb[1] and the
9th measurement as rb[9], etc. The additional information in the table is accessed as additional
members of the table.
Reading buffer designations
There are two non-volatile reading buffers designated as
smuX.nvbuffer1
(Buffer 1) and
smuX.nvbuffer2
(Buffer 2). To access the buffer, simply include the buffer attribute in the
respective command. For example, the following command would store current readings from
Channel A into Buffer 1:
smua.measure.overlappedi(smua.nvbuffer1)
Buffer storage control attributes
Buffer storage attributes are summarized in
. Read-only attributes used to access buffer
parameters are listed in
. To control which elements are stored in the buffer, simply
assign the desired attribute to the specific buffer. Control examples for Channel A, Buffer 1 are
shown in
, while read-only attribute programming examples are listed in
.
NOTE You must clear the buffer using the
smuX.nvbufferX.clear()
command before changing buffer control attributes.
