2600S-901-01 Rev. C / January 2008
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7-7
Series 2600 System SourceMeter® Instruments Reference Manual
Section 7: Buffer (Data Store)
Similarly, the following would return 100 Channel A source values from buffer 1:
printbuffer(1, 100, smua.nvbuffer1.sourcevalues)
Note that
readings
is the default reading attribute and can be omitted. Thus, the following would
also return 100 Channel A readings from buffer 1:
printbuffer(1, 100, smua.nvbuffer1)
Table 7-6
Recall attributes
Recall attribute
1
Description
measurefunctions
An array (a LUA table) of strings indicating the function measured for
the reading (Current, Voltage, Ohms or Watts).
measureranges
An array (a LUA table) of full scale range values for the measure range
used when the measurement was made.
readings
An array (a LUA table) of the readings stored in the reading buffer. This
array holds the same data that is returned when the reading buffer is
accessed directly, i.e., rb[2] and rb.readings[2] are the same value.
sourcefunctions
An array (a LUA table) of strings indicating the source function at the
time of the measurement (Current or Voltage).
sourceoutputstates
An array (a LUA table) of strings indicating the state of the source (Off
or On).
sourceranges
An array (a LUA table) of full scale range values for the source range
used when the measurement was made.
sourcevalues
If enabled, an array (a LUA table) of the sourced values in effect at the
time of the reading.
statuses
An array (a LUA table) of status values for all of the readings in the
buffer. The status values are floating-point numbers that encode the
status value into a floating-point value (see
timestamps
An array (a LUA table) of time stamps, in seconds, of when each read-
ing occurred. These are relative to the
basetime stamp
for the buffer
(
1. The default attribute is
readings
and can be omitted. For example,
smua.nvbuffer1
and
smua.nvbuffer1.readings
will both return readings from Channel A, buffer 1.
Time and date values
All time and date values are represented as the number of seconds since the unit was powered
on. The
os.clock()
function returns values in this format.
Representing time as the number of seconds will be referred to as “standard time format.” Note
that because TSL numbers are floating point numbers, the precision of time and date values
relative to power-on will decrease the longer the unit is powered on. This decrease in precision is
approximately 0.06ppm of the total elapsed time. This precision is generally much better than the
time base of the instrument and should not present any problems in practice. It is worth noting
because the user can directly see the affects as compared to the less obvious time-base drift.
