Remote Reading Buffer Programming - Keithley 2651A Reference Manual

Section 3: Functions and features
Timestamp
If the timestamp is enabled, the first source-measure reading stored in the buffer (#0000001) is
timestamped at 0.000 seconds. Subsequent readings are timestamped relative to when the first
measurement was made. The interval between readings depends on the reading rate.
Displaying other buffer readings and statistics
To display other readings and statistics in the reading buffer:
1. While still in the buffer recall mode, if viewing the data stored in the buffer, turn the navigation
wheel
navigation wheel
navigation wheel
wheel
MINIMUM, MAXIMUM, and PK-PK.
2. To exit from the reading buffer recall mode, press the EXIT (LOCAL) key.

Remote reading buffer programming

Readings can be obtained in multiple ways, including synchronous or overlapped measurements.
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 (for example, "In Compliance" or "Overranged") is also an element of data
associated with a particular reading.
All routines that return measurements can also store the measurements in the reading buffers.
Overlapped measurements always return readings in a reading buffer. Synchronous measurement
functions can return single-point measurement values or store multiple values in a reading buffer.
A reading buffer is based on a Lua table. The measurements are accessed by ordinary array
accesses. If rb is a reading buffer, the first measurement is accessed as rb[1] and the 9th
measurement as rb[9], and so on. The additional information in the table is accessed as additional
members of the table.
The load, save, and write operations for reading buffers function differently in the remote state. From
a remote command interface, you can extract data from reading buffers as the instrument acquires
the data.
Reading buffer designations
The source-measure unit (SMU) contains two dedicated reading buffers:
•
smua.nvbuffer1 (buffer 1)
• smua.nvbuffer2 (buffer 2)
To access the reading buffer, include the name of the SMU in the attribute. For example, the following
command would store readings from channel A into buffer 1:
smua.measure.overlappedi(smua.nvbuffer1)
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Model 2651A High Power System SourceMeter® Instrument Reference Manual
to increment and decrement the selected digit of the location number by one. Press the
and then turn it or use the CURSOR keys to move to the next digit that the
will change. If viewing the statistics stored in the buffer, turn the navigation
or use the CURSOR keys to scroll between MEAN, STD DEV, SAMPLE SIZE,
2651A-901-01 Rev. A / March 2011