Section 7: Introduction to TSP operation
Model 2461 Interactive SourceMeter® Instrument Reference Manual
7-40
2461-901-01 A/November 2015
Memory considerations for the run-time environment
The Model 2461 reserves a large amount of memory for use with interactions with the front panel,
commands, and test scripts. The amount of memory usage is affected by the following product
features:
•
Reading buffers (including local default and user-created reading buffers; if they are on a remote
node, they only affect the remote node)
•
Lua variables (large arrays)
•
TriggerFlow trigger models
•
Configuration lists
The more a feature is used or the larger its definition, the more memory it consumes. For normal
usage, reading buffers commonly reserve large amounts of memory. The amount of memory used
depends on the number of readings and the buffer style.
The Model 2461 notifies you when the system runs out of memory. If the instrument encounters
memory allocation errors (errors that specifically state “Out of Memory”), the state of the instrument
cannot be guaranteed. After attempting to save any important data, turn off power to the instrument
and turn it back on to reset the runtime environment and return the instrument to a known state.
Unsaved scripts and reading buffers will be lost.
If you encounter memory problems, examine the test script or SCPI commands that were being
executed when the memory problems occurred. Take action to reduce the size of the elements that
are consuming memory. If you are using TSP commands and scripting, also consider using the
collectgarbage()
command to clean up unused memory. For information on
collectgarbage()
, refer to
The default size settings for the default reading buffers (
defbuffer1
and
defbuffer2
) are large. If
your application does not use these buffers, you can set them to the minimum of 10 readings to
conserve space. For information on adjusting the buffer size, refer to
Setting reading buffer capacity
The buffer style is set when you create a user-defined reading buffer. The buffer style cannot be
changed, so to eliminate memory problems caused by the style, you may need to delete or adjust the
capacity of the buffers. Refer to
for information on the effects of styles.
The amount of memory used by a sweep configuration is based on the number of source points. The
actual memory consumption can vary greatly depending on how often the source-measure unit
(SMU) take readings during the sweep, but as a general rule, each source point can be expected to
consume at least 24 bytes.
It is possible for the memory used for the run-time environment, sweep configuration, and reading
buffers to exceed 32 MB. When this occurs, there is a risk that memory allocation errors will occur
and instrument will not execute commands as expected.
About TSP Commands
This section contains an overview of the TSP commands for the instrument. The commands are
organized into groups, with a brief description of each group. Each section contains links to the
detailed descriptions for each command in the TSP command reference section of this
documentation (see
(on page 8-7)).
