CHANGELOG.md

v2.1

• Remove usage of deprecated np.complex. Thanks to @jco-c!
• Made create_lua_attr idempotent on attribute existence.

v2.0.2

Plots of ResultTable data will now show a legend by default.

v2.0.1

Fixes an error where a voltage sweep would end with an AttributeError: cannot set property busy.

v2.0.0

This release completely overhauls how Keithley commands are generated. Instead of hard- coding available commands for a particular series or model of Keithley, all available commands are retrieved on demand from the Keithley itself. This is possible because the Keithley's TSP scripts use the Lua programming language which allows such introspection.

The main disadvantage of this approach is that most Keithley attributes will only be generated after connecting to an instrument. The main advantage is that all Keithley commands of all models which use TSP are supported and support for any future commands will be automatic. This removes the need to update the driver as the command set evolves, barring changes to the syntax, and enables automatic support for models with different command sets or a different number of SMUs. Furthermore, there have been issues in the past with missing commands and constants due to oversight. Those will no longer occur.

The second major change is a switch from camel-case to snake-case for the public API. For example, Keithley2600.applyVoltage has been renamed to Keithley2600.apply_voltage.

Other changes include:

• Type hints are used throughout.
• The Python syntax has been modernised for Python 3.6.
• The Keithley no longer beeps at the end of custom sweeps.
• Added API Keithley2600.send_trigger to send a trigger signal to the Keithley. This can be used to manually start a pre-programmed sweep.
• Added API KeithleyClass.create_lua_attr to create a new attribute in the Keithley namespace. Use Keithley2600.create_lua_attr to create global variables.
• Added API KeithleyClass.delete_lua_attr to delete an attribute from the Keithley namespace. Use Keithley2600.delete_lua_attr to delete global variables.
• Keithley2600.connect() now returns True if the connection was established and False otherwise.

v1.4.1

Changed:

• Replaced deprecated visa import with pyvisa.

v1.4.0

Added:

• Save time stamps with measurement data.

Changed:

• Renamed ResultTablePlot.update_plot to ResultTablePlot.update.
• Improved documentation of (live) plotting.
• Added SENSE_LOCAL, SENSE_REMOTE and SENSE_CALA to dictionary.

Fixed:

• Fixed explicitly defined methods such as Keithley2600.applyVoltage not appearing in dictionary.

v1.3.4

Fixed:

• Fixed a typo in the column labels of the dataset returned by outputMeasurement.

v1.3.3

Added:

• Added __dir__ proprty to Keithley2600 and its classes to support autocompletion. The dictionary of commands is craeted from the Keithley reference manual.

Changed:

• Remember PyVisa connection settings which are passed as keyword arguments to Keithley2600. Previously, calling Keithley2600.connect(...) would revert to default settings.

Fixed:

• Explicitly set source mode in Keithley2600.applyCurrent and Keithley2600.applyVoltage.

v1.3.2

This release drops support for Python 2.7. Only Python 3.6 and higher are supported

Fixed:

• Fixed a bug in rampToVoltage where the target voltage would not be set correctly if it was smaller than the step size.

v1.3.1

Added:

• Optional argument raise_keithley_errors: If True, the Keithley's error queue will be checked after each command and any Keithley errors will be raised as Python errors. This causes significant communication overhead but facilitates the debugging of faulty scripts since an invalid command will raise a descriptive error instead of failing silently.

Fixed:

• Thread safety of communication with Keithley. Keithley2600Base now uses its own lock instead of relying on PyVisa's thread safety.

v1.3.0

This version includes some API changes and updates to the documentation and doc strings.

Added:

• Accept range (Python 2 and 3) and xrange (Python 2) as input for voltage sweep lists.

Changed:

• Methods header and parse_header of ResultTable are now private.
• Cleaned up and updated documentation.

Removed:

• Removed deprecated function Keithley2600.clearBuffer(). Use buffer.clear() and buffer.clearcache() instead where buffer is a Keithley buffer instance, such as Keithley2600.smua.nvbuffer1.

v1.2.2

Added:

• Added shape property to ResultTable.
• Added string representation of ResultTable which returns the first 7 rows as neatly formatted columns (similar to pandas dataframes).

v1.2.1

Fixed:

• Fixed a critical error when initializing and appending columns to an empty ResultTable instance.

v1.2.0

Added:

• New method readErrorQueue which returns a list of all errors in the Keithley's error queue.
• Support for Keithley TSP functions with multiple return values. Previously, only the first value would be returned.
• Added ResultTablePlot class to plot the data in a ResultTable.
• Added live plotting to ResultTable and its subclasses. Pass the keyword argument live=True to the plot method for the plot to update dynamically when new data is added.

Changed:

• Optimized I/O: Keithley function calls to only use a single query call instead of consecutive query and read calls.
• Emtpy strings returned by the Keithley will always be converted to None. This is necessary to enable the above change.
• Renamed TransistorSweepData to FETResultTable. Renamed sweep_data module to result_table.

Removed:

• Removed IVSweepData. The was no clear added value over using ResultTable directly.

v1.1.1

Fixed:

• Fixed a thread safety bug: Fixed a bug that could cause the wrong result to be returned by a query when using Keithley2600 from multiple threads.

v1.1.0

Added:

• Sphinx documentation.

v1.0.0

Added:

• Added the base class ResultTable to store, save and load tables of measurement data together with column titles, units, and measurement parameters. The data is stored internally as a 2D numpy array and can be accessed in a dictionary-type fashion with column names as keys. Additionally, ResultTable provides a basic plotting method using matplotlib.

Changed:

• TrasistorSweepData and IVSweepData now inherit from ResultTable and have been significantly simplified. Formats for saving and loading the data to files have slightly changed:

  • The line with column headers is now marked as a comment and starts with '#'.
  • All given measurement parameters are saved in the file's _header. Specifically, TrasistorSweepData.load() expects the parameter sweep_type to be present in the _header and have one of the values: 'transfer' or 'output'.
  • Options to read and write in CSV format instead of tab-delimited columns are given.

  As a result, data files created by versions < 1.0.0 need to be modified as follows to be recognized:

  • Prepend '#' to the line with column titles.
  • Add the line '# sweep_type: type' to the _header where type can be 'transfer', 'output', or 'iv'.

Removed:

• clearBuffers method from Keithley2600 has been deprecated. Clear the buffers directly with buffer.clear() instead, where buffer is a keithley buffer instance such as k.smua.nvbuffer1.

v0.3.0

Added:

• Keithley2600 methods now accept Keithley2600 objects as arguments, for instance, one can now write

  # assume we have a Keithley2600 instance 'k'
  k.smua.measureiv(k.smua.nvbuffer1, k.smua.nvbuffer2)

  instead of needing to use their string representation:

  k.smua.measureiv('smua.nvbuffer1', 'smua.nvbuffer2')

• Keyword arguments can now be given to Keithley2600() and will be passed on to the visa resource (e.g., baud_rate=9600).

Changed:

• Code simplifications resulting from the above.
• k.readBuffer(buffer) no longer clears the given buffer.
• When attempting to create a new instance of Keithley2600 with the name VISA address as an existing instance, the existing instance is returned instead.

Removed:

• k.clearBuffers(...) now logs a deprecation warning and will be removed in v1.0. Clear the buffers directly with buffer.clear() instead.