keithley2600 1.3.0

Full Python driver for the Keithley 2600 series.

keithley2600

A full Python driver for the Keithley 2600 series of source measurement units.

About

Keithley driver with access to base functions and higher level functions such as IV measurements, transfer and output curves, etc. Base commands replicate the functionality and syntax from the Keithley's internal TSP functions, which have a syntax similar to Python.

Warning:

There are currently only heuristic checks for allowed arguments in the base commands. See the Keithley 2600 reference manual for all available commands and arguments. Almost all Keithley TSP commands can be used with this driver. Not supported are:

• All Keithley IV sweep commands. We implement our own in the Keithley2600 class.
• Keithley TSP functions that have same name as a Keithley TSP attribute (and vice versa). The driver cannot decide whether to handle them as a function call or attribute access. Currently, there is only one such case:
  • io.output() has been dropped because it conflicts with smuX.source.output, which is more commonly used.
• Keithley TSP commands that have the same name as built-in attributes of the driver. Currently, this is only:
  • lan.trigger[N].connected: conflicts with the connected attribute of Keithley2600.

Usage

Connect to the Keithley 2600 and perform some base commands:

from keithley2600 import Keithley2600

k = Keithley2600('TCPIP0::192.168.2.121::INSTR')

k.smua.source.output = k.smua.OUTPUT_ON   # turn on SMUA
k.smua.source.levelv = -40  # sets SMUA source level to -40V
v = k.smua.measure.v()  # measures and returns the SMUA voltage
i = k.smua.measure.i()  # measures current at smuA

k.smua.measure.v(k.smua.nvbuffer1)  # measures the voltage, stores the result in buffer
k.smua.nvbuffer1.clear()  # clears nvbuffer1 of SMUA

Higher level commands defined in the driver:

data = k.readBuffer(k.smua.nvbuffer1)  # reads all entries from nvbuffer1 of SMUA
errs = k.readErrorQueue()  # gets all entries from error queue

k.setIntegrationTime(k.smua, 0.001)  # sets integration time in sec
k.applyVoltage(k.smua, 10)  # turns on and applies 10V to SMUA
k.applyCurrent(k.smub, 0.1)  # sources 0.1A from SMUB
k.rampToVoltage(k.smua, 10, delay=0.1, stepSize=1)  # ramps SMUA to 10V in steps of 1V

# sweep commands
k.voltageSweepSingleSMU(k.smua, range(0, 61), t_int=0.1,
                        delay=-1, pulsed=False)
k.voltageSweepDualSMU(smu1=k.smua, smu2=k.smub, smu1_sweeplist=range(0, 61),
                      smu2_sweeplist=range(0, 61), t_int=0.1, delay=-1, pulsed=False)
k.transferMeasurement( ... )
k.outputMeasurement( ... )

Singleton behaviour:

Once a Keithley2600 instance with a visa address 'address' has been created, repeated calls to Keithley2600('address') will return the existing instance instead of creating a new one. This prevents the user from opening multiple connections to the same instrument simultaneously and allows easy access to a Keithley2600 instance from different parts of a program. For example:

>>> from keithley2600 import Keithley2600
>>> k1 = Keithley2600('TCPIP0::192.168.2.121::INSTR')
>>> k2 = Keithley2600('TCPIP0::192.168.2.121::INSTR')
>>> print(k1 is k2)
True

Data structures:

The methods voltageSweepSingleSMU and voltageSweepDualSMU return lists with the measured voltages and currents. The higher level commands transferMeasurement and outputMeasurement return ResultTable objects which are somewhat similar to pandas dataframes but include support for column units. ResultTable stores the measurement data internally as a numpy array and provides information about column titles and units. It also provides a dictionary-like interface to access columns by name, methods to load and save the data to text files, and live plotting of the data (requires matplotlib).

For example:

import time
from  keithley2600 import Keithley2600, ResultTable

k = Keithley2600('TCPIP0::192.168.2.121::INSTR')

# create ResultTable with two columns
rt = ResultTable(column_titles=['Voltage', 'Current'], units=['V', 'A'],
                 params={'recorded': time.asctime(), 'sweep_type': 'iv'})

# create live plot which updates as data is added
rt.plot(live=True)  

# measure some currents
for v in range(0, 20):
    k.applyVoltage(k.smua, 10)
    i = k.smua.measure.i() 
    rt.append_row([v, i])

# save the data
rt.save('~/iv_curve.txt')

See the documentation for all available methods.

Installation

Install the stable version from PyPi by running

$ pip install keithley2600

or the latest development version from GitHub:

$ pip install git+https://github.com/OE-FET/keithley2600

Documentation

See the Keithley 2600 reference manual here for all available commands and arguments.