FNGWiki

Electrical Measurements with Pymeasure

Martin Tweedie 2018 05 24

Clean Install

1. Install latest versions of the following software from National Instruments:
   • Labview http://sine.ni.com/np/app/main/p/docid/nav-104/lang/en/fmid/1765/
   • 488.2 http://www.ni.com/download/ni-488.2/7272/en/
   • VISA http://search.ni.com/nisearch/app/main/p/bot/no/ap/tech/lang/en/pg/1/sn/catnav:du,n8:3.1637,ssnav:sup/
2. Download and install Anaconda navigator for Python 3, available here: https://anaconda.org/anaconda/anaconda-navigator
3. Run Anaconda Prompt
4. Enter: 'pip install pymeasure' & 'pip install easygui'
   • These are the only packages you should need but if you return a 'no module named x' error then use 'pip install x'
5. Run Anaconda Navigator
   • Pymeasure documentation is available in the Pymeasure Scripts folder. Additional information can be found online, including guides for how to easily create/modify your own scripts: http://pymeasure.readthedocs.io/en/latest/

Performing Measurements

1. In Anaconda Navigator, run Spyder
2. Power up Keithley units and unsure GPIB converter is connected. For gated measurements, a second Keithley should be bridged to the first. The connection to the units can be verified via NI MAX software (packaged with VISA).
3. With Spyder running, open desired script (available below; save as .py (not .txt) as wiki does not allow upload of files with extension .py).
4. Run script.
5. A pop-up window appears with information about the script. Press ok.
6. A second pop-up window will open enabling you to select the file destination. Files will save to this destination with names containing measurement type, date, and test number.
7. With file destination selected, the measurement window will open. Enter desired parameters and press queue to begin the measurement. One or both Keithley units will emit a beep indicating output on.
   • Multiple measurements can be queued and will run sequentially. Should you wish to cancel a measurement, pressing abort will stop the current measurement; press resume to continue from the next measurement in the queue. Queued measurements may be removed by right-clicking. Completed measurements may also be saved to any desired location and many other outputs including graphs are possible in-window.
   • At time of writing there are 2 bugs with all measurement scripts:
     1. The second time any script is run, Python will crash. This is likely due to the process containing the instrument not closing properly resulting in a new process attempting to access a serial port that is already in use by this first process. Once the kernel restarts the script may be run as normal.
     2. The measurement window will occasionally crash at the end of a measurement or when a measurement is aborted. As before, the script may be re-run once the kernel restarts. This appears to occur more frequently with scripts calling both Keithleys.

Scripts

Attach:IV.txt

Attach:IV_Gate.txt

Attach:I_over_t.txt

Attach:I_over_t_Gate.txt

Attach:I_Gate_Sweep.txt