Ru Estimation Experimental Sequence

  1. Framework™ creates a runner window, and the Get Ru.exp script is run in this window.
  2. The script creates the Setup dialog box, which becomes the active window and accepts changes in the experimental parameters. This Setup box remembers the experimental settings from the last time this script was run. To restore the parameters to the values defined in the script, click the Default button. If the Advanced Pstat Setup is on, a second Setup dialog box with hardware configuration details becomes the active window, allowing you to modify the hardware configuration used during the experiment.
  3. The script next obtains the use of the potentiostat specified during Setup. No data file is created in this script; instead you must record the final Ru manually.
  4. The following sequence of events occurs to measure the Ru of the cell:
    1. The selected voltage is applied to the cell.
    2. A controlled potential EIS measurement is made at a 7 mV rms applied amplitude and a 100 kHz frequency.
    3. The phase-angle and real portion of the impedance are recorded.
    4. The frequency is successively decreased to 500, 200, 10, 5, 2, 1, 0.5 kHz. An EIS measurement is made at each frequency.
    5. If the phase-angle is less than ±7.5° at the frequency in use, the “real” impedance is reported on the computer screen as the Ru estimate.
    6. If the phase-angle is more than 7.5°, the phase-angle between the last two EIS measurements is compared.If the phase-angle diverges from zero at lower frequency, the real impedance at the higher frequency is reported as Ru and the user is warned that the Ru determination may be in error.
  5. After the software estimates Ru, the cell is turned off. The measured Ru value is displayed in a window. The script then waits for you to click the Skip button. When you do so, the script closes everything that’s open, including the runner window.