Ru Estimation Experimental Sequence

  1. Framework creates a runner window, and the GetRu.Exp script runs 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 ran. To restore the parameters to the values defined in the script, click the Default button. If the Advanced Pstat Setup is switched to the on position, a second Setup dialog box containing 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; 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 1 MHz 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.
    7. If the phase-angle diverges from zero at lower frequency, the real impedance at the higher frequency is reported as Ru and you are warned that the Ru determination may be in error.
  1. When an Ru value is estimated, the cell is turned off. The measured Ru value is displayed in a dialog box. The script then waits for you to click the Skip button. After you do so, the script closes everything that is open, including the runner window.