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<< Click to Display Table of Contents >> Navigation: Experiments > E - Physical Electrochemistry > Techniques > Multi-Step Chronoamperometry > Multi-Step Chronoamperometry - Experimental Sequence |
Run the Multi-Step Chronoamperometry standard technique by selecting Experiment > Physical Electrochemistry > Multi-Step Chronoamperometry from the Framework™ menu bar. This initiates the following sequence of events:
1.Framework™ creates a Runner window, and the Multiple-Step Chronoamperometry.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 window 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 in 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 now obtains the use of the potentiostat specified during Setup and opens the data file using the Output name. If the potentiostat is in use or the file cannot be opened, the script returns you to the Setup dialog box. The file header information is written to the data file. This information is written to the file prior to data acquisition. If the experiment is aborted, the file contains only this information. This header information includes:
•Tags identifying possible analyses.
•The current time and date.
•A list of the Setup parameters.
4.If Initial Delay is on, then the cell is turned or left off and the specimen's Eoc is measured for the time specified as the Initial Delay time, or until the potential stabilizes to a value less than the stability setting. A plot of potential versus time is always displayed. The last measured potential is recorded as Eoc. If Initial Delay is off, this step is skipped and Eoc is assumed to be 0.0 V vs. Eref.
5.The script conditions the electrode if Conditioning was specified in the Setup. Conditioning is done by applying a fixed potential for a defined time. It establishes a known surface state on the corrosion specimen. A plot of current versus time is displayed during the Conditioning. No data are saved during this step.
6.The electrode and the solution are allowed to equilibrate for a defined time. The cell is turned on during this step and the stirrer is off. No data are saved during this step.
7.The actual data acquisition process starts. The potential is set to Step 1 Voltage and held at that value for Step 1 Time. The potential is then stepped to the subsequent step voltage and held at that value for set time. Steps are skipped if the subsequent times are zero. Current and voltage readings at fixed time intervals (Sample Period) are taken during the steps in Multi-Step Chronoamperometry.
8.If Auto-ranging was selected in Setup, at each point the current range is automatically switched to the optimal range for the measured cell current.
9.If Positive Feedback iR-compensation has been selected all data is continuously corrected for iR-drop. If Current Interrupt iR-compensation has been selected, each potential is corrected for the measured iR-drop of the preceding point. Plots of I and E vs. time are displayed during the steps.
10.The data are written to the output file, and the script cleans up and halts.
11.When the scan is over, the cell is turned off. The acquired data are written to the output file.
12.The script then waits for you to click the F2-Skip button. When you do, the script closes everything that is open, including the Runner window.