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Run the Multiplexed Rp/Ec Trend standard technique by selecting Experiment > Multiplexed DC Corrosion > Multiplexed Rp/Ec Trend from the Framework™ menu bar. This initiates the following sequence of events:
1.Framework™ creates a Runner window, and the Multiplexed RpEc Trend.exp script is run in this window.
2.The script creates the Setup dialog box and accepts changes in the experimental parameters. This dialog box allows you to specify the channels to be run, information concerning each channel, and global information about the entire experiment on all channels.
3.The script opens the electrochemical parameters file (SYSTEM.SET) and recovers the electrochemical system characteristics (βs, density , Equiv. Wt.) for each active cell from the file. If the script cannot open the file or find the System Name, the script warns you and then returns you to the Setup dialog box.
4.The script now opens the data file associated with each active Multiplexer channel to see if there are any problems with the composite (base plus channel number) file name.
5.The script obtains the use of the potentiostat and Multiplexer specified in the script or in the Setup dialog box. It initializes the Multiplexer so that all the cells are held at open circuit when they are not being measured. If the potentiostat or Multiplexer are 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.
6.If the elapsed time for this experiment is greater than the total experiment time, the script posts a warning and returns to the Setup dialog box.
7.If Conditioning was selected in the Setup, the local potentiostats in the Multiplexer condition all the Multiplexer channels. This includes both channels selected for data acquisition and cells that are not selected.
8.The script switches the Multiplexer to the first selected channel. A complete Polarization Resistance experiment is run on this cell.
9.An optional Initial Delay is performed prior to each scan. In all cases, Eoc is measured prior to the scan.
10.Finally, the actual polarization resistance scan occurs. The potential of the sample is swept from the Initial E to the Final E. Current readings at fixed time intervals are taken during the sweep. At each point, the current range is automatically switched to the optimal range for the measured cell current. If iR-compensation has been selected, each potential is corrected for the measured iR-drop of the preceding point. When the scan is over, the potentiostat cell switch and multiplexer channel are turned off.
11.The script calculates Rp from a linear least-squares fit of the current-versus-potential data. The resulting data point is appended to the data file for that channel, and the data file is closed.
12.Steps 7 through 10 are now repeated for every other active channel.
13.When all the channels have been run, the script checks the repeat cycle time and delays if necessary. After this delay it repeats the cycle though the active channels starting with step 6.