Multiplexed Rp/Ec Trend Experimental Sequence
Run the Multiplexed RpEc standard technique by selecting Experiment > Multiplexed DC Corrosion > Multiplexed Rp/Ec Trend from the Framework™ menu bar. This initiates the following sequence of events:
- Framework creates a runner window, and the MUXRPEC.EXP script is run in this window.
- The script outputs a Setup dialog box which becomes the active window. 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. Clicking the OK button accepts the parameters and starts the experimental run.
- 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 file cannot be opened or the requested Setup Name cannot be found, the script warns you and then returns you to the Setup dialog box.
- The script opens the data file associated with the each active multiplexer channel to see if there are any problems with the composite (base plus channel number) filename.
- The script now obtains the use of the potentiostat and ECM8 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 is in use or the ECM8 cannot be opened, the script returns to the Setup dialog box.
- 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.
- If Conditioning was selected in Setup, the local potentiostats in the ECM8 condition all the ECM8 channels. This includes both channels selected for data-acquisition and cells that are not selected.
- The script switches the multiplexer to the first selected channel. A complete Polarization Resistance experiment is run on this cell.
- An optional Init. Delay is performed prior to each scan. In all cases, Eoc is measured prior to the scan. 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 is 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.
- 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.
- Steps 7 though 9 are now repeated for every other active channel.
- 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.