Mutiplexed Corrosion Potential Experimental Sequence

Run the Multiplexed Corrosion Potential standard technique by selecting Experiment>Multiplexed DC Corrosion>Multiplexed Corrosion Potential from the Framework™ menu bar. This initiates the following sequence of events:

1. The Framework creates a runner window, and the Multiplexer Corrosion Potential.EXP script is run in this window.

2. 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.

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 the each active multiplexer channel to see if there are any problems with the composite (base plus channel number) filename.

5. The script 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 in the off state specified in the script. If the potentiostat is in use or the ECM8 cannot be opened, the script displays a warning and returns you to the Setup dialog box.

6. 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.

7. The script calculates the number of loops as Total Time divided by Sample Time. For example, a two-hour test with 5 minute Sample Time generates 24 data points.

8. The script switches the multiplexer to the first selected channel. A two-second open-circuit-potential-versus-time curve is recorded on this channel’s cell. The last measured potential is recorded and placed into the Corrosion Potential versus time curve for that channel.

9. Step 8 is repeated for every other active channel.

10. The loop number is compared to the loops needed. If all the loops have been executed, the data-acquisition loop terminates. The script relinquishes control of the potentiostat and multiplexer, and closes any open data files.

11.If the test is not done, the script compares the script’s elapsed time to the next required Sample Time, and delays if necessary. After this delay it repeats the cycle though the active channels starting with step 8.