Multiplexed Corrosion Potential - Setup Parameters

<< Click to Display Table of Contents >>

Navigation:  Experiments > D - Multiplexed DC Corrosion > Techniques > Multiplexed Corrosion Potential >

Multiplexed Corrosion Potential - Setup Parameters

Description

 

1 - Multiplexed Corrosion Potential

 

Parameter

Description

Units

Pstat

Select the potentiostat/galvanostat to perform the experiment. Each radio button corresponds to an installed potentiostat. You can select only one potentiostat at a time. Potentiostats that are already in use are marked with an asterisk. They can be selected but cannot be used.

 

Gamry tip bulb

Only potentiostats that are paired with a Multiplexer can be selected.

 

Channel

There is one Channel Setup switch for each of the 8 channels. Click the checkbox to select a specific channel. As the script loops through the channels, it only runs tests on channels that are selected. The selected channel numbers do not have to be continuous.

 

Identifier

A string that is used as a name. It is written to the data file, so it can be used to identify the data in database or data manipulation programs.

 

The Channel Identifier string is virtually identical to the Test Identifier string. The only difference is that in multiplexed tests, the Identifier refers to an experiment run on a single cell and not to the entire experimental run.

 

System

Select a set of electrochemical parameters relevant to your particular test system. The parameters are recovered from the system parameter database file. The recovered parameters are all used for the calculation of the corrosion rate. They are the sample's equivalent weight, density, anodic β and cathodic β. When you attempt to run an experiment, the system searches the SYSTEM.SET file for a parameter set stored under the name in the System parameter. If the software finds no parameter set, an error message appears and you are returned to the Setup dialog box.

 

Area

The electrode area that is used in calculations. It can be set individually for each channel.

cm2

Notes

Enter several lines of text that describe the experiment. There is a separate entry for each channel in a multiplexed test. A typical use of Channel Notes is to record the experimental conditions for a data set.

 

The Channel Notes controls are similar to the Notes control described for non-multiplexed experiments.

 

Sample Period

The time between the start of each loop through the selected cells. Because the time to measure a point on each cell is almost constant, the Sample Period also approximates the time between readings on each cell.

 

The Sample Period is always entered in minutes. Fractional minutes can be entered as decimal numbers. The Sample Period must be longer than the time required to record a data point on all the selected cells. When you click the OK button in the Setup dialog box, the script estimates the time required to loop through the selected cells. If this time is close to or longer than the entered Sample Period, Framework™ produces an error message and returns to the Setup.

minutes (min)

Base Filename

Each channel has its own data file. The Base Filename is used to derive the filenames for these files. The filename for Channel N (1–8) is created by appending the character N to the Base Filename, then adding a *.DTA filename extension.

 

If the Base Filename is MYMUXDATA, the data file for Channel 1 is named MYMUXDATA1.DTA. The filename resulting from the concatenation of the Base Filename and the channel number must adhere to Windows® filename conventions. Avoid punctuation characters (the underscore, "_", is OK). You are allowed a maximum of 250 (not 255) characters in the Base Filename. The extra characters are reserved for the channel number appended to the Base Filename. Do not include *.DTA when specifying the Base Filename. It is automatically added when the full data file name is generated.

 

Total Time

The duration of the experimental run. The script keeps track of the elapsed time from the start of the experiment. At the start of each test, the elapsed time is compared to the Total Time. If the elapsed time is greater than or equal to the Total Time, the experiment is halted and the Runner window is closed.

 

Gamry tip bulb

A Total Time of zero results in no tests being run.

hours (hr)

Conditioning

You may condition the electrode as the first step of the experiment, for example to remove an oxide film from the electrode or to grow one. Conditioning ensures that the metal sample has a known surface state at the start of the experiment. This step is done potentiostatically for a set amount of time.

 

Gamry tip bulb

If you select Conditioning, all Multiplexer cells are conditioned. This includes non-selected channels. This could potentially damage electrochemical cells attached to channels that you thought would be inactive throughout the experiment.

 

Turn the conditioning phase On or Off with the Conditioning switch check box. Conditioning E is the potential applied during the conditioning phase of the experimental sequence. The conditioning potential has an allowed range of ±8 V. The resolution is 0.25 mV. If you have iR-compensation enabled for the data acquisition phase of your experiment, it is also turned on during conditioning. Conditioning E is always specified vs. Eref, because the open-circuit potential is not measured until after Conditioning is completed.

 

The Conditioning Time is the length of time that the sample is potentiostatted at Conditioning E. The minimum time is 1 s and the maximum time is 400000 s (more than 4 days). Below 1000 seconds, the time resolution is 1 s. Between 1000 and 10000 seconds, the resolution is 10 s, and 100 s above 10000 seconds.

seconds (s), volts (V)

IR Comp

Choose to turn iR-compensation either On or Off. Turning on IR Comp causes the applied potential to be adjusted for the estimated iR-drop.

 

Gamry potentiostats are able to estimate uncompensated voltage-drop caused by cell resistance. They do so by performing a current-interrupt experiment after every data point.