Importing data from GPES/FRA/ASCII · Case study: importing data from GPES, FRA and other sources?...

NOVA Technical Note 16

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Importing data from GPES/FRA/ASCII

Case study: importing data from GPES, FRA and other sources?

1 – Importing data

NOVA can import data from different sources, in order to compare the external data to experimental data obtained with NOVA. Presently, using dedicated commands provided in the Data handling group of commands, NOVA can import data from three different sources:

• Import GPES data: this command can be used to import data obtained with the Autolab GPES software.

• Import FRA data: this command can be used to import data obtained with the Autolab FRA software.

• Import ASCII data: this command can be used to import data from any properly formatted ASCII file.

These three commands can be used in any NOVA procedure, to import data from the specified source file into a NOVA file. These commands can be embedded into any procedure, however, since these are data handling commands, they cannot be inserted into a Timed procedure.

This technical note illustrates the use of these three commands to import data from different sources.

Note

Using the Import GPES data, Import FRA data or Import ASCII data command introduces a small time delay in the experiment while the data is imported.

NOVA Technical note 16

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2 – The Import GPES data command

The Import GPES data command can be used to import GPES data files into NOVA. This command can be found in the Data handling group of commands (see Figure 1).

Figure 1 – The Import GPES data command can be found in the Data handling group of commands

To use the Import GPES data command, the command can be dragged into any procedure. To illustrate this, a new procedure will be used.

Create a new procedure by clicking the button in the toolbar in NOVA (see Figure 2).

Figure 2 – Create a new procedure by clicking the button in the toolbar

Using the drag and drop method, add an Import GPES data command to the new procedure (see Figure 3).

Note

If no measurement commands are present in the procedure, the procedure can be used with no Autolab connected to the computer.


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Figure 3 – Adding the Import GPES data command to the procedure

The Import GPES data command has the following parameters:

• Filename: provides the name and the location of the file. • Number of columns: this parameter specifies the number of columns in

the GPES data file.

To specify the filename of the GPES file, click the button located next to the Filename parameter (see Figure 4).

Figure 4 – Specifying the filename of the GPES file (1/2)

A dialog window will be displayed. Using this dialog, the path and filename of the GPES file can be specified (see Figure 5).

Note

A warning symbol ( ) is shown in the procedure editor when no filename is specified in the Import GPES data command.


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Figure 5 – Specifying the filename of the GPES file (2/2)

Click the button after the file has been selected to close the dialog. The procedure editor will be updated (see Figure 6).

Figure 6 – The updated procedure editor

Depending on the extension of the GPES filename, the number of columns parameter and the names of the signals are adjusted. The plot generated by the command is also adjusted.


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Table 1 provides an overview of the supported GPES file extensions and the type of data contained in these files.

Extension Type of data Signals Plots

.ocw Cyclic voltammetry, Linear sweep voltammetry

i, E i vs E

.oxw Chrono methods i, t i vs t

.oew Voltammetric analysis i, E i vs E

.opw Potential stripping analysis E, dt/dE dt/dE vs E

.onw Electrochemical noise E, i, t E vs t

.odw Multimode electrochemical detection i, t i vs t

Table 1 – Overview of the supported GPES files and the signals and settings used in the Import GPES data command

To illustrate this, Figure 7 shows an example of the use of the Import GPES data command to import chronopotentiometry data, contained in a file with a .oxw extension.

Figure 7 – Importing a GPES chronopotentiometry data file (.oxw extension)

To import the data, simply run the procedure (click the Start button). When the Import GPES data command is executed, the data from the specified file is read and plotted according to the plot settings specified in the command (see Figure 8). The data is saved to the database at the end of the experiment.


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Figure 8 – Importing the data from the GPES file Democv02.ocw

After saving the data, the imported data will be available for data analysis in the analysis view of NOVA.

2.1 – Limitations

The GPES data buffer format is not supported by the Import GPES data command. Data saved in this GPES format must first be opened in the GPES software and then saved in one of the specified file formats indicated in Table 1.


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3 – The Import FRA data command

The Import FRA data command can be used to import FRA data files into NOVA. This command can be found in the Data handling group of commands (see Figure 9).

Figure 9 – The Import FRA data command can be found in the Data handling group of commands

To use the Import FRA data command, the command can be dragged into any procedure. To illustrate this, a new procedure will be used.



Using the drag and drop method, add an Import FRA data command to the new procedure (see Figure 11).

Note



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Figure 11 – Adding the Import FRA data command to the procedure

The Import FRA data command has the following parameter:

• Filename: provides the name and the location of the file.

To specify the filename of the FRA file, click the button located next to the Filename parameter (see Figure 4).

Figure 12 – Specifying the filename of the FRA file (1/2)

Note

A warning symbol ( ) is shown in the procedure editor when no filename is specified in the Import FRA data command.


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A dialog window will be displayed. Using this dialog, the path and filename of the FRA file can be specified (see Figure 13).

Figure 13 – Specifying the filename of the FRA file (2/2)



To import the data, simply run the procedure (click the Start button). When the Import FRA data command is executed, the data from the specified file is read and plotted according to the plot settings specified in the command (see Figure 15). The data is saved to the database at the end of the experiment.


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Figure 15 – Importing the data from the FRA file Frademo.dfr file

After saving the data, the imported data will be available for data analysis in the analysis view of NOVA. The data can be analyzed using the analysis tools described in the Impedance measurements tutorial, available from the Help menu in NOVA.

3.1 – Limitations

The potential, current or time scan data format is not supported by the Import FRA data command. Data saved in this FRA format must first be opened in the FRA software and then saved as individual .dfr files.

Note

Imported FRA data is always plotted as a Nyquist plot (Z’ vs –Z”) and as a Bode plot. Additional plots can be added, if necessary.


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4 – The Import ASCII data command

The Import ASCII data command can be used to import ASCII data files into NOVA. This command can be found in the Data handling group of commands (see Figure 16).

Figure 16 – The Import ASCII data command can be found in the Data handling group of commands

To use the Import ASCII data command, the command can be dragged into any procedure. To illustrate this, a new procedure will be used.



Using the drag and drop method, add an Import ASCII data command to the new procedure (see Figure 11).

Note



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Figure 18 – Adding the Import ASCII data command to the procedure

The Import ASCII data command has the following parameter:

• Filename: provides the name and the location of the file. • Number of columns: specifies the number of columns in the file and the

names of the signals for each column. • Column delimiter: specifies the column delimiter used in the ASCII file. • Decimal separator: specifies the decimal separator used in the ASCII file. • Number of rows to skip: specifies the number of lines to skip in the ASCII

file. This can be used to ignore the header section commonly included in ASCII files.

These parameters need to be specified properly for the Import ASCII data command to work properly.

To specify the filename of the ASCII file, click the button located next to the Filename parameter (see Figure 19).

Note

A warning symbol ( ) is shown in the procedure editor when no filename is specified in the Import ASCII data command.


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Figure 19 – Specifying the filename of the ASCII file (1/2)

A dialog window will be displayed. Using this dialog, the path and filename of the ASCII file can be specified (see Figure 20).

Figure 20 – Specifying the filename of the ASCII file (2/2)



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The number and names of the columns can be specified in the command. To edit the columns, click the button located next to the Number of columns parameter (see Figure 22).

Figure 22 – Editing the columns of the ASCII data file

A dialog window will be displayed, allowing the number of columns to be specified (see Figure 23).


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Figure 23 – Setting the number of columns used in the ASCII file

The same dialog can be used to assign a name to each column in order to identify the values contained in the file. To change the name of one of the columns, select a column from the list and click the button. The name of the signal can be assigned to the selected column and units can be provided (see Figure 24).

Figure 24 – Editing the name and units of the columns (1/2)

Predefined names and units are provided in the drop-down lists in the Edit signal window. The names of the signal and units can also be specified manually (see Figure 25).


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Figure 25 – Editing the name and units of the columns (2/2)

Using this method, the columns names and units can be customized as needed. When all the columns have been edited, click the button to close the dialog and return to the procedure editor (see Figure 26).

Figure 26 – Click the button to close the editor

The signal names will be updated (see Figure 27).


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The column delimiter and the decimal separator can be specified in the procedure editor using the provided drop-down lists (see Figure 28).

Figure 28 – Specifying the column delimiter and the decimal separator

Finally, the number of rows to skip can be specified in the procedure editor (see Figure 29).


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Figure 29 – Specifying the number of rows to skip

Additionally, one or more plots can be added to the Import ASCII data command, if necessary by adding a Custom plot command to the Import ASCII data command (see Figure 30).

Figure 30 – A custom plot can be added to the Import ASCII data command

To import the data, simply run the procedure. When the Import ASCII data command is executed, the data from the specified file is read and plotted


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according to the plot settings specified in the command (see Figure 31). The data is saved to the database at the end of the experiment.

Figure 31 – Importing the data from the ASCII file

After saving the data, the imported data will be available for data analysis in the analysis view of NOVA.

4.1 – Settings for impedance data from external sources

When importing impedance data from ASCII files, it is mandatory for the names of the columns to be specified properly, otherwise the impedance data analysis tools will not work properly.

The signal names Z’, -Z”, -Phase, Z are available in the dropdown list and must be used to identify the impedance data (see Figure 32).

Note

Impedance data is assumed to be defined according to the Z = Z’ – jZ” convention.


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Figure 32 – The settings for importing impedance data from external sources

Importing data from GPES/FRA/ASCII · Case study: importing data from GPES, FRA and other sources?...

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