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NOVA Technical Note 16
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.
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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.
Note
If no measurement commands are present in the procedure, the procedure can
be used with no Autolab connected to the computer.
Create a new procedure by clicking the
Figure 2).
button in the toolbar in NOVA (see
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).
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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.
Note
A warning symbol ( ) is shown in the procedure editor when no filename is
specified in the Import GPES data command.
To specify the filename of the GPES file, click the
Filename parameter (see Figure 4).
button located next to the
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).
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NOVA Technical note 16
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.
Note
If no measurement commands are present in the procedure, the procedure can
be used with no Autolab connected to the computer.
Create a new procedure by clicking the
Figure 10).
button in the toolbar in NOVA (see
Figure 10 – Create a new procedure by clicking the button in the toolbar
Using the drag and drop method, add an Import FRA data command to the new
procedure (see Figure 11).
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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.
Note
A warning symbol ( ) is shown in the procedure editor when no filename is
specified in the Import FRA data command.
To specify the filename of the FRA file, click the
Filename parameter (see Figure 4).
button located next to the
Figure 12 – Specifying the filename of the FRA file (1/2)
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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)
Click the
button after the file has been selected to close the dialog. The
procedure editor will be updated (see Figure 14).
Figure 14 – The updated procedure editor
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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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.
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.
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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.
Note
If no measurement commands are present in the procedure, the procedure can
be used with no Autolab connected to the computer.
Create a new procedure by clicking the
Figure 17).
button in the toolbar in NOVA (see
Figure 17 – Create a new procedure by clicking the button in the toolbar
Using the drag and drop method, add an Import ASCII data command to the new
procedure (see Figure 11).
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Figure 18 – Adding the Import ASCII data command to the procedure
Note
A warning symbol ( ) is shown in the procedure editor when no filename is
specified in the Import ASCII data command.
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
Filename parameter (see Figure 19).
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button located next to the
NOVA Technical Note 16
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)
Click the
button after the file has been selected to close the dialog. The
procedure editor will be updated (see Figure 21).
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Figure 21 – The updated procedure editor
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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Figure 27 – The updated procedure editor
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
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