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Navigation: Welcome to DigiElch! > SW-Simulation Document > Tab-Window: Experiments

Menu Command: Import

This command opens a Windows File dialog box. The current curve(s) involved in the selected ASCII-file(s) will be merged to the existing ones when setting the Option: Import Data in the Property-Window correspondingly. Otherwise, all simulation objects will be removed from the active document before importing the selected file(s).

Import DigiElch use-File

Full use-format

the full use-format contains the current curve and a full description of the experimental parameters. The latter must be written to the file in exactly the same form as on the Property Page: Simulation Parameters:

DigiElch_SW_Header

experimental parameters:

key_word_1: Value_1

key_word_2: Value_2

.
species parameters:

[name of species_1] (M/l): Canal_1

[name of species_2] (M/l): Canal_2

experimental SW-data:
number of E (V), I1 (A) | I2 (A) couples : N

E1_1 , I1_1

E2_1 , I2_1

E1_2 , I1_2

E2_2 , I2_2

E1_N , I1_N

E2_N , I2_N

•DigiElch_SW_Header:
source program: DigiElch for Windows
program version: 3.0
file type: SW

•key_word_i and Value_i
key word and value referring to the i-th parameter. The value must be in point-format and separated from the key word by a colon. The keywords and parameter values are identical to those shown on the Property Page: Simulation Parameters. For example,

Pre-Equilibrium: enabled
Diffusion: Semi-Infinite 1D
Geometry: Planar
Area (cm²): 0.05
Ru (Ohm): 0
Cdl (F): 0
Temp. (K): 298.2
C1 (F/V): 0
C2 (F/V²): 0
C3 (F/V³): 0
C4 (F/V²V²): 0
Potential steps (V): 0.001
Estart (V):-0.75
Segment: 1
Eend (V): -1.55
f (Hz): 100
Segment: 2
Eend (V): -0.75
f (Hz): 100

•name of species_i and Canal_i
the name of the i-th species in brackets and the analytical concentration in point-format. For example

[NiL] (M/l): 0.001
[NiL-] (M/l): 0
[DP] (M/l): 0.1
[NiLDP] (M/l): 0
[NiLDP-] (M/l): 0

•N
the number of data couples

oE1_i and I1_i
numbers (separated by comma) representing the Voltage-Current-couple associated with the i-th forward step

oE2_i and I2_i
numbers (separated by comma) representing the Voltage-Current-couple associated with the i-th backward step

E1_i and E2_i are the potential values to which the current points, I1_i and I2_i, refer.

Minimum use-format

Data measured with third-party electrochemical instruments are usually exported in file formats which differ from instrument to instrument. The minimum use-format enables the user to produce an importable use-file with a minimum of effort provided the experimental data files satisfy the following prerequisites:

•The experimental current curve is available in ASCII-format.

•The current points refer to equal time steps. Only small deviations from equally spaced time intervals do not matter.

The minimum use-format is as follows:

DigiElch_SW_Header

number of E (V), I1 (A) | I2 (A) couples : N

E1_1 , I1_1

E2_1 , I2_1

E1_2 , I1_2

E2_2 , I2_2

E1_N , I1_N

E2_N , I2_N

oE1_i and I1_i
numbers (separated by comma) representing the Voltage-Current-couple associated with the i-th forward step (see above picture) .

oE2_i and I2_i
numbers (separated by comma) representing the Voltage-Current-couple associated with the i-th backward step(see above picture) .

tipbulb Files in minimum use-format do not contain any information about experimental parameters such as scan rate, electrode surface, electrode geometry or species concentrations. It is therefore not possible for the fitting procedure to recognize to which parameter combination a particular experimental curve refers. Consequently, such files are useful only for viewing experimental current curves. Apply the Edit/Modify command to add the experimental parameters to each file.

Import Third-Party (*.txt, *.dat) - File

This command is active only in Build 8189 (or later) of DigiElch. It opens a dialog box that offers the user to define an import-filter for importing data stored in an ASCII-format which is not compliant with DigiElch's use-file format.

SWImportFilterDlg

After leaving with OK, the files which are to be imported can be selected by a standard Windows file dialog .

•Selected Import-Filter
By default DigiElch offers predefined import filters for

oCH-I SW txt-files

oUser Defined

The last one can be freely configured by the user. Use Add New if more than one user defined import filter is required.

•Keywords in Header
Usually an ASCII-file consists of an header followed of a data section containing the current-voltage data. If the ID-String is not empty, DigiElch is searching for Keywords in the Header. In the above example the DigiElch parameter dEs (V) will be assign to the value associated with the Keyword "Incr E (V)". Analogously, f(Hz) and Esw(V) will be assign to the values associated with the Keywords "Frequency (Hz)" and "Amplitude (V)", respectively. In the case of Esw(V) an additional scaling factor is applied in order to make this DigiElch parameter compatible with data referring to Osteryoung square wave voltammetry.

•ID-String marking begin of Data Section and Data Format
This string marks the end of the header and the begin of the data section.

tipbulb The ID-String may be empty unless the header contains data arranged in columns which can be confused with those containing the current-voltage values.

•Data Format
When the ID-String has been reached, the program checks whether the imported line contains data which are compliant with the specified Number of columns and the selected Separator. If yes, another set of current-voltage data is added to the experimental SW using the assignment defined in Eav refers to column, I1 refers to column and I2 refers to column (I1 is the forward current, I2 is the backward current defined in the above picture and Eav = 1/2(E1 + E2)). Adjust the scaling factors correspondingly, if the unit of the imported current is not given in Ampere (but μA, for instance) or if the unit of the voltage is not given in Volt but mV.

tipbulb The scaling factor must be greater 0. If you need to change the current convention (DigiElch requires the classical convention where cathodic current is positive) use the Option: Import Data provided on the Properties windows.

•Open "Edit/Modify Dialog" automatically
Data files produced by third-party instruments do usually not contain information about experimental parameters such as uncompensated Ohmic resistance, electrode area, electrode geometry or species concentrations. It is therefore not possible for the fitting procedure to recognize to which parameter combination a particular experimental curve refers. Consequently, without modification the imported files are useful only for viewing experimental current curves. Apply the Edit/Modify command to add the correct experimental parameters to each file. The Edit Modify Dialog will be automatically opened if this check-box is ticked.