Figure 1. Wiring diagram of the electrochemical equipment.
Figure 2. Screen shot of the control panel of "ECHAN". (1) Present track and "Updown button" for selecting a track. (2) "Combo box" for the conversion between reference potentials (3) Information table for the present track. (4) Graph area of the present track.
Table 1. Command in ECHAN.
|Open||Open experimental data sets in ECHAN format.|
|Save as||Save experimental data sets in ECHAN format.|
|Import Track||Import an experimental data set from another file.|
|Search Track||Search experimental data sets by keywords and measurement condition.|
|Copy All as Text Data||Copy an experimental data set and its information to clipboard.|
|Copy I-E (or t) as Text Data||Copy an experimental data set to clipboard.|
|Replace Words in each title||Replace words in each title|
|Special Copy||Copy an optimized experimental data set to clipboard.|
|Edit Tracks||Copy or Move an experimental data set to another track.|
|Edit a Track||Edit an experimental data set.|
|Delete a Track||Delete an experimental data set.|
|Paste from Clipboard||Paste to the present track from clipboard (tab separated values only).|
|Copy I-t Table (Multipotentiostat Only)||Copy current-timeable measured by multipotentiostat mode to clipboard.|
|Copy V-I Table (Multipotentiostat Only)||Copy voltage-current table measured by multipotentiostat mode to clipboard.|
|Cyclic Voltammogram||Measure a cyclic voltammogram under hydrostatic or hydromic condition.|
|RDE||Measure a rotating ring-disk voltammogram under hydrostatic or hydrodynamic condition.|
|Potential Step||Measure a potential step measurement under hydrostatic or hydrodynamic condition.|
|RPM vs. I||Measure a rotating-speed sweep measurement under hydrodynamic condition.|
|Multipotentiostat||Measure time, current and voltage with multipotentiostat.|
|FFT Filter||Smooth an experimental data set by FFT low pass filter.|
|Smoothing||Smooth an experimental data set by the simple moving average or the Savizky-Golay method.|
|Calculation||Calculate between two tracks.|
|Koutecky-Levich Analysis||Analyze a data set based on Koutecky-Levich or Levich equation|
|%H2O Analysis||Calculate percentages of 4-electron reduction in total oxygen reduction reaction|
|Cottrell Equation Analysis||Analyze a data set based on Cottrell equation|
|Coulomb Number Calculation||Calculate Coulomb number in desired range of a data set.|
|Tafel Analysis||Analyze a data set on the basis of Tafel plot|
|Power Control||Show a power control module|
|Macro||Show a macro editor for automatic measurement|
Figure 3. Form module for searching data sets by keywords and measurement conditions. (1) "Directory list box" and "Drive list box" for specifying a folder. (2) Dialogue area for search conditions (3) Result table matched to the condition (4) "Updown button" for a destination track.
Table 1 shows the commands of ECHAN allocated to the menu bar. Since many functions are equipped in this software, some of the menus are described below as examples. The details of the usage are written in a help file.
1) File menu
An original text file format ".ech" is used in "ECHAN". Figure 3 shows the screen shot of a form module for searching tracks. The user can search data sets by keywords and measurement conditions in a specific folder.
2) Edit menu
Figure 4 shows a "Special Copy" form module displayed by [Edit] - [Special copy]. The user can not only reduce the points of a data set but also convert the y-scale for exporting to the windows clipboard with this module. Figure 5 shows the illustration of a reduction algorithm. In the figure, the points of A to D express part of the experimental data. d is the maximum distance allowed as a next point. To maintain the characteristic of the data, the points are selected as follows: After the aspect ratio of an electrochemical data set is adjusted to 1, first (Figure 5, A) and second point (Figure 5, B) are adopted as a yardstick and as points for exporting to the clipboard. If the third point C is satisfied with a function of an angle (q) and a distance (d) (Figure 5, hatched region), the point C is skipped , and the next point D is examined in the same way. If the position of C is located to that of C', which is out of the hatched area, the point C' is adopted as a point for exporting to the clipboard, and the point B and the point C' are adopted as a new yardstick. The number of the data points decreases with increasing d value, and large q enables to skip scattered points. The user can confirm the reduced data points in a preview window (Figure 4, (1)) as black points after clicking the [Go] button.
3) Measurement menu
In the program, the user select measurements from the menu of cyclic voltammetry, rotating ring-disk voltammetry, potential step chronoamperometry, measurement of current vs. rotating speed at a fixed potential, and multipotentiostat measurement either hydrostatically or hydrodymanically. Figure 6 shows a form module of rotating speeds vs. current measurement at a fixed applied potential. The user can use not only the manual settings of rotating speed but also a sweep mode for the rotation speed that is conducted by a D/A output of PCI-9112, connected to a speed controller.
4) Calculation menu
Data sets obtained by measurements can be processed for noise elimination by a FFT low pass filter, for smoothing by the simple moving average or the Savitzky-Golay method  and for data transformation (addition, subtraction and multiplication) between two data sets.
5) Analysis menu
The user can analyze data sets by means of the Koutecky-Levich equation, the Levich equation, the Cottrell's equation, the coulomb number calculation, the Tafel equation and the electron number calculation concerned with oxygen reduction reaction .
6) Tools Menu
Successive electrochemical measurements can be performed using an original macro language when a GPIB-based function generator is used. A program written in the macro language can be executable on "ECHAN" which is equipped with a simple macro editor. "ECHAN" interprets the program in a sequential order. Since the templates for the measurements are equipped in the macro editor, the users can input a sequential program very easily. List 1 shows a sample program list of the macro language. In the sample program, after the program finishes measurement of a cyclic voltammogram at hydrostatic condition and then a rotating ring-disk voltammogram measurement at a rotation speed of 300 rpm, it sends a message to a specific e-mail address.
List 1. Sample program list of the macro language.
|CV.Voltage 0.6 1.25 -0.25|
|RDE.Voltage 1 -0.3 1|
|Mail.Subject Measurements have been finished!|
|Mail.MsgNote Measurements have been finished!|
Figure 4. Screen shot of "Special Copy" form module. (1) Preview window for native data (blue dots) and reduced data (black dots). (2) Dialogue for specifying parameters.
Figure 5. Illustration for the optimization of data points adopted in ECHAN. The points of A - D are experimental data points. d is a maximum distance (from A to E) allowed to next point, which is variable by the user. q is a user-setting angle to reduce the interference of noise.
Figure 6. Form module of rotating speed vs. current measurement.
We thank Mr. Noriyuki Ueno for making the power control unit.