All cable connections to the epsilon system are made at the rear panel.
The epsilon system requires a grounded power supply, providing either 120 or 240 V at 50/60 Hz. Before connecting the power cord, check that the indicator next to the power connection shows the correct voltage (Fig1).
Figure 1. Power connection.
If the indicator does not show the correct voltage, pry open the cover to the right of the connector and pull out the voltage selector card (Fig2).
Figure 2. Accessing the voltage selector card.
Orient the card so that the label for either 120 V or 240 V (do NOT use 100 V or 230 V) gets inserted first, with the writing facing towards your left. Slide the plastic indicator around so it nestles in the correct slot opposite the indicated voltage, then reinsert the circuit board. Install the cover and make sure that the correct voltage is indicated.
Older model epsilons require serial port (COM port) computer connection and newer models use USB connection to the computer. Note the difference in the back panels at the beginning of this section. If the epsilon does not have a USB connecter in the upper right corner of the back panel, then it requires a serial port connection. The two connections are discussed below.
Serial port connection
The epsilon system requires a Pentium III or better computer, 50 MB available hard drive space running Windows 98, ME, 2000, or XP (Windows NT cannot be used to run the epsilon software after version 1.40.67). Connect a standard 9-pin, RS-232 serial cable between any COM port on the computer and the COMPUTER port on the epsilon (Fig3a).
The epsilon system requires at least a Pentium III or better computer with 128 MB RAM, 50 MB available hard drive space running Windows 2000, XP, or Windows 7. Connect a standard USB cable between any USB port on the computer and the USB port on the epsilon (Fig3b).
Figure 3. Computer connection: a. COMPUTER port for serial control and b. USB port.
The installation disk contains a Readme.txt file which explains the changes from the last version. It also contains three different installation programs. Selection of the proper installation program depends computer connection (Serial or USB) and on the operating systems of the computer. Examples are shown below. (Note that names may be slightly different on upgrade disk.)
To install the new software, place the CD in your CD ROM drive. Open the appropriate file for your computer. Follow the instructions as they appear on the monitor. Alternatively, EC epsilon software may be downloaded from the BASi® web site.
The cell lead cable is the group of wires that connects the epsilon to the electrodes of the electrochemical cell. If the epsilon has only one active channel (i.e., it is a mono-potentiostat), one end of this cable plugs into W1 on the rear panel of the epsilon (Fig4), and the other end is attached to the electrodes. If there is more than one active channel (i.e., a bipotentiostat), there is also a lead to connect the additional working electrode that plugs into W2-W4 (note that this port is larger than the W1 port).
Figure 4. Cell lead connections W1 and W2-W4.
WARNING: NEVER CONNECT OR ADJUST THE CELL LEADS DURING AN EXPERIMENT OR WHEN CELL=ON. DOING SO COULD DAMAGE THE SENSITIVE AMPLIFIERS AND VOID YOUR WARRANTY.
The end of the cell lead that is attached to the electrodes may be a direct connection using the general purpose cable sent with the epsilon or one for attachment to a cell stand such as the BASi C3 Cell Stand. The general purpose cable terminates with alligator clips that attach directly to the cell electrodes (Fig5).
Figure 5. Cell (electrode) end of cell lead.
There are 3 electrode leads and 1 grounded (shielding) lead. The color code is:
|Black covered wire:||Working electrode lead|
|Red covered wire:||Auxiliary electrode lead|
|White covered wire:||Reference electrode lead|
|Bare or black wire w/lug:||Earth ground connector|
A plastic mounting lug near the end of the cell cable provides relief by preventing movement of the line or cell.
Figure 6. Analog input and output.
Analog inputs and outputs (Fig6) can only be used for potentiostatic techniques. An analog output is provided for each of the available epsilon channels (only W1 and W2 are currently available for the EC epsilon), and must be activated from within the software from the Manual Settings dialog box in the Experiment menu (check External I Out). These outputs have a full scale output of ± 10 V and are provided for connection to chart recorders and other data-acquisition devices. The W1 or W2 terminal should be connected to the "high" or "+" input of the peripheral device, and the GND terminal to the "low" or "-" input (do not use any additional grounding that may be available on the peripheral device.
An output (E OUT ) is provided to monitor the potential applied to the cell on W1 (or the potential of the working electrode in the Open Circuit Potential technique), and an input (E IN) is provided to apply a potential to W1 from an external source (this external potential is summed to the potential applied by the epsilon). The E IN function must also be activated from the Manual Settings dialog box in the Experiment menu (check External E In). It should be noted that noise may be introduced into the system when E IN is activated.
Figure 7. Remote Start/Stop.
The remote start and stop connections (Fig7) provide several alternatives for sending and receiving signals to and from other instruments. These functions are fixed in time and can not be modified. For programmable triggers to remote instruments, see Timed Events below.
|START IN||Allows an external device to trigger the start of an experiment. Note that this is not the start of data acqusition, and several hundred msec plus the Quiet Time may elapse from the trigger until data acquisition starts. A switch closure or TTL-low of at least 55 msec across the START IN terminal and its ground will trigger the run when the check box for Run - External Trigger has been selected in the Change Parameters dialog box.|
|START OUT||Used to trigger other instruments at the start of an experiment. It provides a 1 s TTL-low when the Run is activated.|
|STOP IN||Not applicable in the EC epsilon.|
|STOP OUT||Used to trigger other instruments at the end of an experiment. It provides a TTL-low of 1 sec duration at the end of the run. The time between the last data point acquired and the STOP OUTsignal depends upon the technique and its parameters.
Figure 8. Timed Events.
Timed Events are programmable switch closures that provide exceptional flexibility for controlling peripheral instruments. Four switches are provided, which can be connected in a normally-open (NO) or a normally-closed (NC) configuration (Fig9). Two possible configurations to create TTL signals are shown below (Fig10 & Fig11). With both configurations the trigger line will normally be at 5 V and will step to 0 V when activated. In Fig11, the resistor (e.g., 1 - 10 kohm) is required to limit the current drawn from the 5 V power supply. These switches may be manually activated from the Manual Settings dialog box in the Experiment menu or programmed in the Sequential Techniques dialog box.
|Figure 9||Figure 10||Figure 11|
The maximum specifications of the relays are: 3 VA, 28 V DC or peak AC, 250 mA switching, 500 mA carry.
The most important part of starting the epsilon is establishing the link between the epsilon and the PC. The epsilon should be switched on first, and then epsilon PC software should then be opened. The link between the PC and the epsilon will automatically be established. The status of the link will be displayed in the CS Link Dialog box, which will disappear once connection has been established. The CS Link Dialog box is slightly different, depending serial or USB connection.
There is a comm link indicator (Comm1, Comm2, Comm3, Comm4, or DEMO) in the status bar of the main window. This is used to distinguish between multiple open files when controlling more than one epsilon from a single PC.
Figure 12. CS Link Dialog box.
If the link is not established (this is indicated by the message in Fig13), first check that the correct com port has been selected, then try to establish the link using the Retry button.
Figure 13. CS Link Dialog box with link failed message.
A similar CS Link Dialog box is displayed with the USB connection, except it does not contain the comm. port selection. There is a link indicator (USB or DEMO) in the status bar of the main window.
If the link is broken after it has been established, the PC and epsilon can be reconnected using Reconnect epsilon in the Experiment menu.