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complex switch with driving electronics. One of the eight cell cables on
the EIS Box is switched so that it connects to the instrument's cell cable.
All the wires (including sense leads and shields) in the cell cable are
switched.
Switching from channel to channel
involves electromechanical relays. You
will hear a click each time relays
activate during the switching process.
The system computer also controls the instrument. When a cell is
connected to the instrument cell leads, the computer causes a test to be
run on that cell. The test can be as simple as a single current or potential
measurement or as complex as a cyclic scan. The computer software and
instrument are responsible for taking the measurement and storing it.
The EIS Box instrument in Figure 3-1 is shown as a "black box". The
relays in the EIS Box can carry currents up to 5 A.
In a typical EIS Box experiment, the system computer cycles through the
cells. Each cell is connected in turn to the instrument and used to collect
a measurement. Usually the computer delays at the end of each cycle
through the cells so that the measurements on each cell are separated
by a fixed time period.
Keyword Definitions
Active Cell
The active cell is the cell (if any) currently connected to the system
potentiostat. Any electrochemical measurements are made on the active
cell.
Cell
The term cell is used to describe either an electrochemical cell or the
switches needed to connect an electrochemical cell to the instrument.
Channel
An EIS Box contains eight channels. A channel includes cell-switching
relays. The term cell is used when only the cell-switching portion of a
channel is being discussed.
Inactive Cell
The term inactive cell is any cell not currently connected to the
instrument.
Instrument
This is the instrument responsible for making electrochemical
measurements on the cells used in the experiment. The instrument is
typically an EIS Box.
System Computer
The computer responsible for coordinating operation of an EIS Box-
based electrochemical test system, not to be confused with the very
simple micro-controller buried within the EIS Box.
Switching and Inactive Cell Control
In the Operation Overview, we said you can think of the EIS Box as a
complex switch with controller. Each of the eight EIS Box channels is
made up of an independent set of switches and control circuits. All the
switches are under control of the system computer. The system
computer must insure that only one cell at a time is connected to the
instrument, therefore a main switch controls which cell is active.
The system computer communicates with the EIS Box via an ethernet
connection or a USB cable.
Installation
We assume the EIS Box is installed as part of a Gamry Instruments'
Framework-based electrochemical measurement system containing a
Microsoft Windows® compatible computer.
Figure 4-1 Front View of the EIS Box
Physical Location
Normally users place their EIS Box on a flat workbench surface. Keep
easy access to the rear of the instrument because some cable
connections are made from the rear. The EIS Box is generally operated in
a "flat" position (see Figure 4-1). Operation in other orientations is
possible as long as you insure that air movement through the chassis is
not restricted.
Caution: Do not block the airflow into or out of the EIS
Box chassis. The EIS Box will entar a power-down state if
it becomes overheated. If this occurs during data-
acquisition, you may lose experimental data.
If you place your EIS Box within an enclosed space, make sure that the
internal temperature within that space does not exceed 45°C, the
maximum ambient temperature for the EIS Box. Be particularly careful if
a computer or other heat-dissipating equipment is mounted in the same
enclosure as the EIS Box.
Computer Requirements
Before you connect an EIS Box to a computer, you must make sure that
your computer meets these requirements:
•
A computer based on one of the x86 or x64 families of Intel
microprocessors, or a 100%-compatible processor from
another vendor,
•
Microsoft® Windows 7 or higher is required. Both 32-bit and
64-bit versions of these operating systems are supported. See
the Gamry website "www.gamry.com" if you have a newer
edition of Windows®.
•
An ethernet port or a USB port.
Software Installation
The EIS Box is compatible with the Windows® Plug & Play configuration
system. Like most Plug & Play hardware, it is best if you install the
software for the EIS Box before you install the instrument hardware.
Gamry Instruments' software can be installed from a physical medium
such as a DVD or a pre-programmed software flash drive, or it can be
installed via an Internet download. The most up-to-date download can
be found on www.gamry.com.
If you install from a physical medium, Gamry Software Setup program
will normally start automatically when you place the Gamry Instruments'
installation medium into your computer.
An Internet download of Gamry Instruments' software will download a
self-extracting .EXE file. Running this file will extract the software and
begin the same installation process as you get with a physical medium.
If you have inserted the Gamry DVD or flash drive into your computer
and the Gamry Setup program does not start automatically:
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