eDAQ Picostat, User Manual

Page: 14 / 122

10 eDAQ Potentiostats
The Potentiostat provides two signals: the current signal (I Out)
indicating the current flow between the working and auxiliary
electrodes, and the potential signal (E Out) indicating the potential
difference between the working and reference electrodes. Note that the
E Out signal is inverted with respect to the applied potential.
For most situations I Out is connected to e-corder input channel 1, and
E Out to e-corder input channel 2. However, when you are using Chart
software and recording data from various sources on more that just two
channels you may want to connect the Potentiostat to other
e-corder
input channels.
I
2
C Connectors
The Potentiostat back panel, Figure 2–3 , has two DB-9 pin ‘I
2
C bus’
connectors labelled Input and Output. The Input connector provides
power to the Potentiostat and carries the various control signals (for
gain range and filter selection) to and from the
e-corder . A cable is
provided with the Potentiostat for this purpose. The pin assignments are
shown in
Figure 2–4 .
The Output connector can be used for the attachment of other eDAQ
Amps.
More information about the I
2
C connector can be found in your
e-corder Manual .
Grounding Connector
The Potentiostat back panel, Figure 2–3 , has a 4 mm grounding socket.
This enables connection of a Faraday cage (with the green grounding
cable included with the Potentiostat) the use of which can greatly
diminish electrical noise. The Potentiostat is supplied with a green
colored ground cable terminated with a 4 mm pin (attaches to
Potentiostat back panel) and an alligator clip (for attachment to
Faraday cage). If your Faraday cage is already earthed by its own
ground connection then you should not use this cable (otherwise a
second pathway to earth would exist which could result in a ‘ground
loop’ and increased signal interference! You can try grounding the
Faraday cage via its own connection to earth,
or via the Potentiostat
ground cable — but not by both methods simultaneously.
▲ WARNING!
The I
2
C connectors are
for the power and
control of
eDAQ Amps,
page 2
, and should not
be used for connection
to any other device.