eDAQ Picostat, User Manual

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18 eDAQ Potentiostats
Inverting the Signal
The Invert checkbox, allows you to reassign the direction (up or down)
of an anodic (or cathodic) current. Please note that this affects the
display of the signal only — it does not reverse the direction of actual
current flow at the electrodes!
Cell Control
The Potentiostat can be in one of three cell modes, controlled by the
Cell radio buttons:
• Standby : If Standby mode is selected the electrode lead wires are
disconnected, and the internal dummy cell is connected. The
external (real) cell is not connected until the Potentiostat Control
window is closed and the Chart, Scope or EChem Start button is
clicked. This mode is used if you do not wish to alter the state of the
external cell until the method is actually performed. The Applied
Potential slider bar control is disabled in this mode.
• Dummy : the Potentiostat is connected to the internal 1 MΩ dummy
cell. You can then use the Applied Potential slider control to vary the
voltage applied to the dummy cell. The Potentiostat will remain
connected to the dummy cell even when the Potentiostat Control
window is closed and Chart, Scope or EChem is recording. This is
useful for testing the Potentiostat.
• Real : the external electrodes are connected to the Potentiostat. The
Applied Potential slider control, Figure 2–7 and Figure 2–8 , can be
used to set the potential applied to the electrodes while the
Potentiostat control window is open. When you close the control
dialog (using EChem or Scope software) the Potentiostat will revert
to Standby mode until the Start button is clicked to begin a scan. If
you are using Chart software, the Potentiostat will remain in Real
mode when the dialog is closed — so that when you start and stop
recording data the electrodes will remain active. This allows
periodic recording of the signal from, for example, amperometric
biosensors without disturbing the environment around the electrodes.
High Stability Operation
If the High Stability box is ticked then extra capacitance is introduced
into the Potentiostat control loop. This stabilizes the Potentiostat in