eDAQ Picostat, User Manual

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Chapter 4 — The QuadStat 51
• the current signals from the various working electrodes will still be
correctly monitored; however
• the corresponding potential signals at E Out are not accurately
monitored, and the overload light may come on, but this does NOT
indicate a fault condition. Only the overload light of Channel 1
(where the reference and auxiliary electrodes are connected) is able
to correctly indicate an overload.
When you use a common reference and auxiliary electrode with
multiple working electrodes, AND use an external waveform at E In on
Channel 1, then this waveform will be effectively applied to all working
working electrodes, whether or not the separate E In connectors are
linked together (as shown
Figure 4–6 ). Thus it is recommended to use
the connections shown in Figure 4–6 so that the signals seen at E Out
on each channel will be correct. For example if a triangular waveform
is applied at QuadStat Channel 1 then all the QuadStat channels will
perform cyclic voltammetry. The triangular potential waveform can be
offset at each separate working electrode by using the Applied
Potential control,
page 57 .
Finally, when you use a common reference and auxiliary electrode with
multiple working electrodes make sure that all the QuadStat channels
are set to the same cell mode (Standby, Dummy or Real),
page 56 .
Recording signals with some channels set on Dummy, while others are
on Real/Standby can cause incorrect current signals.
Using Multiple References and Auxiliaries
The QuadStat can also be used to conduct experiments in different
reaction vessels. In this case you should use a set of three electrodes
(working, reference, auxiliary) in each reaction vessel. Each QuadStat
channel behaves as a separate potentiostat. Independent signals can
be applied at each QuadStat channel E in connector, if desired, so that
different experiments can be run in each reaction vessel.
Please note that the use of multiple reference and auxiliary electrodes in
the same reaction vessel will almost certainly lead to unpredictable
effects and is not recommended!