eDAQ e-corder, Manual

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Chapter 4 — The QuadStat 41
If two-electrode operation is required the auxiliary and reference
electrode leads (red and yellow) can be attached to the single ‘counter
electrode’.
The Online Indicators
Along the lower edge of the QuadStat front panel are a series Online
indicators,
Figure 4–1 . When lit, they indicate that the software (such
as EChem, Chart or Scope) has located and initialised that QuadStat
channel. If the light does not go on when the software is run, check that
the QuadStat is properly connected. If there is still a problem, please
refer to Appendix B
Troubleshooting, page 85 .
The Overload Indicators
Also along the lower edge of the front panel are the Overload
indicators,
Figure 4–1 . When lit, these indicate either that the QuadStat
has overloaded, which usually occurs because it has gone out of
compliance because of an open circuit (such as an unconnected AE or
faulty electrode), or the resistance is too high in the electrochemical cell.
High resistances can be often be encountered when electrodes are
fouled by the products of electrolysis reactions. The QuadStat tries to
compensate by increasing the compliance potential (that is, the
potential of the auxiliary electrode). If the compliance voltage exceeds
specification, about 11 V, potential control of the cell is lost and
drifting, or oscillation, of the signal can be seen. Any data collected
during this period is unreliable and should be discarded.
The QuadStat Overload indicators will remain lit once an overload has
occurred — they will be reset once the scan has finished.
Color Electrode
Yellow Reference
Green Working
Red Auxiliary
Table 4–1
Color-coding on the
leads of the electrode
cables.