11.3.3 Aux
The 3465 Detector has four freely programmable TTL outputs, AUX1 – AUX4 (pins 7 – 10).
These contacts are default “high” 3.3 V (inactive); when active, the status is “low” 0 V.
11.3.4 Overload
The overload output (pin 11) can be used to monitor if the cell current goes out of range during a
chromatographic run. An “Out of range” error appears when the cell current (Icell) exceeds the
limit of the current range at which the measurement is performed.
Figure 11–2: Example of a chromatogram where the cell current exceeds the maximum
current level and the signal is "out of range".
Note:
It is important to recognize an “out of range” (overload) situation, because it may lead to
erratic results when quantifying analyte concentrations in samples.
If, for instance, the cell current goes out of range during the recording of an analyte peak, it can in
most cases be easily recognized by a flat peak top and a very abrupt transition to the flat top at
the edges.
By default, the status of the overload output is “high” 3.3 V. When the cell current has the status
“out of range”, the overload output changes status to “low” 0 Volt, until the cell current returns to a
value within the measurement range. The overload output (pin 11) is one of the configurable I/Os.
Figure 11–3: Overload output
The configurable I/Os can be programmed in the IO menu, which is a submenu of the CONFIG
menu. By default, the overload output is assigned to cell 1: “P11 (OVLD) = 1”. This means that
only when the cell current of cell 1 is out of range does the status of the overload output change
to “low” 0V. For all other cells present in the 3465 Detector, an “out of range” situation does not
trigger a response on pin 11.
December 16, 2021, 715007395 Ver. 00
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