Waters 2475, Operator'S Manual, Page: 92 / 228

3-20 Using the Detector
• Analog out (single
λ
pair)
• Emission – Fluorescence output corresponding to the data units
selected.
• Reference Energy – Charts the lamp energy from the reference
photodiode located in the excitation optic bench. Reference scaling is
fixed at 10,000 units per volt.
• Output Off– Output set to zero volts.
• Analog out (multi λλ ) – In addition to the selections for single λ , you can
chart the same parameters on the other channel at a different excitation
and emission wavelength pair, and you can chart the following
parameters:
•
MaxPlot – Charts the fluorescence of multiple compounds with
different fluorescence values at different excitation and emission
wavelength pairs on a single data channel. Scaling for MaxPlot is
the same as for Fluorescence, except that the charted fluorescence is
the larger of the fluorescences measured on channels A, B, C, and D.
The detector uses the EUFS, data offset, and voltage offset of the
selected fluorescence channel regardless of which channel is larger.
Volts out = Larger fluorescence (A or B) × 1 V/EUFS (of selected
channel)
• Difference Plot (A-B and B-A) – Charts the difference in
fluorescences at two different wavelength pairs. The scaling for the
difference plot is identical to emission or sample energy selections,
except that the charted fluorescence is the difference in value of the
two fluorescences measured on channels A and B. The detector uses
the EUFS (of the selected channel), emission offset, and voltage
offset of the selected channel for scaling.
Volts out = Fluorescence difference (A – B or B – A) × 1 V / EUFS
• Time constant – Adjusts the noise filter (time constant) to achieve the
optimum signal-to-noise ratio without changing the sensitivity setting
(see page 1-12 ).
• Voltage offset – Adjusts the charted analog output signal. Specified in
millivolts, voltage offset adjusts the 1-V signal by the entered value.
This is useful for making minor adjustments, and for nulling any offset
between the detector and a connected external data system.
• Chart polarity – Inverts the chromatogram on the analog output.
Entering the plus symbol (+) produces a normal chromatogram; entering