Waters 2489, Operator'S Manual

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Operational modes 1-11
Operational modes
The detector operates in single or dual wavelength mode, allows spectrum
scanning using a flow cell or a cuvette, and provides RatioPlot, difference plot,
and MaxPlot functions.
Single wavelength mode
Single wavelength is the default mode of operation for the detector. The
detector supports monitoring of a single wavelength from 190 nm to 700 nm,
settable in 1-nm increments on channel A. You can configure the analog
outputs for channel B while the detector is operating in single wavelength
mode, so you can use channel B to obtain additional information about the
wavelength selected on channel A.
In single wavelength mode, the detector automatically engages the second
order filter for wavelengths 370 nm and above and removes it for wavelengths
under 370 nm. The second order filter is an optical filter that blocks unwanted
ultraviolet (UV) light from striking the diffraction grating and interfering
with absorbance detection above 370 nm.
You can configure several additional parameters when using the detector in
single wavelength mode.
Primary parameters
The following are the major parameters you can use in single wavelength
mode:
• Wavelength in nm – Specifies a wavelength for channel A from 190 to
700 nm settable in 1-nm increments.
• Sensitivity in AUFS – Specifies the scaling factor for the analog output
channels and corresponds to the absorbance unit (AU) value where the
analog outputs saturate at full-scale values. Absorbance units full-scale
(AUFS) vary from 0.0001 to 4.000 AU.
Note: Changing the sensitivity (AUFS) setting affects the 2-V output.
• Chart polarity (+ or –) – Reverses the polarity of the charted
chromatogram. Select
+
for a normal chromatogram, or – for an inverted
chromatogram. This function changes the direction of the plot on the 2-V
output, similar to reversing the leads to an external chart recorder.