Wavelength Verification And Test - Waters 2487 Dual A Operator's Manual

2. The beamsplitter, located just ahead of the flow cell, diverts a portion of the light
to a reference photodiode.
3. When you enter a new wavelength through the 2487 Detector's front panel (or
through the Millennium
rotates the grating to the appropriate position.
4. The preamplifier board integrates and digitizes the currents from the
photodiodes for processing by the signal processing electronics and output to a
computer, chart recorder, or integrator.

1.2.2 Wavelength Verification and Test

The 2487 Detector deuterium arc lamp and the integral erbium filter exhibit peaks in the
transmission spectrum at known wavelengths.
Upon startup, the 2487 Detector verifies calibration by comparing the locations of these
peaks with expected wavelengths based on calibration data stored in the detector's
memory. If the results of this verification differ from the stored calibration by more than 1.0
nm, the detector displays a Wavelength Verification Failure message. The 2487 Detector
verifies rather than recalibrates on startup to avoid errors that may occur because of
residual materials left in the flow cell and/or the cuvette.
Note: Always ensure that the cuvette is removed and the cuvette holder and left front
panel door are secured during startup verification.
You may initiate a manual wavelength calibration at any time. A manual calibration
replaces the previous calibration data with new data. See
Calibration, for the manual wavelength calibration procedure.
The verification and calibration algorithms are virtually identical. However, the verification
algorithm may issue an error message indicating that actual data does not match stored
data, where the calibration algorithm replaces the stored data with the new data.
The 2487 Detector wavelength verification procedures establish an approximate home
position using a grating homing sensor. Once home is established, the 2487 Detector
locates and references the 656.1 nm peak in the deuterium lamp emission spectrum.
The integral erbium filter moves into the common light path ahead of the flow cell entrance
slit, enabling the 2487 Detector to locate three additional spectral features at these
wavelengths:
• 256.7 nm (UV)
• 379.0 nm
• 521.5 nm
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software or other system software control), the detector
Section 3.3.3, Wavelength
Principles of Operation
1
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