Waters 2489, Обзор и руководство по обслуживанию

Страница: 22 / 150

June 11, 2015, 715004752 Rev. A
Page 22
The detector wavelength verification procedures establish an approximate Home
position using a grating homing sensor. Once Home is established, the 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 detector to locate three additional spectral features at
these wavelengths:
• 256.7 nm (UV)
• 379.0 nm
• 521.5 nm
The verification tests for the detector require 5 minutes of lamp warmup time.
If you run the detector continuously, Waters recommends that you perform
wavelength verification weekly by cycling power to the detector. See “Wavelength
calibration” on page 69 .
1.3 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.
Note that these modes are for local control of the detector only. Please check the
Empower and MassLynx online help for additional control information in these
environments.
1.3.1 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 of 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.