Waters 2489, Overview And Maintenance Manual

Page: 80 / 150

June 11, 2015, 715004752 Rev. A
Page 80
Figure 3–23: Scan of erbium standard in a cuvette from 190 nm to 600
nm at 200 nm/min without tick marks
Specify these parameter values when you select a scan: zero or sample.
When you select a zero scan, the detector displays three additional screens, labeled 2
of 4, 3 of 4, and 4 of 4. You can change all parameters on these screens, including
starting and ending wavelength, and the pace parameter.
When you select a sample scan, the detector displays two additional screens, labeled
2 of 3 and 3 of 3 (see the figure on page 83 ). You cannot change the starting and
ending wavelength values or the pace parameter.
When you run a zero scan, you establish starting and ending wavelengths, pace, tick
marks, and sensitivity for both the zero scan and subsequent sample scans. Run
sample scans within 15 minutes of the baseline zero scan.
The most recent zero scan performed or retrieved remains current until you perform
or retrieve another scan. The zero scan should be appropriate for the subsequent
sample scans you perform. The sample scan adopts the starting and ending
wavelengths and the pace from the most recent zero scan. Only when those values
are identical for both the zero and sample scans can the zero scan be subtracted.
You use the SCAN key (Shift Chart-mark) to run a new zero or sample scan, store,
review, subtract and review, and replay stored or existing scans.
During a sample scan, data are charted via analog channel A using the specified AUFS
setting. At the same time, sample energy at 150 nA/V is charted via channel B.
During a zero scan, data are charted via analog channel A. At the same time,
reference energy, at 150 nA/V, is charted via channel A, at the AU specified on
channel A.
3.3.2 Scanning new spectra
To specify a new spectrum:
1. Press SCAN (Shift Chart-mark).
Result:
A Scan choice list appears.
Wavelength (nm)
290 390 490
AU
0.6
0.5
0.4
0.3
0.2
0.1
0.0