Waters 2475 - Creating a Difference Spectrum (Subtracting a Spectrum); Replaying a Spectrum; Conserving Lamp Life

Conserving lamp life 3-67
Creating a difference spectrum (subtracting a spectrum)
To create a difference spectrum:
1. Select SCAN (Shift, Chart Mark).
2. Press 5 Subtract & Review.
Tip: To subtract one spectrum from another, the starting and ending
wavelengths (λ1 and λ2) and the pace of both spectra must be identical.
3. Specify the storage slot number (1 through 5) of the spectrum you want
to subtract from the current (or retrieved) spectrum, and then press
Enter.
The message “Subtracting spectrum n” appears. The detector reviews
and subtracts the spectrum specified from the current spectrum and,
after a brief wait, displays the difference spectrum. You can store the
results in one of the five storage slots.
Replaying a spectrum
To replay a spectrum:
1. Select SCAN (Shift, Chart Mark).
2. Press 6 Real-time replay.
3. Specify the storage slot number (1 through 5) of the spectrum you want
to play back, and then press Enter.
Tip: The default is the last spectrum acquired.
After a pause to retrieve the selected spectrum, the detector plays the
spectrum on the analog connection, and then the spectrum graph
appears.
Conserving lamp life
To conserve the lamp without shutting down the detector, you can leave the
instrument on and extinguish the xenon lamp in these ways:
• Manually
• By programming a timed event
• By using the external contact closure