Bio-Rad BioLogic QuadTec™ Detector and Components - Manual (Page 34)

4.3.1 Selecting Wavelength(s)
Use the green Left arrow to select the View menu and then:
1. Position the cursor on one of the two wavelength fields and select the wavelength by entering the
desired values with the numeric keys. If you want to use one single wavelength, enter a zero in the
unused fields. Entering zero deactivates the respective wavelength.
2. If you use both wavelengths, the grating monochromator moves between the positions
corresponding to the selected wavelengths. This movement is performed with a frequency of 10 Hz
that cannot be changed. You can hear the motor of the monochromator as a high frequency tone.
3. A cutoff filter for suppressing secondary grating orders is activated automatically if one or both
wavelength(s) exceed 381 nm and a deuterium lamp is installed. The use of the filter is displayed by
a superscripted +.
4.3.2 Output Options
The output of absorption signals can be configured. Move the cursor to the signal fields and choose between
the different options by pressing any numeric key. The following options are available:
• Signal inversion (indicated by a superimposed minus sign).
• Two different ratio plots are available:
• Wavelength (1) divided by wavelength (2)
• Wavelength (2) divided by wavelength (1)
Ratio plots are indicated by symbol 1/2 and respectively 2/1 at the decimal point of the absorption value.
Figure 4-9. Inversion of Signal and Ratio Plots: Set/Indicated Output Options
Ratio plots contain information on peak purity by dividing the intensity values at two different wavelengths. It
is possible to measure the absorption at one wavelength and to monitor simultaneously the ratio of
absorption between this wavelength and another one. Ratio plots can be accessed at the analog out
connector to a chart recorder.
The scaling of the analog outputs can be adjusted to different values of absorption units or to different
voltage values. For details see “Analog Out Full Scale” on page 4-4: in the section “Setup Menu”.
4.3.3 Events
The EVENTS outputs on the rear of the detector provide time programmed signals to other instruments. This
is described in section 4.8, “Connecting Other Instruments to QuadTec Detector.” When working without a
time program, using Events enables fraction collection (see “Fraction” on page 4-4).
USE AS A STAND-ALONE SYSTEM SYSTEM INSTALLATION AND SETUP
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