Metrohm 844 UV/VIS Compact IC - Manual (Page 78)

Table of contents
VIS lamp VIS lamp
Turn VIS lamp on.
Turn VIS lamp off.
Records a new zero spectrum.
The zero spectrum is a reference spectrum. It
should be recorded at a time at which there is
no sample in the measuring cell. It is used for
calculating the absorption spectrum.
Opens the SPECTRUM window (see Section
3.3.3).
Wavelength, nm Sets the wavelengths at which the
chromatograms are to be recorded (for max.
three measuring channels).
Bunching, nm Sets the bunching of the wavelengths defined
above.
Channel 1, nm Measuring channel 1.
Channel 2, nm Measuring channel 2.
Channel 3, nm Measuring channel 3.
The relationship between
Wavelength and Bunching is explained by using
an example:
Set values: Wavelength = 500 nm, Bunching = 21 nm
An upper and a lower limit for the measured wavelengths of the
corresponding measuring channel are calculated from these values.
For these calculations the following equation applies: subtract "1"
from the Bunching value, divide the new value by 2, and subtract/add
the resulting value from/to the Wavelength value.
Result: wavelengths between 490 nm (lower limit) and 510 nm
(upper limit) will be included in the chromatogram.
Time program
On the Program tab of the system settings window a user-defined time
program for instrument control can be entered. This program is started
automatically as defined in the
Start mode window (see Section 4.3.3)
either at the moment the determination is started ( Start with
determination ) or at the moment the sample is injected ( Start with inject ).