ABB AO2000-LS25 Laser analyzers



ABB AO2000-LS25 Laser analyzers

principle is illustrated in Figure 1-1. The laser wavelength is scanned across a chosen absorp tion line of the gas to be measured.
The absorption line is carefully selected to avoid cross

technique is employed: the laser wavelength is slightly modulated while scanning the absorp tion line. The detector signal is
spectrally decomposed into frequency components at har monics of the laser modulation frequency. The second harmonics
of the signal is used tomeasure the concentration of the absorbing gas. The line amplitude and line width are both

gas, thus not being sensitive to the molecules bound with some other molecules into com plexes and to the molecules attached to or
dissolved in particles and droplets. Care should be

The transmitter unit contains the laser module with a temperature stabilized diode laser, col limating optics, and the main electronics in a coated Aluminum box.
The receiver unit con tains a focusing lens, the photodetector and the receiver electronics in a coated Aluminum

supplied directly to the transmitter unit). The power supply box is connected to the transmit ter box with a cable. The 4–20 mA input signals from external
gas temperature/pressure sen sors can be connected to the screw terminals inside the power box or directly to the cable

The receiver electronics is connected with the transmitter electronics with a cable. The de tected absorption signal from the photodetector is amplified and
 transferred to the trans mitter unit through this cable. The same cable transfers the required power from the trans mitter unit to the receiver unit.