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AO2000-LS25 LASER ANALYZERS | OI/AO2000-LS25-EN REV. D
... 10 Configuration, parameterization
... Description of menus and parameters
Line position:
The position of the line peak (maximum absorption) in samples
of the AD converter [0–63]. The value should be close to the
reference line position, which is given in the menu <Gas specific
parameters> for the corresponding line. The instrument
automatically tracks the line, i.e. if it deviates more from the
reference position than a given value, the instrument adjusts the
laser temperature and thereby the wavelength.
Line amplitude:
Relative measure of the peak of the absorption line of the
second harmonic signal. If this value approaches 0.5 to 1.0 the
absorption is strong and saturation of the AD converter may be
very close (actual saturation initiates the ERROR). In the region
from 0.01 to 0.1 the signal is good.
Below 0.01 the signal is approaching the low level below which
line width cannot be measured and line tracking is off.
Transmission (%):
Indicates how much light the receiver detects in % of the
maximum value. If the optical windows are covered with dust
and the transmission drops below a pre-set level, a warning will
appear on the display of the transmitter unit.
The optical windows of the instrument should then be cleaned.
The warning will also appear for improper alignment of the
transmitter and receiver.
Gas temperature (C):
The temperature currently used to calculate the gas
concentration.
It may be a fixed value set by the user, the value measured by a
4 to 20 mA current temperature probe or the value measured by
the device itself optically or electrically.
Optically measured temperature is called Spectral temperature.
Electrically measured temperature is the temperature measured
by the embedded temperature sensors (only used when the gas
temperature is equal to ambient temperature) offset-corrected
to be equal the ambient air temperature. In the example above
the gas temperature is set equal to the Spectral temperature.
These settings can be configured in the <Measurement
configuration> menu.
Gas Pressure (Bar abs.):
The current absolute pressure used to calculate the gas
concentration. It may be a fixed value set by the user, the value
measured by a 4 to 20 mA pressure sensor or the value
measured by the device itself using the embedded pressure
sensor (mainly for O
devices and only used when the gas
2
pressure is equal to the ambient air pressure). This is configured
in the <Measurement configuration> menu.
Dry conversion factor:
Factor currently used to multiply the gas concentration if dry
basis conversion is selected (see Dry basis conversion on
page 60).
The initial (wet) concentration reading may be converted to dry
reading if the H
O concentration is known. If dry basis
2
conversion is not activated the factor is always 1.0.
Max. Direct:
Maximum value of the direct signal in the levels of AD converter
[0–4096]. This value together with Dark Direct determines the
value of the light transmission.
Dark Direct:
Optical zero of the direct signal measured when the laser is
switched off for a short period. The unit is the same as for "Max.
Direct".
Laser temp. (V):
The voltage across the thermistor located in the vicinity of the
diode laser. Higher voltages indicate lower laser temperature.
Changing laser temperature changes the laser wavelength.
Laser temp. error:
The amplified difference in Volts between the measured Laser
Temp and the reference value. Should be around 0.000. It
indicates the quality of the laser temperature regulation and
thus the quality of the wavelength stabilization.
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