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AO2000-LS25 LASER ANALYZERS | OI/AO2000-LS25-EN REV. D
Optical path through gas (m)
1 Transmitter unit
Figure 41: Optical lengths needed for setting initial parameters
The length (in meters) of the optical path through the gas to be
measured (Lg in Figure 41). It is normally equal to the stack
diameter or the free space between insertion tubes. In case of
installations with a measurement cell it is equal to the length of
the cell.
Optical path through flanges (m)
The combined length of the flanges (Lf1+Lf2 in Figure 41).
This parameter is important only if the measured gas is present
in the flange region and the instrument must compensate for
this extra gas absorption. This is usually the case for O
CO
, CH
monitors, e.g. devices for measuring atmospheric
2
4
gases.
Note
For this compensation to work, the gas concentration in the
flanges must be specified in the "Gas specific parameters" menu
(Gas specific parameters <Gas specific parameters> on
page 61).
2 Receiver unit
, H
O,
2
2
Optical path through RU & TU (m)
The optical path through the transmitter and receiver units
(TU + RU). This is the internal optical path of the instrument.
The value is set by the factory.
If this parameter is changed, the original value should be noted
down in order to be able to restore the original setting when
required.
This parameter is only important if the measured gas is present
in the internal device volume so that the additional gas
absorption must be compensated for.
Note
For this compensation to work, the gas concentration in the RU
and TU must be specified in the "Gas specific parameters" menu
(Gas specific parameters <Gas specific parameters> on
page 61).
Gas temperature in flanges (C)
The average temperature of the gas in the flanges is stated in
degrees Celsius. If the measured gas is not present in the
flanges, the flange temperature is irrelevant.
Note
Proper setting of the optical path parameters is important for
correct measurements.
Concentration averaging
The amount of primary measurements used to calculate the
averaged concentration ("Concentration Avg" parameter in
"Measurements" menu).
The instrument measures and calculates the gas concentration
at regular intervals.
A primary measurement ("Concentration Instant" parameter in
"Measurements" menu) takes approximately 1 to 4 seconds
depending on the gas type.
The instrument calculates a "running" average of the primary
measurements, which is then output in the following ways:
•
On the LCD of the electronic unit
•
By means of the desired or ordered outputs of the
AO2000 system (e. g. 4 to 20 mA analog, PROFIBUS®,
Ethernet, etc.).
All output types use the averaged gas concentration. The
amount of averaging is specified by the averaging count (T
× T
).
prim
59
N
av =
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