58 AO2000-LS25 LASER ANALYZERS | OI/AO2000-LS25-EN REV. D
… 10 Configuration, parameterization
… Description of menus and parameters
Gas pressure and temperature
The strength of the absorption line and line width are pressure
and temperature dependent. This is compensated for by
calculating a correction factor based on deviation of pressure
and temperature from the standard atmosphere (P = 1,013 bar,
T = 23 °C).
For relative concentration units (ppm, %, mg/Nm
3
, g/Nm
3
) the
gas pressure and temperature are in addition directly involved in
calculation of the concentration through the ideal gas law.
Therefore, correct setting of gas pressure and temperature is
important for the accuracy of the measurement.
“Current pressure” and “Current temperature” are the values for
calculating the current state. These values are only downloaded
from the device after an update of parameters or explicitly after
pressing <Reload readings (P, T, date)>.
The gas pressure is always given in bar absolute.
• To convert pressure from Psig to bar absolute, use the
following formula:
P(bara) = 1,013 + P(barg)
• To convert pressure from Psig to bar absolute, use the
following formula:
P(bara) = 1,013 + P(psig)/14,5
The gas temperature is always given in Celsius.
• To convert temperature from Fahrenheit to Celsius, use the
following formula:
T(C) = (T(F) − 32)/1,8
• To convert temperature from Kelvin to Celsius, use the
following formula:
T(C) = T(K) − 273
Pressure and temperature input method
The <Pressure/Temperature input method> specifies whether
the values are fixed or are read using any of the following
methods:
• If method “Current loop” is activated the values are input
from the corresponding current 4 to 20 mA values. In this
case, the parameters “PLC 4 mA” and “SPS 20 mA” must
be specified.
• Method “Internal” sets the gas pressure equal to the
ambient pressure measured by the internal pressure
sensor (Air pressure in “Measurements” menu). The gas
temperature is set equal to the average of the measured
temperatures inside the RU and TU (
TU
and
RU Temp
in
“Measurements” menu), which are offset corrected to be
approximately equal to the ambient temperature.
• Method “Spectral” (only for temperature) sets the gas
temperature equal to the temperature measured
spectroscopically. This method is only applicable for
devices measuring gas temperature like the O
2
+Temperature monitor.
• Method “Serial”: Pressure and temperature input through
RS-232 or Ethernet connector (requires special data
packet, please contact ABB Service).
Figure 40: Menu “Config”, page 2
To Next Page
Loading...
Need help?
General
