Campbell IRGASON, Product Manual, Page: 27 / 91

7.11.3 Fixed pressure value
If Pressure Sensor is None, the EC100 will use the value of this setting for the barometric pressure.
This mode is intended for troubleshooting only. In normal operation, this setting is not used.
7.12 Pressure differential enable
This setting should remain disabled. It is used only for closed-path analyzers.
7.13 Heater control
An advantage of the IRGASON’s low power consumption (5 W) is that the instrument remains at
a temperature very close to ambient air temperature, which is an important feature for eddy-
covariance measurements. Under some environmental conditions, however, the analyzer can
become colder than ambient air temperature which may increase the likelihood of frost or
condensation building on the optical windows. This will affect signal strength. The IRGASON
design includes internal heaters located at the optical windows, which aid in minimizing data loss
during these specific environmental conditions.
An automatic heater control algorithm can be activated from either Device Configuration Utility
or ECMon by putting in a value of –2, or deactivated by putting in a value of –1.
NOTE:
Automatic heater control is available in EC100 OS version 4.07 or greater and is turned on by
default starting with the OPEC program version 3.2.
The algorithm uses the internal heaters to maintain a temperature that is a couple of degrees
above the ambient dewpoint (or frost point) to prevent condensation and icing from forming on
the surface of the optical windows.
The heater control will be disabled under any of the following conditions:
l
Temperature of the detector housing is outside the –35 to 55 °C range
l
Temperature of the source housing exceeds 40 °C
l
Ambient temperature is outside the –35 to 55 °C range
l
The supply voltage is below 10 V
The algorithm uses the following environmental parameters to control the heater:
l
Analyzer body temperature, measured inside the source housing (heater control does not
allow the body temperature to drop below ambient air temperature)
IRGASON® Integrated CO
2
/H
2
O Open-Path Gas Analyzer and 3D Sonic Anemometer 23