Teledyne GFC 7001EM Pneumatic Operation of the CO2 Sensor, 16 CO2 sensor Theory of Operation

Optional Hardware and Software Model GFC7001E Carbon Dioxide Analyzer

Figure 5-16: CO2 sensor Theory of Operation

The sensor computes the ratio between the reference signal and the measurement signal to determine the degree of light absorbed by CO2 present in the sensor chamber. This dual wavelength method the CO2 measurement allows the instrument to compensate for ancillary effects like sensor aging and contamination.

5.9.2.2.Operation within the GFC 7001E/EM Analyzer

The CO2 sensor option is transparently integrated into the core analyzer operation. All functions can be viewed or accessed through the front panel, just like the functions for CO.

The CO2 concentration is displayed in the upper right-hand corner, alternating with CO concentration.

Test functions for CO2 slope and offset are viewable from the front panel along with the analyzer’s other test functions.

CO2 sensor calibration is performed via the front panel CAL function and is performed in a nearly identical manner as the standard CO calibration. See Section 9.7.2 for more details.

Stability of the CO2 sensor can be viewed via the front panel (see Section 9.7.2.3).

The CO2 concentration range is 0-20%. See Section 9.7.2.1 for information on calibrating the CO2.

5.9.2.3.Pneumatic Operation of the CO2 Sensor

Pneumatically, the CO2 sensor is placed in line with the sample gas line between the particulate filter and the analyzer’s sample chamber. It does not alter the gas flow rate of the sample through the analyzer.

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