Teledyne T100 Manuale Utente

The CO

2

 sensor probe measures the concentration of carbon dioxde in the sample gas; a 

Logic PCA conditions the probe output and issues a 0-5 VDC signal to the analyzer’s 
CPU, which computes the CO

2

 concentration by scaling the values of the CO

2

_SLOPE 

and CO

2

_OFFSET recorded during calibration  

The CO

2

 sensor assembly itself does not have any serviceable parts and is enclosed in an 

insulated canister. 

The optional CO

2

 sensor is a silicon based Non-Dispersive Infrared (NDIR) sensor.  It 

uses a single-beam, dual wavelength measurement method. 

An infrared source at one end of the measurement chamber emits IR radiation into the 
sensor’s measurement chamber where light at the 4.3 μm wavelength is partially 
absorbed by any CO

2

 present.  A special light filter called a Fabry-Perot Interferometer 

(FPI) is electronically tuned so that only light at the absorption wavelength of CO

2

 is 

allowed to pass and be detected by the sensor’s IR detector. 

A reference measurement is made by electronically shifting the filter band pass 
wavelength so that no IR at the CO

2

 absorption wavelength is let through.   

 

The sensor computes the ratio between the reference signal and the measurement signal 
to determine the degree of light absorbed by CO

2

 present in the sensor chamber.  This 

dual wavelength method the CO

2

 measurement allows the instrument to compensate for 

ancillary effects like sensor aging and contamination. 

06807C DCN6650