Teledyne Model Vehicle T400 User Manual

an Internal Zero Span (IZS) or an external zero air scrubber option, it is capable of 
creating zero air. For analyzers without an IZS or external zero air scrubber option, an 
external zero air generator such as the Teledyne API Model 701 can be used 

Calibration gas is a gas specifically mixed to match the chemical composition of the 
type of gas being measured at near full scale of the desired reporting range.  Because 
ozone (O

3

) quickly breaks down into molecular oxygen (O

2

), this calibration gas cannot 

be supplied in precisely calibrated bottles like other gases.   

  If the T400 analyzer is not equipped with the optional internal zero air generator 

(IZS), an external O

3

 generator capable supplying accurate O

3

 calibration mixtures 

must be used.   

  Also, some applications, such as EPA monitoring, require multipoint calibration 

checks where Span gas of several different concentrations is needed.  

  In either case, we recommend using a Gas Dilution Calibrator such as a TAPI 

Model T700 with internal photometer option. 

In the case of O

3

 measurements made with the Model T400 photometric ozone analyzer, 

it is recommended that you use a span gas with an O

3

 concentration equal to 90% of the 

reporting range for your application. 

EXAMPLE:   

  If the application is to measure between 0 ppm and 500 ppb, an appropriate 

span gas would be 450 ppb.  

  If the application is to measure between 0 ppb and 1000 ppb, an appropriate 

span gas would be 800 ppb.  

 

 

06870C DCN6332