Teledyne T100 Manuale Utente

195 

Under the best conditions, the accuracy off the SO

2

 effusion rate of the IZS option’s 

permeation tube is about ±5%. This can be subject to significant amounts of drift as the 
tube ages and the amount of SO

2

 contained in the tube is depleted.  Whereas this may be 

sufficient for informal calibration checks, it is not adequate for formal calibrations and is 
not approved for use by the US EPA as a calibration source.  

Therefore, for formal calibrations of an instrument with an IZS option installed the 
following provisions must be followed. 

  Zero air and span gas must be supplied to the analyzer through the sample gas inlet 

as depicted in Figure 9-1 of Section 9.2. 

  The calibration procedure must be initiated using the CAL button, not the CALZ or 

CALS buttons, using the procedure defined in Section 9.2. 

  Using the CAL button does not activate the zero/span or sample/cal valves of the 

IZS option, thus allowing the introduction of zero air and sample gas through the 
sample port from more accurate, external sources such as a calibrated bottle of SO

2

 

or a Model T700 Dilution Calibrator. 

SAMPLE           RANGE = 500.000 PPB          SO2 =XXX.X   

 
< TST  TST >   

CAL     CALZ     CALS  

        

SETUP

 

Use for formal 

calibration 

operations. 

Use only for 

informal calibration 

checks. 

 

 

Zero and span checks using the zero/span valve or IZS option are similar to that 
described in Section 9.3, with the following exceptions: 

  On units with an IZS option installed, zero air and span gas are supplied to the 

analyzer through the zero gas inlet and from ambient air. 

  On units with a zero/span valve option installed, zero air and span gas are supplied 

to the analyzer through the zero gas and span gas inlets from two different sources. 

  The zero and calibration operations are initiated directly and independently with 

dedicated buttons CALZ and CALS. 

06807C DCN6650