Error Stipulated by the Reference Pressure Instability

The contribution of the reference oxygen partial pressure Po2(l) into the results of measurement can vary and usually depends on the RE type. If an air RE is used (ambient air), the oxygen concentration C, in relation to the normal conditions (Cn, = 20.8%), can change from 20.3% to 20.9%. Consequently, the error of measurement (5Po2(II))po2(d stipulated by this component can be approximately -3%. However, the exchange chambers can be used for reducing the component of error of measurement stipulated by the reference air. Then, (8Po2(II))p ,2(d can be reduced down to 0.6-1.0%. 

Both components decrease with the temperature growth. As a consequence of this, the summary error contributed by this component changes from 7.0% at 500°C to 4.2% at 1000°C at the deviation of the temperature of the RE on 0.5°C. 

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