Division 2.6.2: Calculation procedure - Commission Delegated Regulation (EU) 2017/654 of 19 December 2016 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery

The drift correction shall be calculated by means of equation (7-76):

c_{i driftcor} = c_{refzero} + (c_{refspan} - c_{refzero}) \frac{2 c_{i} - (c_{prezero} + c_{postzero})}{(c_{prespan} + c_{postspan}) - (c_{prezero} + c_{postzero})}

(7-76)

Where:

c_i _driftcor

concentration corrected for drift [ppm]

c _refzero

reference concentration of the zero gas, which is usually zero unless known to be otherwise [ppm]

c _refspan

reference concentration of the span gas [ppm]

c _prespan

pre-test interval gas analyzer response to the span gas concentration [ppm]

c _postspan

post-test interval gas analyzer response to the span gas concentration [ppm]

c_i or

\bar{c}

concentration recorded, i.e. measured, during test, before drift correction [ppm]

c _prezero

pre-test interval gas analyzer response to the zero gas concentration [ppm]

c _postzero

post-test interval gas analyzer response to the zero gas concentration [ppm]

Division 2.6.2 Calculation procedure