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Performance Optimisation 3098 Technical Manual
A-6
SUMMARY
This appendix describes the major systematic errors of the 3098 meters and methods of minimising their effects by correct
selection of the reference chamber pressure and calibration procedure to be used. Whether calibration is performed using
truly representative calibration gases or whether pure gases such as methane and nitrogen are used will, to some extent,
depend upon the availability of each of those gases. If using pure gases for calibration, the method and example clearly
show how better accuracy can be achieved on the sample gases by using modified values of base density for the
calibration gases. These modified values are as determined from Table A1 Column 15 (
؞
s
ind
) and the resultant errors
are as shown in Column 14.
An alternative method of deriving the modified values of base density has been included in the calculations for Table A2.
Its results compares favourably with the tabulated result in Column 15 but is not as informative in error identification as
Table A2.