8 Metrological Features
141
instead of "calculated" to "Constant value". The range of the constant entered is not limited.
Fig. 68 Setting the constant compressibility value for calculating C (SW Compass)
8.4 Volumes Measurement and Calculation
To measure and calculate volumes, the following counters are used for each channel in the
device:
Volume counter under the measurement conditions (primary volume)
Corrected volume under the measurement conditions (volume corrected
based on the correction profile of the meter)
Operating volume counter at error conditions (substitute primary
volume)
Volume counter at base conditions
Base volume counter at error conditions
8.4.1 Calculation of conversion number C for volume conversion
As stated in paragraph 7.9.1, the following relation applies to the calculation of volume under
basic conditions:
V
b
= V * C
The following applies to the conversion number:
The conversion number C depends on the degree of compressibility of the gas K, the reference
conditions (pb, Tb), the gas pressure p and the gas temperature t.