KROHNE CORIMASS MFC 85 EN - Manual (Page 15)

15
Beginning from measuring mode:
Key Line 1 Line 2 Comments
→↑↑
Fct. (3).0 INSTALL
→↑
x9 Fct. 3.(10).0 CONC. MEAS.
→
Fct. 3.10.(1) SOLUTE R20
→
+4.0000000 (g)/cm
3
Use
↑
to select mass units.
↑
+4.0000000 (kg)/cm
3
→
+4.0000000 kg/(cm
3
) Use
↑
to select volume units.
↑
x3 +4.0000000 kg/(m
3
) Units set here must match
those used in calculations
→
+(4).0000000 kg/m
3
Enter the calculated value
↑↑
+(6).0000000 kg/m
3
→
+6(.)0000000 kg/m 3
↑↑
+600(.)00000 kg/m
3
→↑
x5 +600.(5)0000 kg/m
3
→
x8 +6(0)0.50000 kg/m
3
↑
x4 +6(4)0.50000 kg/m
3
→↑
x8 +64(8).50000 kg/m
3
↵↑
Fct. 3.10.(2) SOLUTE K1
→
(+)0.0000000 /°C Enter K1 as calculated
↑
(-)0.0000000 /°C
→→→↑
-0.(1)000000 /°C
→↑
x3 -0.1(3)000000 /°C
→↑
x5 -0.13(5)0000 /°C
↵↑
Fct. 3.10.(3) SOLUTE K2 Enter K2 as calculated
→
(+)0.0000000 /°C2
→
x5 +0.00(0)0000 /°C2
↑
+0.00(1)0000 /°C2
→↑
x5 +0.001(5)000 /°C2
↵↑
Fct. 3.10.(4) LIQUID
→
(NON WATER) Select the carrier as water.
↑
(WATER)
↵
Fct. 3.10.(4) LIQUID
↵
x4 Save changes and return to
measurements.
5. Practical Considerations when using Concentration Measurements
5.1 Accuracy of Concentration Estimation
The results of the concentration estimation depend on the accuracy of the density
measurements and on the “fit” of the algorithm used to infer the concentration value. Of the
two factors the density measurement itself is obviously the most critical. In order to assess
the effect of inaccuracies in the density measurement it is necessary to consider the amount
density will change over a given range of interest..
For instance, it is required to measure concentrations in the range 5 to 10% by mass. Over
this range density varies from 1.018 to 1.038 g/cm
3
, a change of 0.020 g/cm
3
. If the density
accuracy of the flow meter is
±
0.002g/cm
3
, then , assuming that the variation of density with
concentration is linear, the approximate accuracy of the measurement will be:
± Ч ± Ч = ±
Change in Concentration
Change in Density
Density Accuracy =
5
0 02
0 002 0 5
.
. .