Endress+Hauser Proline Promag 51, Руководство по эксплуатации

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6 Commissioning Proline Promag 51
74 Hauser
6.1.4 Definitions
Cold water
Fluid temperature between 0...+30 °C
Flow ranges
F06-x1xxxxxx-05-xx-xx-xx-000
Fig. 42: Flow ranges and error limits in custody transfer mode for cold water
1 = Lower range (error limit: ±5%)
2 = Upper range (error limit: ±2%)
Metrological classes
Metrological classes A / B indicate the range in which the approved custody transfer flowmeter
can measure, from full scale value (Q
max
) down to Q
min
. The error limits within this range are set
by the standards authorities and must not be exceeded.
Q
max
Maximum flow of the flowmeter without exceeding the maximum permissible error.
Q
n
Nominal flow rate is half the value of the maximum flow rate Q
max
and characterises
the flowmeter (see Page 23).
Q
min
Minimum flow rate above which the totalizer is within the error limits.
It is dependent on the nominal flow rate (Q
n
) and the metrological class.
Q
t
“Transitional flow rate”, which separates the lower from the upper maximum
permissible range. Lower or upper range differ from each other by the permitted
error limits for custody transfer measurements (Fig. 42):
• Lower range (Q
min
...Q
t
)
→
Error limits: ±5%
• Upper range (Q
t
...Q
max
)
→
Error limits: ±2%
Nominal flow rate Qn
< 15 m
3
/h
≥
15 m
3
/h
Class A
Qmin = Qn x 0.04
Qt = Qn x 0.10
Qmin = Qn x 0.08
Qt = Qn x 0.30
Calss B
Qmin = Qn x 0.02
Qt = Qn x 0.08
Qmin = Qn x 0.03
Qt = Qn x 0.20
Qmin Qmax Qt
±5
%
Q [m /h]
3
±2
0
Qn
1 2