YOKOGAWA VY Series - Page 20

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19
IM 01F07A01-02EN
(2) Flowrateunitconversioncoe󰀩cient(Uk)
The ow rate conversion coe󰀩cient Uk is calculated according to the measured uid and
the selected ow rate unit, as indicated below.
a) Steam
For M (mass):
U
k
= ρ
f
×U
ρf
×U
k
(kg)
For Q
f
(ow rate):
U
k
= U
k
(m
3
)
b) Gas
For Q
n
(ow rate):
U
k
= {P
f
/ P
n
}×{(T
n
+273.15) / (T
f
+273.15)}×1 / K×U
k
(Nm
3
)
For M (mass):
U
k
= ρ
f
×U
ρf
×U
k
(kg)
For Q
f
(ow rate):
U
k
= U
k
(m
3
)
[Flow rate unit] N: Normal conditions
c) Liquid
For Q
f
(ow rate):
U
k
= U
k
(m
3
)
For M (mass):
U
k
= ρ
f
×U
ρf
×U
k
(kg)
d)Foruser-speciedunits
U
k
= U
k
(User)
(3) Massowratecalculation(forinstrumentswithbuilt-intemperaturesensorand
analog input)
a) Steam
In the case of saturated steam, calculate the mass ow rate by using the built-in saturated
steam table to determine the density based on the measured temperature value.
In the case of superheated steam, calculate the mass ow rate by using the built-in steam
table to determine the density based on the measured temperature value. For the pressure,
use the xed value input in the parameters or the analog input value from an external
pressure gauge.
M = ρ
ft
×Q
f