Emerson 8800A, Product Manual

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Rosemount Model 8800C Vortex Flowmeter
E-10
For a given input frequency, you may also determine the current
output. Use the prior example with an input frequency of 275 Hz:
URV= 3600 kg/hr LRV= 0 kg/hr F
in
(Hz) = 275
= 10.48 mA
Therefore, an input frequency of 275.00 Hz represents an output
current of 10.48 mA.
Example 3 (SI units)
Fluid = Natural Gas URV = 10,000 NCMH
Line size = 80 mm LRV= 0 NCMH
Line press. = 1000 kPaG C
20
= C
x
/sp. units factor (from Table E-1)
Temp op. = 10 °C Density(
r
) = 9.07754 kg/cu-mtr (oper)
Viscosity = 0.01 cp
K-factor(compensated) = 10.797 (via HART communicator or AMS)
= 700/{10.797 (.0733811/10.48)}
= 9259.2 NCMH
Therefore, an input frequency of 700.00 Hz represents a flow rate of
9259.2 NCMH in this application.
For a given input frequency, you may also determine the current
output. Use the above example at the 8.0 mA point:
URV= 10000 NCMH LRV= 0 NCMH F
in
(Hz) = 375.00
= 11.94 mA
Therefore, an input frequency of 375.00 Hz represents a current output
of 11.94 mA.
I
F Hz
( )
K C
16
™ ‰
LRV –
URV LRV
–
-----------------------------------------------------------
16
( ) ™
Í Ý
Ë Û
4 + =
275 10.715 0.017602
)
0
–
™ ( ‰
3600 0 –
------------------------------------------------------------------------------
16
( ) ™
Í Ý
Ì Ü
Ë Û
4 + =
I
F Hz
( )
K C
20
™ ( ) ‰
LRV
–
URV LRV –
----------------------------------------------------------------
16
( ) ™
Í Ý
Ë Û
4 + =
375 10.797 0.0070020
)
0 –
·
™ ( ‰
10000 0 –
-------------------------------------------------------------------------------
16
( ) ™
Í Ý
Ì Ü
Ë Û
= 4 +