Emerson 8800A, Руководство по эксплуатации продукта

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Rosemount Model 8800C Vortex Flowmeter
E-4
Calculating Output
Variables with Known
Input Frequency
Use the following equations with a known input frequency for
verification of a flow rate or 4–20 mA output within a given
calibrated range. Select the proper equation depending on if
you are verifying a flow rate, mass flow rate, 4–20 mA output, or
special units. Example calculations starting on page E-6 may
clarify how these equations are used.
To Verify a Flow Rate
For a given frequency F (Hz), and K-factor (compensated), find the
flow rate Q:
where C
x
is the unit conversion (Table E-1).
To Verify a Standard or Normal Flow Rate
To Verify a Mass Flow Rate
For a given mass frequency F (Hz), and K-factor (compensated), find
the mass flow rate M:
where C is the unit conversion and
r
is density at operating conditions:
where C
x
is the unit conversion using density (
r
) (Table E-1).
To Verify a 4–20 mA Output
For a given input frequency F (Hz), and K-factor (compensated), find
output current I:
where C
x
is the unit conversion (Table E-1), URV is the upper range
value (user units), and LRV is the lower range value (user units).
To Verify a Special Units Output
For special units, first divide the special unit-conversion factor into the
base unit factor C
x
.
C
20
= C
x
/sp. units conv. factor (Table E-1).
Q F Hz
( )
K C
™
x
( ) ‰
=
Q F Hz
( )
DensityRatio
( )
(
™
K C
™
x
( ) ‰
)
=
M
F
K
r ) ‰ (
C
¼
------------------------- =
M F Hz
( )
KCx
( ) ‰
=
I
F Hz
( )
K Cx
™ ‰ )
LRV –
(
URV LRV –
--------------------------------------------------------------
16
( )
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