Fluke PG9000 Series, Руководство по эксплуатации и обслуживанию

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PG9602™ OPERATION AND MAINTENANCE MANUAL
© 2011 Fluke Calibration Page
184
7.2 Defined Pressure Calculations
Sections 7.2.1 and 7.2.2 document the calculations used by PG9000 piston gauges to obtain the defined
pressure.
Table 27 defines the pressure calculation variables used in Sections 7.2.1 and 7.2.2.
Table 27. PG9000 Defined Pressure Calculation Variables
VARIABLE DEFINITION UNITS SOURCE OF VALUE
/
π Α
P
θ
,
Piston radius at temperature
θ
and
pressure P
m Calculated.
A
20,0
Piston effective area at 20°C, P
atm
mm
2
Piston-cylinder module file (3.12.1.3).
A
θ
,P
Piston effective area at temperature
θ
,
pressure P
m
2
Calculated from A
20,0
in piston-cylinder
module file (3.12.1.3).
G Local gravity m/s
2
Local, standard or user as specified in
current SETUP file (3.11, 3.12.6).
K
N
Nominal mass-to-pressure conversion
coefficient for a given piston-cylinder size
Pa/kg Calculated from A
20,0
and standard
conditions.
M Mass load kg Current mass loading instruction (3.6,
3.10.11).
P
A
Absolute pressure Paa Calculated.
P
atm
Atmospheric (ambient) pressure Paa
Internal measurement, user entered value
or standard as specified by SETUP file (3.11).
P
G
Gauge pressure Pa Calculated.
P
HA
Fluid head correction in absolute mode Pa Calculated using device heights and
medium (7.2.2, 3.10.7, 3.12.3).
P
HG
Fluid head correction in gauge mode Pa Calculated using device heights and
medium (7.2.2, 3.10.7, 3.12.3).
P
nom
Nominal pressure Pa
In pressure-to-mass mode
P
nom
=P
req
In mass-to-pressure mode P
nom
=M·K
N
P
offset
Difference between PG9000 and RPM at
the static pressure of differential mode Pa Determined experimentally in PG9000
differential mode operation (see Section
3.10.4.1,
Selecting Differential Mode,
Setting Static Pressure, Finding RPM
Offset (<1run>)
P
RPM
.
Current static pressure reading from
reference pressure monitor Paa Read automatically from external atm P
source specified by SETUP file. Used in
differential mode only (3.11, 3.10.4.1).
∆
P
D
Differential pressure Pa Calculated. Differential mode only
(3.10.4.1).
Γ
Surface tension coefficient N/m Piston-cylinder module file (3.12.1.3).
α
C
Cylinder linear thermal expansion coefficient °C
-1
Piston-cylinder module file (3.12.1.3).
α
P
Piston linear thermal expansion coefficient °C
-1
Piston-cylinder module file (3.12.1.3).
λ
Piston-cylinder pressure coefficient Pa
-1
Piston-cylinder module file (3.12.1.3).
θ
Temperature of piston-cylinder °C
Internal measurement, user entered value
or standard as specified by SETUP file (3.11).
ρ
a
Air density kg/m
3
Calculated from standard air density
corrected for actual atmospheric pressure,
ambient temperature and relative humidity
(atm p, humidity and temp source are
specified by SETUP file) (3.11).
ρ
m
Mass density kg/m
3
Mass set file (3.12.1.8).