Fluke RPM4-AD, Руководство по эксплуатации и обслуживанию

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RPM4-AD™ OPERATION AND MAINTENANCE MANUAL
© 2005-2007 DH Instruments, a Fluke Company Page 134
7.2 UNIT CONVERSION
7.2.1 PRESSURE
RPM4-AD performs all internal calculations in SI units. Numerical values input or output in
other units are converted to SI immediately after entry and back to other units just before
output as needed.
Table 33 provides the conversion coefficients used by RPM4-AD to convert numerical values
expressed in SI units to corresponding values expressed in other units.
Table 33. Pressure unit of measure conversion coefficients
TO CONVERT FROM Pa To MULTIPLY BY
Pa Pascal 1.0
mbar millibar 1.0 E-02
hPa ector Pascal 1.0 E-02
kPa kilo Pascal 1.0 E-03
bar Bar 1.0 E-05
mmWa @ 4°C millimeter of water 1.019716 E-01
mmHg @ 0°C millimeter of mercury 7.50063 E-03
psi pound per square inch 1.450377 E-04
psf pound per square foot 1.007206 E-06
inWa @ 4°C inch of water 4.014649 E-03
inWa @ 20°C inch of water 4.021732 E-03
inWa @ 60°F inch of water 4.018429 E-03
inHg @ 0°C inch of mercury 2.953 E-04
kcm
2
kilogram force per centimeter square 1.019716 E-05
mTorr milliTorr (micron of mercury 7.50063
Torr Torr (millimeter of mercury) 7.50063 E-3
user User User defined coefficient
ft feet of altitude see Section 7.2.2
m meter of altitude see Section 7.2.2
kts knots see Section 7.2.3
km/h kilometers per hour see Section 7.2.3
mph miles per hour see Section 7.2.3
mach mach number see Section 7.2.3
7.2.2 ALTITUDE
Quantities expressed in units of altitude follow MIL-STD-859A
“Static Pressure, p, in Inches of Mercury for Values of Pressure Altitude, H,
in Geopotential Feet.” MIL-STD-859A provides tables of pressure in inches of mercury as a
function of altitude in feet. RPM4-AD uses a set of equations to model the pressure/altitude
relationship. The worst case deviation between the MIL-STD-859A table and the calculated
pressure is 0.0001 inches of mercury (0.3 Pa). The pressure quantity expressed in inches of
mercury is converted to Pascal following Table 33 above. For altitude expressed in meters,
meters are converted to feet using 1 m = 3.28084 ft.
The following formulas are used to convert altitude in ft (H) into pressure (P) in inHg and from
pressure to altitude. There are three different equations depending on the range.