DH Instruments PPC2+, Manual

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PPC2+™ Operation and Maintenance Manual
©2001 DH Instruments, Inc.
Page 152
7 . 3 U N I T C O N V E R S I O N
7.3.1 PRESSURE
PPC2+ 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 22 provides the conversion coefficients used by PPC2+ to convert numerical values
expressed in SI units to corresponding values expressed in other units.
Table 22. Conversion Coefficients
TO CONVERT FROM Pa To MULTIPLY BY
Pa Pascal 1.0
mbar millibar 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
user user User defined coefficient
ft feet of altitude see Altitude Note below
m meter of altitude see Altitude Note below
Altitude Note: 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. PPC2+ 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 22
above. For altitude expressed in meters,
meters are converted to feet using 1 m = 3.28084 ft.