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3. OPERATION
To measure airspeed and altitude using this mode, use [RANGE] (see Section
3.3.1.1) to select the <Hi> Q-RPT or the <airspeed & altitude> shortcut. If the
shortcut is not used, once the Q-RPT has been selected, use [MODE] (see
Section 3.3.3) to set absolute and differential measurement mode and [UNIT]
(see Section 3.3.2) to set the desired airspeed unit. Use [DISPLAY], <4RPT> to
change the altitude unit if desired.
The two Q-RPTs measuring absolute pressure in parallel: Altitude only,
with lowest uncertainty
TM
In parallel mode (//m
), the two Q-RPTs are connected together internally, the
TEST (Ps) port is opened and the TEST (Pt) port is closed using the SDS
valves.
RPM4 measures the absolute pressure applied to the TEST (Ps) port with both
Q-RPTs and averages the two (see Section 3.2.5). The absolute pressure is
converted to altitude (see Section 7.2.2).
To measure altitude using this mode, use [RANGE] (see Section 3.3.1) to select
the <HL> Q-RPT or the <altitude, parallel> shortcut. If the shortcut is not used,
once the Q-RPT has been selected, use [MODE] (see Section 3.3.3) to set
absolute measurement mode and [UNIT] (see Section 3.3.2) to set the desired
altitude unit.
The two Q-RPTs measuring gauge pressure in parallel: Airspeed at ground
altitude only
In parallel mode, the two Q-RPTs are connected together internally, the TEST
(Pt) port is opened and the TEST (Ps) port is closed using the SDS valves.
RPM4 measures the gauge pressure applied to the TEST (Pt) port with both Q-
RPTs and averages the two (see Section 3.2.5). Since the gauge pressure is the
difference from atmospheric pressure, it directly provides the differential pressure
used to calculate airspeed. The value of static pressure, Ps, is the current value
of atmospheric pressure. The gauge pressure is converted to airspeed (see
Section 7.2.3).
The value of ground altitude corresponding to ambient
atmospheric pressure can also be displayed. If a true airspeed unit of measure
has been selected, altitude and entered temperature are also used in the
airspeed calculation.
To measure airspeed using this mode, use [RANGE] (see Section 3.3.1.1) to
select the <HL> Q-RPT or the <airspeed, parallel> shortcut. If the shortcut is
not used, once the Q-RPT has been selected, use [MODE] (see Section 3.3.3) to
set gauge measurement mode and [UNIT] (see Section 3.3.2) to set the desired
airspeed unit.
3.2.3.2
RPM4-AD A350K/A160K (FIXED WING)
RPM4-AD A350K/A160K has two Q-RPTs. A 350 kPa absolute Q-RPTs is in the
HIGH RPT (Pt) position and a 160 kPa absolute is in the LOW RPT (Ps) position.
Air data measurements are normally made in the following conditions:
The two Q-RPTs are separated internally. One is connected to the TEST (Ps)
port and the other is connected to the TEST (Pt) port.
RPM4 measures the absolute pressures applied to the TEST (Ps) and TEST (Pt)
ports. The absolute pressure measured on the TEST (Ps) port is converted to
altitude. The difference between the TEST (Pt) and TEST (Ps) pressure (Pt –
Ps) is converted to airspeed (see Section 7.2.3).
If a true airspeed unit of
measure has been selected, altitude and entered temperature are also used in
the airspeed calculation.
Page 19
© 2005-2007 DH Instruments, a Fluke Company
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