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5.5.3
DRIVER BOARD
The driver board is controlled by the mini micro board (see Section 5.5.1). It supports:
•
12 V drivers for internal solenoid valve actuation
•
Frequency counters (2) for reading Q-RPTs (see Section 5.5.5)
•
On-board barometer power and output (see Section 5.5.4)
•
Power to the system cooling fan
•
Remote [ENT]
•
Keypad and display
•
Beeper
5.5.4
ON-BOARD BAROMETER
The on-board barometer supports a board mounted, barometric range, micro machined silicon
sensor and an ambient temperature sensor. The barometer readings are used for dynamic
atmospheric pressure compensation when measuring gauge pressure (see Section 3.2.2). The
temperature sensor is used for temperature compensation of the barometric sensor.
5.5.5
Q-RPT MODULE
The Q-RPT module is an integrated Quartz Reference Pressure Transducer (Q-RPT) assembly.
The module includes a Q-RPT, brackets to hold the transducer, interconnecting tubing.
RPM4-AD models use a single interconnection manifold for the two Q-RPT modules. The
manifold includes the TEST(Ps), TEST(Pt), VENT ATM ports.
System) and Hi Q-RPT/Lo Q-RPT bypass solenoid valves are mounted on the manifold.
A Q-RPT provides very high precision, low uncertainty pressure measurement. The basic
sensing principle is the measurement of the change in the natural oscillating frequency of a
quartz tuning fork in response to changes in temperature and mechanical stress resulting from
the change in pressure applied to a connecting bellows or bourdon tube. Two independent
quartz elements are used. One quartz element is subjected to pressure related stress. The
other quartz element is used only to monitor temperature. See Section 1.2.2.1 for Q-RPT
specifications.
See Section 5.6 for pneumatic schematics Q-RPT module configuration and valve states.
5.5.5.1
HI Q-RPT MODULE
RPM4-AD is always equipped with a Hi Q-RPT module.
A160K/A160K (rotary wing), the Hi Q-RPT is designated A160K and has a range
of 160 kPa absolute (23 psi). In RPM4-AD A350K/A160K (fixed wing) the Hi
Q-RPT is designated A350K and has a range of 350 kPa absolute (51 psi).
5.5.5.2
LO Q-RPT MODULE
RPM4-AD is always equipped with a Lo Q-RPT module. In both RPM4-AD
A160K/A160K (rotary wing) and RPM4-AD A350K/A160K (fixed wing) the Lo Q-
RPT is designated A160K and has a range of 160 kPa absolute (23 psi).
5.5.6
DISPLAY
2 x 20 character vacuum fluorescent display.
5. MAINTENANCE, ADJUSTMENTS AND CALIBRATIONS
Page 125
© 2005-2007 DH Instruments, a Fluke Company
The SDS (Self Defense
In RPM4-AD
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