DH Instruments E-DWT-10000-AF, Руководство по эксплуатации и обслуживанию

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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATIONS
Page 105 © 2008 DH Instruments, a Fluke Company
5.5.5.1 MICRO BOARD
The micro board supports a Motorola 68302 micro-controller, EPROM,
EEPROM, 128k x 16 bit NVRAM, 8 Mbit flash memory; RS-232 and IEEE-488.2
communications; keypad and display control. An I/O port controls other ports
and devices in RPM4-E-DWT.
5.5.5.2 DRIVER BOARD
The driver board is controlled by the micro board (see Section 5.5.5.1). It
supports:
•
Frequency counters (2) for reading Q-RPTs (see Section 5.5.5.4)
•
On-board barometer power and output (see Section 5.5.5.3)
•
Power to the system cooling fan
•
Remote [ENT]
•
Keypad and display
•
Beeper
5.5.5.3 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 with an absolute quartz reference pressure
transducer (see Section 3.9.1). The temperature sensor is used for temperature
compensation of the barometric sensor.
5.5.5.4 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 and a manifold with
TEST(+) and ATM ports.
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 1.2.3.1 for Q-RPT
specifications.
See Section 5.5.6, Figure 15 for a pneumatic schematic of the Q-RPT module
configuration.
HI Q-RPT MODULE
The RPM4-E-DWT A70M/A7M-AF Hi Q-RPT is an A70M. The A70M has a
pressure range of atmosphere to 10 000 psi (70 MPa) gauge.
LO Q-RPT MODULE
The RPM4-E-DWT A70M/A7M-AF Lo Q-RPT is an A7M. The A7M has a
pressure range of atmosphere to 1 000 psi (7 MPa) gauge.