DH Instruments E-DWT-H, Руководство по эксплуатации и обслуживанию

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E-DWT-H OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company Page 106
5.4.4.3 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.
5.4.4.4 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 5.4.5, Figure 16 for a pneumatic schematic of the Q-RPT module
configuration.
HI Q-RPT MODULE
The RPM4-E-DWT Hi Q-RPT may be any range from A7M to A200M (see Section
1.2.3, Table 1), providing a maximum pressure of up to 200 MPa (30 000 psi).
LO Q-RPT MODULE
The Lo Q-RPT module is optional. If included, it may be any range from A7M to
A40 M. (see Section 1.2.3, Table 1), providing a maximum pressure of up to 40
MPa (6 000 psi).
5.4.4.5 Display
2 x 20 character vacuum fluorescent display.
5.4.4.6 Cooling Fan
The cooling fan is mounted on the RPM4-E-DWT rear panel and connected to
the main board. It is a 12V brushless DC fan.
5.4.5 Hydraulic Schematic of Q-RPT Module
Figure 16. Hydraulic schematic RPM4-E-DWT Q-RPT Module