MANUAL
FOR
HART/FIELD
DEVICES
PRESSURE
FLOW
AND
LEVEL
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WIRING DIAGRAM
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PRESSURE TRANSMITER:-
When pressure, force or acceleration is applied to a
quartz crystal, a charge is
Developed across the crystal that is proportional to
the force applied.
The fundamental difference between these crystal
sensors and static-force devices
Such as strain gages is that the electric signal
generated by the crystal decays
Rapidly. This characteristic makes these sensors
unsuitable for the measurement of
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Static forces or pressures but useful for dynamic
measurements.
Piezoelectric devices can further be classified
according to whether the
Crystal’s electrostatic charge, its resistivity, or its
resonant frequency electrostatic
Charge is measured. Depending on which
phenomenon is used, the crystal sensor
Can be called electrostatic, piezoresistive, or
resonant.
When pressure is applied to a crystal, it is elastically
deformed. This deformation
Results in a flow of electric charge (which lasts for a
period of a few seconds). The
Resulting electric signal can be measured as an
indication of the pressure which was
Applied to the crystal. These sensors cannot detect
static pressures, but are used to
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Measure rapidly changing pressures resulting from
blasts, explosions, pressure
Pulsations (in rocket motors, engines, compressors)
or other sources of shock or
vibration. Some of these rugged sensors can detect
pressure events having "rise
times" on the order of a millionth of a second, and
are described in more detail later
in this chapter.
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Flow Transmitter
The Diff.Pressure transmitter shall be a combination
of DP transmitter and screw piston type pressure
pump in one unit. The DP transmitter shall take 0 -
500 mmWC as input and in turn shall provide output
in the range of 4 – 20mA.One Digital Indicator
display 4 to 20mA and second digital indictor
display 0 – 500 mmWc.
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The Diff. Pressure trainer consists of DP transmitter
and screw piston type pressure pump. Output of the
screw pump given as an input to the DP transmitter.
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Ultrasonic level Transmitter
The ultrasonic level Indicator is a low-cost,
noncontact and easy-to-install measurement
device. It is able to meet the every-day needs of
commercial production, as well serving a more
specialized role in the technologically-advanced
aero-space industry, thus placing it firmly in the
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category of high-level measurement
technology. Unlike other level indicators with
limited uses, the easy-to-install ultrasonic level
indicator is a highly-accurate device with
enough specialized uses to ensure that the
needs of the customer are met.
A noninvasive ultrasonic liquid level indicator for
indicating the level of a liquid in a reservoir is
disclosed which comprises an ultrasonic
transducer assembly, structures for holding the
transducer assembly in a dry coupled
attachment with the reservoir at selectable
locations against an exterior surface of the
reservoir, and a monitor for revealing a change
in liquid height. The transducer assembly
conveys signals regarding changes in liquid
height to a monitor which warns the user in time
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to add more liquid or replace the reservoir
before the liquid supply "runs dry." The
manners for holding the assembly in place
include, but are not limited to, a strap, a clamp,
or adhesive material, such as tape. These allow
the user to selectively place the transducer
assembly along the reservoir at the desired
triggering point.
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OPERATING PROCEDURE:
Before connecting any transmitter please switch
OFF mains power supply.
Now First of all connect banana pin to positive
terminal of + 24 VDC power supply to and +
terminal of pressure transmitter. Then connect -
terminal of pressure transmitter to + terminal of
current output indicator exactly given above
pressure transmitter. Now connect - terminal of
current output indicator to - terminal of 24 VDC
power supply. Now switch ON mains power
supply. Now we can see the output current
reading of transmitter on current indicator.
By repeating same procedure given above we
can connect flow transmitter and level
transmitter.
For your reference we have done for one.
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