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General
Description |
The DML2000 is a
sophisticated, state-of-the-art locator that is highly reliable and
user-friendly. It
weighs
just 1.6 pounds but is built rugged enough to operate under the most
demanding field conditions. Four alkaline AA batteries provide up to 100
hours of operation.There are only two controls so it does not take long to become efficient using the locator.
Turn the
Volume Control clockwise to activate the instrument and to select a volume
setting that gives you a comfortable signal level, the Sensitivity switch
should be set to 3 (nominal setting).
When power is applied and
there are no iron or steel objects in the immediate vicinity of the
locator, you will hear a steady 20 Hz tone. As you walk the
search pattern, slowly sweep the locator back and forth. The audio signal
will remain constant until you begin to approach a target. The pitch
(frequency) of the audio tone increases and peaks when the locator's tip
is positioned directly over a target.
You'll never have to be
concerned about replacing batteries in the middle of a search operation.
The Low-Battery LED indicator begins flashing when the remaining life of
the batteries reaches 20 to 25 hours.
The separate Power/Volume
and Sensitivity controls allow the operator to leave the instrument on a
preferred sensitivity setting when the instrument is deactivated. Later
when operation is resumed the Sensitivity control will be unchanged.
The DML2000
is so sensitive that an operator's watch, steel
arch supports/toe protectors or a pocket knife can cause
magnetic interference and must be avoided while locating targets.
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Searching |
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Low Battery Indicator |
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Field Operation
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Good instrument performance goes
hand-in-hand with proper operation:
When searching for survey benchmarks or underground ferrous targets,
the magnetic locator should be held in the vertical or near vertical
position. In this position the instrument audio output is
facing the operator and the controls are readily accessible. The
picture to the left of this page shows how to hold the instrument for
optimum operation.
To pinpoint your target, rotate the
instrument to the vertical and use and "X" or crossing
pattern. The audio output will peak directly over your target.
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All Weather Operation
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The sensor
housing is waterproof and the electronics water-resistant.
Moreover, the circuit design and component selection ensures proper
operation whether the ambient temperature is -20oF or 120oF.
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Unparalleled
Reliability
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For added strength and reliability, the electronics package is made of
impact resistant ABS plastic, while the sensor tube and base plate are
made of
6061-T6
aluminum, welded together. Moreover, the two sensing elements are
shock-mounted on there own individual support tube, inside the yellow
sensor tube. This added sensor isolation guarantees that the
sensor alignment and overall instrument performance will withstand
normal physical abuse and harsh weather conditions. In addition, all
electronic components have been carefully selected for long life and
harsh environment operation.
With
normal handling, this combination of quality electronic components,
shock-mounted sensors, and robust package design, should ensure a
lifetime of maintenance free operation from your DML2000 magnetic
locator.
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Theory of Operation |
All magnetic locators
operate on the same basic principle; two fluxgate magnetometer
sensors, securely
mounted inside a rigid sensor support tube, measure the local magnetic
field.
The
two-magnetometer sensors are vector sensors, mounted 20” apart
and each measures
the average magnetic field component along
their sensitive axis, i.e. the magnetic field component along the
longitudinal axis of the sensor tube.
For a magnetic locator to work
properly, the magnetometer sensors are aligned opposing so that the
magnetic field measured by one sensor is the negative of the
magnetic field measured by the other. The locator then sums the
output of the two sensors. By summing the two output signals, you
cancel any field common to both sensors, such as the Earth’s
Magnetic Field, and leave only the differential magnetic field.
The differential
magnetic field, the magnetic field detected by one sensor and not
the other, is the magnetic field of interest and hopefully
represents the magnetic field of your target and not the field of
your pocketknife, watch or the steel arch support in your shoes. The
drawing on the left shows the construction of a typical magnetic
locator and the location of the two sensing elements
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