Radiodetection rd7000+, Руководство по эксплуатации

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© 2014 Radiodetection Ltd 21
Section 6 - Depth and current readings
6.1
TruDepth™
The locator provides automatic depth of
buried conductors, sondes and RF utility markers when
the locator is correctly orientated above the target line
sonde or in close proximity of the RF marker.
Current readings can also be displayed by holding down
the antenna key until the letter ‘A’ is displayed. The
depth reading will now be replaced with the current
reading. To switch back to the depth reading, hold
down the antenna key until the letter ‘M’ is displayed
(feature not available in sonde, RF utility markers or
passive frequency modes).
Depth range and accuracy varies depending on the type
of target (cable, sonde, or RF marker), its depth and by
external environmental factors like electromagnetic
noise or interferences.
WARNING: The accuracy of depth measurement is
subject to a number of factors and is meant as a guide
only. Exercise caution when performing any excavation.
Refer to appendix 12 for further information about
depth range and accuracy.
The depth measurement is to the center of the pipe,
cable, sonde or RF marker. The best readings are
typically detected from signals outputted by a
transmitter rather than from passive sources.
The marker locator is capable of determining
cable depth when locating passive power signals.
However passive signals on lines are less suited for
measuring depth because accuracy is questionable due
to the passive signal being present on more than one
line.
WARNING! Do not make depth measurements near
bends or tees in the line. Go at least 5m (16ft) from a bend
for best accuracy.
6.1.1 TruDepth for RF Markers
The locator is capable of automatically
estimating the depth of a buried marker when it is in
close proximity to it.
In order to get the best possible accuracy it is important
to ensure the locator is directly above the marker
position by pinpointing its exact position first as
described in paragraph 4.5.
6.1.2 TruDepth for buried conductors
or sondes
TruDepth and Compass
It is important to note that the locator will only
display depth and current (in applicable modes) when
the locator is correctly orientated above the target line,
cable or sonde. To ensure the locator is correctly
orientated, use the Compass feature.
When locating lines, make sure the Compass display is
in the North/South orientation position.
When locating sondes (see Section 8.5.5), make sure
the Compass display is in the East / West orientation.
Figure 6.1: Taking a depth reading
To avoid signal distortion, do not apply the signal by
induction. If direct connection or signal clamping is not
possible, place the transmitter at least 15m (49ft) from
the point of any depth measurements.
Depth measurements may not be accurate if there is
audible interference or if part of the transmitter signal
has coupled to a nearby line.
Confirming the peak position coincides with a null
position indicates that the position is suitable for making
a depth estimate.
Figures 6.2: Depth readings

Pinpoint the target line accurately with the
locator

Check the locator is directly over the line, the
antennae are at right angles to it and the locator
is vertical. Adjust sensitivity level to bring the
bar graph indication on scale

Press the antenna button to alternate between
depth and current readings
If the ground appears to radiate a strong field, perhaps
near a radio station, check depth by holding the bottom
of the antenna 50mm (2”) above the ground and
subtract this reading from the indicated depth.