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Section 5 – Depth and current readings
5.1 Depth readings
The RD7000+ can measure the depth of buried
conductors down to depths of approximately 6 meters
(20 feet) for a line, or 15 meters (50 feet) when using
a sonde. RD7000+ will locate to greater depths but
accuracy may be reduced. The depth measurement is
to the center of the pipe or cable. The best readings are
detected from signals outputted by a transmitter rather
than from passive sources.
The RD7000+ is capable of determining 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.
NOTE: 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.
WARNING! Do not make depth measurements
near bends or tees in the line. Go at least 5 meters
from a bend for best accuracy.
5.1.1 TruDepth and Compass
It is important to note that the RD7000+ will only display
depth when the locator is correctly oriented above the
target line, cable or sonde. To ensure the locator is
correctly oriented, use the LCD Compass:
When locating lines, make sure the Compass displays the
line in the 6 o'clock position.
When locating sondes (see Section 10.4), make sure the
Compass displays the line in the East / West position.
Figure 5.1: Taking a depth reading
16 RD7000+ Operation Manual
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 15 meters from the
point of any depth measurements.
Depth measurements are not 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.
Figure 5.2: 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 depth button to toggle 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 above the ground and subtract this
reading from the indicated depth.
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