9 Using the vLocPro2
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Now measure the distance between these two points. Divide the distance by two. The result will indicate the
depth of the target line.
If the 70% rule is used, do not divide by two, the depth is equal to the distance between the points.
Current Measurement
Measure the current. This is displayed when you briefly press the “i” pushbutton to measure depth. The signal
from the transmitter will attenuate with distance. The further you are away from the transmitter the less signal
will radiate from the buried line. By locating at several points along the buried line you will identify an
approximate rate of signal loss (beware that where a pipe or cable divides the signal will reduce more rapidly).
If the signal at the point you are pinpointing is different from the trend would suggest – between that, it may
not be the buried line you expect.
WARNING
NEVER mechanically dig over the path of a buried pipe or cable. ALWAYS dig
carefully.
9.3.9
Signal Direction Precision Identification
(Available for vLocPro2-SD model only)
Some models in the vLoc series of locators contain a feature called “SIGNAL DIRECTION”. This feature is
used to verify if the line being located is the line to which the transmitter has been connected.
When a transmitter is connected to a target line the signal travels along it and finds the easiest way to travel
back, usually via the ground and ground stake. However, very often the signal will travel back along adjacent
cables or pipes as these can offer an easier route.
As a result there can be multiple signals radiating from cables and pipes in the area making it difficult to
identify the target line. These return signals are typically traveling in the opposite direction than the applied
signal. The Signal Direction feature identifies which direction the signal is flowing and hence the target line.
To use the signal direction system:
•
Connect the transmitter to the target line using a direct connection only.
•
Turn the transmitter and receiver on and set both to:
o
SD-USA – if in North America or any territory where the power system is 60Hz.
o
SD-EUR – if in Europe or any territory where the power system is 50Hz.
•
The receiver may, or may not be flashing the “SD” icon and compass bezel. "A flashing icon and
bezel indicates that the unit needs to be synchronized with the transmitter.” Even if the icon is not
flashing it is always good practice to synchronize the system at the beginning of a survey to ensure
reliable results and to maximize the distance to the next synchronization point.
