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D
ETERMINING THE DEPTH OF A LINE
8 DETERMINING THE DEPTH OF A LINE
Even after the depth has been determined successfully, all excavation work should be
done with caution. This is particularly important if depth is measured using the manual
method.
8.1 Depth measurement - automatic
The Elcometer 701 receiver has an automatic depth measurement feature. This feature will only
operate if the following conditions are met:
•
A clear signal from the transmitter is coupled onto the conductor to be measured.
•
The signal from the transmitter is continuous (not pulsed) - see "Transmitter setup options" on
page 9.
•
The receiver must be set to Transmitter mode; it will not function if set to Power Grid or
Radio mode - see "Receiver setup options" on page 18.
To use the automatic depth measurement feature, follow the procedure given in section 8.4 up to
step 6.
8.2 Depth measurement - manual
If the conditions described in 8.1 are not met, a rough estimate of the depth may be made using the
manual method - follow the procedure given in section 8.4.
8.3 Depth measurement - non-metallic pipes
If the depth of a non-metallic pipe needs to be determined, the measurement has to be made with
aid of a Probe - see "Signal coupling in non-metallic pipes" on page 15. In this instance, in order to
accommodate the transmission characteristics of a probe, the receiver has a special depth
measurement feature which has to be activated before depth measurement is carried out - see
section 5.3.2, step 5, on page 19.
8.4 Procedure
Follow the steps below to determine the depth of a metallic conductor:
Step Action
1.
If the depth of the conductor is to be determined with the aid of the transmitter, couple
the transmitter's signal to the metallic conductor in such a way that there is as little
signal loss as possible and switch on the transmitter.
Do not forget to set the transmitter to continuous signal, not a pulsed signal when
measuring depth.
2.
Switch on the receiver.
3.
Select the desired operating mode by pressing button # 3.
The symbol for the currently selected operating mode is shown in the lower right-hand
corner of the display.
4.
With a steady grip, hold the receiver perpendicular to the position of a known metallic
conductor, e.g. above a location which was marked during the probing of the site.
The signal strength bargraph should show zero.
22
R
10
5
18
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