
KharkovEnergoPribor Ltd. | KEP Ltd.
+380 57 393 1069
www.kep.ua | [email protected]
17
USER MANUAL
As far as you move along the line, the Tracer gain and the sound
volume shall be adjusted depending on the strength of the received
signal. Along the route the signal strength may change depending on
the cable core twists. The strength of signal may also drop
considerably in the areas where the cables are laid under pipelines
or near connecting sleeves, or in the areas where they are shielded
with metal pipes.
In some cases, the peak scale is not sufficient, e.g. when the pipeline
branch of smaller diameter is traced deeply under the ground.
At that, some portion of tracing current leaks through the branch, and
the peak signal strength over the main pipeline drops slightly, and
this may go unnoticed.
The «peak scale expansion 1:4» option reduces the scale divisions
to increase its resolution. The «
» icon (Pos. 11 in Figure 4) will
be displayed, a yellow s
trip will appear under the «peak» scale to
show the expansion bar graph relative to the normal (unexpanded)
scale.
Using the gain up/down buttons, place the end of the extended
«peak» bar graph within the visible area of the display. The gain-up
button is expands the scale. The gain- down button makes the scale
shorter.
The optimum gain and scale for a specific signal intensity may be
obtained by pressing the
«
» button.
The option of the peak scale extension may be selected by scrolling
the MENU options as follows:
Menu > Indication> TRACE scale >
Peak type > Extension 1:4
.
4.5.2.2. The null method
The method of null provides precise tracing of single utilities. The null
signal is within the abrupt area of the characteristic curve.
In Figure 5 shows relationship between the null signal intensity and
the displacement of the antenna away from the target utility. When
the antenna is exactly over the axis of the utility, the signal will be on
its minimum. When you move the antenna away from the utility, you
will get the signal gain, and there will be more lighted segments of
the barograph towards the utility. Subsequent disposal of the
antenna will result in smooth signal attenuation.