Megger L1070, Инструкция по эксплуатации

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M
AVTM651070 Rev B Nov 2006
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1. A junction where the signal divides (lower)
2. A break in the cable or shield (lower)
3. A change in depth of the cable or pipe (higher or lower)
4. An insulated pipe fitting (lower)
5. A slack loop of cable (lower)
If you can no longer trace the path, even with the gain set to maximum, connect
the transmitter to the far end of the cable, and trace back to the point where you
lost the signal.
Mark straight sections of the path every few feet. Mark sharp curves, loops, and
cable bundles every few inches. Sharp changes in the path cause the receiver
Peak and Null indications to behave differently than when tracing a straight path.
Practice on a path that you know has turns and laterals in it, so you will recognize
these conditions in the field.
Absolute Signal Strength
The receiver provides a direct measurement of the received signal strength. This
measurement is displayed continuously at the top of a three-digit LCD, in a range
from 0 to 999 indicating a very weak signal to a very strong signal, respectively.
As the receiver nears the buried cable, the numbers increase. As the receiver
moves away from the buried cable, the numbers decrease. These numbers
indicating signal strength are sometimes referred to as Signal Power Indicators or
SPI numbers.
Although signal strength is independent of the gain setting, the gain setting will
have an effect. If the gain is adjusted too far above mid-scale, the signal strength
indicator will blank out. You will know you have adjusted the gain low enough
when the signal strength display reappears.
NOTE: Do not confuse Signal Strength with Signal Strength Adjusted for
Depth (Current Measurement). Signal Strength gives the operator a
measurement of how much signal is actually being received from the
conductor. For a given amount of current on the target cable, you will
measure a higher signal power when the cable is close than when the cable
is farther away.
Signal Strength Adjusted for Depth takes the depth of
the conductor into consideration. As the depth of the conductor changes,
Signal Strength Adjusted for Depth measurements will remain the same.
Signal Strength Adjusted for Depth is actually giving the operator an
indication of the amount of signal current through the conductor.