38 RD8000 Operation Manual
Section 12. – Current direction (CD)
12.1 Understanding CD
Current direction recognition is a feature that helps
to positively identify a line at points distant from the
application of the signal. It is highly desirable, if not
essential, for positive identification of long distance lines.
These lines can be traced and positively identified through
congested areas or when running parallel to other lines.
The CD feature on the RD8000PDL and PDLB receivers
indicates the direction of the current flow on a line. Identity
of the target line is established if the receiver display
indicates that the current is flowing forward and away
from the point of application of the transmitter signal.
NOTE: CD mode is not supported on the RD8000 PXL
and PXLB.
A signal that has coupled onto adjacent lines finds a
return path to the point of the original signal application.
This is indicated by the receiver arrow pointing back
towards the transmitter.
This is in contrast to the forward pointing arrow indicating
the target line.
The CD transmitter signal must be directly coupled to
the target line and with a remote ground connection. It
cannot be applied by normal clamp or induction but can
be applied with a transmitter CD clamp.
12.1.1 Using Current Direction (CD) to
aid identification
The RD8000 PDL and PDLB receiver and Tx10 and
Tx10B transmitters feature several CD frequencies to help
you determine the direction of current through a
target line.
Note: The transmitter and receiver must both have the
same CD frequency or frequencies installed to enable
the feature to be used. If you have more than one CD
frequency installed ensure that the transmitter and
receiver are both set to the same CD frequency.
Figure 12.1: Current direction
To select the CD frequency, proceed as follows:
RD8000 transmitter
Connect the transmitter to target cable
or pipe, either by direct connection or by
using a CD clamp.
Switch the transmitter on.
Press the key until the CD frequency is
displayed.
CD is a combination of two frequencies, a CD frequency
and a locate frequency.
RD8000PDL or PDLB receiver
Switch the receiver on.
Press the key until the CD frequency is
displayed, indicated by the two small arrows
above the frequency value.
The receiver will switch back to locating mode.
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