Specific Locating; Polarity - Emerson RIDGID MR-10 Operator's Manual

"AUTO NULL " sections for information to
improve locates. See Figures 7 and 8 for
locating signal patterns.
Signal for a
Vertically
Oriented
Target -
Greatest
Over Top
+/-
Figure 7 – Signals and Polarity from Vertical
and Horizontal Targets
A - Along Pipe
B - Crossing Pipe
Figure 8 – Signal Patterns from Cast-Iron Pipe
Signal for a
Horizontally
Oriented
Target -
Greatest
Over Ends
+ -
MR-10 Magnetic Locator

Specific Locating

1. When the signal source has been gener-
ally located, move the locator to the verti-
cal position.
2. Lower the gain if necessary.
3. Move the locator in a cross pattern (Figure
9).
The signal bar graph and audio tone will
be highest when locator is over the target.
Figure 9 – Specific Locate Signal

Polarity

The MR-10 Magnetic Locator includes a fea-
ture to determine the polarity of a magnet.
Polarity can be used to help better identify
an object during locating.
All magnets have two poles (+ and -, positive
and negative), and those poles generally follow
the shape of the object. For instance, a long,
thin object such as pipe will typically have a
pole at either end. The orientation of the object
being located may be implied through the use
of polarity.
A long thin ferrous object oriented vertically,
such as a pipe, survey spike, rebar or nail
will show a single pole, either positive or neg-
ative. A long thin ferrous object oriented hori-
zontally, such as a pipe or rebar will show a
strong reading at either end (pole) with little
signal in between the poles. One end will be
positive and the other negative. See Figure 8.
When locating along a run of pipe, you may
see the polarity reading flip from positive to
negative or vise versa at the joint. This will only
happen if the pipe ends are isolated (not con-
nected) to each other.
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