3M 2220M Cable Box User Manual


 
7
Induction Method
If you cannot make a direct connection, or use the 3M
Dynatel
Dyna-Coupler
clamp to apply a locating signal on the target, use the induction method. This
method uses the internal coil of the transmitter to generate a magnetic field.
This is the least preferred method of applying a signal on a target conductor
because it can easily be picked up by other non-target conductors in the area.
However, it is the preferred method of applying a signal to multiple cables/pipes
in the same trench.
1. Verify battery level of transmitter and remove any cables from the output
jack.
2. Position the transmitter over the target facility, with the hinge of the
transmitter over and in line with the cable/pipe path.
3. Align the Induction Direction arrows on the transmitter with the target
conductor.
4. Turn on the transmitter by pressing the frequency key.
5. Select High Output level for the best signal-to-noise ratio.
Note: If nothing is plugged into the output jack of the transmitter, the
transmitter will automatically turn on the internal antennae, and 82 kHz
will broadcast in induction mode. For best results, the receiver should be
at least 40 feet (12 m) away from the transmitter to begin tracing the target
path. Attempting to trace the target close to the transmitter may lead to false
indications due to the receiver detecting the large magnetic field radiating
from the transmitter.