
4
Again holding the search coil well away from any metal, adjust the
control knob until the unit is on the verge of producing a low-frequency
buzz or tickover sound. This is the most sensitive setting. In use it
will usually be found that the knob can be turned back somewhat from
this position.
When metal is detected, the sound will rise in frequency to a whine and
the red LED will illuminate.
The most sensitive point of the search coil is its centre.
The Valve Box Locator M 130 has a built-in reject circuit against small
pieces of metal (such as silver foil from cigarette packs, screws, etc.) so
that no signal is given when the search coil is over these objects.
During operation, it is recommended to hold the search coil at 100 to 150
mm above the ground to avoid picking up larger surface clutter.
The outline of manhole covers etc. can be identified by bringing the
search coil up to the side of the object from different sides. Then, note the
points at which signals are given. Due to the resultant outline you can then
determine whether the correct object has been found.
It is advisable to turn back the control knob (and thus to reduce sensitivity)
so that the edge of the target is easier to identify.
After use
To conserve battery live, remember to switch the unit off when not in
use. If the unit is not going to be used for a period of time, remove the
batteries before storing it away.
HERMANN SEWERIN GMBH
Robert-Bosch-Str. 3
D- 33334 Gütersloh
Phone: +49 - (0) - 5241 / 934-0
Fax: +49 - (0) - 5241 / 934-4 44
www.sewerin.com