Velleman CS102 - Manual (Page 5)

CS102
19/04/2010 © 2008 Velleman Components nv 5
• Note that detection also depends on the size, shape, depth… of the metal.
Ferromagnetic
• Substances that usually conduct very poorly or not at all can become magnetized when inside a
magnetic field, resulting in a strong signal picked up by the receiver. However, this signal shows
little or no phase shift. Soils containing small grains of iron-bearing minerals will show
ferromagnetic characteristics.
Discrimination
• Since any given metal will respond with its own characteristic phase shift, it will be possible to
distinct between them. The process of distinguishing between different metals is called
discrimination.
Ground balance
• As mentioned earlier, soils that contain iron will produce a response signal which can be a lot
stronger than the signal produced by a metallic object concealed in it. This is also the case for
places where ground water contains a lot of dissolved salt.
• However, the phase shift caused by the ground, the ground effect, remains fairly constant over a
limited area when the search head is kept at a steady height.
• Accurate ground balance makes it possible to precisely pin-point the location and depth of an
object. It is essential when working in ‘all metal’ mode.
7. Preparation
• Prior to use, the CS102 must be assembled.
• Mount the search coil [M] on the lower shaft [K]. Push the bolt through the holes and tighten
with the nut knob [L]. Do not tighten the search coil fixation too hard e.g. do not use pliers or
other tools.
• Slide the extension shaft [G] into the control shaft [B]. Rotate the extension shaft [G] until the
spring-loaded buttons snap into place.
• Line up the spring-loaded buttons [I] of the lower shaft [K] with the holes in the extension shaft
[G]. Slide the lower shaft [K] into the extension shaft [G].
• To determine the ideal shaft length, stand upright holding the metal detector by the handle [B]
and your arm on the arm rest [A]. When holding your arm relaxed next to your body, the search
coil [M] should be about ½” to 2” (max.) above the ground. To adjust the length, press on the
spring-loaded button [I] and move the lower shaft [K] to the desired length.
• Turn the locking nut [J] counter clockwise (top view) to secure the lower shaft.
• Loosen the search coil fixation knob, adjust the search coil [M] so it is parallel to the ground and
tighten the nut knob.
• Wind the cable [H] around the shaft, leaving enough slack. Insert the plug into the 5-pin input
jack [F]. The slotted connector only fits in one way, do not force.
• Insert batteries (see §14).
8. Operation
• It is strongly advised to test the detector at home before going into the field. Perform tests with
different metals e.g. coins, golden ring, silver spoon…
o Perform indoor tests by placing the detector on a wooden or plastic table, search coil [M]
facing the ceiling and slowly moving a metal object over the coil. Be sure not to wear
jewellery as these will influence the reading. Hold the metal object under different angles
while moving across the coil and notice the difference in detection. Note that the volume will
increase quickly as the metal object passes directly in front of the search head, with the
loudest sound occurring when the search head is centred immediately over the metal object.
As the object passes beyond the search head the sound will quickly fade.
Note: Never test the detector on a floor inside a building. Most buildings have metal of some
kind in the floor, which might interfere with the objects you’re testing or mask the signal
completely.
The search coil will not detect without motion. You must move the object since you are
not sweeping with the detector at this time.
If the detector does not detect the material, check the battery power and verify that the
search coil is properly connected.
o Also perform outdoor tests to learn the influence of the soil type on the detector and to
practise ground balancing. Place a metal object on the ground and slowly sweep the search
coil [M] over it. Be careful when using valuable metals for outdoor testing – make sure you
can always retrieve them.