10
GROUND BALANCE
Ground balance can be performed in three ways with the INVENIO:
Automatic, Manual and Tr acking.
The ground balance screen is a separate window in detection screens
(except for the Ground Anomaly & Cavity mode). In the detection screen
with the IPTU sensor , you can remove the ground balance screen by
pressing the INFO button but it is fixed in the detection screen without
the IPTU sensor . The ground balance window is divided into 2 parts:
The top part shows the instant ground balance value changes while
searching and the bottom part shows the adjusted ground balance
value.
If the trigger is pushed forw ard while performing an automatic or
manual ground balance, the device will switch to All Met al mode
automatically on the background without any indication to the user ,
regardless of the selected search mode.
Upon completion of ground balance, the ground balance value is shown
under ''Adjusted'' in the ground balance window .
Automatic Ground Balance
Automatic ground balance is performed as follows in all search modes:
1) First, find a spot of ground where there is no metal present.
2) Push the ground balance trigger forward and hold it. The ground
balance screen will be displayed aut omatically and the word
''Automatic'' will appear bigger on screen.
3) Hold the search coil parallel t o the ground. Continue to push and
hold the trigger forward and start pumping the search coil up and
down from about 20 cms. (~8'') abov e the ground down to 5 cms. (~2'')
off the ground with smooth mo vements and k eeping it parallel to the
ground (this is also shown by animation on the screen).
4) Continue until a beep, indicating the completion of ground balance,
is heard. Based on ground conditions, it usually tak es about 2-4 pumps
for the ground balance to be completed.
5) When the ground balance trigger is released, the device continues to
operate in the All Met al mode for a short period of time and the ground
balance window stays on screen. The w ord ''Manual'' will appear bigger
on screen. This makes it possible to manually fine tune the automatic
ground balance value. Refer to the following "Manual Ground Balance"
section for further information regarding this feature. If no button is
pressed for a while, the device will revert back to the detection screen
automatically. If you do not want to wait for the timeout period, you
can switch to the detection screen by pulling and releasing the trigger
once.
6) Upon completion of the aut omatic ground balance, ground balance
value will be shown under ''Adjusted'' in the ground balance window
and it will be same as the ''Inst ant'' value. The device continues to
ground balance and produce a beep sound as long as you keep the
trigger pushed forw ard and pump the coil. In order to ensure that
the ground balance is proper , ground balance at least 2-3 times and
check the ground balance values on screen. In general, the difference
between the values shall not be higher than 1-2 numbers.
7) If you cannot ground balance, in other w ords, if no beep sound is
produced, it means that either the ground is t oo conductive or not
mineralized or there is a target right below the search coil. In such
a case, retry ground balancing at a different spot. If you still cannot
ground balance, read the section titled ''Important Det ails Concerning
Ground Balance''.
NOTE : If the Stabilizer value is set high, the device may not auto
ground balance. In such a case, go to the SETTINGS of the All Met al
mode and select Stabilizer . Lower the St abilizer value first. After
ground balancing, set the St abilizer value back to its original level.
Manual Ground Balance
Allows you to manually modify the ground balance value. It is not
preferred mostly because it t akes time. However , it is the preferred
option in cases where a successful ground balance cannot be
performed using other methods or minor corrections are required for
the automatic ground balance.
INVENIO is designed to allow for automatic ground balancing
conv eniently on any type of ground. Therefore, it is recommended
to perform automatic ground balance upon start up. However , the
ground may not be suit able for aut omatic ground balancing in some
cases and the device cannot ground balance on such grounds. F or
instance, wet beach sand, soils containing alk ali or salty wat er ,
trashy sit es, ploughed fields, highly mineralized grounds and grounds
with very low mineralization are not suitable for automatic ground
balance. In such terrains, you can perform manual ground balancing.
Howev er , manual ground balance requires a skill which develops o ver
time through pr actice.
T o perform manual ground balance :
1) First, find a spot of ground where there is no met al present and
switch the device to All Metal mode.
2) You need to listen to the sounds coming from the ground in order
to perform manual ground balance. Pump the search coil up and down
from about 20 cms. (~ 8'') above the ground down to 5 cms. (~2'') off the
ground with smooth movements and keeping it parallel to the ground.
If the sound gets higher when lifting off the search coil abo ve the
ground, the ground balance value is too low , in other words, the effect
from the ground is negative and the ground balance v alue needs to
be increased by using the plus ( + ) button. On the other hand, if the
sound gets higher when lowering the search coil to the ground, the
ground balance v alue is t oo high, in other words, the effect from the
ground is positiv e and the ground balance value needs to decreased
by using the minus ( - ) button.
3) Push the ground balance trigger forw ard once and release it. The
ground balance screen will open up and st ay on screen for a while.
You can return t o the ground balance screen by pushing the ground
balance trigger forw ard if the screen switches.
Manual ground balance functions within the r ange of 0,00 -99,80.
Ho w e v er , each v alue co v ers 5 st eps used for fine tuning within itself
and these st eps are indicat ed as multiples of 20.
Press plus ( + ) or minus ( - ) butt on t o increase or decrease the ground
balance v alue, respectiv ely. If the butt on is pressed once at a time, the
v alues count one by one and if it is held do wn, the v alues will change
quickly.
4) R epeat the abo v e procedure until the sound heard from the ground
is eliminat ed.
The sound may not be eliminat ed complet ely in some areas. In these
cases, list en t o the sounds produced when mo ving the search coil
t o w ards and a w ay from the ground t o check if the ground balance
is correct. If there is no diff erence betw een the tw o sounds then the
ground balance is set properly.
The de vice will return t o the det ection screen aut omatically aft er a
short period of time upon completion of ground balance. If you do not
wish t o w ait for the timeout period, just pull and release the trigger
once t o go t o the det ection screen inst antly.
IMPOR T ANT! Experienced det ect orists adjust the ground balance
setting t o a slightly positiv e response (w eak but audible sound is
produced when mo ving the search coil closer t o ground). This method
may produce f a v or able results for experienced users in cert ain fields
where small t argets are searched for .
T r acking
This f eature is present in the Motion modes only and not a v ailable in
the Non-motion modes.
In this option, the user does not need t o mak e any adjustments.
T r acking f eature is activ at ed by selecting it from the settings of the
motion modes and by switching it t o on position. The w ord ''T r acking''
will be displayed in green at the bott om of the ground balance windo w .
The de vice updat es the ground balance aut omatically as long as the
search coil is swung o v er the ground and sho ws the ground balance
v alue in the ground balance windo w . It does not pro vide any f eedback
t o the user (lik e the beep sound in aut omatic ground balance).
While tr acking is activ e, the de vice can initially produce a loud signal
when it det ects a diff erent ground structure (for inst ance a miner al
rock) or a t arget. In this case, swing the search coil o v er the spot where
the de vice produces the signal . If the sound remains the same and
the de vice sho ws an ID , it is possibly a t arget. If the sound att enuat es
t oo much or is lost aft er a f e w swings, it means that the de vice has
produced a signal for the diff erent ground structure or a st one.
NO TE : It is recommended that you use tr acking in the All Met al mode
and not in the discrimination modes.
NO TE : T r acking is not a mode specific setting, when it is turned on it
will be activ e in other motion modes as w ell. If you switch t o one of the
non-motion modes while tr acking is on, it will be turned off and once
you switch back t o a motion mode, it will be activ e again aut omatically.
T r acking is suit able for use in areas where diff erent soil structures are
present within the same land or in fields where miner alized rocks are
scatt ered widely apart. If you use ground tr acking in areas where hot
rocks are int ensely present, the de vice may not be able t o eliminat e
these highly miner alized rocks or you may miss the smaller or deeper
met als.
IMPOR T ANT! Ensure that tr acking is off during air t ests. Otherwise,
the de vice will att empt t o perform ground balance on the t arget and
the depth will be reduced.
Ground Balance V alue
Ground balance v alue pro vides information about the ground you are
searching on. Some typical ground types are as follo ws :
0-25 Wet salt w at er or w et alk ali soils
25-50 Wet salt w at er and w et alk ali soils co v ered with dry layers
50-70 R egular , lo w-quality soils
7 0 - 9 0 Highly magnetic soils, magnetit e or maghemit e and similar
highly miner alized soils, black sand.
Import ant Det ails Concerning Ground Balance
1) Upon st art up, the ground balance v alue is set t o 90. The de vice can
perform ground balance aut omatically within the follo wing r anges for
each type of search coil :
INV28 search coil : 40,00 - 99,00
INV40 search coil : 20,00 - 99,00
INV56 search coil : 0,00 - 99,00
2) If the ground miner alization is t oo lo w , aut omatic ground balance
may f ail. In such a case, you can try manual ground balancing.
3) You can t est the accur acy of the ground balance with pinpointing
in motion modes. Aft er ground balancing, if you receiv e no sound or a
w eak one when you mo v e the search coil closer t o the ground in the
pinpoint mode, then the ground balance is successful. If the sound
gets louder when you mo v e the search coil closer t o the ground, then
the ground balance is not successful. In this case, simply change your
location. If ground balance is not possible despit e these efforts, you
should continue your search without performing ground balance.
You cannot search in the All Met al and Non-Motion modes (except for
the Ground Anomaly & Ca vity) without ground balancing. You need t o
use one of the discrimination modes and increase the Discrimination
v alue until the noise is eliminat ed.
4) Once the ground balance is set, it will remain satisf act ory for a
long time in most areas. Ho w e v er , if you encount er an exca v at ed,
backfilled or geologically composit e soil structure, ground balancing
should be performed again t o adapt t o the v arying soil structure.
In addition, re-ground balancing is recommended if you change the
oper ating frequency of the INVENIO Pro (5kHz / 14kHz / 20kHz) in
cert ain ground conditions.
5) When using the optional large coil, pump the coil more slo wly and
do not k eep it v ery close t o the ground.
6) In some cases where the St abilizer v alue is set high, the de vice may
not be able t o ground balance aut omatically. In such a case, first lo w er
the St abilizer v alue and aft er ground balancing switch it back t o its
pre vious le v el.
7) If the vibr ation f eature is enabled, e v en if you are using one of the
non-motion modes where this f eature is not activ e, the de vice w ould
vibr at e during ground balancing because it switches t o All Met al mode
t o perform the ground balance.