ABEM Terrameter SAS 1000 / SAS 4000
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6.2.3
Recommended Additional Equipment
Often additional equipment is required for efficient acquisition of good quality data. The
following list is an attempt to summarize frequently needed additional equipment.
•
It is strongly recommended to power SAS 1000 /4000 from an external gelled lead-acid
battery or a car battery (25 – 70
8
Ah) via an adapter.
•
A set of walkie-talkies if cables with long electrode take-out spacing is used (i.e. more than
2 meters between each take-out).
•
Polyurethane hammers of Stanley type (two or more) for hammering down electrodes.
•
Plastic bottles for water with added salt and viscosity increasing polymer, to improve
electrode contact in dry ground. A drill mud polymer (such as Johnson Revert or similar)
added to the water can increase the viscosity to prevent draining away during measurement
in permeable soils. Mix salt and polymer with water to suitable viscosity, it may be wise to
do this in buckets before pouring the mixture into plastic bottles of convenient size.
•
At least an additional double amount of electrodes and jumpers if operating in areas with
dry ground giving contact difficulties.
•
Spray paint and pegs to mark out profile lines.
•
Non-metallic ruling tape to measure distance from profile line to reference objects, or to
measure electrode spacing if smaller spacing than the take-out spacing are to be used.
•
Levelling equipment and / or GPS receiver.
•
Remote electrode cable(s) if pole-pole or pole-dipole array is used.
•
Pocket multimeter with continuity check function for error detection.
6.2.4
Field Procedure for 2D Electrical Imaging
Ensure that the batteries for the Terrameter and Electrode Selector are charged before going to
the field! To ensure proper function, SAS 1000 / 4000 should be powered from a gelled lead-
acid battery or a car battery of sufficient capacity.
The following field procedure assumes that the standard ABEM Lund equipment with a set of
4 cables with 21 electrode take-outs each is used.
For all protocol files using the standard Lund Imaging System cable layout, of four cables
with 21 take-outs each, the procedure described below is recommended. By using this
procedure, high near surface resolution towards the ends of the measured section is achieved.
This is important not only for the resolution at shallow depths, but it also affects the
resolution at depth.
At the first measurement station start laying out and connecting three cables only, and connect
the instrument between the first two cables. In the data acquisition software these cables are
designated as Cable 2, Cable 3 and Cable 4 (see Figure 10), where the instrument is connected
between Cable 2 and Cable 3, and Cable 1 is excluded at the first station. Note that the last
and the first electrode take-outs shall overlap at the cable ends.
8
A battery capacity of 60-70 Ah is recommended for heavy duty applications, i.e. continuous work for several hours with a
high current setting.
