Resistivity and IP - frequently asked questions
Single-channel ARES and 10-channel ARES II can perform 1D, 2D, 3D and cross hole surveys. ARES II supports also 4D (automatically repeated and scheduled start) and continuous (from water level) surveys. ARES can drive up to 200 electrodes in one line while ARES II can drive up to 65000 electrodes in one line.
No, both instruments are produced and offered simultaneously without time limitation. ARES is classic economic single-channel instrument. ARES II is advanced 10-channel instrument with cheaper single-channel version ARES II/1; both its versions have rich methodical and SW equipment.
There is a possibility of upgrade of ARES II/1 (single channel) to ARES II (10-channel), which passes at user's place. New firmware with some additional accessories is sent to user. Upgrade of ARES to ARES II is not possible.
All ARES measuring accessories can be operated from ARES II units and vice versa. Available number of channels is limited by the kind of accessories - like 1-, 5- and 10-channel multielectrode cables and switchboxes. For example, active single-channel multielectrode cable sections (MCS5) can be operated both from ARES and from ARES II etc.
Both units have the same transmitter (850 W, 2000 Vp-p, 5 A) and can be supplied either from 12 V lead battery (car battery or attachable battery pack) or from AC/DC convertor.
These parameters are different with respect to natural conditions, with respect to applied electrode array and with respect to used measuring method (multielectrode cable measurement or VES). For resistivity imaging AB max of 1500 m (with depth range between 300 - 400 m) was tested using multielectrode cables. More than 100 m depth range of smooth IP result was reached with multielectrode cable and 10-channel system. Resistivity depth range of VES exceeds 600 m.
Measuring time widely depends on set electrical parameters of current pulses (timing), on parameters of automatic data management (requested standard deviation), on applied electrode array and chosen density of points in section, on selection of IP option, on interruptive factors like rolling along etc. Thus e.g. 40 electrode cable line can be measured from 2-3 minutes to several tens of minutes (or more).
Passive cables are typical with uniform multiconductor structure (like seismic cables) so no optimization of current and potential lines is possible. Rolling along possibility as well as use of large multielectrode arrays with many tens of electrodes are significantly cumbersome.
Active cables are typical with switching divided along line and with reduced number of conductors that are optimized to decrease power loss and noise level. They can be easily swapped during roll along and assembled in lines with hundreds of electrodes. No central switchbox is used.
Basic, frequently used multielectrode imaging sets with ARES and ARES II are offered in section Recommended sets. For qualified decision regarding your measuring purpose it is recommended to contact our company specialist or local consultants.
Required HW and SW usual for PC are changing much more faster than geophysical measuring instruments. With respect to very easy way of data download to own PC it is much more comfortable to process data on a close convenient place (e.g. in a car) than directly on the ground at the measuring unit. Such built-in unit would considerably increase size and weight of the instrument and risk of its damage during work.
10-channel measurement gives up to 10 simultaneous potential responses for each current pulse. This way is quite necessary for continuous measurement from water level with GPS positioning and very useful for measurement of long lines with many electrodes and big depth range of survey. Application of advanced technique of IP measurement is also possible in this case.
The multielectrode cables and their accessories are not submersible and are not designed to be exposed to heavy rains. For measurements in fresh water, please use the special water cable sections. The water cable sections are not designed for permanent use in salt water.