DT BARLOW RESISTIVITY SYSTEM
FREQUENTLY ASKED QUESTIONS
Does the price of DCRES-200 DC Resistivity system include the cost of cables and electrodes?
The price does not include cables, reels or electrodes. We can supply these for an additional fee. If the unit needs to be delivered out of South Africa then shipping for the cables and electrodes works out quite expensive so we normally suggest international clients have their own made up at a local engineering company. We can assist with diagrams etc.
How is the apparent resistivity value obtained? Is it a direct read-out value or by manually computing V/I
The user is required to manually compute the apparent resisitivity. We have deliberately kept the system simple as we have found that it takes a more highly trained or more experienced operator to spot problems (current leakage, etc.) when they are simply pressing a button and getting apparent resisitivity values. If the operator is required to write the values down they tend to spot anomalous readings immediately, enabling them to troubleshoot the problem there and then. Otherwise we found that the clients would end up with poor quality data without realising that there was a problem with the setup (too high contact resistance, current leakage, etc.). They would then need to go back into the field and redo all their work. By keeping the system simple we are able to help the operator avoid costly delays caused by problems with the setup going undetected. Keeping it simple also keeps the system affordable and robust.
The depth obviously depends on earth conductivity. The higher the conductivity the shallow the depth. Suffice to say, the DCRES-200 is sufficiently powerful to run Schlumberger soundings of AB=500m over most terrain.
The system is only dangerous if used by unqualified personnel. Voltages are high and the danger of electric shock is a real one. The operator and assistants need to be made aware that the system is live, and that, should they come into contact with any of the live components (eg. current electrodes) during a measurement cycle, there is a possibility of receiving an electric shock.
The system can be built into a plastic container at additional cost. These are watertight and weatherproof. The standard container is wooden as this is robust, offers good insulation, and is easy to repair in the field should it be damaged.