Resistivity System OMEGA-48


Overview

OMEGA-48 is a multichannel Resistivity system designed for vertical electrical sounding (VES) and induced polarization (IP) methods on electrical resistivity tomography (ERT) technology.

 

Resistivity system OMEGA-48 consists of

• Multi-electrode 10-channel Resistivity instrument which includes transmitter, receiver and switching unit connected to current and measuring lines in a single heavy duty cable with waterproof enclosure

• Two sections of multi-core cable with 24 electrode each

• Industrial laptop

• Software for system control, results acquisition, data processing and interpretation

  - developing field measuring protocol, SEQ files,
  - managing measuring process, data collection and storage,
  - visualization and editing field data,
  - automatic data 2D inversion,
  - visualization of inversion result.

 

Resistivity instrument measures amplitude parameters of output current of the transmitter, electrical potential difference between measuring electrodes (apparent resistivity), time parameters of chargeability (apparent chargeability) determined on voltage decay curve at measuring electrodes after switching off the current:

 

OMEGA-48 brochure

Specifications

Resistivity instrument measures amplitude parameters of output current of the transmitter, electrical potential difference between measuring electrodes (apparent resistivity), time parameters of chargeability (apparent chargeability) determined on voltage decay curve at measuring electrodes after switching off the current:

 

Specifications

 Number of measuring and current electrodes connected to the multi-core cable 48, the multi-core cable consist of two sections, 24 electrodes each, the unit is located in the center 
 Number of channels for simultaneous measuring operation 1 to 10. A pair of receiving electrodes for each channel is selected according to protocol
 Number of current lines in simultaneous operation 1. Transmitting electrodes pair is selected according to protocol 
 Electrode spacing 1 to 10 m
 Multi-core cable lenght 50 to 500 m (two sections with length from 25 to 250 m)
 Signal form direct current bipolar impulses of regulated duration with pauses
 Power supply 24 V, external
 Operating temperature -20 to +50°C (option down to -40°C)

 

Transmitter

 
 Number of input channels 1 (or 2 lines) (commutation multi-core cable is possible)
 Direct current bipolar impulses of regulated duration with pauses 
 Impulses duration 0.2048, 0.4096, 0.8192, 1.6384, 3.2768, 6.5536, 13.1072, 26.2144, 52.4288 seconds
 Duty ratio 0.2 .. 0.5
 Output voltage 30, 100, 300, 500 V
 Instability of output voltage under variation of load resistance 1% at most
 Output current 10 mA to 5A
 Maximum output  capacity 0.5 kW (500 V - 1 A, 100 V - 2 A, 30 V - 5 A)
 Time for complete current cut-off on active load 10 μs at most
 Protection from short circuits on the output 

 

Receiver

 
 Number of input channels 1 to 10 pairs of dipoles
 Input resistance of each channel at least 20 MOhm
 Range of measured signals 10 μV to 12 V
 Amplitude response of each channel at least 2 to 3 μV
 Instant dynamic range at least 90 dB
 Voltage of in phase signal on the input 12.5 V at most
 Amplification rate of the prime amplifier 1, 10, 100, 1000
 Bit length of Sigma-delta analog-digital converter (ADC) 24
 Level of in phase interference suppression at least 80 dB
 level of industrial interference suppression with frequencies 45 to 55 and 55 to 65 Hz at least 80 db
 Operating temperature from -20 to +50°C (option down to -40°C)
Software