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Elrec-T Specifications @ Fugro Instruments

Iris Instruments offer a comprehensive range of geophysical instruments, environmental monitoring equipment and geotechnical instruments. Information about IRIS Induced Polarization and Proton Magnetic Resonance systems may be viewed by following the links. For a complete listing of Iris Instruments products, click on the rotating Ohm symbol to visit the IRIS web site.

Elrec 6 Induced Polarisation Receiver
Measured parameters
- Measurement and display of current, voltage, standard deviation, SP.
- Computation and display of apparent resistivity for main electrode arrays : Schlumberger, Wenner, Gradient, dipole-dipole.
- Measurement and display of IP chargeability with four windows. Delay time and windows widths individually programmable (in the transmitter-receiver mode only).
- Display of noise level before measurement.
- Measurement and display of ground resistance (electrode check)
Technical specifications
TRANSMITTER SPECIFICATIONS
- Maximum output voltage : 800 V (1600 V peak to peak)
- Maximum output current : 2.4 A
- Output current specifications : Resolution : 10 µA ; Accuracy : standard 0.3 % (max. 1 % from -20°C to +70°C)
- Output current waveform : Frequency domain ON+, ON- for resistivity ; Time domain ON+, OFF, ON-, OFF for resistivity and chargeability.

RECEIVER SPECIFICATIONS
- Input impedance : 10 Mohms
- Input overvoltage protection
- Input voltage range : -5 V to +5 V
- Automatic SP bucking (-5 V to +5 V) with linear drift correction (up to 1 mV/s)
- 50 Hz and 60 Hz power line rejection
- Ground resistance measurement : from 0.1 to 1 000 kohms
- Voltage measurement specifications : Resolution : 1 µV after stacking ; Accuracy : standard 0.3 % (max. 1 % from -20°C to +70°C)
- Chargeability measurement specifications : Resolution : 0.1 mV/V ; Accuracy : 1 % of displayed value for a voltage greater than 10mV
- Continuous digital stacking up to 250 stacks

TWO DIPOLE RECEIVER MODE SPECIFICATIONS
- Requires a Time Domain waveform transmitter with 0.5, 1 or 2 s pulse duration
- Automatic synchronization with 10 ms sampling rate
- Common mode rejection between channels 86dB (for RS = 0)

GENERAL SPECIFICATIONS
- LCD display of 2 lines of 20 characters
- Weather-resistant case
- Dimensions : 31x21x21 cm
- Weight : 6 kg, including dry cells
- Power supply : six 1.5 V D size dry cells (over 300 hours operation autonomy at 20°C)
- Operating temperature range : -20°C to +70°C (-40°C to +70°C in option)
- Storage temperature : -40°C to +80°C
 ELREC T, Resistivity meter and two dipole IP receiver

The The most versatile instrument for IP surveys

 Combined Transmitter-Receiver and Two-dipole Receiver unit

For medium depth investigations, ELREC T is a powerful and compact resistivity meter with up to 800 V output voltage.

For deep investigation, ELREC T is a two dipole receiver, while a separate transmitter (VIP 4000, ...) will transmit the current whenever more power or a greater voltage is required.

ELREC T OUTSTANDING FEATURES

ELREC T has been designed as a versatile Resistivity and Time Domain Induced Polarization System:

- In its Transmitter-Receiver mode, ELREC T includes all the functions and specifications of the well-known SYSCAL R2 resistivitymeter : powered by an external DC source, ELREC T can deliver up to 800 V voltage, with a current which can reach 2.4 A.

- In its Two-dipole Receiver mode, ELREC T includes all the functions and specifications of the ELREC 2 receiver, and can be used with any more powerful separate transmitter (VIP 3000Ö) generating a standard Time Domain IP waveform.

In both modes, ELREC T features the following benefits:

- Automatic measurement - Digital stacking for signal enhancement, with computation of standard deviation - Computation of apparent resistivity for most electrode configurations (Schlumberger, Wenner, Gradient, dipole-dipole,...) - Computation of apparent chargeability, with up to 4 preset or programmable IP windows - Internal memory for data storage, for up to 1 000 readings - Serial link for data transfer to computer for plotting and interpretation

Memory Operations:
- Storage of data in the internal memory (up to 1 022 readings). Each reading includes current, voltage, SP, resistivity, chargeability, spacings, station number, etc. - Reading of data stored in the memory on the LCD display. - Transfer of data to a computer (ASCII, binary files) through RS-232 serial link. - Direct transfer of data to a printer. - Remote control of the unit by a computer, through the serial link. - Pulse duration (ON time) programmable from 0.25 to 10s, with preset values of 0.5s, 1s and 2s. - Thermal circuit breaker for overheating protection.

Induced Polarization:
In addition to apparent resistivity, ELREC T also measures the apparent chargeability (Time Domain IP parameter) - For a pulse current waveform (ON+, OFF, ON-, OFF), ELREC T analyses the IP delay curve with up to four chargeability windows. - The average value (M) of the four partial chargeabilities (Mi.) is computed and displayed during measurement, while the four Mi. values are available after the measurement. - The chargeability values normalized with respect to a standard decay curve can be displayed for the detection of EM coupling or noise effects.


Copyright © 1998 IRIS Instruments

 
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