MARY-24

MULTIFUNCTION LOW-FREQUENCY GEOPHYSICAL EM RECEIVER

Measuring instrument MARY (Multifunctional receiver for electrical and electromagnetic prospecting) represents the newest development in the field of creation of the portable geophysical equipment. Compactness and simplicity of use of the device are combined with opportunities which until recently were inherent in only large-sized electroprospecting stations. The Scope of a measuring instrument includes structural, mapping, exploration, hydro-geological, engineering-geological, archeological, geotechnical and ecological researches.

The geophysical instrument «MARY» (Multifunctional receiver for electrical and electromagnetic prospecting) is designed for the measurements of electrical and electromagnetic fields during geophysical explorations. It is intended for measurement of parameters of a constant and variable pressure in field conditions at electroprospecting surveys.

The device allows to conduct surveys by methods of resistance (the amplitude of the basic harmonic of a signal is measured), Induced polarization (IP), self potential (constant electric fields are measured) (SP) and frequency sounding (amplitudes of harmonics of a signal are measured, and also differential phase parameters on an output of electric and magnetic gauges in a wide range of frequencies) (FS). The choice of a method defining adjustment of units of the device is carried out from its main menu (individual adjustment is supposed also)

The «MARY» meter consists of two main units: direct current amplifier and micro controller. The amplifier has two dirigible cascades and includes the compensator of the constant component of the signal, band-elimination (notch) filter (50 or 60 Hz), low-pass filter (LPF), high-pass filter (HPF), band filter (BF), calibration signal shaper.

The operation of all units is coordinated by micro controller. The controller is designed on the basis of 80L188EC (Intel) microprocessor and includes 16-bit analog-digital converter (ADC), 2 Mbytes of nonvolatile memory to store programs, data and processing results, 128 Kbytes of operative memory, autonomous real-time clocks with calendar, standard external interface for the connection with a personal computer.

The meter includes a liquid crystalline display and a keyboard. Power supply is provided by a 4.8 – 6 V storage batteries.

Specifications:

Operating frequencies, Hz:	First set of frequencies: 0.019, 0.038, 0.076, 0.153, 0.305, 0.610, 1.221, 2.441, 4.883, 9.766, 19.53, 39.06, 78.13, 156.3, 312.5, 625.0Hz Second set of frequencies: 0.021, 0.032, 0.042, 0.063, 0.083, 0.125, 0.167, 0.250, 0.333, 0.500, 0.667, 1.000, 1.333, 2.000, 2.667, 4.000, 5.333, 8.000, 10.67, 16.00, 21.33, 32.00, 42.67, 64.00, 85.33, 128.0, 170.7, 256.0, 341.3, 512.0 Hz Additional frequencies: 50, 60, 100, 120
Input signal range, V	-3.0 : +3.0
Minimum input signal, µV	1
Input Resistance, MOhm	>10
LPF cutoff frequency, Hz	0.61 : 5000
LPF steepness, dB/oct	16
HPF cutoff frequency, Hz	1.0
HPF steepness, dB/oct	20
BPF frequency, Hz	1.22 : 625
BPF quality	25 / 50
Notch filter frequency, Hz	50 / 60
Input signal compensation range, V	-1.25 : +1.25
Compensation error, µV	6
Amplification factor	200 … 215 = 32768
ADC precision, bit	16
ADC conversion time, mcs	4
Micro processor	Intel 180L88EC
Memory size, MB	2
Interface type	RS232
Speed of data transmission, bod	115200
Input power, V	4.8 – 6
Battery capacity, mA/h	7000
Consumption current strength, mA: In energy-saving mode In work mode	50 350
Keyboard, buttons	16
Graphic LCD, pixels	128×64
Dimensions, mm	220 x 140 x 80
Weight (with accumulators), kg	2.5
Working temperature, °C	-10°C … +40°C