GEOTECHNICAL SEISMIC RECORDER IS128-03

Manufacturer NPP “Intromag”, Perm, Russia

Applications
• seismoacoustic investigations with frequency range from 2 Hz up to 8000 Hz
• profiling at the ground surface and in shallow boreholes
• upper part of geological section studying via refracted, reflected and surface wave techniques
• geotechnical investigations
• technical condition, environment control and monitoring of the on-land and off-shore structures
• acoustic investigations of the road surfacing, substructures and foundations
• off-shore shallow seismic surveys and continuous subbottom profiling in single-channel and multi-channel modes
During operations with relatively weak power sources of the seismic pulse initiations the recorder provides low signal stacking. Hardware stacking of seismoacoustic signals is carried out before record transmitting into the long duration memory on a hard disk. Remote 16-th channel distributed modules with low power consumption can be connected to the central module via two-wire high-speed USB-RS485 or WiFi interface.

Main peculiarities
• Portable and cheap multi-purpose seismic recorder for on-land, underground and off-shore shallow seismic surveys
• Available with stand-alone 32-48-th channel host module and expanded with connection of remote distributed modules
• Available with 16 channels per remote distributed module
• Data transmission from remote to host module via high-speed USB-RS485 or WiFi interface, transmit speed up to 1 Mbod
• Very low noise high-speed 24-bit delta/sigma Texas Instrument AD converters
• 2 Hz to 8000 Hz bandwidth (0.033 ms to 50 ms sampling) for high resolution reflected or low frequency surface wave engineering surveys
• Wide range of amplifier gains: 6 to 36 dB
• Ruggedized optional design reliable for harsh environments
• 32-bit stacker, vertical stack of up to 256 shots
• Ruggedized field notebook Panasonic CF-29 as a root module
• Operation under Windows-XP, Windows-7, Windows-10
• System software has a familiar menu interface, which capable to configure recorder for different kind of surveys
• Low consumption, low weight, low cost
For geodetic data definition and storage during continuous off-shore profiling a GPS receiver is used (NMEA-183 protocol). WGS-84 coordinates are continuously recorded in seismic trace labels.


Seismoacoustic recorder IS128.03 set with a single remote module

Connection diagram of interface and remote modules to the charger

 

Configuration
The synchronization system excitation and reception:
• by generating a trigger pulse and transmitting it to the oscillation source,
• receive synchro pulse from an external source
The recorder has a means of simple software interactive diagnostics, including a device for generating test signals with analog output, which facilitates monitoring of equipment performance, search and troubleshooting in the field.
The design of the recorder allows its use in dust and humidity conditions. The instrument can operate under an ambient temperature of 0 to +40 degrees C, relative humidity up to 98% at +25 deg.C and relative pressure (750 + / -30) mm Hg.art.
Service program provides accumulation of signals, saving in a file and visualization of data on the monitor screen. The program also allows to perform simple procedures for express processing of records immediately after they are received, as well as spectral analysis of records. The set of procedures also includes analysis of amplitude-frequency characteristics of seismic channels in different registration modes by test records.
For geodetic reference of data when working on water areas, the GPS receiver is connected to the COM-port of the main control computer and the coordinates are continuously recorded in the label of the seismic traces.
Focused primarily on performing works in remote areas, in engineering wells, inside industrial structures and underground workings, the recorder is implemented as a distributed system of seismic data collection. Designed on the basis of the latest electronic components, it has a very high performance in energy consumption, weight and size characteristics and simplicity of communication lines.
The presence of a number of autonomous remote modules in the recorder allows to implement sufficiently flexible linear, areal and spatial observing systems. Optionally, two or more remote modules can be placed in the housing of the central module, and then the recorder represents a conventional engineering seismic station with the number of channels from 16 to 64.
The central power module is supplied from a DC source from 9 to 18 In, usually from an external lead-acid battery 12 to 17 A/h. Remote modules have built-in lithium battery 7.4 V 6 A/h. The current consumed by the remote module in the operating mode (buffer is disabled), not more than 250 mA, with the buffer included 350 mA. The inclusion of the buffer increases the input impedance, which allows to increase the sensitivity of the seismic channel. When the RS485 interface cable is disconnected, the module enters into sleep mode with a consumption of no more than 30 µa. When the minimum voltage on the battery is reached, the module is automatically switched off.

Main technical characteristics of the complex


The program for the data collection and processing

Mostly convenient for field work technology of and for a noise stability of recorded signals is a wiring sheme for remote modules connection to a conventional portable Notebook computer via an USB port using a specialized high-speed converter USB-RS485 interface and synchronization unit records.
In this case, separate geophone sections are connected directly to the remote modules on the profile, which are connected to each other and then connected to the interface module via a digital two-wire communication line, thereby significantly reducing the level of electromagnetic interference to the connecting signal cables and extensions. Data transfer from the interface module to the computer is carried out either via a two-wire line, or, at distances up to 100-120 m, on the radio using the WiFi interface.

 

Schematic of field arrangements

Typical scheme of the observing system for the method of reflected and refracted waves (a) and surface waves (b)

Service program for registration and data collection

The service program runs in the Windows/XP-Windows-7/10 operating system environment. The test module of the program allows you to check the basic technical parameters of seismic recording channels, channel view and calculation of statistical characteristics of signals, perform spectral analysis of records.
A set of window menus gives to the operator the ability easily and clearly set the parameters of registration and geometry of receivers placement.
The working window of the collection program displays a summary seismogram obtained after sending records from a set of remote modules, the charge level of the built-in batteries of remote modules, the number of the current excitation in the series of accumulations, the number of the current record and the process of passing signals. Using the scroll bar, you can view long records with the selected detail.

When continuous seismic-acoustic profiling is performed, the multichannel seismogram from the previous excitation can optionally be displayed on the screen, or a time section along an arbitrary but predetermined channel of any hydrophone section. In addition, the number of the current record from the beginning of the profile and the coordinates obtained from the GPS receiver without hydrophone sections offsets are displayed.

Working window of the program registration in multi-channel subbottom profiling