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HARDWARE: DAS-1


MPT-DAS-1

MPT-EIT2000 Series

Resistivity System Accessories

Custom ERT Cables
The MPT DAS-1 Electrical Impedance Tomography System is an integrated induced polarization (IP) system, with 8 channels, each channel containing a 24-bit A to D converter and microprocessor for improved dynamic range. It is capable of collecting 3-D subsurface images using Electrical Resistivity Tomography (ERT) or Electrical Impedance Tomography (EIT). Additional multiplexers can be added to increase array size.

The system has five data acquisition modes:
  • Time Domain
  • Frequency Domain
  • Spectral IP
  • Data Stream
  • Self Potential
In Time Domain mode, the system collects IP data using 1 to 35 user assignable windows at base frequencies from 1/64 Hz to 9 Hz.

In Frequency Domain mode, the system can acquire phase and amplitude data from 1/64 Hz to 5 Hz.

The Spectral IP data mode allows the user to collect frequency domain spectral IP data. The DAS-1 will make measurements at one or more of seventeen preassigned frequencies from 225 Hz to 1/64 Hz.

The Data Stream mode allows the user to store incoming data streams of up to 128 points and then apply their own data averaging and noise rejection methods.

The Self Potential method allows the system to measure the self-potential value at one or more receiver pairs without transmitting current.

The DAS-1 is portable, fast (utilizing 8-channels), can be run from a 12 volt battery and is well suited for large scale low frequency applications. All of the multiplexer channels are fully independent allowing essentially arbitrary arrays. Each channel is optically isolated from the others and from the transmitter and communications circuits allowing for common mode voltages as large as 400 volts. The main unit contains the transmitter, receivers, interface, and an eight channel to 64 electrodes multiplexer. The system can address up to 255 multiplexers (16,384 electrodes total) and can be operated either from its internal interface or autonomously, which requires an external Microsoft Windows compatible computer. The data are stored in ASCII format either on the external computer or on micro secure-digital card in FAT32 format.

The DAS-1 interfaces directly with our proprietary ERTLab 3-D Inversion Software which allows three-dimensional topographical modeling and inversion, creation of 2D and 3D arrays/schedules of electrical resistivity measurement and a powerful graphical environment for displaying resistivity and IP models.

The specifications are available in Adobe Acrobat Reader™ format.

If you don't have Adobe Acrobat reader or need an updated version, visit the Adobe™ website to get your free download.




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