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DataTaker

DT85G GeoLogger

The DataTaker DT85G is an intelligent, low-power, and highly rugged data logger specifically optimised for geotechnical and structural monitoring applications. The “G” in the model name stands for Geotechnical, signifying its built-in support for vibrating wire sensors commonly used in civil engineering, mining, and structural health monitoring.

An overview of its core capabilities, features, and technical specifications includes the following:

Key Geotechnical Focus

Unlike general-purpose DT85 data logger, the DT85G is tailored to interface directly with major geotechnical sensor brands (such as Geokon, RST Instruments, Slope Indicator, and Soil Instruments).

  • Vibrating Wire Support: It has specialised onboard circuitry to pluck and read vibrating wire sensors (measuring strain, pressure, or displacement) over a frequency range of 500 Hz to 5 kHz.
  • Capacity: It features 16 analogue channels capable of reading up to 16 vibrating wire sensors with temperature compensation (thermistors), or up to 48 vibrating wire sensors if temperature compensation isn’t required.
  • Sensor Compatibility: Direct support for Extensometers, Piezometers, Inclinometers, Strain Gauges, Pressure Cells, Crack Meters, and Tiltmeters, as well as Carlson, Electrolevel, and LVDT devices.

Universal Analogue & Digital Channels

Beyond geotechnical sensors, the DT85G functions as a highly flexible universal logger:

  • Analogue Inputs: Supports up to 48 single-ended (common reference) or 16 isolated 3- or 4-wire analogue inputs. It natively measures voltage (±50V max), current (4-20mA loops via internal shunts), resistance, and frequency.
  • Expandability: If 16 to 48 channels aren’t enough, it can be expanded up to 960 analogue inputs using DataTaker Channel Expansion Modules (CEM20).
  • Digital I/O: Features 12 bi-directional digital channels, high-speed counters, and 1 latching relay output to trigger external alarms or control hardware.

Data Storage & Communication

The logger is designed to operate reliably in remote environments where consistent physical oversight isn’t possible.

  • Massive Memory: Can store up to 10 million data points in its internal non-volatile memory, which can be configured to overwrite older data or stop logging once full.
  • Connectivity: Equipped with RS232, USB, and Ethernet ports.
  • Networking Protocols: Built-in Web and FTP client/server functionality allows it to automatically push data to an office server or email reports on a scheduled basis. It also supports Modbus (master/slave) for easy integration into SCADA systems and SDI-12 for environmental sensor networks.

Software & Usability

  • dEX 2.0 Web Interface: The DT85G features a pre-installed, built-in browser interface. There is no proprietary software to install; you simply connect via USB or Ethernet, open a web browser, and configure your logging schedules, view live charts, mimic diagrams, or download CSV files.
  • Calculated Channels: Allows users to program complex mathematical expressions, polynomials, and statistical calculations directly onto the logger so data is linearised and scaled before storage.

Physical & Environmental Specs

  • Robust Construction: Housed in a powder-coated steel and anodised aluminium chassis.
  • Operating Temperature: Extremely wide operational threshold from -45°C to 70°C (though the integrated LCD screen’s functionality reduces outside of -15°C to 50°C).
  • Power: Highly power-efficient with internal battery options and smart sleep modes, making it ideal for solar-powered setups in remote areas like dams, tunnels, landslides, and open-pit mines.

Applications

Automating long-term tracking of pore water pressure, structural seepage, and concrete core temperature arrays using vibrating wire piezometers.
Continuous parsing of structural deformation, rock strain profiles, and lateral wall movement using multi-point borehole extensometers and load cells.
Real-time analysis of load distribution, structural integrity, and curing stresses in deep piles, bridges, and high-rise foundations via cross-brand vibrating wire arrays.
Acting as an autonomous, low-power mountain telemetry hub tracking slope movement and shear strain via in-place inclinometer networks over FTP networks.
High-capacity logging of deep strata stability, groundwater shifts, and mechanical stress profiles under punishing underground conditions.

Frequently Asked Questions

â–¶ Q: What explicitly distinguishes the DT85G from the standard industrial DT85 model?
A: The fundamental distinction is the native onboard geotechnical sensor core found exclusively inside the DT85G. While the standard DT85 is a universal industrial data logger for standard process loops and thermal couplings, the DT85G includes integrated single-pulse pluck excitation circuits, frequency counters, and sensor diagnostics designed to directly monitor vibrating wire sensors without any external hardware cards.
â–¶ Q: How does the channel configuration breakdown change when utilising vibrating wire sensors with thermistors?
A: Because vibrating wire sensors deployed in civil applications typically integrate a thermistor for thermal expansion adjustments, they require separate signal runs. The DT85G natively supports 16 vibrating wire sensors when paired concurrently with their accompanying internal thermistors. If processing raw, uncompensated vibrating wire frequency lines alone, the logger can accept up to 48 distinct sensor points.
â–¶ Q: What major geotechnical instrument brands are supported by the DT85G's input deck?
A: The DT85G features a broad universal entry system compatible with virtually all dominant global manufacturers of geotechnical monitoring sensors. This provides native field validation for hardware lines produced by Geokon, Soil Instruments, RST Instruments, Slope Indicator, Roctest, and AGI (Applied Geomechanics Inc.).
â–¶ Q: How do the CEM-20 expansion modules scale the overall architecture up to 960 channels?
A: Each external CEM-20 module delivers 20 multiplexed analogue input channels to the platform. By daisy-chaining these modules onto the serial expansion terminal of the DT85G, users can steadily increase processing density. The system accommodates complex arrays up to a maximum threshold of 960 common-referenced entries or 320 isolated sensor configurations with thermistor mappings.
â–¶ Q: Does the dEX 2.0 browser software require an active internet connection or ongoing licensing fees?
A: No. The dEX 2.0 software application is embedded directly inside the physical memory of the DT85G data logger. It acts as a locally hosted server webpage, meaning you can configure recording schedules, view historical trending blocks, and set system thresholds completely offline by connecting directly over USB or local Ethernet via a desktop, laptop, or tablet with zero licensing costs
DT85G

DT85G

Datataker DT85G series stand alone data logger, mains or battery powered, with 16-48 analogue inputs ( universal input type ), 12 digital I/O, MODBUS and SDI-12 serial input, USB memory up to 512 MB ( 50 million readings ), Logging rates 25 Hz to 99 days.

£5,710.00
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CEM-20

CEM-20

The CEM20 is the Channel Expansion Module for DT80 and DT85 data loggers Series 2 and above. This allows a further 60 single ended inputs (voltage, current or Thermocouple) or 20 fully differential inputs (PT100 or bridge) to be added to the DT80 or DT85. One full analogue input channel on the logger is used to connect the CEM 20.

£1,100.00
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