Delta-T Devices Ltd.

- Model GP2 - Advanced Data Logger and Controller


The GP2 is a powerful 12 channel data logger that is easy to use, SDI-12 compatible, versatile, rugged and reliable. It can log most sensor types and accepts voltage, resistance, current, potentiometer, bridge, counter, frequency, and digital state inputs. DeltaLINK software helps the user set up logging sequences and provides control over reading frequency, sensor type, thresholds, units and much more. All Delta-T sensors can be selected from a menu.

  • Powerful and rugged field data logger
  • 12 differential (or 24 single ended) channels
  • SDI-12 enabled
  • Ideal for demanding research applications
  • Compatible with DeltaLINK-Cloud online data sharing platform
  • Calculation of full Penman-Monteith evapotranspiration equation

The Resource Centre contains a wide range of application information and tutorials – covering irrigation control, evapotranspiration, vapour pressure deficit, and much more. Visit the GP2 Resource Centre.

The GP2 Data Logger features advanced controller functionality, and sophisticated programs can be easily created via a simple scripting editor.

As the user’s needs change, the GP2 can adapt. An optional lid is available for additional cable entry points, or wider diameter cable entry points.

The GP2 Data Logger can log most sensor types and accepts voltage, resistance, current, potentiometer, counter, frequency, and digital state inputs.

The GP2’s analog inputs can be fully customised. Each channel can have its own input type and recording parameters. DeltaLINK software gives the user control over reading frequency, thresholds and units, and provides statistical recording options for Average, Minimum, Maximum, Standard Deviation and more. Specialised wind options are available including wind rose, gusts and wind averaging.

Users can add their own custom sensor types to the sensor library, exploiting the GP2’s detailed configuration options. The GP2 provides 4 input ranges down to microvolt resolution with adaptive auto-ranging, excellent analog accuracy, and configurable sensor excitation – enabling it to support nearly all analog sensors.

Calculations based on the measurements from several input channels can be recorded and displayed as additional virtual channels (calculated measurements).

The GP2 is the ideal data logger for field work, with applications ranging from agronomy, meteorology and hydrology to eco-physiology and soil science. We can supply complete systems including sensors, enclosures, solar power and communications options.

The GP2 Data Logger is compatible with all Delta-T sensors. For the Delta-T WET Sensor there is a dedicated input channel.

Delta-T has decades of experience of instrumentation for environmental research and can advise on all aspects of system specification.

Simple point and click software makes it easy to configure channel set-up and recording intervals. The menus that support the advanced customisation options can be displayed or hidden as required.

Sensor connections are laid out logically with clear, easy-to-follow diagrams and notes.

The GP2’s weatherproof case, battery power and convenient accessories make it very easy to install in the field – often without the need for a secondary enclosure.

This unique software feature allows logging programs to be tested before real-world activation. For applications involving weather data, irrigation or soil moisture recording, the environmental variables can be changed to test how the program responds. Years of logging time can be simulated in just a few minutes.

4 MB of FLASH memory enable storage of 2.5 million readings (typical). Data can be collected by a laptop locally via USB/RS232 or remotely using the cellular modem options.

The GP2 has 6 alkaline AA internal batteries as standard. An optional mains power adapter is available (type GP2-PSU). Up to 7 GP2s can share power and communications using an M12 cabling network. GP1 Data Loggers can be integrated into such a network via an adapter cable.

The GP2 Data Logger supports SDI-12 inputs as standard. GP2s supplied before March 2016 can be easily updated via a software download.

Key features:

  • Huge additional input capacity for SDI-12 sensors
  • Analogue and digital channels fully available
  • Highly flexible logger + sensor networks

The GP2 Data Logger and DeltaLINK software (versions 3.7 and later), in combination with relevant sensors, enables the full ASCE/FAO-56 Penman-Monteith equation for calculating reference evapotranspiration (ETo).

ETo is calculated by the GP2 Data Logger using the available measurements of relative humidity, wind speed, solar radiation, and air temperature. This ET implementation includes the ability to vary crop albedo/LAI, canopy resistances, crop height and sensor heights.

The functionality can be easily accessed by users as a selectable recording option within DeltaLINK. Calculated ET can be recorded as hourly and daily values – and may be used in further bespoke calculations or to guide field irrigation decisions.

This enhancement also applies to the WS-GP2 Weather Station – an advanced research-grade system.

The GP2 Data Logger has a wide range of environmental, agricultural and industrial applications: Horticulture and Irrigation, Soil Science, Plant Physiology, Agronomy Climate Research and Meteorology, Agriculture, Turf and Gardens, Amenity Landscaping, Ecology, Field Trials, Eco-Physiology.

  • Input connections:
    • 12 differential (or 24 single-ended) analog inputs configurable as: Voltage, Resistance (12 3-wire or 24 2-wire), Bridge (12), Potentiometer (12)
    • 4 digital inputs as: Counters, (2 fast + 2 slow), Frequency, Digital state
    • 1 Delta-T WET sensor channel
    • Unlimited virtual channels
  • Serial input channel: 62 SDI-12 sensors or a single WET Sensor
  • Control outputs: 2 relay outputs expandable to 6 (1 A)
  • Readings stored: 2.5 Million
  • Recording rate: 1 second to 24 hours
  • Configuration: DeltaLINK
  • Communication options: USB, RS232, ethernet or modem
  • Sensor excitation: Calibrated 3V reference, +5 V and +12 V regulated, or 5 to 10.5 V (battery or external power), user selectable
  • Power: 6 AA alkaline batteries or external power 10-15 V DC
  • Battery life (dependent on usage): >310K readings, lasting 530 days
  • Enclosure rating: IP65
  • Temperature range: -20 to +60°C
  • Display: –
  • Size: 225 x 185 x 75 mm
  • Typical applications:
    • Demanding research projects
    • Environmental monitoring
    • Varied control applications

Sensor compatibility (maximum number of sensors that could be connected [1]

  • ML3: ✓ (6) with temp / (12) without temp
  • SM150T: ✓(6) with temp / (12) without temp
  • PR2: ✓(2 PR2/6) (3 PR2/4)
  • PR2 SDI-12: ✓ (50)
  • WET Sensor: ✓ (1)
  • EQ3: ✓ 6 with temp / 12 without temp
  • Temperature: ✓ (12)
  • Tensiometers: ✓ (12)
  • Counters or Events: ✓ (4) 2 fast 2 slow
  • Relay Output: ✓(2) expandable to (6)