GP1 Data Logger

    How to Buy
GP1 2 – Green label – smaller file – CopyGP1 3 – Green label – smaller file – CopyGP1 4 – Green label – smaller file – CopyGP1 5 – Green label – smaller file – Copy


  • Monitor soil moisture and other key growing conditions
  • Use data to optimise irrigation
  • Directly control irrigation using onboard relay

With the GP1 Data Logger it is possible to control irrigation, with measurable water savings of up to 60% achievable without reductions in yield or decline in quality.*

Irrigation can be controlled using combined sensor inputs – soil water, temperature, RH, rainfall, volume of water applied – with or without clock inputs.

The GP1 is also a versatile general purpose 7 channel data logger.


The benefits of optimising crop irrigation can include reduced water use, less fertiliser, reduced run-off, lower pumping costs, better crop quality and reduced labour cost – all leading to increased profits.

NB: Our GP2 Advanced Data logger and Controller offers even more advanced irrigation control capabilities.





Input connections2 voltage channels
2 temperatures or 2 additional SM150T Sensors [3]
2 counters (33 kHz & 50 Hz)
1 WET Sensor
Control outputs1 relay (1 A)
Readings stored600,000
Recording rate1 second to 24 hours
Communication optionsRS232 USB [1] or modem
Sensor excitation1 switched logger power
1 5 V precision reference
Power9 V 6LR61 (PP3) alkaline or external power 11-24 V
Battery life (dependent on usage)>76k readings
lasting >130 days
Enclosure ratingIP67
Temperature range-20 to +60°C
Size140 x 105 x 45 mm
Typical applicationsMonitoring soil moisture
General data logging
Controlling irrigation


Sensor compatibility (maximum number of sensors that could be connected [2]
ML3✓ (2) with temp ✓ (4) excl. temp [3]
SM150T✓ (2) with temp ✓ (4) excl. temp [3]
PR2 SDI-12
WET Sensor✓(1)
EQ3✓(2 as mV only)
Tensiometers (bridge sensors)✓(2) each requires GP-PBA-X50
Counters or Events✓(2) 1 fast 1 slow
Relay Output✓(1)


[1] With USB to RS232 Adapter Cable type USB-RS232

[2] With appropriate expansion cards and power supply arrangements

[3] Temperature channels provide only single-ended inputs so should not be used with long cables or in noisy environments when used with soil moisture sensors. The accuracy figures quoted for GP1 soil moisture readings do not apply to these resistance channels when configured as soil moisture inputs.


For full GP1 specification please see the GP1 data sheet or Quick Start Guide

Product Resources

Data Sheets

Case Studies



Technical Notes


Regulatory Information