EQ3 Equitensiometer for measuring Matric Potential

Delta T


Equitensiômetro: Sensor de Potencial Matricial de Solo

850,00 €

Add to wishlist

The Sensor measures: Matrix potential
Output Signal: 0-1V differential
Power Supply: 5 to 15V, 20mA for 1s

The EQ3 uses class leading ThetaProbe technology to avoid the many problems of water-filled tensiometers. It measures water potential (matric potential) in the range 0 to -1000 kPa and provides an accurate loggable output. It is particularly well suited for use in dry soils.

How it works:
The EQ3 tensiometer offers maintenance-free operation over a wide soil water potential range. It provides reliable matric potential measurements as well as soil temperature.

EQ3s measuring rods are embedded in a porous material (the equilibrium body). This material has a known, stable relationship between water content and matric potential.
When the EQ3 tensiometer is inserted into the soil, the matric potential within the equilibrium body equilibrates to that of the surrounding soils.
The water content of the matric material is measured directly by the EQ3, and this can be converted into the matric potential of the surrounding soil using the calibration curve supplied with each Equitensiometer.

Installation and usage:
The EQ3 Tensiometer is buriable (IP68) and maintenance-free.
The unit can be inserted into augured holes or positioned in the wall of a trench (which is then carefully back-filled).
Optional extension tubes assist deployment and removal when burying at depth.

The EQ3 is a rugged, maintenance-free (no refilling, degassing, or topping up required), frost resistant and low powered unit. This means it can left installed at remote sites over long periods of time.
In such cases it is possible to access sensor data wirelessly via a modem, using a data logger such as the Delta-T GP2.

Note that despite its many strengths, the EQ3 should not be seen as a rapid response sensor that covers the full range of water potentials at high accuracy.
Such a sensor does not yet exist. EQ3 equilibration time is typically several hours.

Data logging:
The EQ3 can be logged by any Delta-T data logger, including the powerful GP2.
It is also compatible with many other manufacturers’ data loggers.
The EQ3 can also be used with an HH2 Moisture Meter, but only the unconverted millivolt output is displayed, and the temperature reading is not available.

New features
The incorporation of thermistor sensor to the EQ3 enables the simultaneous logging of soil temperature and water potential. A new cabling system makes it very easy to extend or replace cables, offering a choice of 1m, 5m, 10m and 25m extensions. EQ3 cables and connectors are buriable (IP68).


Matric Potential


±10kPa over 0 to -100kPa,

±5% of reading over -100 to -1000kPa

Measurement range

0 to-1000kPa (-10bar)



Not detectable if the change of matric potential is slower than 0.1kPa/min

Soil types

Suitable for all non-saline soil types

Output signal


0-1V differential, non-linear. 
(Calibration data and graph supplied with each sensor)

Output compatible with

GP1, GP2, DL6, DL2e, HH2

Temperature (EQ3 must be fully buried to accurately measure soil temp)

Sensor accuracy

±0.5°C over 0-40°C
not including logger or cabling error


Resistance: 5.8kΩ to 28kΩ

Output compatible with

GP1, GP2, DL6 1, DL2e, HH2

Cabling error 
(for temperature readings)

Negligible for GP1, GP2 & DL6 (100m cable limit)
Negligible for DL2e (with 5m cable) 2


Max cable length

100m (GP1, GP2 & DL6 data loggers)
100m (DL2e: water content measurement)
25m (DL2e: temperature measurement)

Power requirement

5 to 15V, 20mA for 1s

Operating range

-0 to +40°C 
(Not damaged by use in frozen soils)




181mm x 40.5mm dia./260 gm 
(without cable)

The EQ3 Equitensiometer is ideally suited to static long term monitoring of water potential in soils and substrates. It can even be left installed in frozen soils.
The typical applications of the EQ3 include environmental, plant, soil, ecology and geo-sciences research, as well as civil engineering and agricultural engineering applications.

The EQ3’s full range is 0 to -1000 kPa but best accuracy is achieved between -100 and -500 kPa. This makes it well suited to plant water stress studies – even in very dry soils.

EQ3 connection cable:
 SMSC/lw-05 SMS cable 5m, long bare wire IP68 M12 connector (f) to bare wire. 200mm flying cables.
This cable also connects: WET150, ML3, SM150T, EQ3 or PR2 SDI-12 soil moisture sensor for data loggers.

Extension Cables:

EXT/5W-01    1m extension cable, 5-way M12
5m extension cable, 5-way M12
10m extension cable, 5-way M12
25m extension cable, 5-way M12

The EXT/5W-xx range of cables can be connected together to create cable runs to the length required.
The final EXT/5W-xx cable is connect to an SMSC/lw-05 cable (bare wires suitable for connections to a data logger).
EXT/5W cables are compatible with ML3, SM150T, EQ3 and PR2 SDI-12 soil moisture sensors, and with GP2 cable network
All cables are IP68 M12 connector (f) to IP68 M12 connector (m)

30 other products in the same category: