Introduction
Cables
To meter
Extension cables
To GP2 and other loggers
Connector
Fully waterproof
M12 connector -
SDI-12
Industry-standard digital interface, compliant to version 1.3
Installation
Threads enable extension rods to be screwed on for easy insertion in augured holes – minimising soil disturbance
Detectors
Soil moisture content and EC are detected by sensitive circuits operating at 100MHz
Outputs
Sophisticated correction algorithms ensure accurate readings across the full range of water content, EC and temperatures
Temperature
Thermistor is located within the base – equilibrates to the soil temperature when installed, less well for portable measurements
Sensing field
Extends ~100mm into the soil, but field is strongest close to the rods - install carefully to avoid air gaps
Introduction ⚫ 5
Description
•
•
•
The WET150 Sensor is a multi-parameter sensor for use in soils, substrates and other growing media. It measures the dielectric properties of the soil and calculates:
W ater Content
E lectrical Conductivity
T emperature
The sensor converts the measured dielectric properties into
Water Content over the full range, 0 to 100%, being most accurate, ±3%, over 5 to 100% water content and over 0 to 500 mS/m soil bulk conductivity. Generalised calibrations are provided for most common soil types.
The WET150 Sensor also measures the bulk electrical conductivity of soil ( EC b
) over 0 to 2000 mS/m, being most accurate, ±(10 mS/m + 6%), from 0 to 1200 mS/m.
It also calculates Pore Water Conductivity , the electrical conductivity of the water within the pores of the soil ( EC p
).
Temperature is measured by a miniature sensor built into the body of the sensor.
The WET150 Sensor works with the WET150 Meter and the
GP2 logger controller.
It can also be used with other SDI-12 loggers, and with SDI-12 fertigation and irrigation control systems.
Advantages of the WET150 Sensor
•
Fast, accurate, adaptable and easy to use
•
Rapid measurements (~1 second) of all 3 parameters
•
In-situ Pore Water Conductivity measurements
•
Easy insertion into growing media and soil
•
Works with many different soils and growing media
•
Stable, accurate readings from
5 to 100% water content
0 to 1200 mS.m
-1
-20 to +50°C
•
Lightweight ergonomic design
•
Versatile SDI-12 digital output
•
Systems integrator friendly
•
Wide choice of settings, outputs and units
•
Low power for long battery life
•
2-year warranty extends to 5 years if registered on delivery
6 ⚫ Introduction
How the WET150 Sensor works
Measurement Principle
When you insert the WET150 Sensor into soil and take a reading...
...it generates a 100 MHz signal...
...which is applied to the pins and produces a small electromagnetic field within the soil.
The water content, electrical conductivity, and composition of the soil surrounding the pins...
...determines its dielectric properties .
➔
The WET150 sensor detects these dielectric properties from their influence on the electromagnetic field and calculates ...
… Soil Moisture and Pore Water Conductivity .
It also records Temperature and uses that to improve the accuracy of the other measurements
… and sends the results, on demand, to either an
WET150 meter, GP2 logger-controller or other SDI-12 enabled device
Introduction ⚫ 7
Parts and Accessories
WET150 sensor
WET150 Kit WET150 + WET150 Meter
SMSC/lw-05
EXT/5W-01
EXT/5W-05
EXT/5W-10
EXT/5W-25 ]
GP2-NTP
ML/EX50
ML/EX100
5m cable with 200 mm flying leads.
Connects WET150 to GP2 directly, or via SDI-12 network of EXT/5W-xx cables
1 m, 5 m,10 m and 25 m extension cables with 5way M12 connectors.
Connects WET150 to an
SDI-12 sensor network
3-way network T- Piece for connection WET150 and
EXT/5W-xx cables
Extension tubes,
50 and 100 cm
SM-AUG-100 Spiral Auger 1.2 m
8 ⚫ Introduction
Care and Safety
The pins of the WET150 are sharp in order to ease insertion. Care must be taken and handling precautions followed.
•
Avoid touching the pins or exposing them to other sources of static charge, particularly when powered up.
Keep the WET150 in its protective package when not in use.
•
Take care when attaching cables to ensure that the connectors are clean, undamaged, and properly aligned before pushing the parts together.
•
Do not pull the WET150 out of the soil by its cable.
•
If you feel strong resistance when inserting the WET150 into soil, it is likely you have encountered a stone. Stop pushing and re-insert at a new location.
•
WET150 is unsuitable for use in hard soils unless holes are preformed. Rough handling may cause irreparable damage to the pins
Introduction ⚫ 9
