GroPointProfile

Multi-segment soil moisture and temperature profiling probe

GroPoint™ Profile provides cost-effective measurement of volumetric water content over multiple depths using a single probe, eliminating the cumbersome excavation required for multiple sensors placed at different depths. It can be deployed in irrigation-sensitive zones to enable full control of precision irrigation needs, providing an understanding of water movement through the soil.

The sleek, lightweight design installs quickly with minimal soil disruption using a pilot rod and slide hammer tool. Designed for vertical installation, the sensor takes measurements over multiple soil layers, with each measurement zone (segment) providing the average volumetric soil moisture content over a 15 cm range (approximately 6 inches).


The Most Accurate and Cost-Effective Soil Profiling Solution Available

  • Eliminates need for multiple sensors and cabling systems.
  • Installs quickly and easily without excavating.
  • One SDI-12 address is used to read all segments, providing for simplified installations. Optional RS-485 output.
  • Moisture readings can be user-calibrated with 3rd-order polynomials to meet custom requirements.
  • Low power requirements—suitable for remote, autonomous applications.
  • Patented TDT5 technology for scientific-grade accuracy and excellent long-term stability of measurements.
  • Fully potted electronics for excellent durability.

Configurations

GroPoint Profile is available in six different multi-segment lengths, suitable for a wide range of agricultural crop monitoring.

You can also choose from two different configurations for temperature sensors, depending on your requirements. You can configure it with no temperature sensors if you only require moisture measurement, or the standard configuration places temperature sensors every 1 or 2 segments.

Choose the number of 15 cm (6") segments that are right for your application. Custom lengths also available.

Moisture

Measurement range

0% to 100% of VMC

Accuracy

±1.0% *

Precision

< 0.2%

Temperature

Measurement range

-20°C to +70°C (-4°F to 158°F)

Accuracy

±0.5°C

Electrical

Output

SDI-12 V1.3 (RS485 optional)

Connection

Bare wire (optional 4 pin, IP66/IP68 rated environmental connector)

Input voltage

6 to 14 VDC max. 18 VDC

Current consumption

Quiescent: <0.5mA
Active: 15-20 mA (depending on number of segments) for 100 mS

Warm-up time on power up

< 1 second

Environmental

Operating temperature

-20°C to 70°C (-4°F to 158°F)

Storage temperature

-40°C to 85°C (-40°F to 185°F)

Physical

Length

Each segment is approximately 15 cm (5.9") long. Total length is the number of segments multiplied by 15 cm. For example, a 3-segment probe is about 45cm long.

Probe weight

2 segments: 292 g (10.3 oz.)
3 segments: 351 g (12.4 oz.)
4 segments: 408 g (14.4 oz.)
5 segments: 468 g (16.5 oz.)
6 segments: 526 g (18.6 oz.)
8 segments: 642 g (22.6 oz.)

Cable weight

38 g per m (0.42 oz. per foot)

Standard cable

5 m (16.3 ft.)
4xAWG22 dual-shielded, twisted pair, rated for direct burial

Warranty

1-year limited parts and labour

* 8% to 42% VMC, in controlled laboratory conditions; factory calibrated for most agricultural soils. In field applications, accuracy may slightly decrease due to the inevitable heterogeneity of soil texture, soil compaction, moisture and fluctuation in soil temperature. The accuracy may also decrease in difficult soil conditions (higher clay and salinity content). In normal conditions, GroPoint sensors will maintain their accuracy from permanent wilting through field capacity in sandy loam through clay soils with less than 60% clay particles. Under moderately saline conditions. GroPoint sensors will maintain their accuracy up to 6 ds/m.

Is it compatible with all data loggers?

Yes, GroPoint Profile will work with virtually any data logger that supports the SDI-12 standard.

Can it be used as a portable solution?

GroPoint Profile is for permanent or semipermanent installations only. For proper accuracy it must be installed properly, not just poked in the ground for a quick reading. However, given the ease of installing (no excavation required, no access tube required) and its low price point relative to other soil profiling sensors, there's little reason not to use permanent GroPoint Profile installations for monitoring soil moisture throughout your site.

What kind of soils can it be used in?

GroPoint Profile probes can be used in virtually any soil.

Does it need to be calibrated for different soil types?

GroPoint probes are factory-calibrated for use in most soils. There are also two other standard calibrations that can be used, which you can specify when you order. Below is an image of a standard soil texture triangle. By default, calibration is done for a wide variety of soil types represented by the red area. You can also request that your sensor is calibrated for clay or highly saline soil (the green area) or sandy soils (blue area).
Soil moisture probe
Custom calibration can be done at our facility upon request. End customers can also perform their own calibration (documented in the User Manual).

If I use a sensor calibrated for a different type of soil than I have, will I lose accuracy?

If you're using a sensor with the wrong calibration, measurements will have a small absolute/relative error, read either too high or too low by up to 4%.

My soil horizons span sandy, loamy and clay mixtures. Can each segment be calibrated differently to more accurately measure the different soil horizons?

Yes! Each segment can be calibrated for different soil horizons via SDI-12 extended commands entered through a small software utility.

Can the sensor cable be buried, and is it durable enough to be left exposed on the surface of the ground?

GroPoint sensors are furnished with a high quality cable suitable for direct burial or exposure to direct sunlight. It is resistant to damage from insects, abrasion and normal environmental exposure. However, mechanical damage from hoes, coyotes, gophers, other animals, and cultivators can easily cut this cable. Any problem with this sensor will most likely be due to damage to the electrical cable. To prevent damage, it is strongly recommended that the cable be installed in 3/4-inch electrical conduit. This size conduit is required to accommodate the passage of the plug connector.

What is the maximum length of cable that can be used with the sensor?

According to the SDI-12 specification, the combined length of all sensors connected to a data logger cannot exceed 610 m (2,000 feet). So one sensor with a 610 m cable or 10 sensors each with a 61 m cable.

Can I use my own cable to extend the length of the standard cable?

Custom cable lengths can be ordered from us, or cable may be spliced by the customer. Each cable has three wires. The cable must be 22 gauge copper or larger.

All connections should be made inside a waterproof box using silicone filled, waterproof, wire nut connectors. These waterproof connectors are available at local electrical/hardware suppliers, such as The Home Depot.

Why is it so accurate? Most soil sensors I see are only accurate to 3%.

GroPoint sensors feature an accuracy rating of < ±1% (< ±0.01m3m-3) volumetric soil moisture, between the range of 8% to 42% VMC (this is the normal range for agricultural applications). We obtain this accuracy through a patented technique which improves the performance of the already reliable TDT method of soil moisture measurement. This patented technology is called TDT5, which you can read about here.

While the < ±1% accuracy rating is achieved in controlled laboratory conditions, GroPoint sensors are factory calibrated for most agricultural soils. In field applications, accuracy may slightly decrease due to the inevitable heterogeneity of soil texture, soil compaction, moisture and fluctuation in soil temperature. The accuracy may also decrease in difficult soil conditions (higher clay and salinity content). In normal conditions, GroPoint sensors will maintain their accuracy from permanent wilting through field capacity in sandy loam through clay soils with less than 60% clay particles. Under moderately saline conditions, GroPoint sensors will maintain their accuracy up to 6 ds/m.

What is TDT5? How does it differ from other soil measurement methods?

TDT5 is a proprietary technology based on Time Domain Transmission (TDT), which is a refined version of Time Domain Reflectometry (TDR). TDT measures the time taken for an electromagnetic wave to propagate (travel) along a given length of a transmission line in the soil. Moisture in the soil changes the soil’s dielectric properties, so that the electro-magnetic wave travels at different rates in wet soil compared to dry soil. This allows for the accurate determination of the soil moisture content.

However, we add our own engineering designs that result in a less expensive, more robust and more accurate (with greater repeatability) sensor than with pure TDT alone. This enhances TDT in five (hence "TDT5") key ways:

  1. Measures with an antenna 5 times longer than the physical length of the probe, to reduce the impact of noise - boosts accuracy to ±1% and repeatability to < 0.2%
  2. Filtering 400,000 pulses for each measurement - boosts accuracy to ±1% and repeatability to < 0.2%
  3. Captures measurement in less than 100ms - reduces power consumption
  4. Embeds antenna and circuitry on a single board - dramatically reduces cost to manufacture
  5. Encases entire sensor in a durable, sealed polycarbonate housing - maximizes durability

I'm not in BC, Canada. Can I buy and obtain support for GroPoint products locally?

GroPoint has dealers in several international locations as well as across Canada. You can find your local dealer on the Dealers page.

GroPoint products are also sold online and we offer several self-help support resources, as well as unlimited support via phone, email and online chat.

What is the area of influence for the sensor?

GroPoint Profile probes detect water as much as 5 centimetres (2 inches) from the surface of the probe fins although, like all dielectric based sensors, moisture closest to the surface of the probe has more influence on the readings than moisture further away so that soil closely surrounding the sensor will have a greater influence on the soil moisture reading than the soil.

The slide hammer is quite expensive to ship to the US from Canada. Can I purchase it from and ship it within the US?

Our longtime partner, and the manufacturer of the slide hammer, AMS out of Idaho, sells it on their website. Here is a link to the product page.

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Extend the standard 5m cable of your GroPoint sensor. Choose the additional length to add to the standard 5 m length.

Weight: 38 g/m | 0.026 lb/ft



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Installing a GroPoint Profile probe is quick and easy with no excavation required. Attach the slide hammer to the sturdy steel pilot rod.

Slide the top segment of the slide hammer up as much as it goes, then down forcefully. It will strike the bottom segment and drive the attached pilot rod into the soil.

The hole will be the exact size of the probe, so not only is there minimal disruption to the surrounding soil, there will be no air gaps between the probe and the undisturbed soil. This clever design further increases measurement accuracy.

The slide hammer is used to extract the pilot rod again, with a couple of quick upward movements.

This single GroPoint Profile probe is equivalent to 4 separate probes. It measures soil moisture at 4 different depths simultaneously.

Each segment averages
the volumetric moisture
content measured over 15 cm (5.9").

Analyze water movement
through the soil

TDT5GroPoint's patented technique for soil moisture measurement

Our proprietary TDT5 technology delivers an exceptional price:performance ratio, with performance as good (in most cases better) as sensors costing much more.


How does it work?

GroPoint™ sensors are based on the field-proven Time Domain Transmission (TDT) method of reliably measuring soil moisture, which is a refined version of Time Domain Reflectometry (TDR). TDT-based sensors do not need to be calibrated to each type of soil they will be buried in to deliver excellent accuracy and stability, however we do calibrate for 3 specific soil types for even greater accuracy.

TDT5 enhances TDT in 5 key ways:

Antenna length per segment: 15cm

Effective length (if stretched out): 75cm

1:Extreme accuracy

Our patented design weaves the antenna through the circuit board 20 times per centimetre, and much like a coiled spring the effective length of the antenna is 5 times the physical length it consumes. It's like having a 75cm long antenna in a single 15cm sensor. A larger antenna increases the resolution of each sample, allowing more noise to be filtered out, improving the accuracy to ±1% (between 8% to 42% VMC).

2:Reduced manufacturing cost

Unlike other moisture probes, Gropoint sensors do not have separate components for electronics and bulky metal antennas. By integrating the antenna and all electronics into the same circuit board (possible thanks to the patented antenna design), manufacturing costs are dramatically reduced.

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3:Repeatable accuracy

Each time a measurement is taken, GroPoint sends 400,000 pulses through the sensing element to generate data for the measurement, then employs advanced filtering to eliminate outlying readings (noise) before averaging the data and sending the measurement as SDI-12 output. This ensures that the same extreme accuracy (±1%) is obtained each and every time moisture is measured.

400000

pulses filtered per measurement

4:Low power consumption

Even with 400,000 pulses for each measurement, the total time to take the measurement is less than 100 ms. This means that power consumption is minimal, and that permits GroPoint sensors to be operated for many months with small 9V battery-powered data loggers.

power consum
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5:Maximum durability

Unlike typical sensors, the antenna is not exposed to the soil, so there's nothing to bend or break. The entire sensor circuit board is sealed in epoxy then encased in a sealed polycarbonate housing.

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Epoxy sealant

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Polycarbonate housing


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Soil moisture sensor product catalog