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5TM Soil Moisture Sensor

Measurements:
Applications:

Many a researcher has looked over a soil moisture data set and thought, "I wish I had temperature data with this..."

Temperature Integrated with Soil Moisture

The 5TM delivers temperature, measured by an onboard thermistor, along with accurate volumetric water content.

Engineered for Accuracy

The 5TM determines volumetric water content (VWC) by measuring the dielectric constant of the soil (or other media) using capacitance/frequency domain technology. Signal filtering minimizes salinity and textural effects, making the 5TM accurate in most soils and soilless media. Factory calibrations are included for mineral soils, potting soils, rockwool, and perlite.

Easy Installation

The 5TM's small size makes it easy to install--perfect for in field installations. This robust probe can be pushed directly into undisturbed soil to ensure good accuracy. Its compact design makes it useful not only in the field, but also in labs or greenhouses.

Plug and Read

Get straight to the data with an Em50-series data logger. Just install the 5TM, plug it into the Em50, set the clock and measurement intervals, and start logging data. No programming required.

Want to Use a Different Logger? No Problem!
The 5TM comes standard with both serial and SDI-12 communication options, meaning easy integration with systems manufactured by other companies (such as Campbell Scientific).

Reasons to pick the 5TM:

If you want to measure volumetric water content, AND

Are interested in mechanisms that are affected by temperature
Want to use SDI-12
Anticipate temperature change in your soil (or soilless media)
Don't want to be one of those researchers saying, "I wish I had temperature data with this..."

Specifications

Part number 40490 (Stereo), 40491 (Pigtail), 40492 (Custom)

Accuracy

Apparent Dielectric Permittivity (ε_a): ± 1 ε_a from 1 - 40 (soil range); ± 15% from 40 - 80

Soil Volumetric Water Content (VWC):

Using Topp equation: ± 0.03 m³/m³ (± 3% VWC) typical in mineral soils that have solution electircal conductivity < 10 dS/m
Using medium specific calibration, ± 0.02 m³/m³ (± 2% VWC) in any porous medium

Temperature: ± 1°C

Resolution

ε_a: 0.1 ε_a from 1-20, < 0.75 ε_a from 20-80

VWC: 0.0008 m³/m³ (0.08% VWC) from 0 to 50% VWC

Temperature: 0.1°C

RANGE

ε_a: 1 (air) to 80 (water)

Temperature: -40 - 50°C

Dimensions

10 cm x 3.2 cm x 0.7cm

Cable Length

5 m standard, custom cable lengths available upon request

Measurement Time

150 ms (milliseconds)

Power

3.6 - 15 VDC, 0.3 mA quiescent, 10 mA during 150 ms measurement

Output

RS232 or SDI-12

Connector Types

3.5mm "stereo" plug, or stripped and tinned lead wires (3)

Data Logger Compatibility (not exclusive)

Decagon: Em50 series loggers, ProCheck

Campbell Scientific: Any logger with serial I/O (CR10X, CR850, CR1000, CR3000, etc.)

Other: Any data acquisition system capable of 3.6-15V excitation and serial or SDI-12 communication

Warranty

One year, parts and labor

Comparisons

ANALOG SENSORS		DIGITAL SENSORS
SENSOR	EC-5	10HS	5TM	5TE	GS3	MPS-2
MEASURES	volumetric water content, dielectric permittivity	volumetric water content, dielectric permittivity	volumetric water content, dielectric permittivity, temperature	volumetric water content, dielectric permittivity, temperature, electrical conductivity	volumetric water content, dielectric permittivity, temperature, electrical conductivity	water potential, temperature
VOLUME OF INFLUENCE	0.3 L	1 L	0.3 L	0.3 L	0.3 L	N/A
DATA LOGGER COMPATIBILITY	Em5b, Em50, Em50R, Em50G, ProCheck, ECH₂O Check, Campbell Scientific*	Em5b, Em50, Em50R, Em50G, ProCheck, ECH₂O Check, Campbell Scientific*	Em50, Em50R, Em50G, ProCheck, Campbell Scientific*, SDI-12 capable	Em50, Em50R, Em50G, ProCheck, SDI-12 capable	Em50, Em50R, Em50G, ProCheck, SDI-12 capable	Em50, Em50R, Em50G, ProCheck, SDI-12 capable
MEASUREMENT RANGE	0 to 100% VWC	0 to 53% VWC	0 to 100% VWC -40 to 50°C	0 to 100% VWC -40 to 50°C 0 to 23 dS/m	0 to 100% VWC -40 to 50°C 0 to 23 dS/m	-10 to -500 kPa (pF 2 - pF 3.71) -40 to 50°C
BEST IF	VWC is all that you need. You're establishing a large sensor network.	You want a large volume of influence.	You have high temperature variability in your soils. You are monitoring shallow or desert soils where data must be corrected for temperature effects. You need to monitor soil temperature for biological activities. You want to use SDI-12.	You are managing salts in your system. You want to use SDI-12.	You are measuring water content of soilless substrates. You need high accuracy EC.	You want to compare soil moisture at different research sites. You want to determine water available for plant growth. You are monitoring deficit irrigation. You want to measure water potential.
BUT NOT IF	You cannot apply a regulated voltage (only applies to non-Decagon data loggers).	You are measuring in nursery pots. You are installing in rocky soil.	N/A	You want to monitor soiless substrates or potting soils.	You are doing downhole installations.	You want to monitor soils at or near saturation.

Compatibility and Programming Specifications for Campbell Scientific and Other (non-Decagon) Data Loggers

Note: ECH₂O sensors are “plug and read” on Decagon data loggers. You do not need to program any of this information (or ANY information) into a Decagon logger.

SENSOR	CAMPBELL COMPATIBILITY	OTHER LOGGERS	OUTPUT	VOLTAGE REQUIREMENTS
EC-5	CR10X, 21X, 23X, CR1000, CR3000, etc.	Any data acquisition system capable of switched 2.5 to 3.6 V excitation and single ended voltage measurement at 12 bit or better resolution. (Note: some people take their chances with resolution as low as 3 bits, but resolution lower than 10 bits will leave the data quite choppy).	Voltage, correlated linearly (soil) or polynomially (growing media) with VWC	2.5-3.6 V
10HS	CR10X, 21X, 23X, CR1000, CR3000, etc.	Any data acquisition system capable of 3-15 VDC excitation and single ended voltage measurement at 12 bit or better resolution.	Voltage correlated with VWC, independent of excitation	3-15 V
5TE	Any logger with serial I/O (CR10X, CR850, CR1000, CR3000, etc.)	Ask a Decagon representative for an integrator’s guide to interfacing the 5TE	Digital ASCIII stream or SDI-12	3.6-15 V
5TM	Any logger with serial I/O (CR10X, CR850, CR1000, CR3000, etc.)	Ask a Decagon representative for an integrators guide to interfacing the 5TM	Digital ASCII Stream or SDI-12	3.6-15 V
GS3	Any logger with serial I/O (CR10X, CR850, CR1000, CR3000, etc.)	Ask a Decagon representative for an integrators guide to interfacing the GS3	Digital ASCII Stream or SDI-12	3.6-15 V
MPS-2	Any logger with serial I/O (CR10X, CR850, CR1000, CR3000, etc.)	Ask a Decagon represenative for an integrators guide to interfacing the MPS-2	Digital ASCII Stream or SDI-12	3.6-15 V

Accessories

Auger Kit

For use with deep installation of the ECH₂O probes. Includes a regular and sand auger (2.75" [7 cm] diameter), two 2' (0.6 m) extension rods, a standard rubber handle, and a ratchet handle.

Cable Armor

Give your cables a higher level of protection from the elements and rodents. Also organizes your cables as you run them to your datalogger.

Splice Kit

Repair damaged cables in the field with few tools and less time.

Support

Software & Downloads

How-To Articles

Calibrating Soil Moisture Sensors

Application Notes

Video

Manuals

Manual 5TM

Information Sheet

Request Support

Email: support@decagon.com
Phone: 800-755-2751 or
509-332-2756
Fax: 509-332-5158