®
TEROS 11

Advanced Soil Moisture + Temperature

TEROS 11

You need sensor longevity

Soil can be highly variable in space, requiring numerous measurements and frustrating amounts of your research dollars. Not to mention the extra cost and hassle of replacement sensors if you need long-term data. Make long-term, large sensor networks simpler, longer-lasting, and more affordable with the ultra-dependable TEROS 11 soil moisture and temperature sensor.

TEROS 11: with you for the long haul

The culmination of our new TEROS water content line, the TEROS 11 makes your life easier with a large volume of influence, reduced sensor-to-sensor variability, and a near-bulletproof form factor—which lasts up to 10 years in the field. These innovations, along with our well-published capacitance technology, an accuracy verification standard, and a blazing fast installation tool have combined to generate our most accurate, easy-to-use, highly durable—yet still economical—soil moisture sensor. In fact, we’re so confident about the long life of our TEROS sensor line, we’ve increased our standard warranty from one to three years.

Legendary technology—long-lasting performance

Backed by over 20 years of soil moisture research, the TEROS 11 combines METER’s trademark 70 MHz circuitry with an extremely ruggedized epoxy fill and securely attached, sharpened stainless steel needles that easily slip into the soil and are resistant to salts, so you can worry less about sensor deterioration. Very low power consumption and a high resolution provide increased precision over a longer period of time.  

Small sensor lets you think bigger

The TEROS 11 delivers the best volume of influence to sensor size on the market so you’re less susceptible to soil variability errors. We’ve optimized the circuitry in this 9.4-cm sensor to deliver an incredible one-liter volume of influence (versus the 200 mL typical for most sensors). Most soil sensors that measure this much volume are 20 cm or longer, causing installation headaches. Not only that, you can cut your installation time in half or more when you install with the new Borehole Installation tool. The tool mistake-proofs installation, eliminating common errors that cause uncertainty in the data—like air gaps, or preferential flow.

Better accuracy—verified

The TEROS 11 uses a completely new calibration procedure that maximizes accuracy and minimizes sensor-to-sensor variability while keeping the cost reasonable. So you can be confident that every sensor you install is going to read exactly like the next one. Unlike other sensors on the market which spec an unverifiable  ±1.0% VWC accuracy, the TEROS 11 was rigorously tested by our soil physicists across a challenging range of soil types and EC levels so you can be confident in the accuracy of your data.

Plus, TEROS sensor repeatability can be checked with an accuracy verification standard. No other soil moisture sensor has this ability. Just slide the verification clip onto a sensor and plug it into a logger. If it reads within the right range, your sensor is good to go.

Near-instant data gratification

Easy and reliable data collection is part of the TEROS experience. Combine the TEROS 11 with the new ZL6, where all data is connected and delivered in near-real time through the cloud. All you have to do is sit back and let the data flow.

Now you can have everything

We created the TEROS line to eliminate barriers to good accuracy: installation inconsistency, sensor-to-sensor variability, and sensor verification. The TEROS 11 is a long-life, accurate, easy-to-install sensor that combines METER’s legendary technology with an ultra-rugged form and a new calibration procedure to deliver an unbeatable price-to-performance ratio. If you’re planning a long-term large sensor network and want long-lasting performance for less work and less of your research budget, then choose the TEROS 11.

Request a quote Contact us Knowledge Base TEROS 11

Features

  • Increased volume of influence (1010 mL)
  • Easy installation (minimizes air gaps for cleaner readings)
  • Dependable, long-life sensor
  • Reduced sensor-to-sensor variability
  • Repeatability can be checked with an accuracy verification standard
  • Robust, epoxy body for tough field conditions
  • Minimizes salinity and textural effects by using 70 MHz frequency capacitance technology
  • Steel needles cut through the soil for better soil-sensor contact
  • Easy-to-read voltage output for various data loggers
  • Ferrite core eliminates cable noise

Specifications

MEASUREMENT SPECIFICATIONS

Volumetric water content (VWC)

Range:
Mineral soil calibration: 0.00–0.70 m3/m3
Soilless media calibration: 0.0–1.0 m3/m3
Apparent dielectric permittivity (εa): 1 (air) to 80 (water)

NOTE: The VWC range is dependent on the media the sensor is calibrated to. A custom calibration will accommodate the necessary ranges for most substrates.

Resolution:
0.001 m3/m3
Accuracy:
Generic calibration: ±0.03 m3/m3 typical in mineral soils that have solution electrical conductivity <8 dS/m
Medium specific calibration: ±0.01–0.02 m3/m3 in any porous medium
Apparent dielectric permittivity (εa): 1–40 (soil range) , ±1 εa (unitless) 40–80, 15% of measurement

Dielectric measurement frequency

70 MHz

Temperature

Range: −40 to 60 °C
Resolution: 0.1 °C
Accuracy: ±1 °C from −40 to 0 °C
±0.5 °C from 0 to +60 °C

NOTE: Temperature measurement, for applicable sensors, may not be accurate if sensor is not fully immersed in the medium of interest, due to longer equilibration time.

COMMUNICATION SPECIFICATIONS

Output

DDI serial or SDI-12 communication protocol

Data logger compatibility

METER ZL6, EM60, and Em50 data loggers or any data acquisition system capable of 4.0- to 15-VDC power and serial or SDI-12 communication (see compatibility chart)

Measurement volume

See comparison article

PHYSICAL SPECIFICATIONS

Dimensions

Length: 9.4 cm (3.70 in)
Width: 2.4 cm (0.95 in)
Height: 7.5 cm (2.95 in)

Probe length

5.5 cm (2.17 in)

Cable length

5 m (standard)
75 m (maximum custom cable length)

NOTE: Contact Customer Support if a nonstandard cable length is needed.

Connector types

3.5-mm stereo plug connector or stripped and tinned wires

ELECTRICAL AND TIMING CHARACTERISTICS

Supply voltage (VCC) to GND

Minimum: 4.0 VDC
Typical: NA
Maximum: 15.0 VDC

Digital input voltage (logic high)

Minimum: 2.8 V
Typical: 3.6 V
Maximum: 3.9 V

Digital input voltage (logic low)

Minimum: –0.3 V
Typical: 0.0 V
Maximum: 0.8 V

Digital output voltage (logic high)

Minimum NA
Typical 3.6 V
Maximum NA

Power line slew rate

Minimum: 1.0 V/ms
Typical: NA
Maximum: NA

Current drain (during 25-ms measurement)

Minimum: 3.0 mA
Typical: 3.6 mA
Maximum: 16.0 mA

Current drain (while asleep)

Minimum: NA
Typical: 0.03 mA
Maximum: NA

Operating temperature range

Minimum –40 °C
Typical NA
Maximum +60 °C

NOTE: Sensors may be used at higher temperatures under certain conditions; contact Customer Support for assistance.

Power up time (DDI serial)

Minimum: 80 ms
Typical: NA
Maximum: 100 ms

Power up time (SDI-12)

Minimum: NA
Typical: 245 ms
Maximum: NA

Measurement duration

Minimum: 25 ms
Typical: NA
Maximum: 50 ms

COMPLIANCE

Manufactured under ISO 9001:2015
EM ISO/IEC 17050:2010 (CE Mark)
2014/30/EU and 2011/65/EU
EN61326-1:2013 and EN55022/CISPR 22

California requires the following notice:

⚠️ WARNING: This product may contain chemicals including ethylene glycol, lead, nickel, styrene and cadmium, which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov

Support

Have a question? Our team is ready to help!

We manufacture, test, calibrate, and repair every instrument in-house. Our scientists and technicians use the instruments every day in our product testing lab. No matter what your question is, we have someone who can help you answer it.

Email Europe: sales.europe@metergroup.com
Phone US: +1 509-332-5600
Phone Europe: +49 89 12 66 52 0

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