TEROS 11 Tech Specs
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Technical Specifications

Volumetric water content (VWC)
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.
0.0010 m3/m3
Generic calibration: ±0.03 m³/m³ (±3.00% VWC) typical in mineral soils that have solution EC <8,000 μS/cm
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
Measurement Specifications
Dielectric measurement frequency
70 MHz
Measurement volume
Range: −40 to +60 °C
Resolution: 0.1 °C
Accuracy: ±1.0 °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
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
Physical Specifications
Length: 9.4000 cm (3.70 in)
Width: 2.4000 cm (0.95 in)
Height: 7.5000 cm (2.95 in)
Probe length
5.5000 cm (2.17 in)
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.
Cable Length
5 m (standard)
75 m (maximum custom cable length)

NOTE: Contact Customer Support if a nonstandard cable length is needed.
Cable Diameter
0.165 ±0.004 (4.20 ± 0.10mm) with minimum jacket of 0.030 (0.760 mm)
Connector Types
3.5-mm stereo plug connector or stripped and tinned wires
Stereo Plug Connector Diameter
3.5000 mm
Conductor Gauge
22-AWG / 24-AWG drain wire
Electrical and Timing Characteristics
Supply Voltage (VCC to GND)
Minimum: 4.0000 VDC
Typical: NA
Maximum: 15.0000 VDC
Digital Input Voltage (logic high)
Minimum: 2.8000 V
Typical: 3.6000 V
Maximum: 3.9000 V
Digital Input Voltage (logic low)
Minimum: -0.3000 V
Typical: 0.0000 V
Maximum: 0.8000 V
Digital Output Voltage (logic high)
Minimum: NA
Typical: 3.6000 V
Maximum: NA
Power Line Slew Rate
Minimum: 1.0000 V/ms
Typical: NA
Maximum: NA
Current Drain (during 25-ms measurement)
Minimum: 3.0000 mA
Typical: 3.6000 mA
Maximum: 16.0000 mA
Current Drain (while asleep)
Minimum: NA
Typical: 0.0300 mA
Maximum: NA
Power Up Time (SDI-12)
Minimum: NA
Typical: 245 ms
Maximum: NA
Power Up Time (DDI Serial)
Minimum: 80.0000 ms
Typical: NA
Maximum: 100 ms
Power Up Time (SDI-12, DDI Serial disabled)
Minimum: 145 ms
Typical: 155 ms
Maximum: 165 ms
Measurement Duration
Minimum: 25.0000 ms
Typical: NA
Maximum: 150.0000 ms
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