Introduction to Sensor
The TEROS 12 is a durable, long-life soil sensor designed to measure soil moisture, temperature, and electrical conductivity (EC) in demanding field environments. With a large 1010 mL volume of influence, robust epoxy construction, and excellent price-to-performance, it provides reliable and consistent measurements for long-term soil monitoring applications.
Specifications
Specifications
Volumetric Water Content
| Parameter | Specification |
|---|---|
| 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 | 0.0010 m3/m3 |
| Accuracy | 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
| Parameter | Specification |
|---|---|
| Temperature | Range: –40 to +60 °C Resolution: 0.10 °C Accuracy: ±1.0 °C from –40 to 0 °C±0.5 °C from 0 to +60 °C |
| Dielectric Measurement Frequency | 70 MHz |
| Bulk Electrical Conductivity (EC) | Range: 0–20,000 μS/cm (bulk) Resolution: 1 μS/cm Accuracy: +/- (5% + 10 μS/cm) from 0–10,000 μS/cm+/- 8% from 10,000–20,000 μS/cm |
| Measurement Volume | 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 comparison article |
Communication Specifications
| Parameter | Specification |
|---|---|
| Output | DDI serial or SDI-12 communications 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 |
Physical Specifications
| Parameter | Specification |
|---|---|
| Dimensions | Length: 9.4 cm (3.70 in) Width: 2.4 cm (0.95 in) Height: 7.5 cm (2.95 in) |
| Needle Length | 5.5 cm (2.17 in) |
| Operating Temperature Range | Minimum: -40.00 °C Typical: NA Maximum: 60.00 °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 in (4.20 ± 0.10mm) with minimum jacket of 0.030 (0.760 mm) |
| Connector Types | Stereo plug connector or stripped and tinned wires |
| Stereo Plug Connector Diameter | 3.5 mm |
| Conductor Gauge | 22-AWG / 24-AWG drain wire |
Electrical and Timing Characteristics
| Parameter | Minimum | Typical | Maximum |
|---|---|---|---|
| Supply Voltage (VCC to GND) | 4.0 VDC | NA | 15.0 VDC |
| Digital Input Voltage (Logic High) | 2.8 V | 3.6 V | 5.0 V |
| Digital Input Voltage (Logic Low) | -0.3 V | 0.0 V | 0.8 V |
| Digital Output Voltage (Logic High) | NA | 3.6 V | NA |
| Power Line Slew Rate | 1.0 V/ms | NA | NA |
| Current Drain (During 25-ms Measurement) | 3.0 mA | 3.6 mA | 16.0 mA |
| Current Drain (While Asleep) | NA | 0.0 mA | NA |
| Power Up Time (DDI Serial) | 80 ms | NA | 100 ms |
| Power Up Time (SDI-12) | NA | 245 ms | NA |
| Power Up Time (SDI-12, DDI Serial Disabled) | 145 ms | 155 ms | 165 ms |
| Measurement Duration | 25 ms | NA | 150 ms |
Other
| Parameter | Specification |
|---|---|
| Compliance | EM ISO/IEC 17050:2010 (CE Mark) 2014/30/EU and 2011/65/EU EN61326-1:2013 and EN55022/CISPR 22 EN 55011:2016/A1:2017 (GROUP 1, CLASS A-RCM mark) Prop 56 warning EU Declaration of Conformity |
| GSA | View GSA details |
Features
Applications