Introduction to Sensor
The TEROS 31 Lab Tensiometer is a compact and precise solution for measuring soil water potential in laboratory environments. Its small size and fast response make it ideal for measurements in tight spaces, while its extended measurement range provides reliable data across a wide range of soil conditions. With accurate zero-tension readings, the TEROS 31 delivers dependable point-to-point soil water potential measurements for research and laboratory applications.
Specifications
Specifications
Measurement Specifications
| Parameter | Specifications |
|---|---|
| Water Potential | Range: –85 to +50 kPa (up to –400 kPa during boiling retardation) Resolution: ±0.0012 kPa Accuracy: ±0.15 kPa |
| Temperature | Range: –30 to +60 °C Resolution: ±0.01 °C Accuracy: ±0.3 °C between 5 °C to 35 °C (±1.5 °C outside that range) NOTE: If the sensor unit is not buried, measured temperature may diverge from soil temperature. |
Communication Specifications
| Parameter | Specifications |
|---|---|
| Output | DDI serial SDI-12 communication protocol TensioLINK™ communication protocol Modbus™ RTU communication protocol |
| Data Logger Compatibility | METER ZL6 and EM60 data loggers or any data acquisition system capable of 3.6- to 28.0-VDC excitation and SDI-12, Modbus RTU, or TensioLINK communication. |
Physical Specifications
| Parameter | Specifications |
|---|---|
| Dimensions | Width: 23.5 mm (0.93 in) Height: 49.0 mm (1.93 in) Depth: 17.5 mm (0.69 in) |
| Tensiometer Shaft Diameter | 5 mm (0.19 in) |
| Tensiometer Shaft Length | 2, 5, 7, 10, 15, or 20 cm |
| Materials | Ceramic: Al₂O₃, bubble point 500 kPa Shaft: PMMA Sensor Unit: PMMA and TPE IP Rating: IP67 |
| Operating Temperature Range | Minimum: 0.00 °C Maximum: 50.00 °C |
| Cable Length | 1.5 m |
| Cable Diameter | 3.0 mm (0.12 in) |
| Connector Types | 4-pin stereo plug connector |
| Stereo Plug Connector Diameter | 3.5 mm |
| Conductor Gauge | 31 AWG drain wire |
Electrical and Timing Characteristics
| Parameter | Specifications |
|---|---|
| Supply Voltage (VCC to GND) | Minimum: 3.6 VDC Typical: 12.0 VDC Maximum: 28.0 VDC |
| Digital Input Voltage (Logic High) | Minimum: 1.6 V Typical: 3.3 V Maximum: 5.0 V |
| Digital Input Voltage (Logic Low) | Minimum: -0.3 V Typical: 0.0 V Maximum: 0.9 V |
| Digital Output Voltage (Logic High) | Typical: 3.6 V |
| Power Line Slew Rate | Minimum: 1.0 V/ms |
| Current Drain (During Measurement) | Minimum: 18.0 mA Typical: 25.0 mA Maximum: 30.0 mA |
| Current Drain (While Asleep) | Minimum: 0.03 mA Typical: 0.05 mA Maximum: 0.90 mA |
| Power Up Time (DDI Serial) | Minimum: 125 ms Typical: 130 ms Maximum: 150 ms |
| Power Up Time (SDI-12) | Minimum: 125 ms Typical: 130 ms Maximum: 150 ms |
| Power Up Time (SDI-12, DDI Serial Disabled) | Minimum: 125 ms Typical: 130 ms Maximum: 150 ms |
| Measurement Duration | Minimum: 60 ms Typical: 65 ms Maximum: 70 ms |
Other
| Parameter | Specifications |
|---|---|
| BARO Module | When using the METER tensiometers TEROS 31 and TEROS 32 in combination with a non-METER data logger, a highly accurate barometric compensation is needed to get the most precise soil water potential measurement. The BARO Module can be used as a stand-alone sensor for measuring atmospheric pressure at a measuring site. It is also available with different connectors, so the BARO Module can be connected directly in between a tensiometer and a data logger. BARO Module can also act as a digital/analog converter to connect a tensiometer with serial output to a data logger with analog input channels. The logger obtains a barometric compensated analog matric potential signal. The BARO Module can be used for varied logger communications: SDI-12, Modbus, tensioLINK, analog voltage signal. |
| Compliance | EM ISO/IEC 17050:2010 (CE Mark) |
| Prop 65 Warning | Prop 65 warning |
| GSA | View GSA details |
Features
Applications