TEROS 21 Tech Specs

Measurement Specifications

Water Potential: Range: 0 to −100,000 kPa (1.70 to 6.00 pF)

Resolution: 0 kPa

Accuracy: ±(10% of reading + 2 kPa) from −100 to −5 kPa

NOTE: TEROS 21 Gen 2 can read up to 0 kPa when on a wetting path. The air entry of the soil limits the performance of the sensor to 0 kPa on the drying curve.

NOTE: TEROS 21 is not well calibrated beyond -100 kPa. For more information on using the TEROS 21 beyond this range, see Section 3.3.3 in the user manual

Temperature: Range: -40.00 – 60.00 °C

Resolution: 0.10 °C

Accuracy: ±1.00 °C

Communication Specifications

Data Logger Compatibility: METER ZL6, EM60, and Em50 data loggers or any data acquisition system capable of 3.6- to 15-VDC power and serial or SDI-12 communication

Physical Specifications

Dimensions: Length: 9.6 cm (3.8 in)

Width: 3.5 cm (1.4 in)

Height: 1.5 cm (0.6 in)

Operating Temperature Range: Minimum: -40.00 °C

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.

Electrical and Timing Characteristics

Digital Input Voltage (Logic High): Minimum: 2.8 V

Typical: 3.6 V

Maximum: 5.0 V

Digital Input Voltage (Logic Low): Minimum: -0.3 V

Typical: 0.0 V

Maximum: 0.8 V

Current Drain (During Measurement): Minimum: 3.0 mA

Typical: 5.0 mA

Maximum: 16.0 mA

Other

Compliance: EM ISO/IEC 17050:2010 (CE Mark)
EN 55011:2016 / A1:2017 (RCM Mark)