TEROS 21
Tech Specs
TECHNICAL SPECIFICATIONS
Measurement Specifications
Water Potential
Range: 0 to −100,000 kPa (1.70 to 6.00 pF)
Resolution:Â 0 kPa
Accuracy: ±(10% of reading + 2 kPa) from −100 to −5 kPa
NOTE:Â 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
Dielectric Measurement Frequency
70 MHz
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 3.6- to 15-VDC power and serial or SDI-12 communication
Physical Specifications
Dimensions
Length:Â 9.6 cm (3.8 in)
Width:Â 3.5 cm (1.4 in)
Height:Â 1.5 cm (0.6 in)
Sensor Diameter
3.2 cm (1.3 in)
Operating Temperature Range
Minimum: -40.00 °C
Maximum: 60.00 °C
NOTE:Â 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)
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:Â 3.6 VDC
Maximum:Â 15.0 VDC
Digital Input Voltage (Logic High)
Minimum:Â 2.8 V
Typical:Â 3.6 V
Maximum:Â 5.0 V
Digital Input Voltage (Logic Low)
Minimum:Â -0.3 V
Typical:Â 0.0 V
Maximum:Â 0.8 V
Power Line Slew Rate
Minimum:Â 1.0 V/ms
Current Drain (During Measurement)
Minimum:Â 3.0 mA
Typical:Â 5.0 mA
Maximum:Â 16.0 mA
Current Drain (While Asleep)
Minimum:Â 0.0 mA
Power Up Time (DDI Serial)
Maximum:Â 50 ms
Power Up Time (SDI-12)
Typical:Â 175 ms
Measurement Duration
Typical:Â 175 ms
Other
Product Awards
Winner of the 2022 AE50 Innovation Award
Compliance
EM ISO/IEC 17050:2010 (CE Mark)
EN 55011:2016 / A1:2017 (RCM Mark)
EN 55011:2016 / A1:2017 (RCM Mark)
GSA
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