Tech Specs

TEROS 54 Tech Specs


Volumetric Water Content
Mineral Soil Calibration: 0.00−0.70 m3/m3
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.
Soilless media calibration: 0.00-1.00 m3/m3
0.001 m3/m3
Generic Calibration: ±0.05 m3/m3 typical in mineral soils that have solution EC < 8 dS/m
Medium Specific Calibration: ±0.02–0.03 m3/m3 in any porous medium
Apparent Dielectric Permittivity (εa): 1–40 (soil range), ±1 (εα) (unitless)
40–80, 15% of measurement
Measurement Specifications
Dielectric Measurement Frequency
70 MHz
Range: –20 to +60 °C
Resolution: 0.03 °C
Accuracy: ±0.5 °C from –20°C to +0 °C
±0.25 °C from 0°C to 60 °C
Communication Specifications
DDI Serial and SDI-12 communications protocol
3-wire cable version
4-wire cable version
RS-485 Modbus RTU and tensioLINK serial communications protocol
4-wire version
Data Logger Compatibility
METER ZL6 and EM60 data loggers or any data acquisition system capable of 4.0- to 24.0-VDC power and serial interface with SDI-12 and/or RS-485 interface, Modbus RTU, or tensioLINK communication.
Physical Specifications
Diameter: (Shaft) 6.0 cm (2.36 in)
Length: 75.0 cm (29.53 in)
Width: (Head) 11.0 cm (4.33 in)
Operating Temperature Range
Minimum: –20 °C
Maximum: +60 °C
Cable Length
Standard: 5.0 m (stereo plug and stripped and tinned wires)
75.0 m (maximum custom cable length)
5.0 m (M12 connector)
NOTE: Contact Customer Support if a nonstandard cable length is needed.
Cable Diameter
Stereo Plug: 4.2 ±0.2 mm (0.16 ±0.01 in) with minimum jacket of 0.8 mm (0.031 in)
M12 Plug: 5.5 ±0.2 mm (0.22 ±0.01 in) with minimum jacket of 1.0 mm (0.039 in)
Connector Size
3.50 mm (diameter)
14.4 mm (diameter M12)
Connector Types
Stereo plug connector or stripped and tinned wires
4-pin M12 connector or stripped and tinned wires
Conductor Gauge
Stereo Plug: 22-AWG / 24-AWG ground wire
M12 Plug: 22-AWG
Electrical and Timing Characteristics
Supply Voltage Power to Ground
Minimum: 4.0 VDC
Maximum: 24.0 VDC
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
Digital Output Voltage (Logic High)
Typical: 3.6 V
Power Line Slew Rate
Minimum: 1.0 V/ms
Current Drain (During Measurement)
Minimum: 3 mA (during 500-ms measurement)
Typical: 35 mA (during 500-ms measurement)
Maximum: 50 mA (during 500-ms measurement)
Current Drain (While Asleep)
Minimum: 0.03 mA
Typical: 0.1 mA
Power Up Time (DDI Serial)
Minimum: 500 ms
Maximum: 800 ms
Power Up Time (SDI-12)
Typical: 1,000 ms
Power Up Time (SDI-12, DDI Serial Disabled)
Minimum: 500 ms
Typical: 600 ms
Maximum: 800 ms
Measurement Duration
Minimum: 500 ms (4 depths)
Maximum: 800 ms
EM ISO/IEC 17050:2010 (CE Mark)

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