Introduction to Sensor
The ATMOS 51 directly measures actual evapotranspiration (ET) from plant and soil surfaces, helping ensure accurate irrigation regardless of plant growth stage, canopy closure, or plant water status. It uses Variance Bowen Ratio (VBR) technology to measure fluxes using high-frequency temperature, specific humidity, and solar radiation measurements.
Specifications
Specifications
Measurement Specifications
| Measurement | Specifications |
|---|---|
| Solar Radiation | Range: 0–1750 W/m2 Resolution: 1 W/m2 Accuracy: ±5% of measurement typical |
| Relative Humidity (RH) | Range: 0–100% RH (0.00–1.00) Resolution: ±0.01% RH Accuracy: ±1% RH, typical Long-term drift: ±0.25% of RH/year, typical |
| Humidity Sensor Temperature | Range: –40 to 60 °C Resolution: 0.01 °C Accuracy: ±0.1 °C |
| Barometric Pressure | Range: 26–126 kPa Resolution: 0.01 kPa Accuracy: ±0.003 kPa at 25 °C Equilibration: < 10 ms Long-term drift: < 0.03 kPa/year, typical |
| Tilt | Range: 0°–180° Resolution: 0.1° Accuracy: ±1° |
Communication Specifications
| Parameter | Specification |
|---|---|
| Output | SDI-12 communication |
| Data Logger Compatibility | METER ZL6 and EM60 data loggers or any data acquisition systems capable of 3.6- to 15.0-VDC excitation and SDI-12 communication |
Physical Specifications
| Parameter | Specifications |
|---|---|
| Dimensions | Diameter: 14 cm (5.5 in) Height: 19 cm (7.5 in) |
| Operating Temperature Range | Minimum: –40 °C Typical: NA Maximum: 60 °C Note: Barometric pressure and relative humidity sensors operate accurately at a minimum temperature of –40 °C |
| Cable Length | 5 m (standard)1.5 m (5-pin and 8-pin M12)75 m (maximum custom cable length for additional cost) Note: Contact customer support if a nonstandard cable length is needed |
| Connector Types | 3.5 mm stereo plug or 3 stripped and tinned wires |
| Conductor Gauge | 22-AWG / 24-AWG drain wire |
| Cable Diameter | 0.165±0.004 in (4.20±0.10 mm), with minimum jacket of 0.030 in (0.76 mm) |
Electrical and Timing Characteristics
| Parameter | Specifications |
|---|---|
| Supply Voltage (VCC to GND) | Minimum: 3.6 VDC continuous Typical: NA Maximum: 15.0 VDC continuous Note: ATMOS 51 must be continuously powered to work properly Note: For the ATMOS 51 to meet digital logic levels specified by SDI-12, it must be excited at 3.9 VDC or greater. |
| Digital Input Voltage (Logic High) | Minimum: 2.8 V Typical: 3.0 V Maximum: 5.5 V |
| Digital Input Voltage (Logic Low) | Minimum: –0.3 V Typical: 0.0 V Maximum: 0.8 V |
| Digital Output Voltage (Logic High) | Minimum: NA Typical: 3.6 V Maximum: NA Note: For the ATMOS 51 to meet digital logic levels specified by SDI-12, it must be excited at 3.9 VDC or greater. |
| Current Drain (during GPS fix) | Minimum: 5.0 mA Typical: 8.0 mA Maximum: 10.0 mA |
| Current Drain (during measurement, 75 ms/s) | Minimum: 0.2 mA Typical: 1.0 mA Maximum: 2.0 mA |
| Current Drain (while asleep, 925 ms/s) | Minimum: 0.2 mA Typical: 0.3 mA Maximum: 0.4 mA |
| Measurement Duration | **Minimum:**NA** Typical:**75 ms** Maximum:**100 ms |
Other
| Parameter | Specification |
|---|---|
| Compliance | EM ISO/IEC 17050:2010 (CE Mark) |
Features
Applications