HOBOnet® Wireless Sensor Network
RXW Leaf Wetness Sensor (RXW-LWA-xxx) Manual
23962-C
This sensor measures leaf wetness and is designed to work with the HOBOnet® (HOBO RX)
Wireless Sensor Network in which data is transmitted wirelessly from the sensor mote across
the network to the station and then uploaded to HOBOlink® web-based software. With
HOBOlink, you can monitor sensor readings, view graphs, set up alarms, download data, and
more.
Specifications
Sensor
Measurement Range
0 (dry) to 100% (wet)
Sensor Type
Capacitive grid
Interchangeability
Between Sensors (Over
the Range 10–90% Wet)
±10%
Repeatability
±5%; see Note 1
Resolution
0.59%
Stability (Drift)
< ±5% per year (in typical growth conditions)
Service Life
3 years in typical growth conditions
Wireless Mote
Operating Temperature
Range
-25° to 60°C (-13° to 140°F) with rechargeable batteries
-40 to 70°C (-40 to 158°F) with lithium batteries
Radio Power
12.6 mW (+11 dBm) non-adjustable
Transmission Range
Reliable connection to 457.2 m (1,500 ft) line of sight at 1.8 m (6 ft) high
Reliable connection to 609.6 m (2,000 ft) line of sight at 3 m (10 ft) high
Wireless Data Standard
IEEE 802.15.4
Radio Operating
Frequencies
RXW-LWA-900: 904–924 MHz
RXW-LWA-868: 866.5 MHz
RXW-LWA-921: 921 MHz
RXW-LWA-922: 916–924 MHz
Modulation Employed
OQPSK (Offset Quadrature Phase Shift Keying)
Data Rate
Up to 250 kbps, non-adjustable
Duty Cycle
<1%
Maximum Number of
Motes
50 motes per one RX Wireless Sensor Network
Battery Type/
Power Source
Two AA 1.2 V rechargeable NiMH batteries powered by built-in solar
panel or two AA 1.5 V lithium batteries for operating conditions of -40 to
70°C (-40 to 158°F)
Battery Life
With NiMH batteries: Typical 3–5 years when operated in the
temperature range -20° to 40°C (-4°F to 104°F) and positioned toward the
sun (see
Deployment and Mounting
), operation outside this range will
reduce the battery service life
With lithium batteries: 1 year, typical use
Memory
16 MB
Dimensions
Sensor grid: 4.7 x 5.1 cm (1.8 in x 2.0 inches)
Sensor housing: 12.2 x 1.8 cm (4.8 in x 0.7 inches)
Mounting bracket: 20 x 3 x 0.5 cm (8 x 1.3 x 0.2 inches)
Cable length: 2 m (6.56 ft)
Mote: 16.2 x 8.59 x 4.14 cm (6.38 x 3.38 x 1.63 inches)
Weight
Sensor and cable: 127 g (4.5 oz); with bracket: 290 g (10.2 oz)
Mote: 223 g (7.87 oz)
Materials
Sensor: PVC housing, epoxy potting compound, nylon grommet, FR-4
circuit board, PVC cable jacket
Bracket: PVC mounting bracket, UV-stable nylon cable ties, zinc
dichromate plated steel U-bolts
Mote: PCPBT, silicone rubber seal
RXW Leaf Wetness
Sensor
Models:
•
RXW-LWA-900 (US)
•
RXW-LWA-868 (Europe)
•
RXW-LWA-921 (Taiwan)
•
RXW-LWA-922
(Australia/NZ)
Included Items:
•
Mounting bracket
•
U-bolt
•
Tie wraps
