Onset RXW-LIB-900 Operating Manual

HOBO® RX Wireless Sensor Network

W

O

C

RXW Silicon Pyranometer Sensor (RXW-LIB-xxx) Manual

This sensor measures solar radiation and is designed to work with the HOBOnet Wireless Sensor
Network in which data is transmitted wirelessly from the sensor mote across the network to the
RX3000 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 to 1280 W/m2

Spectral Range 300 to 1100 nm (see Plot A)

RXW Silicon
Pyranometer Sensor

Models:

• RXW-LIB-900 (US)

• RXW-LIB-868 (Europe)

• RXW-LIB-922 (Australia/NZ)

Included Items:

• Cable ties

• Screws

Accessories:

• Light sensor mounting
bracket (M-LBB)

• Light sensor level (M-LLA)

Accuracy Typically within ±10 W/m2 or ±5%, whichever is greater in sunlight;

Angular Accuracy Cosine corrected 0 to 80 degrees from vertical (see Plot B); Azimuth

Resolution 1.25 W/m2

Drift <±2% per year

ireless Mote

perating Temperature

Range

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

Wireless Data Standard IEEE 802.15.4

Radio Operating
Frequencies

Modulation Employed OQPSK (Offset Quadrature Phase Shift Keying)

Data Rate Up to 250 kbps, non-adjustable

Duty Cycle <1%

Maximum Number of
Motes

Battery Type/
Power Source

Battery Life With NiMH batteries: Typical 3–5 years when operated in the

Memory 16 MB

Dimensions Sensor: 4.1 cm height x 3.2 cm diameter (1.61 x 1.26 inches)

Weight Sensor and cable: 109 g (3.85 oz)

Materials Sensor: Anodized aluminum housing with acrylic diffuser and O-ring seal

Environmental Rating Sensor and cable: Weatherproof

ompliance Marks RXW-LIB-900: See last page

Additional temperature induced error ±0.38 W/m
(0.21 W/m

Error <±2% error at 45 degrees from vertical, 360 degree rotation

-25° to 60°C (-13° to 140°F) with rechargeable batteries

-40 to 70°C (-40 to 158°F) with lithium batteries

Reliable connection to 609.6 m (2,000 ft) line of sight at 3 m (10 ft) high

RXW-LIB-900: 904–924 MHz
RXW-LIB-868: 866.5 MHz
RXW-LIB-922: 916–924 MHz

50 motes per one RX Wireless Sensor Network

Two AA 1.2V 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)

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

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)

Mote: 223 g (7.87 oz)

Mote: PCPBT, silicone rubber seal

Mote: IP67, NEMA 6

2

/°F from 77°F)

RXW-LIB-868: The CE Marking identifies this product as
complying with all relevant directives in the European Union
(EU).

RXW-LIB-922: See last page

2

/°C from 25°C

22247-A

RXW Silicon Pyranometer Sensor (RXW-LIB-xxx) Manual

Mote Components and Operation

Mounting
Tab

Solar Panel

Sensor Cable

Sensor Mote Closed, Front Sensor Mote Closed, Back

Solar Panel Cable

Mounting Tab: Use the tabs at the top and bottom of the mote
to mount it (see Deploying and Mounting).

Solar Panel: Position the solar panel towards the sun to charge
the mote batteries (see Deploying and Mounting).

Sensor Cable: This is the cable that connects the mote to the
sensor.

Eyelet: Use this eyelet to attach a 3/16 inch padlock to the
mote for security.

Latch: Use the two latches to open and close the mote door.

Ground Wire Port: Use this port to connect a ground wire (see

Deploying and Mounting).

Antenna: This is the built-in antenna for the radio
communications across the RX Wireless Sensor Network.

Solar Panel Cable: This cable connects the built-in solar panel
to the mote circuitry.

LEDs: There are two LEDs to the left of the LCD screen. The
green LED blinks during the process of joining a network,
blinking quickly while the mote searches for a network and
then slowly as the mote registers with the network. Once the
network registration process is complete, the blue LED blinks at
4 seconds to indicate normal operation. If the mote is not
currently part of a network, the blue LED will be off. If the blue
LED is on and not blinking, there is a problem with the mote.
Contact Onset Technical Support.

Battery Holder: The location where the batteries are installed
as shown (see Battery Information).

Latch

Eyelet

Ground Wire
Port

LEDs

Antenna

Button

USB Port

Battery Holder

Sensor Mote Opened

LCD Screen

USB Port: Use this port to connect to the mote to a computer
via USB cable if you need to update the firmware (see Updating

Mote Firmware).

Button: Push this button for 1 second to illuminate the LCD or 3

seconds for the mote to search for an RX Wireless Sensor
Network to join (see Adding the Mote to the RX Wireless Sensor
Network).

LCD Screen: The mote is equipped with an LCD screen that
displays details about the current status. This example shows all
symbols illuminated on the LCD screen followed by definitions
of each symbol in the table.

LCD Symbol Description

The battery indicator shows the approximate battery
charge remaining.

This is a signal strength indicator. The more bars, the
stronger the signal between motes. If there is no x
icon next to the signal strength indicator, then the
mote is part of an RX Wireless Sensor Network.

An empty signal strength icon plus the x icon
indicates that the mote is not currently part of a
network. See Adding the Mote to the RX Wireless
Sensor Network for details on how to add a mote to
the network.

When the mote is in the process of joining a
network, the signal strength icon will blink and then
the bars in the icon will cycle from left to right. The x
icon will blink during the last step in the network
registration process (see Adding the Mote to the RX
Wireless Sensor Network for details).

This indicates a problem with the sensor itself (the
mote is operational). Check the sensor and make any
adjustments to it as needed. Contact Onset
Technical Support if the problem persists.

Spectral Characteristics

This sensor uses a silicon photodiode to measure solar power
per unit area (watts per square meter). Silicon photodiodes are
not ideal for use as solar radiation sensors and the photodiode
in this silicon pyranometer is no exception (see Plot A). An ideal
pyranometer has equal spectral response from 280 to 2800 nm.
However, when calibrated properly and used correctly, the
silicon pyranometer sensor should perform well in most
situations.

Sun's Relative Intensity and the Typical Relative Response of

the Silicon Pyranometer versus Wavelength

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

Sun's Relative Intensity

0.2

0.1

0.0

250 750 1250 1750 2250

Wavelength (nm)

Silicon Pyranometer
Sunlight

Plot A: Silicon Pyranometer Sensor Response Curve

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

Photodetector Relative Response

0.1

0.0

1-800-LOGGERS 2 www.onsetcomp.com

RXW Silicon Pyranometer Sensor (RXW-LIB-xxx) Manual

The sensor is calibrated for use in sunlight (an Eppley Precision
Spectral Pyranometer is used as reference standard).
Accordingly, if the sensor is used under natural sunlight, the
measurement errors will be small. Note that significant errors
may result from using the sensor under artificial light, within
plant canopies, in greenhouses, or any other conditions where
the spectral content differs from sunlight.

Cosine Correction

The silicon pyranometer sensor housing is designed to give an
accurate cosine response. Plot B shows a plot of relative
intensity versus angle of incidence for a typical sensor and for
the theoretical ideal response. Deviation from ideal response is
less than 5% from 0 to 70 degrees and less than 10% from 70 to
80 degrees.

Note that as the angle approaches 90 degrees, the ideal cosine
response approaches zero. As a result, small errors in measured
intensity will result in very large percentage errors compared to
the ideal response from 80 to 90 degrees.

Typical Cosine Response of Silicon Pyranometer

120

100

80

60

40

Percent Relative Response

20

Ideal Response
Silicon Pyranometer

HOBO RXW Manager is installed in the left slot (module 1)
or twice if it is installed on the right slot (module 2).

Press this button to view the module
where the RXW Manager is installed

3. Press the Search button (the magnifying glass). The
magnifying glass icon will blink while the RX3000 is in search
mode.

Press this button so the station is ready
to have motes join the network

4. Open the mote door and install the batteries if you have not
already done so.

5. Press the button on the mote for 3 seconds. The signal
strength icon will flash and then cycle.

0

0 102030405060708090100

Plot B: Silicon Pyranometer Sensor Typical Cosine Response Curve

Angle from Vertical (Degrees)

Adding the Mote to the RX Wireless Sensor
Network

The mote must join an RX Wireless Sensor Network before it
can begin measuring solar radiation and transmitting data. This
requires accessing the RX3000 station and the mote at the
same time so it is recommended that you complete these steps
before deploying the mote.

Important: If you have not configured the RX3000 station with
the RXW Manager, follow the instructions in the RX3000 Quick
Start before continuing.

To add a mote to the RX Wireless Sensor Network:

1. If the LCD is blank on the RX3000 station, press any button
to wake it up.

2. Press the Select button once (which shows the number of
smart sensors installed) and then press it again once if the

Press this button for 3
seconds for the mote to
join the network

6. Watch the LCD on the mote.

a.

This signal strength icon
blinks while searching for
a network.

c.

This network connection
“x” icon blinks while the
mote completes the
registration process,
which may take up to
five minutes.

b.

Once a network is found,
the icon will stop flashing
and the bars will cycle from
left to right.

d.

Once the mote has finished joining
the network, the “x” icon is
removed and the channel count
on the station LCD increases by
two (one for solar radiation and
one for the mote battery).

This process may take up to five minutes. The green LED
blinks quickly while the mote searches for a network to join

1-800-LOGGERS 3 www.onsetcomp.com