Onset S-LIB Specifications

Silicon Pyranometer Smart Sensor (S-LIB-M003) Manual

C

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The silicon pyranometer smart sensor is designed to work with HOBO® stations. The smart sensor
has a plug-in modular connector that allows it to be added easily to a station. All calibration
parameters are stored inside the smart sensor, which automatically communicates configuration
information to the logger without any programming, calibration, or extensive user setup.

Specifications

Measurement Range 0 to 1280 W/m2

Spectral Range 300 to 1100 nm (see Plot A)

Silicon Pyranometer
Smart Sensor

S-LIB-M003

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

alibration Factory recalibration available

Operating Temperature Range -40° to 75°C (-40° to 167°F)

Environmental Rating Weatherproof

Housing Anodized aluminum housing with acrylic diffuser and O-ring seal

Dimensions 4.1 cm height x 3.2 cm diameter (1 5/8 in. x 1 1/4 in.)

Weight 120 g (4 oz)

Bits per Sample 10

Number of Data Channels* 1

Measurement Averaging Option Yes

able Length Available

Length of Smart Sensor
Network Cable*

* A single HOBO station can accommodate 15 data channels and up to 100 m (328 ft) of smart sensor cable (the digital

communications portion of the sensor cables).

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

2

/°F from 77°F)

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

3.0 m (9.8 ft)

3.0 m (9.8 ft)

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

2

/°C from 25°C

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 smart 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: S-LIB-M003 Silicon Pyranometer Response Curve

6708-E MAN-S-LIB

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

Photodetector Relative R esponse

0.1

0.0

Silicon Pyranometer Smart Sensor (S-LIB-M003) 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 smart 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

0

0 102030405060708090100

Plot B: S-LIB-M003 Typical Cosine Response Curve

Angle from Vertical (Degrees)

Ideal Response
Silicon Pyranometer

Mounting

Bracket Mounting

It is recommended that you mount the silicon pyranometer
smart sensor with the light sensor bracket (M-LBB) on a pole or
tripod. To mount the sensor using the bracket:

5

1. Attach the light sensor bracket to a 1¼ inch - 1
with the provided U-bolts.

Note: The bracket can also be mounted on a flat, vertical
surface using four screws.

2. Position the silicon pyranometer sensor on top of the
bracket with its cable running through the slot in the
bracket.

3. Using the two screws supplied, attach the sensor to the
bracket through the two holes on either side of the slot.

Note: Do not completely tighten the screws until you level
the sensor.

4. Position the bracket so it faces toward the equator,
minimizing the chance of shading.

5. Mount the bracket on the mast with the two U-bolt
assemblies, mounting it high enough on the mast to avoid
the possibility of shading the sensor.

/8 inch pole

Note: If you mount the sensor above eye level, it is
recommended that you use a step ladder or other secure
platform when leveling the sensor so that you can clearly
view the light sensor level (M-LLA).

Mast

Silicon pyranometer
smart sensor

Light sensor

Thumbscrew

Silicon pyranometer
sensor cable

bracket

U-bolt assembly

Silicon Pyranometer Sensor Bracket Mounting

6. Make sure the screws holding the sensor to the mounting
bracket are loose.

7. Place the light sensor level on the silicon pyranometer
smart sensor.

8. Adjust the height of the thumbscrews to level the sensor
(start with the thumbscrews protruding about 1/16

inch

from the bracket).

9. Once the sensor is near level, tighten the Phillips head
screws.

10. Check the level and repeat above steps if necessary.

11. IMPORTANT: Don’t forget to remove the level when you
are done with it.

Light sensor level

Silicon
pyranometer
sensor

(remove for operation)

Leveling the Sensor on

the Light Sensor Bracket

Specialized Application Mounting

To mount the silicon pyranometer sensor using a mounting
plate of your own design:

1. Drill a 0.56 (9/16) inch hole in the middle of the plate, then
drill two #25 holes 1.063 (1-1/16) inches apart on either
side of the center hole. Cut a 0.31 (5/16) inch-wide slot in
the mounting plate. See diagram on next page. The plate
should be a thickness of 1/8 inch or less.

2. Slide the sensor through the 0.31 (5/16) inch-wide slot.

1-800-LOGGERS 2 www.onsetcomp.com