Silicon Pyranometer Smart Sensor (S-LIB-M003) Manual
C
C
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
Silicon Pyranometer Smart Sensor (S-LIB-M003) Manual
3. Attach the sensor using two 6-32 x 3/8 inch screws and lock
washers (not included).
4. Shim the sensor as necessary to level it.
Recommended Mounting Plate Dimensions
Mounting Considerations
• Small errors in alignment can produce significant errors.
Be certain that the sensor is mounted level.
• Mount the sensor where it will not be in a shadow. Any
obstruction should be below the plane of the sensor head.
If that is not possible, try to limit obstructions to below 5
degrees, where the effect will be minimal.
• If possible, avoid locating the sensors in dusty locations.
Dust, pollen, and salt residue that collect on the top of the
sensor can significantly degrade accuracy.
• Refer to the station manual and Tripod Setup Guide for
more information regarding setting up stations.
Maintenance
Dust on the sensor will degrade sensor accuracy. Periodically
inspect the sensor, and if necessary, gently clean the diffuser
with a damp sponge. Do not open the sensor as there are no
user serviceable parts inside.
Warning: DO NOT use alcohol, organic solvents, abrasives,
or strong detergents to clean the diffuser element on the
silicon pyranometer smart sensor. The acrylic material used in
the sensors can be crazed by exposure to alcohol or organic
solvents. Clean the sensor only with water and/or a mild
detergent such as dishwashing soap if necessary. It is
recommended that you use vinegar to remove hard water
deposits from the diffuser element. Under no circumstances
should the smart sensor be immersed in any liquid.
Verifying Sensor Accuracy
It is recommended that you test the silicon pyranometer smart
sensor annually for accuracy. If the sensor is not providing
accurate data, it may be damaged or out of calibration. If you
are unsure of accuracy, send the smart sensor back to Onset for
testing and possible re-calibration. Only Onset can complete
calibration. Contact Onset or your dealer for a Return
Merchandise Authorization (RMA) number before sending the
sensor.
Connecting the Smart Sensor to a Station
To connect the sensor to a station, stop the station from
logging and insert the smart sensor’s modular jack into an
available smart sensor port on the station. See the station
manual for details on operating stations with smart sensors.
Operation
The silicon pyranometer smart sensor supports measurement
averaging. When measurement averaging is enabled, data is
sampled more frequently than it is logged. The multiple
samples are then averaged together and the average value is
stored as the data for the interval. For example, if the logging
interval is set at 10 minutes and the sampling interval is set at 1
minute, each recorded data point will be the average of 10
measurements.
Measurement averaging is useful for reducing noise in the data.
It is recommended that you use measurement averaging
whenever the silicon pyranometer smart sensor is placed in an
area where the light level can vary quickly with respect to the
logging interval (for example, during partly cloudy conditions).
Note that fast sampling intervals less than 1 minute may
significantly reduce battery life. See the station manual for
more details about battery life.
© 2001–2015 Onset Computer Corporation. All rights reserved. Onset and HOBO are trademarks or
1-800-LOGGERS (564-4377) • 508-759-9500
www.onsetcomp.com • loggerhelp@onsetcomp.com
registered trademarks of Onset Computer Corporation. All other trademarks are the property of
their respective companies.
6708-E MAN-S-LIB
Loading...