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SP-LITE Silicon Pyranomete
Revision: 7/04
Copyright © 1998-2004
Campbell Scientific, Inc.
Warranty and Assistance
The SP-LITE SILICON PYRANOMETER is warranted by CAMPBELL
SCIENTIFIC, INC. to be free from defects in materials and workmanship
under normal use and service for twelve (12) months from date of shipment
unless specified otherwise. Batteries have no warranty. CAMPBELL
SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or
replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products.
The customer shall assume all costs of removing, reinstalling, and shipping
defective products to CAMPBELL SCIENTIFIC, INC. CAMPBELL
SCIENTIFIC, INC. will return such products by surface carrier prepaid. This
warranty shall not apply to any CAMPBELL SCIENTIFIC, INC. products
which have been subjected to modification, misuse, neglect, accidents of
nature, or shipping damage. This warranty is in lieu of all other warranties,
expressed or implied, including warranties of merchantability or fitness for a
particular purpose. CAMPBELL SCIENTIFIC, INC. is not liable for special,
indirect, incidental, or consequential damages.
Products may not be returned without prior authorization. The following
contact information is for US and International customers residing in countries
served by Campbell Scientific, Inc. directly. Affiliate companies handle
repairs for customers within their territories. Please visit
www.campbellsci.com to determine which Campbell Scientific company
serves your country. To obtain a Returned Materials Authorization (RMA),
contact CAMPBELL SCIENTIFIC, INC., phone (435) 753-2342. After an
applications engineer determines the nature of the problem, an RMA number
will be issued. Please write this number clearly on the outside of the shipping
container. CAMPBELL SCIENTIFIC's shipping address is:
CAMPBELL SCIENTIFIC, INC.
RMA#_____
815 West 1800 North
Logan, Utah 84321-1784
CAMPBELL SCIENTIFIC, INC. does not accept collect calls.
SP-LITE Table of Contents
PDF viewers note: These page numbers refer to the printed version of this document. Use
the Adobe Acrobat® bookmarks tab for links to specific sections.
1. General Description.....................................................1
1.1 Electrical Properties..................................................................................1
1.2 Spectral Properties....................................................................................2
1.3 Directional/Cosine Response....................................................................3
2. Sensor Specifications.................................................4
3. Installing the SP-LITE..................................................5
4. Wiring............................................................................7
5. Datalogger Programming............................................7
5.1 Datalogger Input Range Codes.................................................................8
5.2 Calibration Factor and Multiplier.............................................................8
5.3 Program Example 1, Average Solar Radiation.........................................8
5.4 Program Example 2, Total Solar Radiation............................................10
5.4.1 Output Format Considerations......................................................10
5.5 Program Example 3, Average and Total Solar Radiation.......................12
6. Maintenance...............................................................13
6.1 Calibration.............................................................................................. 13
7. Troubleshooting ........................................................13
7.1 Pyranometer produces no apparent output..............................................13
7.2 Readings are not as expected..................................................................13
Figures
1. SP-LITE Sensor without Leveling Fixture.................................................1
2. SP-LITE Electrical Circuit..........................................................................2
3. Spectral Sensitivity of Pyranometers Compared with Solar Radiation ......2
4. Cosine Response of a Typical SP-LITE Pyranometer................................3
5. Dimensions of SP-LITE with Leveling Device..........................................4
6. 015ARM Mounting Arm............................................................................5
7. 025STAND and 019ALU Crossarm...........................................................6
8. SP-LITE to Datalogger Connections..........................................................7
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SP-LITE Table of Contents
Tables
1. Datalogger Connections for Differential Measurement............................. 7
2. Datalogger Connections for Single-Ended Measurement.......................... 7
3. Multipliers Required for Flux Density and Total Fluxes........................... 8
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SP-LITE Silicon Pyranometer
The SP-LITE measures incoming solar radiation (sun plus sky radiation) with a photodiode
detector. Output from the photodiode is a current, which is converted to voltage by an
internal shunt resistor. The SP-LITE can be used in solar energy applications such as
plant growth, thermal convection and evapotranspiration.
1. General Description
FIGURE 1. SP-LITE Sensor without Leveling Fixture
The SP-LITE is used for measuring solar radiation. It measures the solar
energy received from the entire hemisphere – i.e. 180° field of view. The
output is expressed in Watts per square meter (W m
The SP-LITE is designed for continuous outside use, and its calibration is valid
only for unshaded natural daylight – not for artificial light. It is most usually
used to measure solar radiation being received on the horizontal plane.
However, the SP-LITE can, if required, be used in an inverted or tilted
position.
1.1 Electrical Properties
The SP-LITE consists of a photodiode complete with housing and cable. The
circuit includes a shunt resistor for the photodiode in order to generate a
voltage output. The electrical specification of the sensor is determined by the
characteristics of the photodiode and resistor. The electrical circuit of the
pyranometer is shown in Figure 2, below.
The electrical sensitivity of the photodiode changes with temperature. A
nominal value for this change is 0.2% change per °C. Calibration is carried out
at 20 °C.
-2
).
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SP-LITE Silicon Pyr an ome ter
1.2 Spectral Properties
FIGURE 2. SP-LITE Electrical Circuit
The spectral properties of the SP-LITE are mainly determined by the spectral
response of the photodiode, which is shown in Figure 3, below.
FIGURE 3. Spectral Sensitivity of Pyranometers Compared with Solar
Radiation
The SP-LITE is calibrated for solar radiation under clear sky conditions. The
spectrum for these conditions, at sea level, is also shown in Figure 3.
Unfortunately, however, the actual solar spectrum varies as a function of cloud
cover, season and solar elevation. Since the pyranometer does not have a flat
sensitivity across the whole solar spectrum, the accuracy of its response will
vary. However, the error range across the whole spectrum has been proven to
be small. The maximum total estimated error will only be in the region of ±5
percent when compared to the calibration conditions.
2
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