Hobo S-LIA-M003 User manual

© 2001–2003 Onset Computer Corporation
Part #: MAN-S-LIA
Doc #: 5942-C
Photosynthetically Active Radiation (PAR)
Smart Sensor (Part # S-LIA-M003)
The Photosynthetically Active Radiation (PAR) smart sensor is designed
to work with the HOBO®Weather Station logger. The smart sensor has a
plug-in modular connector that allows it to be added easily to a HOBO
Weather 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 PAR Smart Sensor
Measurement Range 0 to 2500 µmol/m2/sec, wavelengths 400 to 700 nm (see Figure 1)
Accuracy ±5 µmol/m2/sec or ± 5%, whichever is greater in sunlight.
Additional temperature induced error ±0.75 µmol/m2/sec/˚C from
+25°C (0.42 µmol/m2/sec/˚F from +77°F)
Angular Accuracy Cosine corrected 0 to 80 degrees from vertical; Azimuth Error < 2%
error at 45 degrees from vertical, 360 degree rotation
Resolution 2.5 µmol/m2/sec
Drift < ±2% per year
Calibration 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 x 1 1/4 in)
Weight 120 g (4 oz)
Bits per Sample 10
Number of Data Channels *1
Measurement Averaging
Option
Yes
Cable Length Available 3.0 m (9.8 ft)
Length of Smart Sensor
Network Cable *
3.0 m (9.8 ft)
Part Number S-LIA-M003
Specification This product meets CE specification EN61326 criterion C for ESD, criterion
C for Radiated Immunity, criterion B for Fast Transient, criterion A for
Conducted Immunity, and criterion A for Power Frequency Magnetic Fields.
To minimize measurement errors due to ambient RF, use the shortest
possible probe cable length and keep the probe cable as far as possible
from other cables.
* A single HOBO Weather 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).
Supplied in Australia by Instrument Choice
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PAR Smart Sensor
Page 2 of 5
Figure 1: PAR Smart Sensor Typical Quantum Response
Note: The PAR smart sensor is designed to detect photons between 400-700 nm in wavelength. Ideally
the sensor would count photons with equal efficiency between 400-700 nm and no photons would be
counted outside this range. However, in reality, this sensor undercounts photons between 400-550 nm and
between 670-700 nm, and it over counts photons between 550-670 nm. In most applications (where the
sensor is used in natural sunlight) the error is not significant.
Inside this Package
•PAR Smart Sensor
Mounting
Accessories
•Light Sensor Mounting Bracket (part # M-LBA)
•Light Sensor Level (part # M-LLA)
Mounting Bracket
It is recommended that you mount the PAR smart sensor with the light sensor bracket on a pole or tripod
(see Figure 2). To mount the PAR smart sensor using the bracket:
1. Attach the light sensor bracket to a 1¼ inch - 15/8inch pole with the provided U-bolts. Note: The
light sensor bracket can also be mounted on a flat, vertical surface using four screws.
2. Position the light sensor on top of the light sensor 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 light sensor.
4. Position the bracket so it faces toward the equator, minimizing the chance of shading.
Supplied in Australia by Instrument Choice
Call our scientists on 1300 737 871
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PAR Smart Sensor
Page 3 of 5
5. Mount the light sensor bracket on the mast with the two U-bolt assemblies, mounting it high
enough on the mast to avoid the possibility of shading the light sensor. Note: If you mount the
light 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 (Onset Part # M-
LLA).
Figure 2: PAR Smart 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 light 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 light sensor level and repeat above steps if necessary (see Figure 3).
11. When the light sensor is level, remove the light sensor level from the light sensor.
Figure 3: Leveling the PAR Smart Sensor on the Light Sensor Bracket
Specialized Application Mounting
To mount the light sensor using a mounting plate of your own design:
1. Drill two #25 holes 9/16 inches apart, and a 0.31 inch diameter slot in the mounting plate (see
Figure 4.). Note: The plate should be a thickness of 1/8 inch or less.
2. Slide the sensor through the 0.31 inch diameter slot.
3. Attach the sensor using two 6-32 x 3/8 inch screws and lock washers (not included).
PAR Sensor Level
U-bolt Assembly
PAR Sensor Cable
Thumbscrews
PAR Sensor
Mast
Light Sensor
Bracket
PAR Sensor
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PAR Smart Sensor
Page 4 of 5
4. Shim the sensor as necessary to level it.
Figure 4: Recommended Mounting Plate Dimensions
Mounting Considerations
•Small errors in alignment can produce significant errors. Be certain that the sensor is mounted
level.
•Mount the light sensor where it will not be in a shadow.
•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 HOBO Weather Station User’s Guide for more information regarding setting up
complete HOBO Weather Stations.
Connecting
To start using the PAR smart sensor, stop the logger and insert the sensor’s modular jack into an available
port on the logger. If a port is not available, use a 1-to-2 adaptor (Part # S-ADAPT), which allows you to
plug two sensors into one port. The next time the HOBO Weather Station is launched it will automatically
detect the new sensor. Note that the HOBO Weather Station supports a maximum of 15 data channels;
this sensor uses one data channel. Launch the logger and verify that the sensor is functioning correctly.
See the HOBO Weather Station User’s Guide for more details about connecting smart sensors to the
HOBO Weather Station.
Operation
The PAR 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 PAR smart sensor is used in an area where the light level
can vary quickly with respect to the logging interval (for example, under a partial plant canopy or during
partly cloudy conditions). Note that fast sampling intervals (less than 1 minute) may significantly reduce
battery life. See the HOBO Weather Station User’s Guide for more details about sensor operation and
battery life.
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 PAR smart 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 light sensor. The acrylic material used in the light sensors can be crazed by exposure to
Supplied in Australia by Instrument Choice
Call our scientists on 1300 737 871
www.instrumentchoice.com.au

PAR Smart Sensor
Page 5 of 5
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 check the accuracy of the PAR smart sensor annually. The PAR smart sensor
cannot be user-calibrated. Onset uses precision components to obtain accurate measurements. If the smart
sensor is not providing accurate data, then it may be damaged or out of calibration. If you are unsure of
the smart sensor’s accuracy, you can send it back to Onset for testing and possible re-calibration. Contact
Onset or your dealer for a Return Merchandise Authorization (RMA) number before sending it.
Warranty
This product is warranted to be free from defects in material and workmanship for a period of one year
from the date of original purchase. During the warranty period Onset will, at its option, either repair or
replace products that prove to be defective. This warranty is void if the Onset products have been
damaged by customer error or negligence or if there has been an unauthorized modification.
Tune-up Service
Onset will examine and retest this and any other smart sensor.
© 2001–2003 Onset Computer Corporation, all rights reserved.
Onset and HOBO are trademarks of Onset Computer Corporation.
The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).
Part #: MAN-S-LIA
Document #: 5942-C
Supplied in Australia by Instrument Choice
Call our scientists on 1300 737 871
www.instrumentchoice.com.au