apogee MQ-500 Quantum Meter Owner’s Manual
- June 5, 2024
- APOGEE
Table of Contents
- CERIFICATE OF COMPLIANCE
- INTRODUCTION
- SENSOR MODELS
- SPECIFICATIONS
- Calibration Traceability
- DEPLOYMENT AND INSTALLATION
- BATTERY INSTALLATION AND REPLACEMENT
- Battery Removal
- OPERATION AND MEASUREMENT
- APOGEE AMS SOFTWARE
- MAINTENANCE AND RECALIBBRATION
- TROUBLESHOOTING AND CUSTOMER SUPPORT
- RETURN AND WARRANTY POLICY
- PRODUCTS BEYOND THE WARRANTY PERIOD
- References
- Read User Manual Online (PDF format)
- Download This Manual (PDF format)
MQ-500 Quantum Meter
Owner’s Manual
QUANTUM METER
Models MQ-500
Rev: 1-Jun-2021
APOGEE INSTRUMENTS, INC.
721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA
TEL: 435-792-4700
FAX: 435-787-8268
WEB: APOGEEINSTRUMENTS.COM
Copyright © 2021 Apogee Instruments, Inc.
CERIFICATE OF COMPLIANCE
EU Declaration of Conformity
This declaration of conformity is issued under the sole responsibility of
the manufacturer:
Apogee Instruments, Inc.
721 W 1800 N Logan, Utah 84321 USA for the following product(s):
Models: MQ-500
Type: Quantum Meter
The object of the declaration described above is in conformity with the
relevant Union harmonization legislation:
2014/30/EU………………..Electromagnetic Compatibility (EMC) Directive
2011/65/EU…………………Restriction of Hazardous Substances (RoHS 2) Directive
2015/863/EU………………. Amending Annex II to Directive 2011/65/EU (RoHS 3)
Standards referenced during compliance assessment:
EN 61326-1:2013 Electrical equipment for measurement, control, and laboratory
use EMC requirements
EN 50581:2012 Technical documentation for the assessment of electrical and
electronic products with respect to the restriction of hazardous substances
Please be advised that based on the information available to us from our raw
material suppliers, the products manufactured by us do not contain, as
intentional additives, any of the restricted materials including lead (see
note below), mercury, cadmium, hexavalent chromium, polybrominated biphenyls
(PBB), polybrominated biphenyls (PBDE), bis(2-Ethylhexyl) phthalate (DEHP),
butyl benzyl phthalate (BBP), dibutyl phthalate (DBP), and isobutyl phthalate
(DIBP). However, please note that articles containing greater than 0.1% lead
concentration are RoHS 3 compliant using exemption 6c.
Further note that Apogee Instruments does not specifically run any analysis on
our raw materials or end products for the presence of these substances, but
rely on the information provided to us by our material suppliers.
Signed for and on behalf of
Apogee Instruments, June 2021
Bruce Bugbee
President
Apogee Instruments, Inc.
INTRODUCTION
Radiation that drives photosynthesis is called photosynthetically active
radiation (PAR) and is typically defined as total radiation across a range of
400 to 700 nm. PAR is almost universally quantified as photosynthetic photon
flux density (PPFD), the sum of photons from 400 to 700 nm in units of
micromoles per square meter per second (µmol m-2 s-1, equal to microEinsteins
m-2 s-1). While microEinsteins and micromoles are equal (one Einstein = one
mole of photons), the Einstein is not an SI unit, so expressing PPFD as µmol
m-2 s-1 is preferred. Daily total PPFD is typically reported in units of moles
of photons per square meter per day (mol m-2 d-1) and is often called daily
light integral (DLI).
The acronym PPF is also used and refers to the photosynthetic photon flux. The
acronyms PPF and PPFD refer to the same variable. Both terms are used because
there is not a universal definition of the term flux. Flux is sometimes
defined as per unit area per unit time and sometimes defined as per unit time
only. PPFD is used in this manual.
Sensors that measure PPFD are often called quantum sensors due to the
quantized nature of radiation. A quantum refers to the minimum quantity of
radiation, one photon, involved in physical interactions (e.g., absorption by
photosynthetic pigments). In other words, one photon is a single quantum of
radiation.
Typical applications of quantum sensors include measurement of incident PPFD
on plant canopies in outdoor environments or in greenhouses and growth
chambers, and reflected or under-canopy (transmitted) PPFD measurement in the
same environments.
Apogee Instruments MQ series quantum meters consist of a handheld meter and a
dedicated quantum sensor that is connected by cable to an anodized aluminum
housing. Sensors consist of a cast acrylic diffuser (filter), and photodiode,
and are potted solid with no internal air space. MQ series quantum meters
provide a real-time PPFD reading on the LCD display, that determine the
radiation incident on a planar surface (does not have to be horizontal), where
the radiation emanates from all angles of a hemisphere. MQ series quantum
meters include manual and automatic data logging features for making spot-
check measurements or calculating daily light integral (DLI).
SENSOR MODELS
Apogee MQ series quantum meters covered in this manual are self-contained and
come complete with a handheld meter and sensor.
The sensor model number and serial number are located on a label on the
backside of the handheld meter.
SPECIFICATIONS
| MQ-500
---|---
Calibration Uncertainty| ± 5 % (see calibration Traceability below)
Measurement Range| 0 to 4000 mmol m-2 s-1
Measurement Repeatability| less than 0.5 %
Long-term Drift (Non-stability)| less than 2 % per year
Non-linearity| less than 1 % (up to 4000 vmol m-2 s-1)
Response Time| less than 1 ms
Field of View| 1802
Spectral Range| 389 to 692 nm ± 5 nm (wavelengths where the response is
greater than 50 %)
Spectral Selectivity| less than 10 % from 412 to 682 nm ± 5 nm (see Spectral
Response below)
Directional (Cosine) Response| ± S % at 752 zenith angle (see Cosine Response
below)
Azimuth Error| less than 0.5 %
Tilt Error| less than 0.5 %
Temperature Response| -0.11 ± 0.04 % C-1(see Temperature Response below)
Uncertainty in Daily Total| less than S %
Detector| blue-enhanced silicon photodidode
Housing| anodized aluminum body with acrylic diffuser
IP Rating| IP68
Operating Environment| 0 to 50 C; less than 90 % non-condensing relative
humidity up to 30 C; less than 70 % non-condensing relativity humidity from 30
to 50 C; separate sensors can be submerged in water up to a depth of 30 m
Meter Dimension| 126 mm length; 70 mm width; 24 mm height
Sensor Dimensions| 24 mm diameter; 37 mm height
Mass| 100 g (with 5 m of lead wire)
Cable| 2 m of two-conductor, shielded, twisted-pair wire; additional cable
available; TPR jacket
Calibration Traceability
Apogee MQ series quantum meters are calibrated through side-by-side comparison to the mean of four transfer standard quantum sensors under a reference lamp. The reference quantum sensors are recalibrated with a 200 W quartz halogen lamp traceable to the National Institute of Standards and Technology (NIST).
Spectral Response
Mean spectral response measurements of six replicate Apogee SQ-100X
(original X) and MQ-500 (full-spectrum) series quantum sensors. Spectral
response measurements were made at 10 nm increments across a wavelength range
of 300 to 800 nm with a monochromator and an attached electric light source.
Measured spectral data from each quantum sensor were normalized by the
measured spectral response of the monochromator/electric light combination,
which was measured with a spectroradiometer.
Temperature Response
Mean temperature response of ten MQ-500 series quantum sensors (errors bars
represent two standard deviations above and below mean). Temperature response
measurements were made at 10 C intervals across a temperature range of
approximately -10 to 40 C in a temperature-controlled chamber under a fixed,
broad-spectrum, electric lamp. At each temperature set point, a
spectroradiometer was used to measure light intensity from the lamp and all
quantum sensors were compared to the spectroradiometer. The spectroradiometer
was mounted external to the temperature control chamber and remained at room
temperature during the experiment.
Cosine Response
Directional (cosine) response is defined as the measurement error at a
specific angle of radiation incidence. Error for Apogee MQ-500 series quantum
sensors is approximately ± 2 % and ± 5 % at solar zenith angles of 45° and
75°, respectively.
Mean directional (cosine) response of seven apogee MQ-500 series quantum
sensors. Directional response measurements were made on the rooftop of the
Apogee building in Logan, Utah. The directional response was calculated as the
relative difference of MQ-500 quantum sensors from the mean of replicate
reference quantum sensors (LI-COR models LI-190 and LI-190R, Kipp & Zonen
model PQS 1). Data were also collected in the laboratory using a reference
lamp and positioning the sensor at varying angles.
DEPLOYMENT AND INSTALLATION
Apogee MQ series quantum meters are designed for spot-check measurements and
calculation of daily light integral (DLI; the total number of photons incident
on a planar surface over the course of a day) through the built-in logging
feature. To accurately measure the PFFD incident on a horizontal surface, the
sensor must be level. For this purpose, each MQ model comes with a different
option for mounting the sensor to a horizontal plane.
The AL-100 leveling plate is recommended for use with the MQ-500 (AL-100
leveling plate pictured). To facilitate mounting to a cross arm, the AL-120
mounting bracket is recommended.
The AM-310 Sensor Wand accessory incorporates a mounting fixture at the end of
an extendable telescopic wand (up to 33 inches/84 cm). The wand is not suited
for wet environments; however, it is excellent for greenhouses and growth
chambers. Its ability to retract to a smaller size also makes it ideal for
travel use.
The AM-320 Saltwater Submersible Sensor Wand accessory incorporates a mounting
fixture at the end of a 40-inch segmented fiberglass wand and is well-suited
for saltwater use. The wand allows the user to place the sensor in hard-to-
reach areas such as aquariums.
BATTERY INSTALLATION AND REPLACEMENT
Use a Phillips head screwdriver to remove the screw from the battery cover.
Remove the battery cover by slightly lifting and sliding the outer edge of the
cover away from the meter.
To power the meter, slide the included battery (CR2320) into the battery
holder, after removing the battery door from the meter’s back panel.
The positive side (designated by a “+” sign) should be facing out from the
meter circuit board.
NOTE: The battery cradle can be damaged by using an incorrectly sized
battery. If the battery cradle is damaged, the circuit board will need to be
replaced. To avoid this costly problem, use only a CR2320 battery.
Battery Removal
Press down on the battery with a screwdriver or similar object. Slide battery
out.
If the battery is difficult to move, turn the meter on its side so that the
opening for the battery is facing downward and tap the meter downward against
an open palm to dislodge the battery enough so that it can be removed with
your thumb to slide the battery out of the battery holder.
OPERATION AND MEASUREMENT
MQ series quantum meters are designed with a user-friendly interface allowing
quick and easy measurements.
Press the power button to activate the LCD display. After two minutes of non-
activity, the meter will revert to sleep mode and the display will shut off to
conserve battery life.
Press the mode button to access the main menu, where manual or automatic
logging is selected, and where the meter can be reset.
Press the sample button to log a reading while taking manual measurements.
Press the up button to make selections in the main menu. This button is also
used to view and scroll through the logged measurements on the LCD display.
Press the down button to make selections in the main menu. This button is also
used to view and scroll through the logged measurements on the LCD display.
The LCD display consists of the total number of logged measurements in the
upper right-hand corner, the real-time PPFD value in the center, and the
selected menu options along the bottom. Logging: To choose between manual
or automatic logging, push the mode button once and use the up/down buttons to
make the appropriate selection (SMPL or LOG). Once the desired mode is
blinking, press the mode button two more times to exit the menu. When in SMPL
mode press the sample button to record up to 99 manual measurements (a counter
in the upper right hand corner of the LCD display indicates the total number
of saved measurements). When in LOG mode the meter will power on/off to make a
measurement every 30 seconds. Every 30 minutes the meter will average the
sixty 30-second measurements and record the averaged value to memory. The
meter can store up to 99 averages and will start to overwrite the oldest
measurement once there are 99 measurements. For every 48 averaged measurements
(making a 24-hour period), the meter will also store an integrated daily total
in moles per meter squared per day (mol m-2 d-1).
Reset: To reset the meter, in either SMPL or LOG mode, push the mode
button three times (RUN should be blinking), then while pressing the down
button, press the mode button once. This will erase all of the saved
measurements in memory, but only for the selected mode. That is, performing a
reset when in SMPL mode will only erase the manual measurements, and
performing a reset when in LOG mode will only erase the automatic
measurements.
Review/Download Data: Each of the logged measurements in either SMPL or
LOG mode can be reviewed on the LCD display by pressing the up/down buttons.
To exit and return to the real-time readings, press the sample button. Note
that the integrated daily total values are not accessible through the LCD and
can only be viewed by downloading to a computer.
Downloading the stored measurements will require the AC-100 communication
cable and software (sold separately). The meter outputs data using the UART
protocol and requires the AC-100 to convert from UART to USB, so standard USB
cables will not work. Set-up instructions and software can be downloaded from
the Apogee website (http://www.apogeeinstruments.com/ac-100-communcation-
cable/).
Spectral Error
The combination of diffuser transmittance, interference filter transmittance, and photodetector sensitivity yields the spectral response of a quantum sensor. A perfect photodetector/filter/diffuser combination would exactly match the defined plant photosynthetic response to photons (equal weighting to all photons between 400 and 700 nm, no weighting of photons outside this range), but this is challenging in practice. A mismatch between the defined plant photosynthetic response and sensor spectral response results in a spectral error when the sensor is used to measure radiation from sources with a different spectrum than the radiation source used to calibrate the sensor (Federer and Tanner, 1966; Ross and Sulev, 2000).
Spectral errors for PPFD measurements made under common radiation sources for
growing plants were calculated for Apogee SQ-100 and SQ-500 series quantum
sensors using the method of Federer and Tanner (1966). This method requires
PPFD weighting factors (defined plant photosynthetic response), measured
sensor spectral response (shown in the Spectral Response section on page 7),
and radiation source spectral outputs (measured with a spectroradiometer).
Note, that this method calculates spectral error only and does not consider
calibration, directional (cosine), temperature, and stability/drift errors.
Spectral error data (listed in the table below) indicate errors less than 5 %
for sunlight in different conditions (clear, cloudy, reflected from plant
canopies, transmitted below plant canopies) and common broad-spectrum electric
lamps (cool white fluorescent, metal halide, high-pressure sodium), but larger
errors for different mixtures of light-emitting diodes (LEDs) for the SQ-100
series sensors. Spectral errors for the SQ-500 series sensors are smaller than
those for SQ-100 series sensors because the spectral response of SQ-500 series
sensors is a closer match to the defined plant photosynthetic response.
Quantum sensors are the most common instrument for measuring PPFD because they
are about an order of magnitude lower cost than spectroradiometers, but
spectral errors must be considered. The spectral errors in the table below can
be used as correction factors for individual radiation sources.
Spectral Errors for PPFD Measurements with Apogee SQ-100x and SQ-500 Series
Quantum Sensors
Radiation Source (Error Calculated Relative to Sun, Clear Sky)| SQ-
100X SeriesPPFD Error [%]| SQ-500 Series PPFD Error [%]
---|---|---
Sun (Clear Sky)| 0.0| 0.0
Sun (Cloudy Sky)| 0.2| 0.1
Reflected from Grass Canopy| 5.0| -0.3
Transmitted below Wheat Canopy| 7.0| 0.1
Cool White Fluorescent (T5)| 7.| 0.1
Metal Halide| 7.| 0.9
Ceramic Metal Halide| -9.| 0.3
High-Pressure Sodium| 3.| 0.1
Blue LED (448 nm peak, 20 nm full-width half-maximum)| 15.| -1.
Green LED (524 nm peak, 30 nm full-width half-maximum)| 30.| 3.
Red LED (635 nm peak, 20 nm full-width half-maximum)| -31.| 0.8
Red LED (667 nm peak, 20 nm full-width half-maximum)| -57.| 3.
Red, Blue LED Mixture (80 % Red, 20 % Blue)| -21.| -4.
Red, Blue, White LED Mixture (60 % Red, 25 % White, 15 % Blue)| -30.| –2.0
Cool White LED| 7.| 0.5
Warm White LED| -8.| 0.2
Federer, C.A., and C.B. Tanner, 1966. Sensors for measuring light available
for photosynthesis. Ecology 47:654-657.
Ross, J., and M. Sulev, 2000. Sources of errors in measurements of PAR.
Agricultural and Forest Meteorology 100:103-125.
Yield Photon Flux Density (PFD) Measurements
Photosynthesis in plants does not respond equally to all photons. Relative
quantum yield (plant photosynthetic efficiency) is dependent on wavelength
(green line in the figure below) (McCree, 1972a; Inada, 1976). This is due to
the combination of spectral absorptivity of plant leaves (absorptivity is
higher for blue and red photons than green photons) and absorption by non-
photosynthetic pigments. As a result, photons in the wavelength range of
approximately 600-630 nm are the most efficient.
Defined plant response to photons (black line, weighting factors used to
calculate PPFD), measured plant response to photons (green line, weighting
factors used to calculate YPFD), and SQ-500 series quantum sensor response to
photons (sensor spectral response).
One potential definition of PAR is weighting photon flux density in units of
mol m-2 s-1 at each wavelength between 300 and 800 nm by measured relative
quantum yield and summing the result. This is defined as yield photon flux
density (PFD, units of mol m-2 s-1) (Sager et al., 1988). There are
uncertainties and challenges associated with this definition of PAR.
Measurements used to generate the relative quantum yield data were made on
single leaves under low radiation levels and at short time scales (McCree,
1972a; Inada, 1976). Whole plants and plant canopies typically have multiple
leaf layers and are generally grown in the field or greenhouse over the course
of an entire growing season. Thus, the actual conditions plants are subject to
are likely different than those the single leaves were in when measurements
were made by McCree (1972a) and Inada (1976). In addition, the relative
quantum yield shown in the figure above is the mean from twenty-two species
grown in the field (McCree, 1972a). Mean relative quantum yield for the same
species grown in growth chambers was similar, but there were differences,
particularly at shorter wavelengths (less than 450 nm). There was also some
variability between species (McCree, 1972a; Inada, 1976).
McCree (1972b) found that equally weighting all photons between 400 and 700 nm
and summing the result, defined as photosynthetic photon flux density (PPFD,
in units of mol m-2 s-1), was well correlated to photosynthesis, and very
similar to the correlation between YPFD and photosynthesis. As a matter of
practicality, PPFD is a simpler definition of PAR. At the same time as
McCree’s work, others had proposed PPFD as an accurate measure of PAR and
built sensors that approximated the PPFD weighting factors (Biggs et al.,
1971; Federer and Tanner, 1966). The correlation between PPFD and PFD
measurements for several radiation sources is very high (figure below), as an
approximation, YPFD = 0.9PPFD. As a result, almost universally PAR is defined
as PPFD rather than YPFD, although YPFD has been used in some studies. The
only radiation sources shown (figure below) that don’t fall on the regression
line are the high-pressure sodium (HPS) lamp, reflection from a plant canopy,
and transmission below a plant canopy. A large fraction of radiation from HPS
lamps is in the red range of wavelengths where the YPFD weighting factors
(measured relative quantum yield) are at or near one. The factor for
converting PPFD to YPFD for HPS lamps is 0.95, rather than 0.90. The factor
for converting PPFD to YPFD for reflected and transmitted photons is 1.00.
Correlation between photosynthetic photon flux density (PPFD) and yield photon
flux density (PFD) for multiple different radiation sources. PDF is
approximately 90 % of PPFD. Measurements were made with a spectroradiometer
(Apogee Instruments model PS-200) and weighting factors shown in the previous
figure were used to calculate PPFD and PFD.
Biggs, W., A.R. Edison, J.D. Eastin, K.W. Brown, J.W. Maranville, and M.D.
Clegg, 1971. Photosynthesis light sensor and meter. Ecology 52:125-131.
Federer, C.A., and C.B. Tanner, 1966. Sensors for measuring light available
for photosynthesis. Ecology 47:654-657.
Inada, K., 1976. Action spectra for photosynthesis in higher plants. Plant and
Cell Physiology 17:355-365.
McCree, K.J., 1972a. The action spectrum, absorptance, and quantum yield of
photosynthesis in crop plants. Agricultural Meteorology 9:191-216.
McCree, K.J., 1972b. Test of current definitions of photosynthetically active
radiation against leaf photosynthesis data. Agricultural Meteorology
10:443-453.
Sager, J.C., W.O. Smith, J.L. Edwards, and K.L. Cyr, 1988. Photosynthetic
efficiency and phytochrome photoequilibria determination using spectral data.
Transactions of the ASAE 31:1882-1889.
Immersion Effect Correction Factor
When a radiation sensor is submerged in water, more of the incident radiation
is backscattered out of the diffuser than when the sensor is in the air
(Smith, 1969; Tyler and Smith, 1970). This phenomenon is caused by the
difference in the refractive index for air (1.00) and water (1.33), and is
called the immersion effect. Without correction for the immersion effect,
radiation sensors calibrated in the air can only provide relative values
underwater (Smith, 1969; Tyler and Smith, 1970). Immersion effect correction
factors can be derived by making measurements in air and at multiple water
depths at a constant distance from a lamp in a controlled laboratory setting.
Apogee SQ-500 series quantum sensors have an immersion effect correction
factor of 1.25. This correction factor should be multiplied by PPFD
measurements made underwater to yield accurate PPFD.
Further information on underwater measurements and the immersion effect can be
found on the Apogee webpage (http://www.apogeeinstruments.com/underwater-par-
measurements/).
Smith, R.C., 1969. An underwater spectral irradiance collector. Journal of
Marine Research 27:341-351.
Tyler, J.E., and R.C. Smith, 1970. Measurements of Spectral Irradiance
Underwater. Gordon and Breach, New York, New York. 103 pages
APOGEE AMS SOFTWARE
Downloading data to a computer requires the AC-100 communication cable and the
free ApogeeAMS software. The meter outputs data using the UART protocol and
requires the AC-100 to convert from UART to USB, so standard USB cables will
not work.
The most recent version of ApogeeAMS software can be downloaded at
http://www.apogeeinstruments.com/downloads/.
When the ApogeeAMS software is first opened, it will show a blank screen until
communication with the meter is established. If you click “Open Port” it will
say “connection failed.”
To establish communication, make sure the meter is plugged into your computer
using the AC-100 communication cable. To connect click the dropdown menu
button and “COM#” options will appear. For more details on how to figure out
which COM is the right one, watch our video.
When you have connected to the correct COM#, the software will say
“Connected”.
Click “Sample Data” to view saved sample readings.
“Daily Totals” shows all of the saved Daily Light Integral (DLI) totals per
day.
Click “30 Min Avg” to see the meter’s 99, 30-minute averages.
To analyze the data, click on “File” and “Save As” to save the data as a .csv
file.
Or, you can highlight the numbers, and copy, and paste them into a blank Excel
spreadsheet. Data will need to be comma-delimited.
MAINTENANCE AND RECALIBBRATION
Blocking of the optical path between the target and detector can cause low readings. Occasionally, accumulated materials on the diffuser of the upward- looking sensor can block the optical path in three common ways:
- Moisture or debris on the diffuser.
- Dust during periods of low rainfall.
- Salt deposit accumulation from the evaporation of sea spray or sprinkler irrigation water.
Apogee Instruments’ upward-looking sensors have a domed diffuser and housing
for improved self-cleaning from rainfall, but active cleaning may be
necessary. Dust or organic deposits are best removed using water, or window
cleaner, and a soft cloth or cotton swab. Salt deposits should be dissolved
with vinegar and removed with a cloth or cotton swab. Salt deposits cannot be
removed with solvents such as alcohol or acetone. Use only gentle pressure
when cleaning the diffuser with a cotton swab or soft cloth to avoid
scratching the outer surface. The solvent should be allowed to do the
cleaning, not mechanical force. Never use abrasive material or cleaner on
the diffuser.
Although Apogee sensors are very stable, nominal accuracy drift is normal for
all research-grade sensors. To ensure maximum accuracy, we generally recommend
sensors are sent in for recalibration every two years, although you can often
wait longer according to your particular tolerances.
To determine if a specific sensor needs recalibration, the Clear Sky
Calculator (www.clearskycalculator.com)
website and/or smartphone app can be used to indicate PPFD incidents on a
horizontal surface at any time of day at any location in the world. It is most
accurate when used near solar noon in the spring and summer months, where
accuracy over multiple clear and unpolluted days is estimated to be ± 4 % in
all climates and locations around the world. For best accuracy, the sky must
be completely clear, as reflected radiation from clouds causes incoming
radiation to increase above the value predicted by the clear sky calculator.
Measured PPFD can exceed PPFD predicted by the Clear Sky Calculator due to
reflection from thin, high clouds and edges of clouds, which enhances incident
PPFD. The influence of high clouds typically shows up as spikes above clear
sky values, not a constant offset greater than clear sky values.
To determine recalibration needs, input site conditions into the calculator
and compare PPFD measurements to calculated PPFD for a clear sky. If sensor
PPFD measurements over multiple days near solar noon are consistently
different than calculated PPFD (by more than 6 %), the sensor should be
cleaned and re-leveled. If measurements are still different after a second
test, email
calibration@apogeeinstruments.com
to discuss test results and the possible return of sensor(s).
This calculator determines the intensity of radiation falling on a horizontal
surface at any time of the day in any location in the world. The primary use
of this calculator is to determine the need for the recalibration of radiation
sensors. It is most accurate when used near solar noon in the summer months.
This site was developed and maintained by:
Homepage of the Clear Sky Calculator. Two calculators are available: one for
quantum sensors (PPFD) and one for pyranometers (total shortwave radiation).
Clear Sky Calculator for quantum sensors. Site data are input in blue cells in
the middle of the page and an estimate of PPFD is returned on the right-hand
side of the page.
TROUBLESHOOTING AND CUSTOMER SUPPORT
Verify Functionality
Pressing the power button should activate the LCD and provide a real-time PPFD
reading. Direct the sensor head toward a light source and verify the PPFD
reading responds. Increase and decrease the distance from the sensor to the
light source to verify that the reading changes proportionally (decreasing
PPFD with increasing distance and increasing PPFD with decreasing distance).
Blocking all radiation from the sensor should force the PPFD reading to zero.
Battery Life
When the meter is maintained properly the coin cell battery (CR2320) should
last for many months, even after continuous use. The low battery indicator
will appear in the upper left-hand corner of the LCD display when the battery
voltage drops below 2.8 V DC. The meter will still function correctly for some
time, but once the battery is drained the pushbuttons will no longer respond
and any logged measurements will be lost.
Pressing the power button to turn off the meter will actually put it in sleep
mode, where there is still a slight amount of current draw. This is necessary
to maintain the logged measurements in memory. Therefore, it is recommended to
remove the battery when storing the meter for many months at a time, in order
to preserve battery life.
Low-Battery Error after Battery Replacement
A master reset will usually correct this error, please see the master reset
section for details and cautions. If a master reset does not remove the low
battery indicator, please double-check that the voltage of your new battery is
above 2.8 V, this is the threshold for the indicator to turn on.
Master Reset
If a meter ever becomes non-responsive or experiences anomalies, such as a low
battery indicator even after replacing the old battery, a master reset can be
performed that may correct the problem. Note that a master reset will erase
all logged measurements from memory.
Step 1 : Press the power button so that the LCD display is activated.
Step 2: Slide the battery out of the holder, which will cause the LCD
display to fade out.
Step 3 : After a few seconds, slide the battery back into the holder.
The LCD display will flash all segments and then show a revision number (e.g.
“R1.0”). This indicates the master reset was performed and the display should
return to normal.
Error Codes and Fixes
Error codes will appear in place of the real-time reading on the LCD display
and will continue to flash until the problem is corrected. Contact Apogee if
the following fixes do not rectify the problem.
Err 1: battery voltage out of range. Fix: replace the CR2320 battery and
perform a master reset.
Err 2 : sensor voltage out of range. Fix: perform a master reset.
Err 3: not calibrated. Fix: perform a master reset.
Err 4: CPU voltage below minimum. Fix: replace the CR2320 battery and
perform a master reset.
Modifying Cable Length
Although it is possible to splice additional cable to the separate sensor of
the appropriate MQ model, note that the cable wires are soldered directly into
the circuit board of the meter. Care should be taken to remove the back panel
of the meter in order to access the board and splice on the additional cable,
otherwise, two splices would need to be made between the meter and sensor
head. See the Apogee webpage for further details on how to extend sensor cable
length: (http://www.apogeeinstruments.com/how-to-make-a-weatherproof-cable-
splice/).
Unit Conversion Charts
Apogee SQ-500 series quantum sensors are calibrated to measure PPFD in units
of µmol m-2 s-1. Units other than photon flux density (e.g., energy-flux
density, illuminance) may be required for certain applications. It is possible
to convert PPFD from a quantum sensor to other units, but it requires the
spectral output of the radiation source of interest. Conversion factors for
common radiation sources can be found in the Knowledge Base on the Apogee
website (http://www.apogeeinstruments.com/knowledge-base/; scroll down to
the Quantum Sensors section). A spreadsheet to convert PPFD to energy flux
density or illuminance is also provided in the Knowledge Base on the Apogee
website (http://www.apogeeinstruments.com/content/PPFD-to-Illuminance-
Calculator.xls).
RETURN AND WARRANTY POLICY
RETURN POLICY
Apogee Instruments will accept returns within 30 days of purchase as long as
the product is in new condition (to be determined by Apogee). Returns are
subject to a 10 % restocking fee.
WARRANTY POLICY
What is Covered
All products manufactured by Apogee Instruments are warranted to be free
from defects in materials and craftsmanship for a period of four (4) years
from the date of shipment from our factory. To be considered for warranty
coverage an item must be evaluated by Apogee.
Products not manufactured by Apogee (spectroradiometers, chlorophyll content
meters, EE08-SS probes) are covered for a period of one (1) year.
What has Not been Covered
The customer is responsible for all costs associated with the removal,
reinstallation, and shipping of suspected warranty items to our factory.
The warranty does not cover equipment that has been damaged due to the
following conditions:
- Improper installation or abuse.
- Operation of the instrument outside of its specified operating range.
- Natural occurrences such as lightning, fire, etc.
- Unauthorized modification.
- Improper or unauthorized repair.
Please note that nominal accuracy drift is normal over time. Routine
recalibration of sensors/meters is considered part of proper maintenance and
is not covered under warranty.
Who has Covered
This warranty covers the original purchaser of the product or other party who
may own it during the warranty period.
What Apogee Will Do
At no charge Apogee will:
- Either repair or replace (at our discretion) the item under warranty.
- Ship the item back to the customer by the carrier of our choice.
Different or expedited shipping methods will be at the customer’s expense. How To Return An Item
-
Please do not send any products back to Apogee Instruments until you have received a Return Merchandise
Authorization (RMA) number from our technical support department by submitting an online RMA form at www.apogeeinstruments.com/tech-support-recalibration- repairs/. We will use your RMA number for tracking of the service item. Call 435-245-8012 or email techsupport@apogeeinstruments.com with questions. -
For warranty evaluations, send all RMA sensors and meters back in the following condition: Clean the sensor’s exterior and cord. Do not modify the sensors or wires, including splicing, cutting wire leads, etc. If a connector has been attached to the cable end, please include the mating connector otherwise, the sensor connector will be removed in order to complete the repair/recalibration. Note: When sending back sensors for routine calibration that have Apogee’s standard stainless-steel connectors, you only need to send the sensor with the 30 cm section of cable and one-half of the connector. We have mating connectors at our factory that can be used for calibrating the sensor.
-
Please write the RMA number on the outside of the shipping container.
-
Return the item with freight pre-paid and fully insured to our factory address shown below. We are not responsible for any costs associated with the transportation of products across international borders.
Apogee Instruments, Inc.
721 West 1800 North Logan,
UT 84321, USA -
Upon receipt, Apogee Instruments will determine the cause of failure. If the product is found to be defective in terms of operation to the published specifications due to a failure of product materials or craftsmanship, Apogee Instruments will repair or replace the items free of charge. If it is determined that your product is not covered under warranty, you will be informed and given an estimated repair/replacement cost.
PRODUCTS BEYOND THE WARRANTY PERIOD
For issues with sensors beyond the warranty period, please contact Apogee at
techsupport@apogeeinstruments.com
to discuss repair or replacement options.
OTHER TERMS
The available remedy of defects under this warranty is for the repair or
replacement of the original product, and Apogee Instruments is not responsible
for any direct, indirect, incidental, or consequential damages, including but
not limited to loss of income, loss of revenue, loss of profit, loss of data,
loss of wages, loss of time, loss of sales, accruement of debts or expenses,
injury to personal property, or injury to any person or any other type of
damage or loss.
This limited warranty and any disputes arising out of or in connection with
this limited warranty (“Disputes”) shall be governed by the laws of the State
of Utah, USA, excluding conflicts of law principles and excluding the
Convention for the International Sale of Goods. The courts located in the
State of Utah, USA, shall have exclusive jurisdiction over any Disputes.
This limited warranty gives you specific legal rights, and you may also have
other rights, which vary from state to state and jurisdiction to jurisdiction,
and which shall not be affected by this limited warranty. This warranty
extends only to you and cannot by transferred or assigned. If any provision of
this limited warranty is unlawful, void or unenforceable, that provision shall
be deemed severable and shall not affect any remaining provisions. In case of
any inconsistency between the English and other versions of this limited
warranty, the English version shall prevail.
This warranty cannot be changed, assumed, or amended by any other person or
agreement
APOGEE INSTRUMENTS, INC.
721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA
TEL: 435-792-4700
FAX: 435-787-8268
WEB: APOGEEINSTRUMENTS.COM
Copyright © 2021 Apogee Instruments, Inc.
References
- AC-100: Communication Cable - Apogee Instruments, Inc.
- Software Downloads - Datalogger Programs | Apogee Instruments
- How to Make a Weatherproof Cable Splice
- Support | Apogee Instruments
- Recalibration and Repair | Apogee Instruments
- Underwater PAR Measurements | Apogee Instruments
- Clear Sky Calculator | Apogee Instruments Inc.
- Clear Sky Calculator | Apogee Instruments Inc.
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