OWNER’S MANUAL

USB QUANTUM SENSOR
Model JSQ-420

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TABLE OF CONTENTS
Owner’s Manual ................................................................................................................................................................................................................ 1
Certificate of Compliance.......................................................................................................................................................................................... 3
Introduction .................................................................................................................................................................................................................. 4
Sensor Models .............................................................................................................................................................................................................. 5
Specifications ................................................................................................................................................................................................................ 6
Deployment and Installation ................................................................................................................................................................................... 9
Software Installation ................................................................................................................................................................................................. 10
Operation and Measurement ................................................................................................................................................................................ 11
Windows Software .................................................................................................................................................................................................... 12
Mac Software .............................................................................................................................................................................................................. 17久德電子

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CERTIFICATE OF COMPLIANCE
EU Declaration of Conformity
Models: JSQ-420
Type: Quantum Sensor
The object of the declaration described above is in conformity with the relevant Union harmonization legislation:
2014/30/EU
2011/65/EU

Electromagnetic Compatibility (EMC) Directive
Restriction of Hazardous Substances (RoHS 2) Directive

Standards referenced during compliance assessment:
EN 61326-1:2013
EN 50581:2012

Electrical equipment for measurement, control and laboratory use – EMC requirements
Technical documentation for the assessment of electrical and electronic products with respect to therestriction 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 cadmium, hexavalent chromium, lead,
mercury, polybrominated biphenyls (PBB), polybrominated diphenyls (PBDE).

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INTRODUCTION
Radiation that drives photosynthesis is called photosynthetically active radiation (PAR) and is typically defined as total
radiation between 400 and 700 nm. PAR is often expressed as photosynthetic photon flux density (PPFD): photon flux in unitsof micromoles per square meter per second (µmol m-2 s-1, equal to microEinsteins per square meter per second) summed
from 400 to 700 nm (total number of photons from 400 to 700 nm). While Einsteins 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.
The acronym PPF is also widely used and refers to the photosynthetic photon flux. The acronyms PPF and PPFD refer to thesame parameter. The two terms have co-evolved because there is not a universal definition of the term “flux”. Some
physicists define flux as per unit area per unit time. Others define flux only as per unit time. We have used PPFD in thismanual because we feel that it is better to be more complete and possibly redundant.
Sensors that measure PPFD are often called quantum sensors. A quantum is the minimum quantity of radiation (onephoton), necessary to cause a physical, electrical, or chemical reaction (e.g., absorption by photosynthetic pigments). So one
photon is a single quantum of radiation.
The Quantum Sensor consists of a cast acrylic diffuser (filter), photodiode, and signal processing circuitry
mounted in an anodized aluminum housing, and a cable to connect the sensor to a measurement device. The sensor ispotted solid with no internal air space. It is designed for continuous PPFD measurement in indoor, outdoor and underwater
environments. The JSQ-420 sensor output increases linearly with PPFD under sunlight (natural setting) or electric lights(electric setting). The signal from the sensor is directly proportional to radiation incident on a flat surface where the radiation
comes from all angles of a hemisphere.

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SENSOR MODELSThis manual covers the USB quantum sensor model JSQ-420. For additional models see JSQ-100/JSQ-300 series, JSQ-212/SQ-222
and JSQ-215/JSQ-225, and JSQ-214/JSQ-224 manuals.

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Model

SignalCalibration+SQ-420

USB

Sunlight and Electric light

JSQ-110

Self-powered

Sunlight

JSQ-120

Self-powered

Electric light

JSQ-2120-2.5 V

Sunlight

JSQ-2220-2.5 VElectric light

JSQ-214

4-20 mA

Sunlight

JSQ-224

4-20 mA

Electric light

JSQ-215

0-5 V

Sunlight

JSQ-225

0-5 V

Electric light

JSQ-311

Self-powered

Sunlight

JSQ-321

Self-powered

Electric light

JSQ-313

Self-powered

Sunlight

JSQ-323

Self-powered

Electric light

JSQ-316

Self-powered

Sunlight

JSQ-326

Self-powered

Electric light

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6

SPECIFICATIONS
JSQ-420
Resolution

0.1 µmol m-2 s-1

Calibration Factor

Custom for each sensor and stored in the firmware

Calibration Uncertainty± 5 % (see calibration Traceability below)

Measurement Repeatability
Long-term Drift(Non-stability)
Non-linearity

Less than 1 %Less than 2 % per year
Less than 1 % (up to 3000 µmol m-2 s-1)

Response Time

Software updates every second

Field of View

180ºSpectral Range
Directional (Cosine) Response

410 to 655 nm (wavelengths where response is greater than 50 % of maximum;
see Spectral Response below)± 5 % at 75º zenith angle (see Cosine Response below)

Temperature Response-0.06 ± 0.06 % per C (see Temperature Response below)

Operating Environment-40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m

Dimensions

24 mm diameter; 28 mm height

Mass

Sensor head weighs 90 g

USB Cable

4.6 m (15 ft)

Current Draw (when Logging)

2.1 mA

Calibration Traceability
JSQ series sensors are calibrated through side-by-side comparison to the mean of four Apogee model SQ-110 or SQ120 transfer standard quantum sensors under high output T5 cool white fluorescent lamps. The transfer standard quantum
sensors are calibrated through side-by-side comparison to the mean of at least three LI-COR model LI-190R reference
quantum sensors under high output T5 cool white fluorescent lamps. The reference quantum sensors are recalibrated every
6 months with a LI-COR model 1800-02 Optical Radiation Calibrator using a 200 W quartz halogen lamp. The 1800-02 andquartz halogen lamp are traceable to the National Institute of Standards and Technology (NIST).

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7Spectral Response

Mean spectral response of six sensors (error bars
represent two standard deviations above andbelow mean) compared to PAR (PPFD) weighting
function. Spectral response measurements weremade at 10 nm increments across a wavelength
range of 300 to 800 nm in a monochromator withan attached electric light source. Measured
spectral data from each quantum sensor werenormalized by the measured spectral response of
the monochromator/electric light combination,
which was measured with a spectroradiometer.

Temperature Response

Mean temperature response of eight replicate
sensors (errors bars represent two standard
deviations above and below mean).
Temperature response measurements weremade at 10 C intervals across a temperature
range of -10 to 40 C in a temperature controlledchamber under a fixed, broad spectrum, electric
lamp. At each temperature set point, aspectroradiometer was used to measure lightintensity from the lamp and all quantum sensors
were compared to the spectroradiometer. The
spectroradiometer was mounted external to thetemperature control chamber and remained atroom temperature during the measurements.

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8Cosine Response

Directional, or cosine, response is defined as the measurement
error at a specific angle of radiation incidence. Error for JSQ series
quantum sensors is approximately ± 2 % and ± 5 % atsolar zenith angles of 45° and 75°, respectively.

Mean cosine response of twenty-three
replicate sensors (error bars represent
two standard deviations above andbelow mean). Cosine response
measurements were made by direct sideby-side comparison to the mean of fourreference thermopile pyranometers, withsolar zenith angle-dependent factors
applied to convert total shortwave
radiation to PPFD. Blue points represent
the AM response and red points represent
the PM response.

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DEPLOYMENT AND INSTALLATION
Mount the sensor to a solid surface with the nylon mounting screw provided. To accurately measure PPFD incident on ahorizontal surface, the sensor must be level. An Apogee Instruments model AL-100 leveling plate is recommended for thispurpose. To facilitate mounting on a cross arm, an Apogee Instruments model AM-110 mounting bracket is recommended.

Nylon Screw: 10-32x3/8

Model: AL-100

To minimize azimuth error, the sensor should be mounted with the cable pointing toward true north in the northernhemisphere or true south in the southern hemisphere. Azimuth error is typically less than 1 %, but it is easy to minimize byproper cable orientation.

In addition to orienting the cable to point toward the nearest pole, the sensor should also be mounted such that
obstructions (e.g., weather station tripod/tower or other instrumentation) do not shade the sensor. Once mounted, thegreen cap should be removed from the sensor. The green cap can be used as a protective covering for the sensor when it
is not in use.

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SOFTWARE INSTALLATION
Installing the software on a PC

1.
2.
3.
4.
5.

Double click on the installer package:
On the ‘Welcome’ screen, please click ‘Next’ to continue.
Select the radio button next to “I Agree” to the UELA… and click ‘Next’ to continue.
On the ‘Ready to Install the Program’ screen, click ‘Install’ to continue.
Click ‘Finish’ to complete the installation. There are shortcuts on your desktop and in your start bar.

Installing the software on a Mac
The software will automatically download.

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OPERATION AND MEASUREMENT
Spectral Errors and Yield Photon Flux Measurements
Apogee quantum sensors are calibrated to measure PPFD for either sunlight or electric light. The difference between thecalibrations is 12 %. A sensor calibrated for electric lights (calibration source is T5 cool white fluorescent lamps) will readapproximately 12 % low in sunlight.
In addition to PPFD measurements, JSQ series quantum sensors can also be used to measure yield photon flux
density (YPFD): photon flux weighted according to the plant photosynthetic action spectrum (McCree, 1972) and summed.
YPFD is also expressed in units of µmol m-2 s-1, and is similar to PPFD, but is typically more closely correlated tophotosynthesis than PPFD. PPFD is usually measured and reported because the PPFD spectral weighting function (equal
weight given to all photons between 400 and 700 nm; no weight given to photons outside this range) is easier to define andmeasure, and as a result, PPFD is widely accepted. The calibration factor for YPFD is 10 % lower than the calibration factor for
PPFD.
The weighting functions for PPFD and YPFD are shown in the graph below, along with the spectral response of JSQ
series quantum sensors. The closer the spectral response matches the defined PPFD or YPFD spectral weighting functions,the smaller spectral errors will be. The table below provides spectral error estimates for PPFD and YPFD measurements fromlight sources different than the calibration source. The method of Federer and Tanner (1966) was used to determine spectral
errors based on the PPFD and YPFD spectral weighting functions, measured sensor spectral response, and radiation source
spectral outputs (measured with a spectroradiometer). This method calculates spectral error and does not consider
calibration, cosine, and temperature errors.
Federer, C. A., and C. B. Tanner, 1966. Sensors for measuring light available for photosynthesis. Ecology 47:654-657.
McCree, K. J., 1972. The action spectrum, absorptance and quantum yield of photosynthesis in crop plants. Agricultural
Meteorology 9:191-216.

Radiation weighting factors for PPFD (defined plant
response to radiation), YPFD (measured plant
response to radiation), and JSQ Series
quantum sensors (sensor sensitivity to different
wavelengths of radiation).

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WINDOWS SOFTWARE
When the JSQ-420 sensor is not plugged into the USB port, thesoftware will display a message in the lower left corner, “Device Not
Connected,” indicating it cannot establish communication with thesensor.

Plug the sensor into a USB port and allow some time for the sensor
to automatically establish communication with the software. Onceestablished, the message in the lower left corner will display“Device Connected SN: ####” and real-time PAR readings will
update on the screen. Moving the sensor closer to a light source
should increase the readings, while blocking all light from thesensor should drop the reading to zero.

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Click the ‘Settings’ icon to display the software options.

Clicking ‘Light Source’ will allow the user to change the sensor’s
default calibration reference from Electric to Sunlight. Electricshould be selected when measuring most indoor artificial lightsources, while Sunlight should be selected when measuring
sunlight (such as when evaluating the need for recalibration).

Clicking ‘Calibration’ will display the factory calibrated multiplierand offset values. These values are saved in firmware and can berecovered by clicking the ‘Recover Original’ button. Deriving a new
calibration multiplier and offset is accomplished by clicking the‘Recalibrate’ button. This is applicable if users want to calibrate thesensor to their own specific light source. Note that a reference PAR
value of the light source is required to complete a recalibration.

After clicking the ‘Recalibate’ button the user will be prompted tocover the sensor. Place a dark cap over the sensor and wait for the
real-time PAR reading to settle at zero. Click OK.

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Uncover the sensor and wait for the PAR reading to settle before
entering the reference value. Click OK.

The multiplier and offset values will automatically calculate andupdate in the appropriate field. Be sure to click ‘Save’ to retain the
new multiplier and offset.

Clicking ‘Data Logging’ will allow the user to log intervalmeasurements in a csv file while the software is open andcommunicating with the sensor.

Click ‘Setup’ and the Setup Logging window appears. Click the‘Browse’ button to create or select a csv file.
Select the desired sampling interval. Note that 1 second is theminimum interval allowed. Click ‘Start’.

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The data logging window will start to update at the specified
sampling interval and display the Timestamp, Light Source, and Data
Value. At the same time, data will be written to the csv file. Note that if
the csv file is open in another program new data will not be saved toit.
The data logging window can be closed without affecting logged
data by clicking the ‘Exit’ button. The ‘Stop’ button must be clicked to
end data logging.

The about screen tells you the software and firmware versions. Thesecan be used to help troubleshoot if problems arise.

‘Manage Field Logging’ is used to setup the JSQ-420 for use in thefield. When the JSQ-420 is supplied power from a USB power source itwill log data which you can retrieve. Choose the interval that data is
saved as well as the interval that data is sampled and the light source
used. The shortest sampling interval is 1 second. The longest
sampling or logging interval is 1440 minutes (1 day). Click ‘Load
Settings’ to see current settings and ‘Save Settings’ to save thesettings you want to the sensor. Note: If you don’t click save thesensor won’t change the settings.

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16

Set the sampling interval in minutes or seconds. The sampling interval
is how often a measurement is taken and logging interval is how often
the data is saved. The logged data is the average of the samples. The
logging interval must be evenly divided by the sampling interval. For
example if the logging interval is 5 minutes and the sampling interval is
2 minutes it causes an error. But a sampling interval of 1 minute isacceptable.

Before clicking ‘Get Logged Data’ it is important to set the time of thelast logged data point. This is used to back calculate the timestamps forthe remaining data points. If you just unplugged the sensor andplugged it into the computer the preloaded day and time should be
sufficient.

Click ‘Get Logged Data’ to save the data to your computer. You will be
asked where you want to save the data.
Click ‘Erase Data’ to erase all the saved data. This can’t be undone.

To use additional JSQ-420 devices, open additional ApogeeConnect software windows. The device serial number will display in the lower
left hand corner of the corresponding software window. Devices may be selected by serial number in the tool bar.

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17

MAC SOFTWARE
When the JSQ-420 sensor is not plugged into the USB port, thesoftware will display a message in the lower left corner, “Device Not
Connected,” indicating it cannot establish communication with thesensor.

Plug the sensor into a USB port and allow some time for the sensor
to automatically establish communication with the software. Onceestablished, the message in the lower left corner will display“Device Connected Model: SN ####” and real-time PAR readings
will update on the screen. Moving the sensor closer to a lightsource should increase the readings, while blocking all light fromthe sensor should drop the reading to zero.

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Click the ‘Settings’ icon to display the software options.

Clicking ‘Light Source’ will allow the user to change the sensor’s
default calibration reference from Electric to Sunlight. Electricshould be selected when measuring most indoor artificial lightsources, while Sunlight should be selected when measuring
sunlight (such as when evaluating the need for recalibration).

Clicking ‘Calibration’ will display the factory calibrated multiplierand offset values. These values are saved in firmware and can berecovered by clicking the ‘Recover Original’ button. Deriving a new
calibration multiplier and offset is accomplished by clicking the‘Recalibrate’ button. This is applicable if users want to calibrate thesensor to their own specific light source. Note that a reference PAR
value of the light source is required to complete a recalibration.

After clicking the ‘Recalibrate’ button the user will be prompted tocover the sensor. Place a dark cap over the sensor and wait for the
real-time PAR reading to settle at zero. Click OK.

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19

Uncover the sensor and wait for the PAR reading to settle before
entering the reference value. Click OK.

The multiplier and offset values will automatically calculate andupdate in the appropriate field. Be sure to click ‘Save’ to retain the
new multiplier and offset.

Clicking ‘Data Logging’ will allow the user to log intervalmeasurements in a csv file while the software is open andcommunicating with the sensor.

Click ‘Setup’ and the Setup Logging window appears. Click the‘Browse button to create or select a csv file.
Select the desired sampling interval. Note that 1 second is theminimum interval allowed. Click ‘Start’.

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20

The data logging window will start to update at the specified
sampling interval and display the Timestamp, Light Source, andData Value. At the same time, data will be written to the csv file.
Note that if the csv file is open in another program new data will
not be saved to it.
The data logging window can be closed without affecting logged
data by clicking the ‘Exit’ button. The ‘Stop’ button must be clickedto end data logging.

The about screen tells you the software and firmware versions.
These can be used to help troubleshoot if problems arise.

‘Manage Field Logging’ is used to setup the JSQ-420 for the use in
the field. When the JSQ-420 is supplied power from a USB powersource it will log data which you can retrieve. Choose the interval
the data is saved as well as the interval that data is sampled and thelight source used. The shortest sampling interval is 1 second. The
longest sampling or logging interval is 1440 minutes (1 day). Click‘Load Settings’ to see current settings and ‘Save Setting’ to save thesettings you want to the sensor. Note: If you don’t click save thesensor won’t change the settings.

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21

Set the sampling interval in minutes or seconds. The samplinginterval is how often a measurement is taken and logging interval is
how often the data is saved. The logged data is the average of thesamples. The logging interval must be evenly divided by the
sampling interval. For example if the logging interval is 5 minutes
and the sampling interval is 2 minutes it causes an error. But asampling interval of 1 minute is acceptable.

Before clicking ‘Get Logged Data’ it is important to set the time of
the last logged data point. This is used to back calculate thetimestamps for the remaining data points. If you just unplugged
the sensor and plugged it into the computer the preloaded day
and time should be sufficient.

Click ‘Get Logged Data’ to save the data to your computer. You
will be asked where you want to save the data.
Click ‘Erase Data’ to erase all the save data. This can’t be undone.

To use additional JSQ-420 devices, open additional ApogeeConnect software windows. The device serial number will display in the lower
left hand corner of the corresponding software window. Devices may be selected by serial number in the tool bar.

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www.jetec.com.tw22Spectral Errors for PAR Measurements with +SQ Quantum Sensors
The JSQ-420 quantum sensors are calibrated to measure PAR for either sunlight (natural setting) or electric light. The
difference between the calibrations is 12 %. A sensor calibrated for electric lights (calibration source is T5 cool whitefluorescent lamps) will read approximately 12 % low in sunlight (natural setting).
Radiation Source (Error Calculated Relative to Sun, Clear Sky)Sun (Clear Sky)Sun (Cloudy Sky)
Reflected from Grass Canopy
Reflected from Deciduous Canopy
Reflected from Conifer Canopy
Transmitted below Grass Canopy
Transmitted below Deciduous Canopy
Transmitted below Conifer Canopy
Radiation Source (Error Calculated Relative to Cool White Fluorescent,
T5)
Cool White Fluorescent (T5)
Cool White Fluorescent (T8)
Cool White Fluorescent (T12)Compact Fluorescent
Metal Halide
Ceramic Metal Halide
High Pressure Sodium
Blue LED (448 nm peak, 20 nm full-width half-maximum)
Green LED (524 nm peak, 30 nm full-width half-maximum)
Red LED (635 nm peak, 20 nm full-width half-maximum)
Red, Blue LED Mixture (85 % Red, 15 % Blue)
Red, Green, Blue LED Mixture (72 % Red, 16 % Green, 12 % Blue)
Cool White Fluorescent LED
Neutral White Fluorescent LED
Warm White Fluorescent LED

PPFD Error [%]
0.0
1.4
5.7
4.9
5.5
6.4
6.8
5.3

YPFD Error [%]
0.0
1.6
-6.3
-7.0
-6.8
-4.5
-5.4
2.6

0.0
-0.3
-1.4
-0.5
-3.7
-6.0
0.8
-12.7
8.0
4.8
2.4
3.4
-4.6
-6.7
-10.9

0.0
-1.2
-2.0
-5.3
-3.7
-6.4
-7.2
8.0
26.2
-6.2
-4.4
0.2
-0.6
-5.2
-13.0

Quantum sensors can be a very practical means of measuring PAR from multiple radiation sources, but spectral errors must
be considered. The spectral errors in the table above can be used as correction factors for individual radiation sources.

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