Apogee Instruments SU-100 User manual

APOGEE INSTRUMENTS, INC. | 721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA
TEL: [phone] | FAX: [phone] | WEB: APOGEEINSTRUMENTS.COM
Copyright © 2019 Apogee Instruments, Inc.
OWNER’S MANUAL
ULTRAVIOLET SENSOR
Model SU-100
(including SS model)

TABLE OF CONTENTS
Owner’s Manual ............................................................................................................................................................................... 1
Certificate of Compliance......................................................................................................................................................... 3
Introduction ............................................................................................................................................................................. 4
Sensor Models ......................................................................................................................................................................... 5
Specifications ........................................................................................................................................................................... 6
Deployment and Installation.................................................................................................................................................... 7
Cable Connectors..................................................................................................................................................................... 8
Operation and Measurement .................................................................................................................................................. 9
Maintenance and Recalibration............................................................................................................................................. 12
Troubleshooting and Customer Support................................................................................................................................ 14
Return and Warranty Policy................................................................................................................................................... 15

CERTIFICATE 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: SU-100
Type: Ultraviolet Sensor
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
diphenyls (PBDE), bis(2-ethylhexyl) phthalate (DEHP), butyl benzyl phthalate (BBP), dibutyl phthalate (DBP), and
diisobutyl 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, October 2019
Bruce Bugbee
President
Apogee Instruments, Inc.

INTRODUCTION
Ultraviolet (UV) radiation constitutes a portion of the electromagnetic spectrum from 100 to 400 nm, and is further
subdivided into three wavelength ranges: UV-A (315 to 400 nm), UV-B (280 to 315 nm) and UV-C (100 to 280 nm).
Much of the UV-B and all of the UV-C wavelengths from the sun are absorbed by the Earth’s atmosphere. There
are also many artificial UV light sources available that output a select wavelength range or offer a broadband UV
radiation source.
Most UV sensors designed for sunlight measurements are sensitive to UV radiation in the UV-A and UV-B ranges.
Apogee Instruments SU-100 UV sensors detect UV radiation from 250 to 400 nm and are calibrated in photon flux
units of micromoles per square meter per second (µmol m-2 s-1). The output can also be expressed in energy flux
units of watts per square meter (W m-2, equal to Joules per second per square meter).
Typical applications of UV sensors include incoming UV radiation measurement in outdoor environments (not
recommended for continuous outdoor deployment) or in laboratory use with artificial light sources (e.g.,
germicidal lamps).
Apogee Instruments SU-100 UV sensors consist of a photodiode and signal processing circuitry mounted in an
anodized aluminum housing, and a cable to connect the sensor to a measurement device. Sensors are potted solid
with no internal air space, and are designed for UV radiation measurement in indoor or outdoor environments.
The SU-100 outputs an analog voltage that is directly proportional to UV radiation incident on a planar surface
(does not have to be horizontal), where the radiation emanates from all angles of a hemisphere.

Sensor model number and serial number are
located near the pigtail leads on the sensor cable.
If you need the manufacturing date of your sensor,
please contact Apogee Instruments with the serial
number of your sensor.
SENSOR MODELS
The SU-100 UV sensor is the only stand-alone UV sensor offered by Apogee Instruments. Additional models are
covered in their respective manuals.
Model
Signal
SU-100
Self-powered
SU-420
USB

SPECIFICATIONS
Calibration Traceability
Apogee SU-100 UV sensors are calibrated through side-by-side comparison to the mean of three Apogee model
SU-100 transfer standard UV sensors under high intensity discharge metal halide lamps. The transfer standard UV
sensors are calibrated through side-by-side comparison to an Apogee model PS-200 spectroradiometer under
sunlight (clear sky conditions) in Logan, Utah. The PS-200 is calibrated with a LI-COR model 1800-02 Optical
Radiation Calibrator using a 200 W quartz halogen lamp. The 1800-02 and quartz halogen lamp are traceable to
the National Institute of Standards and Technology (NIST).
Spectral Response
SU-100
Sensitivity
0.2 mV per µmol m-2 s-1; 0.61 mV per W m-2
Calibration Factor
(reciprocal of sensitivity)
5 µmol m-2 s-1 per mV; 1.65 W m-2 per mV
Calibration Uncertainty
± 10 % (see Calibration Traceability below)
Measurement
Repeatability
Less than 1 %
Non-stability
(Long-term Drift)
Less than 3 % per year
Non-linearity
Less than 1 % (up to 300 µmol m-2 s-1)
Response Time
Less than 1 ms
Field of View
180º
Spectral Range
250 nm to 400 nm (see Spectral Response below)
Directional (Cosine)
Response
± 10 % at 75º zenith angle
Temperature Response
Approximately 0.1 % per C
Operating Environment
-40 to 70 C; 0 to 100 % relative humidity
Dimension
24 mm diameter; 28 mm height
Mass
75 g (with 5 m of lead wire)
Cable
5 m of two conductor, shielded, twisted-pair wire; additional cable available in multiples of 5
m; TPR jacket (high water resistance, high UV stability, flexibility in cold conditions); pigtail lead
wires
Spectral response estimate of Apogee
SU-100 UV sensors. Spectral response
measurements were made at 10 nm
increments across a wavelength range
of 200 to 450 nm in a monochromator
with an attached electric light source.
Measured spectral data were
normalized at 350 nm.

DEPLOYMENT AND INSTALLATION
Mount the sensor to a solid surface with the nylon mounting screw provided. To accurately measure PPFD incident
on a horizontal surface, the sensor must be level. An Apogee Instruments model AL-100 Leveling Plate is
recommended to level the sensor when used on a flat surface or being mounted to surfaces such as wood. To
facilitate mounting on a mast or pipe, the Apogee Instruments model AL-120 Solar Mounting Bracket with Leveling
Plate is recommended.
To minimize azimuth error, the sensor should be mounted with the cable pointing toward true north in the
northern hemisphere or true south in the southern hemisphere. Azimuth error is typically less than 1 %, but it is
easy to minimize by proper 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, the green 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.
Nylon Screw: 10-32x3/8
Model AL-100
Model AL-120
Nylon Screw: 10-32x3/8

CABLE CONNECTORS
Apogee started offering in-line cable connectors on
some bare-lead sensors in March 2018 to simplify the
process of removing sensors from weather stations for
calibration (the entire cable does not have to be
removed from the station and shipped with the sensor).
The ruggedized M8 connectors are rated IP68, made of
corrosion-resistant marine-grade stainless-steel, and
designed for extended use in harsh environmental
conditions.
Inline cable connectors are installed 30 cm from the
head
(pyranometer pictured)
Instructions
Pins and Wiring Colors: All Apogee connectors have six
pins, but not all pins are used for every sensor. There
may also be unused wire colors inside the cable. To
simplify datalogger connection, we remove the unused
pigtail lead colors at the datalogger end of the cable.
If you ever need a replacement cable, please contact us
directly to ensure ordering the proper pigtail
configuration.
Alignment: When reconnecting your sensor, arrows on
the connector jacket and an aligning notch ensure
proper orientation.
Disconnection for extended periods: When
disconnecting the sensor for an extended period of time
from a station, protect the remaining half of the
connector still on the station from water and dirt with
electrical tape or other method.
A reference notch inside the connector ensures
proper alignment before tightening.
When sending sensors in for calibration, only send the
short end of the cable and half the connector.
Tightening: Connectors are designed to be firmly
finger-tightened only. There is an O-ring inside the
connector that can be overly compressed if a wrench is
used. Pay attention to thread alignment to avoid cross-
threading. When fully tightened, 1-2 threads may still
be visible.
Finger-tighten firmly

OPERATION AND MEASUREMENT
Connect the sensor to a measurement device (meter, datalogger, controller) capable of measuring and displaying
or recording a millivolt signal (an input measurement range of approximately 0-40 mV is required to cover the
entire range of UV from the sun). In order to maximize measurement resolution and signal-to-noise ratio, the input
range of the measurement device should closely match the output range of the UV sensor. DO NOT connect the
sensor to a power source. The sensor is self-powered and applying voltage will damage the sensor.
VERY IMPORTANT: Apogee changed all wiring colors of our bare-lead sensors in March 2018 in conjunction
with the release of inline cable connectors on some sensors. To ensure proper connection to your data device,
please note your serial number or if your sensor has a stainless-steel connector 30 cm from the sensor head then
use the appropriate wiring configuration below.
Wiring for SU-100 Serial Numbers 2482 and above or with a cable connector
Wiring for SU-100 Serial Numbers range 0-2481
Red: Positive (signal from sensor)
Black: Negative (signal from sensor)
Clear: Shield/Ground
Black: Negative (signal from sensor)
Clear: Shield/Ground
White: Positive (signal from sensor)

Sensor Calibration
The SU-100 has a standard UV calibration factor of exactly:
5.0 µmol m-2 s-1 per mV
Multiply this calibration factor by the measured mV signal to convert sensor output to UV in units of µmol m-2 s-1:
Calibration Factor (5.0 µmol m-2 s-1 per mV) * Sensor Output Signal (mV) = UV (µmol m-2 s-1)
5.0 * 35 = 175
UV-B Measurements and Spectral Errors
Apogee Instruments model SU-100 UV Sensors measure ultraviolet radiation between 250 and 400 nm in
micromoles of photons per square meter per second. Although the UV radiation between 280 and 315 nm (UV-B)
is critically important in photochemical and photobiological reactions, less than 3 % of the UV photons are in this
range. Because only a small fraction of the photons are in the UV-B range, the SU-100 cannot be used to selectively
measure UV-B radiation. The SU-100 is sensitive to UV-B radiation, but it is included with the UV-A radiation to
provide a total measurement of UV radiation.
In addition to naturally occurring UV radiation from the sun, there are many electric light sources that emit UV
radiation (e.g., cool white fluorescent, metal halide, mercury arc, and germicidal lamps). Although the relative
wavelengths of UV radiation differ among sunlight and electric lights, the error estimates shown in the table below
indicate that the SU-100 provides reasonable estimates of UV radiation coming from electric lamps (table provides
spectral error estimates for UV radiation measurements from radiation sources other than clear sky solar
radiation). For common lamps, the error is less than 10 %. The SU-100 is particularly useful for determining the UV
filtering capacity of the transparent plastic and glass barriers that are commonly used below electric lamps.
Example of UV measurement with an Apogee UV sensor. Full
sunlight yields UV radiation on a horizontal plane at the
Earth’s surface of approximately 175 µmol m-2 s-1. This yields
an output signal of 35 mV. The signal is converted to UV
radiation by multiplying by the calibration factor of 5.0 µmol
m-2 s-1 per mV.
Full Sunlight
175 µmol m-2 s-1
Sensor Output
35 mV