Apogee Instruments SU-202 User manual

APOGEE INSTRUMENTS, INC. | 721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA
TEL: [phone] | FAX: [phone] | WEB: APOGEEINSTRUMENTS.COM
Copyright © 2020 Apogee Instruments, Inc.
OWNER’S MANUAL
ULTRAVIOLET-A SENSOR
Models SU-202 and SU-205
(including SS models)

TABLE OF CONTENTS
Owner’s Manual ............................................................................................................................................................................... 1
Certificate of Compliance......................................................................................................................................................... 3
Introduction ............................................................................................................................................................................. 4
Sensor Models ......................................................................................................................................................................... 5
Specifications ........................................................................................................................................................................... 6
Deployment and Installation.................................................................................................................................................... 9
Cable Connectors................................................................................................................................................................... 10
Operation and Measurement ................................................................................................................................................ 11
Maintenance and Recalibration............................................................................................................................................. 14
Troubleshooting and Customer Support................................................................................................................................ 15
Return and Warranty Policy................................................................................................................................................... 17

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-202, SU-205
Type: Ultraviolet-A 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, January 2020
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 Earth’s atmosphere. There are
also multiple artificial UV light sources available.
Most UV sensors designed for sunlight measurements are sensitive to UV radiation in the UV-A or UV-B ranges.
Apogee Instruments SU-200 series UV-A sensors detect UV radiation from 300 to 400 nm and are calibrated in
energy flux density units of watts per square meter (W m-2, equal to Joules per second per square meter). The
output can also be expressed in photon flux density units of micromoles per square meter per second (µmol m-2 s-
1).
Typical applications of UV sensors include incoming UV radiation measurement in outdoor environments or in
laboratory use with artificial light sources (e.g., germicidal lamps).
Apogee Instruments SU-200 series UV-A sensors consist of a cast acrylic diffuser, photodiode, and signal processing
circuitry mounted in an anodized aluminum housing and a cable to connect the sensor to a measurement device.
SU-200 sensors are designed for continuous UV-A radiation measurement in indoor or outdoor environments. The
SU-200 series outputs an analog voltage that is directly proportional to UV-A 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 on the bottom of the sensor. If you need
the manufacturing date of your sensor, please
contact Apogee Instruments with the serial
number of your sensor.
SENSOR MODELS
This manual covers the amplified model SU-202 and SU-205 UV-A sensors (listed below in bold). Additional models
are covered in their respective manuals.
Model
Signal
SU-200
0-10 mV
SU-202
0- 2.5 V
SU-205
0- 5 V

SPECIFICATIONS
Calibration Traceability
Apogee UV series sensors are calibrated through side-by-side comparison to the mean of four transfer standard UV
sensors under UV-enhanced T5 fluorescent tubes. The transfer standard UV sensors are calibrated through side-
by-side comparison to an Apogee model PS-300 spectroradiometer under sunlight (clear sky conditions) in Logan,
Utah. The PS-300 is calibrated with a quartz halogen lamp traceable to the National Institute of Standards and
Technology (NIST).
SU-202-SS
SU-205-SS
Power Supply
3.3 to 24 V DC
5.5 to 24 V DC
Output (sensitivity)
25 mV per W m-2;
8.33 mV per µmol m⁻² s⁻¹
50 mV per W m-2;
16.67 mV per µmol m⁻² s⁻¹
Calibration Factor (reciprocal of
sensitivity)
0.04 W m-2 per mV;
0.12 µmol m⁻² s⁻¹ per mV
0.02 W m-2 per mV;
0.06 µmol m⁻² s⁻¹ per mV
Calibration Uncertainty
± 10 %
Output Range
0 to 2.5 V
0 to 5 V
Measurement Range
0 to 100 W m-2
Measurement Repeatability
Less than 0.5 %
Long-term Drift
Less than 2 % per year
Non-linearity
Less than 1 %
Response Time
Less than 1 ms
Field of View
180°
Spectral Range
300 to 400 nm (wavelengths where response is greater than 10 % of maximum; see
Spectral Response below)
Directional (Cosine) Response
± 2 % at 45°, ± 5 % at 70°
Temperature Response
Less than 0.1 % per C
Operating Environment
-30 to 85 C; 0 to 100 % relative humidity
Dimension
30.5 mm diameter, 37 mm height
Mass (5 m of cable)
140 g
Cable
5 m of shielded, twisted-pair wire; TPR jacket (high water resistance, high UV stability,
flexibility in cold conditions); pigtail lead wires; stainless steel (316), M8 connector

Cosine Response
Cosine Response Graph
Directional, or cosine, response is
defined as the measurement error at
a specific angle of radiation incidence.
Directional error for Apogee SU-200
series UV-A sensors is approximately ±
2 % and ± 5 % at solar zenith angles of
45° and 75°, respectively.
Mean cosine response of four
Apogee UV-A sensors. Cosine
response was calculated as the
relative difference of UV-A
sensors from the mean of
replicate reference UV-A
sensors deployed outdoors.
These data are the average of
the AM and PM response.

Spectral Response
Spectral response
estimate of Apogee SU-
200 UV-A sensors.
Spectral response was
modeled from sensitivity
of the photodetector and
transmittance of the
diffuser.

DEPLOYMENT AND INSTALLATION
Mount the sensor to a solid surface with the nylon mounting screw provided. To accurately measure UV-A 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 black cap should be removed from the sensor. The black 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
Nylon Screw: 10-32x3/8
Model AL-120

CABLE CONNECTORS
Apogee sensors offer cable connectors 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.
Cable connectors are attached directly to the head.
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 a replacement cable is required, please
contact Apogee directly to ensure ordering
the proper pigtail configuration.
Alignment: When reconnecting a 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 sensor head.
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.
WARNING: Do not tighten the connector by
twisting the black cable or sensor head, only
twist the metal connector (blue arrows).
Finger-tighten firmly