Apogee Instruments MU-250 User manual

APOGEE INSTRUMENTS, INC. | 721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA
TEL: [phone] | FAX: [phone] | WEB: APOGEEINSTRUMENTS.COM
Copyright © 2021 Apogee Instruments, Inc.
OWNER’S MANUAL
ULTRAVIOLET METER
Models MU-250
Rev: 1-Jun-2021

TABLE OF CONTENTS
Owner’s Manual ............................................................................................................................................................................... 1
Certificate of Compliance......................................................................................................................................................... 3
Introduction ............................................................................................................................................................................. 4
Sensor Models ......................................................................................................................................................................... 5
Specifications ........................................................................................................................................................................... 6
Deployment and Installation.................................................................................................................................................... 7
Battery Installation and Replacement...................................................................................................................................... 8
Operation and Measurement .................................................................................................................................................. 9
Apogee AMS Software ........................................................................................................................................................... 11
Maintenance and Recalibration............................................................................................................................................. 13
Troubleshooting and Customer Support................................................................................................................................ 14
Return and Warranty Policy................................................................................................................................................... 16

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: MU-250
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, June 2021
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 MU-200 series UV-A meters 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 meters include incoming UV radiation measurement in outdoor environments or in
laboratory use with artificial light sources (e.g., germicidal lamps).
Apogee Instruments MU-200 series UV-A meters are connected by cable to an anodized aluminum housing (MU-
250). Separate sensors consist of a photodiode and filter, and are potted solid with no internal air space. MU series
meters provide a real-time photon flux or energy flux (menu selectable) reading on the LCD display that
determines the UV radiation incident on a planar surface (does not have to be horizontal), where the radiation
emanates from all angles of a hemisphere. MU series meters include manual and automatic data logging features
for making spot-check measurements or calculating integrated daily total values.

SENSOR MODELS
Apogee MU series UV meters covered in this manual are self-contained and come complete with handheld meter
and sensor.
MU-250
Sensor model number and serial number are located on a
label on the backside of the handheld meter.

SPECIFICATIONS
Calibration Traceability
Apogee MU series UV-A meters 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).
Spectral Response
MU-250
Calibration Uncertainty
± 10 % (see Calibration Traceability below)
Measurement
Repeatability
Less than 0.5 %
Non-stability
(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 nm to 400 nm (see Spectral Response below)
Directional (Cosine)
Response
± 2 % at 45°, ± 5 % at 75° zenith angle
Maximum Range
104.9 W per m2
Temperature Response
Less than 0.1 % per C
Operating Environment
0 to 50 C; less than 90 % non-condensing relative humidity up to 30 C; less than 70 % non-
condensing relative humidity from 30 to 50 C
Meter Dimensions
126 mm length; 70 mm width; 24 mm height
Sensor Dimension
30.5 mm diameter, 37 mm height
Mass
180 g
Cable
2 m of two conductor, shielded, twisted-pair wire; TPR jacket (high water resistance, high UV
stability, flexibility in cold conditions)
Spectral response estimate of Apogee
MU series UV-A meters. Spectral
response was modeled from sensitivity
of the photodetector and
transmittance of the diffuser.

AM-310 Extendable Sensor
Wand
DEPLOYMENT AND INSTALLATION
Apogee MU series meters are designed for spot-check measurements, and calculation of integrated daily totals
(total number of photons incident on a planar surface over the course of a day) through the built-in logging
feature. To accurately measure UV-A radiation incident on a horizontal surface, the sensor must be level. For this
purpose, each MU model comes with a different option for mounting the sensor to a horizontal plane.
In addition to leveling, all sensors should also be mounted such that obstructions (e.g., weather station
tripod/tower or other instrumentation) do not shade the sensor.
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 AL-100 leveling plate is recommended
for use with the MU-250. To facilitate
mounting to a cross arm, the AL-120
mounting bracket is recommended.

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
MU 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 the appropriate unit (photon flux or energy flux)
and manual or automatic logging are 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.
Units: To choose between units of energy flux (W m-2) or photon flux density (µmol m-2 s-1), push the mode button
once and use the up/down buttons to make the appropriate selection. Once the desired mode is blinking, press
the mode button three more times to exit the menu.
Logging: To choose between manual or automatic logging, push the mode button twice 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. 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).
The LCD display consists of the total number of logged
measurements in the upper right hand corner, the real-time UV
measurement in the center, and the selected menu options along
the bottom.

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/).
UV-A Measurements and Spectral Errors
Apogee Instruments model SU-200 UV-A sensors are calibrated to measure ultraviolet radiation from the sun
between 300 and 400 nm in Watts per square meter. In addition to naturally occurring UV-A radiation from the
sun, there are many electric light sources that emit UV-A radiation (e.g., cool white fluorescent, metal halide,
mercury arc, and germicidal lamps). Although the relative wavelengths of UV-A radiation differ among sunlight and
electric lights, the error estimates shown in the table below indicate the SU-200 provides reasonable estimates of
UV-A radiation coming from electric lamps (table provides spectral error estimates for UV-A radiation
measurements from radiation sources other than clear sky solar radiation). For most common lamps, the error is
less than 10 %. The SU-200 is particularly useful for determining the UV-A filtering capacity of the transparent
plastic and glass barriers that are commonly used below electric lamps.
Radiation Source (Error Calculated Relative to Sun, Clear Sky)
Expected EFD Error [%]
Expected PFD Error [%]
Clear Sky
0.0
0.0
Overcast
0.0
-1.1
Direct Normal
-0.2
-1.0
Diffused Blue Light
0.3
1.4
CWF T5
8.2
9.2
Metal Halide
1.2
-1.2
Quartz Halogen
-2.3
-3.8
Mercury Arc
16.2
16.9
T12 Fluorescent UV-A Enhanced
12.2
15.2
UV-A LED (365 nm Peak)
37.4
35.3
UV-A LED (386 nm Peak)
1.8
-3.9
UV-A LED (395 nm Peak)
-36.9
-41.2