Apogee MP-100 SOLAR RADIATION METER Owner’s Manual

Apogee MP-100 SOLAR RADIATION METER

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: MP-100, MP-200
• Type: Pyranometer 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 diphenyl (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

INTRODUCTION

Solar radiation at Earth’s surface is typically defined as total radiation across a wavelength range of 280 to 4000 nm (shortwave radiation). Total solar radiation, direct beam and diffuse, incident on a horizontal surface is defined as global shortwave radiation, or shortwave irradiance (incident radiant flux), and is expressed in Watts per square meter (W m-2, equal to Joules per second per square meter). Pyranometers are sensors that measure global shortwave radiation. Apogee MP series solar radiation meters incorporate silicon-cell pyranometers, and are only sensitive to a portion of the solar spectrum, approximately 350-1100 nm (approximately 80 % of total shortwave radiation is within this range). However, silicon-cell pyranometers are calibrated to estimate total shortwave radiation across the entire solar spectrum. Silicon-cell pyranometer specifications compare favorably to specifications for World Meteorological Organization (WMO) moderate and good quality classifications and specifications for International Organization of Standardization (ISO) Class C classification, but because of limited spectral sensitivity, they do not meet the spectral specification necessary for WMO certification. Typical applications of silicon-cell pyranometers include incoming shortwave radiation measurement in agricultural, ecological, hydrological weather networks, and solar panel arrays. Apogee Instruments MP series solar radiation meters consist of a handheld meter and a dedicated pyranometer that is integrated into the top of the meter housing (MP-100) or connected by cable to an anodized aluminum housing (MP-200). Integrated and separate sensors consist of a cast acrylic diffuser (filter), photodiode, and are potted solid with no internal air space. MP series meters provide a real- time irradiance reading on the LCD display that determines the radiation incident on a planar surface (does not have to be horizontal), where the radiation emanates from all angles of a hemisphere. MP series meters include manual and automatic data logging features for making spot-check measurements or calculating daily solar insolation.

SENSOR MODELS

Apogee MP series solar radiation meters covered in this manual are self- contained and come complete with handheld meter and sensor.

Sensor model number and serial number are located on a label on the backside of the handheld meter.

SPECIFICATIONS

| MP-100| MP-200
---|---|---
ISO 9060:2018| Class C (previously known as second class )
Calibration Uncertainty| ± 5 % (see Calibration Traceability below)
Measurement

Repeatability

| Less than 1 %|
Long-term Drift (Non-stability)| Less than 2 % per year
Non-linearity| Less than 1 % (up to 1750 W m-2)
Response Time| Less than 1 ms|
Field of View| 180º|
Spectral Range| 360 to 1120 nm (wavelengths where response is 10 % of maximum; see Spectral Response below)
Directional (Cosine) Response| ± 5 % at 75º zenith angle (see Cosine Response below)
Temperature Response| 0.04 ± 0.04 % per C (see Temperature Response below)

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; separate sensors can be submerged in water up to depths of 30 m

Meter Dimensions| 126 mm length; 70 mm width; 24 mm height;
Sensor Dimensions| 24 mm diameter; 33 mm height
Mass| 150 g| 180 g
Cable| 2 m of two conductor, shielded, twisted-pair wire; TPR jacket (high water resistance, high UV stability, flexibility in cold conditions)

Calibration Traceability

Apogee Instruments MP series solar radiation meters are calibrated through side-by-side comparison to the mean of four Apogee model SP-110 transfer standard pyranometers (shortwave radiation reference) under high intensity discharge metal halide lamps. The transfer standard pyranometers are calibrated through side-by-side comparison to the mean of at least two ISO- classified reference pyranometers under sunlight (clear sky conditions) in Logan, Utah. Each of four ISO-classified reference pyranometers are recalibrated on an alternating year schedule (two instruments each year) at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. NREL reference standards are calibrated to the World Radiometric Reference (WRR) in Davos, Switzerland.

Spectral Response

Spectral response estimate of Apogee silicon-cell pyranometers. Spectral response was estimated by multiplying the spectral response of the photodiode, diffuser, and adhesive. Spectral response measurements of diffuser and adhesive were made with a spectrometer, and spectral response data for the photodiode were obtained from the manufacturer.

Temperature Response

Mean temperature response of four Apogee silicon-cell pyranometers. Temperature response measurements were made at approximately 10 C intervals across a temperature range of approximately -10 to 50 C under sunlight. Each pyranometer had an internal thermistor to measure temperature. At each temperature set point, a reference blackbody pyranometer was used to measure solar intensity.

Cosine Response

Directional, or cosine, response is defined as the measurement error at a specific angle of radiation incidence. Error for Apogee silicon-cell pyranometers is approximately ± 2 % and ± 5 % at solar zenith angles of 45° and 75°, respectively.

Mean cosine response of eleven Apogee silicon-cell pyranometers (error bars represent two standard deviations above and below mean). Cosine response measurements were made during broadband outdoor radiometer calibrations (BORCAL) performed during two different years at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. Cosine response was calculated as the relative difference of pyranometer sensitivity at each solar zenith angle to sensitivity at 45° solar zenith angle. The blue symbols are AM measurements, the red symbols are PM measurements.

DEPLOYMENT AND INSTALLATION

Apogee MP series solar radiation meters are designed for spot-check measurements, and calculation of daily insolation (total solar radiation incident on a planar surface over the course of a day) through the built-in logging feature. To accurately measure global shortwave radiation incident on a horizontal surface, the sensor must be level. For this purpose, each MP model comes with a different option for mounting the sensor to a horizontal plane.

• The AL-210 leveling plate is recommended for use with the MP-100.
  

• The AL-100 leveling plate is recommended for use with the MP-200. To facilitate mounting to a cross arm, the AL-120 mounting bracket is recommended.

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.

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

MP series solar radiation 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 logging (manual or automatic) 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 irradiance 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. Every 48 averaged measurements (making a 24 hour period), the meter will also store an integrated daily total in mega joules per square meter per day (MJ m-2 d-1).
Reset: To reset the meter, in either SMPL or LOG mode, push the mode button twice (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 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 Errors for Measurements with Silicon-cell Pyranometers
Apogee MP series solar radiation meters are calibrated under electric lamps in a calibration laboratory. The calibration procedure simulates calibration under clear sky conditions at a solar zenith angle of approximately 45°. However, due to the limited spectral sensitivity of silicon-cell pyranometers compared to the solar radiation spectrum (see graph below), spectral errors occur when measurements are made in conditions that differ from conditions the sensor was calibrated under (e.g., the solar spectrum differs in clear sky and cloudy conditions, thus measurements in cloudy conditions result in spectral error because sensors are calibrated in clear sky conditions).

Spectral response of Apogee SP series pyranometers compared to solar radiation spectrum at Earth’s surface. Silicon-cell pyranometers, such as Apogee SP series, are only sensitive to the wavelength range of approximately 350-1100 nm, and are not equally sensitive to all wavelengths within this range. As a result, when the spectral content of solar radiation is significantly different than the spectrum that silicon-cell pyranometers were calibrated to, spectral errors result. Silicon-cell pyranometers can still be used to measure shortwave radiation in conditions other than clear sky or from radiation sources other than incoming sunlight, but spectral errors occur when measuring radiation with silicon-cell pyranometers in these conditions. The graphs below show spectral error estimates for Apogee silicon-cell pyranometers at varying solar zenith angles and varying atmospheric air mass. The diffuser is optimized to minimize directional errors, thus the cosine response graph in the Specifications section shows the actual directional errors in practice (which includes contributions from the spectral shift that occurs as solar zenith angle and atmospheric air mass change with time of day and time of year). The table below provides spectral error estimates for shortwave radiation measurements from shortwave radiation sources other than clear sky solar radiation.

• Spectral error for Apogee SP series pyranometers as a function of solar zenith angle, assuming calibration at a zenith angle of 45°.
  

• Spectral error for Apogee SP series pyranometers as a function of atmospheric air mass, assuming calibration at an air mass of 1.5.
  

• Spectral Errors for Shortwave Radiation Measurements with Apogee SP Series Pyranometers

Radiation Source (Error Calculated Relative to Sun, Clear Sky)| Error [%]
---|---
Sun (Clear Sky)| 0.0
Sun (Cloudy Sky)| 9.6
Reflected from Grass Canopy| 14.6
Reflected from Deciduous Canopy| 16.0
Reflected from Conifer Canopy| 19.2
Reflected from Agricultural Soil| -12.1
Reflected from Forest Soil| -4.1
Reflected from Desert Soil| 3.0
Reflected from Water| 6.6
Reflected from Ice| 0.3
Reflected from Snow| 13.7

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, copy, and paste them into a blank Excel spreadsheet. Data will need to be comma delimited.
  

MAINTENANCE AND RECALIBRATION

Moisture or debris on the diffuser is a common cause of low readings. The sensor has a domed diffuser and housing for improved self-cleaning from rainfall, but materials can accumulate on the diffuser (e.g., dust during periods of low rainfall, salt deposits from evaporation of sea spray or sprinkler irrigation water) and partially block the optical path. 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 soft cloth or cotton swab. Never use an 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 your sensor needs recalibration, the Clear Sky Calculator (www.clearskycalculator.com) website and/or smartphone app can be used to indicate the total shortwave radiation incident 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 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 values of total shortwave radiation can exceed values predicted by the Clear Sky Calculator due to reflection from thin, high clouds and edges of clouds, which enhances incoming shortwave radiation. 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 need, input site conditions into the calculator and compare total shortwave radiation measurements to calculated values for a clear sky. If sensor shortwave radiation measurements over multiple days near solar noon are consistently different than calculated values (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 possible return of sensor(s).

Homepage of the Clear Sky Calculator. Two calculators are available: One for pyranometers (total shortwave radiation) and one for quantum sensors
(photosynthetic photon flux).

Clear Sky Calculator for pyranometers. Site data are input in blue cells in middle of page and an estimate of total shortwave radiation is returned on right-hand side of page.

TROUBLESHOOTING AND CUSTOMER SUPPORT

Verify Functionality

Pressing the power button should activate the LCD and provide a real-time irradiance reading. Direct the sensor head toward a light source and verify the irradiance reading responds. Increase and decrease the distance from the sensor to the light source to verify that the reading changes proportionally (decreasing irradiance with increasing distance and increasing irradiance with decreasing distance). Blocking all radiation from the sensor should force the 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 CR2320 battery and perform master reset.
• Err 2: sensor voltage out of range. Fix: perform master reset.
• Err 3: not calibrated. Fix: perform master reset.
• Err 4: CPU voltage below minimum. Fix: replace CR2320 battery and perform master reset.

Modifying Cable Length

Although it is possible to splice additional cable to the separate sensor of the MP-200, 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 Apogee webpage for further details on how to extend sensor cable length: (http://www.apogeeinstruments.com/how-to-make-a-weatherproof-cable-splice/).

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 is Not 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:

1. Improper installation or abuse.
2. Operation of the instrument outside of its specified operating range.
3. Natural occurrences such as lightning, fire, etc.
4. Unauthorized modification.
5. 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 is 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:

1. Either repair or replace (at our discretion) the item under warranty.
2. 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

1. 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.

2. 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.

3. Please write the RMA number on the outside of the shipping container.

4. 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
5. 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.
• How to Make a Weatherproof Cable Splice
• Clear Sky Calculator | Apogee Instruments Inc.

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