Specifications
SR 30 M-2 D-1
| Measurand | hemispherical solar radiation |
| ISO 9060:2018 classification | spectrally flat Class A pyranometer |
| ISO 9060:1990 classification | secondary standard pyranometer |
| IEC 61724-1:2021 compliance | meets Class A PV monitoring system requirements |
| Application | National Meteorological Networks PV monitoring commercial and utility scale meteorology / climatology other |
| Heater | with RVH Recirculating Ventilation and Heating |
| Output | Modbus RS-485 |
| WMO performance level | high quality pyranometer |
| Calibration uncertainty | < 1.2 % (k = 2) |
| Measurand | sensor tilt angle |
| Tilt measurement uncertainty | ± 1 ° (0 to 90 °) |
| Heating | included |
| Ventilation | included |
| Technology employed | Recirculating Ventilation and Heating (RVH™) |
| Standard operating mode | heated and ventilated |
| Power consumption | < 3 W at 12 VDC |
| Zero offset a | < 2 W/m² |
| Calibration traceability | to WRR |
| Calibration registers | accessible to users |
| Spectral range | 285 to 3000) x 10⁻⁹ m |
| Rated operating temperature range | -40 to +80 °C |
| Temperature response | < ± 0.4 % (-30 to +50 °C) |
| Temperature response test of individual instrument | report included |
| Directional response test of individual instrument | report included to 95 ° |
| Tilt sensor test of individual instrument | report included |
| Standard cable length | 5m |
| Rated operating voltage | 8 to 30 VDC range |
| Optional operation in low power mode | |
| Operating condition | heater and ventilator [OFF] in low power mode |
| Zero offset a | 5 W/m² (unventilated) in low power mode |
| Power consumption | < 0.1 W at 12 VDC in low power mode |
| Digital output | |
| Output | irradiance in W/m², instrument body temperature in °C, tilt angle in °, internal humidity in % and ventilator speed in RPM |
| Communication protocol | Modbus |
| Transmission mode | RTU |
| Hardware interface | 2-wire (half duplex) RS-485 |
| Version order codes | SR30-M2-D1, SR30-M2-D1-LM01, SR30-M2-D1-TLM01 |
Options
- spring-loaded levelling mount (Specify article number LM01 when ordering)
- tube levelling mount with set of bolts (Specify article number TLM01 when ordering)
- longer cable; 10 and 20 metres
Downloads
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Heated for high data availability, featuring RVH™ technology
High data availability is attained by heating of the outer dome using ventilation between the inner and outer dome. RVH™- Recirculating Ventilation and Heating – technology, developed by Hukseflux, suppresses dew and frost deposition and is as effective as traditional ventilation systems, without the maintenance hassle and large footprint.
The dome of SR30 pyranometer is heated by ventilating the area between the inner and outer dome. RVH™ is much more efficient than traditional ventilation, where most of the heat is carried away with the ventilation air. Recirculating ventilation is as effective in suppressing dew and frost deposition at less than 3 W as traditional ventilation is at 10 W. RVH™ technology also leads to a reduction of zero offsets.
Heated for high data availability, featuring RVH™ technology
High data availability is attained by heating of the outer dome using ventilation between the inner and outer dome. RVH™- Recirculating Ventilation and Heating – technology, developed by Hukseflux, suppresses dew and frost deposition and is as effective as traditional ventilation systems, without the maintenance hassle and large footprint.
The dome of SR30 pyranometer is heated by ventilating the area between the inner and outer dome. RVH™ is much more efficient than traditional ventilation, where most of the heat is carried away with the ventilation air. Recirculating ventilation is as effective in suppressing dew and frost deposition at less than 3 W as traditional ventilation is at 10 W. RVH™ technology also leads to a reduction of zero offsets.
Remote sensor diagnostics
In addition to solar irradiance, SR30 outputs sensor diagnostics such as:
- tilt angle
- internal ventilator speed (RPM)
- internal humidity
- heater current
Remote diagnostics permits real-time status monitoring, reducing the need for (un)scheduled field inspections.
Tilt angle measurement included
SR30 includes a tilt sensor. This is very practical for remote checks of instrument condition or to monitor PV systems with solar trackers. The sensor measures with high accuracy, within 1 ˚, and is tested and temperature compensated between -30 and + 50 ˚C. SR30-M2-D1 offers improved electronics over its predecessor SR30-D1.
Spectrally flat as required for meteorology and PV monitoring
The new ISO 9060:2018 version defines pyranometer classes A, B and C. The standard also adds a new subclass, called “spectrally flat”. The vast majority of users needs to use instruments of the spectrally flat subclass; only spectrally flat instruments measure with high accuracy, also when a cloud obscures the sun, or when the irradiance includes reflected radiation. These situations occur for example when you measure Global Horizontal irradiance (GHI) under partly or fully cloudy skies, when you measure Plane of Array (POA), albedo or net-radiation. Normal instruments, just of class A, B or C, and not spectrally flat, only measure accurately under clear sunny skies.
New Sensor Manager software
The Hukseflux Sensor Manager software provides a user interface for communication between a PC and digital Hukseflux pyranometers and pyrheliometers with a Modbus interface. The software allows the user to locate, configure and test one or more sensors and to perform simple measurements using a PC. The Sensor Manager software can be downloaded: https://www.hukseflu
x.com/downloads. The new v2021 version of the Sensor Manager replaces previous versions such as v1817 and v1920 beta. Always use the latest version of the software. Need support in using the v2021 software? Please consult the separate Sensor Manager user manual.
SR30-M2-D1 pyranometer is the successor of model SR30-D1. This product page offers you information on SR30-M2-D1. Need support for the discontinued SR30-D1? Please refer to SR30-D1’s separate manual.
Suggested use
- PV system performance monitoring
- scientific meteorological observations
Areas of Application
How does a pyranometer work?
A pyranometer measures the solar radiation received by a plane surface from a 180 ° field of view angle. This quantity, expressed in W/m², is called “hemispherical” solar radiation. The solar radiation spectrum extends roughly from 285 to 3000 x 10⁻⁹ m. By definition a pyranometer should cover that spectral range with a spectral selectivity that is as “flat” as possible.
In an irradiance measurement by definition the response to “beam” radiation varies with the cosine of the angle of incidence; i.e. it should have full response when the solar radiation hits the sensor perpendicularly (normal to the surface, sun at zenith, 0 ° angle of incidence), zero response when the sun is at the horizon (90 ° angle of incidence, 90 ° zenith angle), and 50 % of full response at 60 ° angle of incidence. A pyranometer should have a so-called “directional response” (older documents mention “cosine response”) that is as close as possible to the ideal cosine characteristic.
In order to attain the proper directional and spectral characteristics, a pyranometer’s main components are:
• a thermal sensor with black coating. It has a flat spectrum covering the 200 to 50000 x 10⁻⁹ m range, and has a near-perfect directional response. The coating absorbs all solar radiation and, at the moment of absorption, converts it to heat. The heat flows through the sensor to the sensor body. The thermopile sensor generates a voltage output signal that is proportional to the solar irradiance.
• a glass dome. This dome limits the spectral range from 285 to 3000 x 10⁻⁹ m (cutting off the part above 3000 x 10⁻⁹ m), while preserving the 180 ° field of view angle. Another function of the dome is that it shields the thermopile sensor from the environment (convection, rain).
• a second (inner) glass dome: For secondary standard and first class pyranometers, two domes are used, and not one single dome. This construction provides an additional “radiation shield”, resulting in a better thermal equilibrium between the sensor and inner dome, compared to using a single dome. The effect of having a second dome is a strong reduction of instrument offsets.
• a heater: in order to reduce the effect of dew deposition and frost on the outer dome surface, most advanced pyranometers have a built-in heater. The heater is coupled to the sensor body. Heating a pyranometer can generate additional irradiance offset signals, therefore it is recommended to activate the heater only during night-time. Combining a heater with external ventilation makes these heating offsets very low.
Why use a pyranometer?
There are good reasons why pyranometers are the standard for solar radiation measurement in outdoor PV system performance monitoring.
The purpose of outdoor PV testing is to compare the available resource to system output and thus to determine efficiency. The efficiency estimate serves as an indication of overall performance and stability. It also serves as a reference for remote diagnostics and need for servicing.
The irradiance measurement for outdoor PV performance monitoring is usually carried out with pyranometers. Some standards suggest using PV reference cells. Reference cells are (with some minor exceptions) unsuitable for proof in bankability and in proof of PV system efficiency. Pyranometers are and will remain the standard for outdoor solar energy monitoring.
From a fundamental point of view:
- Pyranometers measure truly available solar irradiance (so the amount of available resource). This is the parameter you need to have for a true efficiency calculation.
- Reference cells measure only that part of solar radiation that can be used by cells of identical material and identical packaging (flat window), so the yield of a certain PV cell type. This is not a measurement that can be used in an efficiency calculation and in fact leads to several percentage points error in efficiency estimates.
The International Energy Agency (IEA) and ASTM standards for PV monitoring recommend pyranometers for outdoor PV monitoring. PV reference cells do not meet IEC 61724-1 class A requirements for irradiance measurement uncertainty: their directional response makes them systematically overestimate daily radiant exposure in J/m2 (or W·hr/m2 ) by more than 2 %, larger on hourly basis.
How do I choose a pyranometer?
- are there standards for my application?
- what level of accuracy do I need?
- what will be the instrument maintenance level?
- what are the interfacing possibilities?
- recommended pyranometer class
- recommended maintenance level
- estimate of the measurement accuracy
- recommended calibration policy
- recommended interface
What is the difference between a pyrheliometer and a pyranometer?
A pyranometer measures hemispherical solar radiation. When measuring in the horizontal plane this is called Global Horizontal Irradiance (GHI). When measuring in “plane of array”, next to PV panels, this is called plane of array POA irradiance.
A pyrheliometer is used to measure Direct Normal Irradiance (DNI). DNI is defined as the solar radiant flux collected by a plane unit surface normal to the axis pointing towards the centre of the sun, within an optical angular aperture. DNI is composed of the solar irradiance within the extent of the solar disk (half-angle 0.266 ° ± 1.7 %) plus some circumsolar radiation.
SHR02
PMF01
PMF02
Sensor Manager
SR30-M2-D1 pyranometer
- Heated for high data availability, featuring RVH™ technology
- Compliant with IEC 61724-1:2021 Class A and B
- Low cost of ownership
- Remote sensor diagnostics
- Liabilities covered: test certificates
