Specifications
SR100-D1 pyranometer :
SR100-D1
| Measurand | hemispherical solar radiation |
| ISO 9060:2018 classification | spectrally flat Class A pyranometer |
| IEC 61724-1:2021 compliance | meets Class B PV monitoring system requirements |
| Dome protector | included (model DP01) |
| Instrument diagnostics | internal humidity |
| Calibration certificate | included (content limited according to ISO/IEC 17025, section 7.8.1.3) |
| Standard cable length (not included) | 3 m |
| EMC and Surge immunity * | : |
| Equipment classification | Industrial Equipment |
| Surge Immunity | Level 2, test level 1 kV |
| with optional SPD01 | Level 4, test level 4 kV |
| Electrical Safety in the workplace | : |
| Safety compliance | EU Low Voltage Directive (2014/35/EU) / USA National Electric Code (NFPA70) |
| Earthing terminal | included on instrument |
| Digital communication | : |
| Communication protocol | Modbus RTU |
| RS-485 isolation voltage | 1.5 kV |
| Hardware interface | 2-wire RS-485 |
| * | at standard cable length of 3 m |
| ** | @ 24 VDC |
We offer accessories for use with the SR100-D1, including electrical and mounting hardware options.
• SPD01 Surge Protection Device (for 1 to 3 instruments) for cables longer than 3 meters and to upgrade Surge Protection to level 4
• PID01 Pyranometer Isolation Disc, electrically insulating the instrument from the mounting platform, spring-loaded for easy levelling
• LM01 spring-loaded levelling mount; a practical mount for easy mounting, levelling, and instrument exchange on flat surfaces
• TLM01 tube levelling mount with a set of bolts
• calibration certificate including customer name and contact information
• DP01 dome protector, set of 5 pieces
• AMF03 albedometer fixture
• PMF01 and PFM02 mounting fixtures
Downloads
(PDF, 496.33 KB)
(PDF, 3.61 MB)
(PDF, 644.47 KB)
(PDF, 296.79 KB)
SR100-D1: affordable industrial-grade pyranometer
SR100-D1 may look like its predecessor, but in many ways it is a completely new instrument. We built upon the measurement capabilities of the earlier pyranometer model SR15-D1 and tailored the SR100-D1 pyranometer to its most common applications in PV system performance monitoring systems and meteorological stations.
SR100-D1 complies with – Industrial-grade – Immunity, Emission, Electrical, Environmental and Safety requirements for use in these outdoor and industrial environments, greatly improving measurement reliability. Ease of operation is further enhanced through extended functionality and diagnostics.
PV System performance monitoring: IEC 61724-1 Class B compliant
SR100-D1 complies with IEC requirements for “Class B” PV system performance monitoring. If you need a pyranometer that complies with all locations and climatic conditions, consider the SR300-D1 pyranometer.
Immunity to high voltages and currents -surges
SR100-D1 is tested and classified for Industrial Environments according to IEC 61326-1 and IEC 61000-6-2. When designing a measuring system, pyranometer users may reach several levels of immunity.
With the optional Surge Protection Device SPD01 this immunity can be increased to 4 kV. Up to 3 pyranometers can be protected with a single SPD01. A third-party SPD with similar specifications may be used instead.
To attain the required level of immunity for a given installation, some general system components should be included, such as:
• lightning protection system
• earthing and grounding network
• external surge protection in addition to the native on-board sensor protection
RS-485 isolation
The RS-485 interface of the industrial pyranometers is galvanically isolated from the internal electronics as well as from the instrument body. Both isolation barriers are rated at 1.5 kV. This contributes to reliable operation, flexibility in system design and reduced integration costs for all industrial pyranometers.
Electrical safety in the workplace
A PV power plant is a potentially hazardous workplace environment. To comply with safety regulations, SR100-D1 features a dedicated earthing terminal for connection to protective earth. When the pyranometer is isolated from the mounting platform, it should still be properly earthed via this terminal. SR100-D1 allows system designers to comply with safety regulations. These are often based on EU and US electrical safety standards such as:
• EN-50110 Operation of Electrical Installations
• NFPA 70 National Electrical Code (NEC)
Comparison between SR300-D1, SR200-D1 and SR100-D1
Table 1: SR300-D1, SR200-D1 and SR100-D1: main specifications compared.
INSTRUMENT SPECIFICATIONS
| ||||
| SR300-D1 | SR200-D1 | SR100-D1 | ||
| ISO 9060:2018 classification | spectrally flat class A | spectrally flat class A | spectrally flat class B | |
| IEC 61724-1:2021 compliance for solar irradiance measurement | meets Class A for all locations and climatic conditions | meets Class A for locations where dew and frost are expected for < 2 % of annual GHI hours | meets Class B for all locations and climatic conditions | |
| Dew and frost mitigation | heating included | – | – | |
| IEC 61724-1:2021 compliance for single axis tracker and pyranometer tilt angle measurement | meets Class A PV monitoring system requirements | – | – | |
| Tilt measurement | Tilt measurement included | – | – | |
| Manufacturer’s estimate of achievable measurement accuracy for daily sums, following ASTM G213 uncertainty evaluation* | 2.3 % | 2.4 % | 4.6 % | |
| On-site diagnostics | ||||
| power and communication status LED | ● | – | – | |
| Remote diagnostics alerts | ||||
| instrument leakage | ● | – | – | |
| heating malfunction | ● | – | – | |
| change of tilt and rotation | ● | – | – | |
| Remote diagnostics measurements | ||||
| Internal humidity | ● | ● | ● | |
| Internal pressure | ● | – | – | |
| Instrument tilt and rotation | ● | – | – | |
* in summer at mid-latitudes, instruments used under rated operating conditions, expanded measurement uncertainties k = 2
Table 2: SR300-D1, SR200-D1 and SR100-D1 test certificates supplied with the instruments.
| CERTIFICATES AND REPORTS | |||
SR300-D1 | SR200-D1 | SR100-D1 | |
| product certificate confirming verification of specifications and classification |
● |
● |
● |
| calibration certificate | ● | ● | ● |
| temperature response test of individual instrument |
● |
● |
– |
| directional response test of individual instrument for 0 to 95 ° angle of incidence |
● |
● |
– |
| accelerometer test of individual instrument (0 to 180 ° tilt, -30 to +50 °C) |
● |
– |
– |
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.
