Specifications
Sensor Manager
| Recommended system specifications | |
| Operating system | Microsoft Windows 10 or later |
| Software | Java Runtime Environment 8 |
| Hardware interface | serial port (COM port), for example: a USB port and an appropriate USB-to-serial convertor, or an RS-232 port and an appropriate serial converter |
| Hukseflux Sensor Manager specifications | |
| Software version | v2222, v2021 |
| Supported sensors | SR05-DA1, SR05-DA2, SR05-D1A3, SR05-D1A3-PV (non-default register mapping), SR05-D2A2, SR15-D1, SR15-D2A2, SR20-D1, SR20-D2, SR22-D2, SR25-D1, SR25-D2, SR30-M2-D1, SR30-D1, DR30-D1, Virtual SR30-D1 (see Appendix of the user manual) |
| Availability | offered as a download |
Options
With the optional addition of VMA01 mounting adapter plate, VU01 ventilated pyranometers can also be in installed on PMF01
There are other mounting options available for SR30, SR15 and SR05 pyranometer series. They allow for simplified mounting, levelling and instrument exchange on a flat surface or a tube. Take a look at the SR30, SR15, SR05 user manuals for these options.
Downloads
(PDF, 1.57 MB)
Digital Hukseflux solar radiation sensors with a Modbus interface can be accessed via a PC. The communication with the sensor can be done via the user interface offered by the Hukseflux Sensor Manager software or by another Modbus testing tool. The Hukseflux Sensor Manager is supplied with the instrument on a USB flash drive or offered as a download. Links to other Modbus testing tools, paid or freeware, are available at www.modbus.org.
This support page, and the accompanying user manual, describes the functionality of the Hukseflux Sensor Manager version v2222 and v2021 only. Support in installing, using and troubleshooting the software for older versions of the Sensor Manager, version v1817 and earlier, can be found in the user manual of your digital solar radiation sensor(s). Always use the latest version of the software, currently version v2222.
Modbus® is a registered trademark of Schneider Electric, licensed to the Modbus Organization, Inc.
Suggested use
user interface for communication between a PC and:
-digital Hukseflux pyranometers
-digital Hukseflux pyrheliometers
most common use is for initial functionality testing and setting the sensor’s Modbus address and serial communication settings. It is not intended for long-term continuous measurement purposes.
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.
Hukseflux Sensor Manager
- provides a user interface for communication between a PC and digital Hukseflux pyranometers and pyrheliometers with a Modbus interface
- allows the user to locate, configure and test one or more sensors and to perform simple laboratory measurements using a PC
