Related Manuals for Hukseflux NR01
Summary of Contents for Hukseflux NR01
- Page 1 Hukseflux Thermal Sensors USER MANUAL NR01 / RA01 NR01 4-component net radiometer RA01 2-component radiometer Copyright by Hukseflux | manual v1710 | www.hukseflux.com | info@hukseflux.com...
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Page 2: Warning Statements
Warning statements Putting more than 12 Volt across the sensor wiring can lead to permanent damage to the sensor. Do not use “open circuit detection” when measuring the sensor outputs. NR01 RA01 manual v1710 2/71... -
Page 3: Table Of Contents
Data quality assurance RA01 2-component radiometer Introduction RA01 Specifications of RA01 Dimensions of RA01 Electrical connection of RA01 Appendices Appendix on cable extension / replacement Appendix on tools for NR01 Appendix on spare parts for NR01 NR01 RA01 manual v1710 3/71... - Page 4 Appendix on calibration hierarchy Appendix on meteorological radiation quantities Appendix on ISO and WMO classification tables Appendix on definition of pyranometer specifications Appendix on terminology / glossary 9.10 Appendix on older NR01 models 9.11 EU declaration of conformity NR01 RA01 manual v1710 4/71...
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Page 5: List Of Symbols
Sunshine duration (see also appendix 9.6 on meteorological quantities) Subscripts relating to the atmosphere surface relating to the ground surface ambient relating to ambient air body relating to the instrument body sensor relating to the sensor NR01 RA01 manual v1710 5/71... -
Page 6: Introduction
2 sensors facing up and 2 facing down. NR01 owes its popularity to its excellent price / performance ratio. Advantages include its modular design, low weight, ease of levelling, and low solar offsets in the longwave measurement. - Page 7 The instrument should be used in accordance with the recommended practices of ISO, WMO and ASTM. Applicable instrument-classification standards are ISO 9060 and WMO-No. 8; Guide to Meteorological Instruments and Methods of Observation. Figure 0.1 NR01 4-component net radiometer NR01 RA01 manual v1710 7/71...
- Page 8 RA01 is a single-sided version of NR01. It measures the 2 incoming components of the surface radiation balance; global solar and downward longwave radiation. RA01 is used for estimating (not measuring) net radiation, in particular when local surface properties are not representative, or if system costs need to be reduced. However, when using RA01 for net radiation estimates, the reflected solar radiation or albedo and the surface temperature or upwards longwave radiation must be estimated by the user.
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Page 9: Ordering And Checking At Delivery
1 x hex key (2 mm) for fixation and removal of sun screens • 1 x shim for optionally mounting NR01 on a ¾ inch NPS tube instead of on a 1 inch • NPS tube (tubes are not included) Please store the certificates in a safe place. -
Page 10: Quick Instrument Check
25 °C or lower. Expose the sensor to a heat source at a short distance from the window of more than 50 °C, for instance a heavy (> 5 kg) painted block of NR01 RA01 manual v1710 10/71... - Page 11 1 x 10 Ω. Most multimeters cannot measure in this range, so please use the highest range. Also check between sensors and heater and between sensors and Pt100. Check the resistance between sensors and body. NR01 RA01 manual v1710 11/71...
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Page 12: Instrument Principle And Theory
. The most common application of NR01 is measurement of net radiation. From the 4 individual components measured by NR01, the net radiation and several other measurands are calculated. - Page 13 Figure 2.1.1 Overview of NR01: upfacing pyrgeometer model IR01 sun screens (3,4) levelling assembly for x- and y-axis upfacing pyranometer model SR01 downfacing pyranometer model IR01 4 x hex bolts for levelling adjustment downfacing pyrgeometer model IR02 NR01 RA01 manual v1710...
- Page 14 (cable 1 at the left, at pyranometer side, cable 2 at the right, at pyrgeometer side) 1 inch NPS mounting tube (not included) Figure 2.1.3 Top view of NR01 fitting a ¾ inch NPS tube (alternative mounting method): levelling assembly for x- and y-axis cable (cable 1 at the left, at pyranometer side, cable 2 at the right, at pyrgeometer side) ¾...
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Page 15: Pyranometers Model Sr01
SR01’s scientific name is pyranometer. A pyranometer measures the solar radiation received by a plane surface from a 180° field of view angle. This quantity, expressed in , is called “hemispherical” solar radiation. NR01 typically is mounted horizontally. Measuring in the horizontal plane, downward solar radiation is called global solar radiation, upward solar radiation is called reflected solar radiation. -
Page 16: Pyrgeometers Model Ir01
The “equivalent blackbody” temperature, as a function of zenith angle, roughly follows the same pattern independent of the exact sky condition (cloudy or clear). This explains why for pyrgeometers the directional response is not very critical. NR01 RA01 manual v1710 16/71... - Page 17 Upwelling longwave irradiance is measured with downfacing instruments. These are presumably looking directly at the surface (absorption and emission of the atmosphere is low over a short distance of around 2 m), which behaves like a normal blackbody. NR01 RA01 manual v1710 17/71...
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Page 18: Typical Measurement Results
(the correct value) to 0 W/m incorrect value and a large error). The daytime measurement of downward longwave may contain a solar offset as specified under “solar offset” as < 15 W/m at 1000 W/m solar irradiance. NR01 RA01 manual v1710 18/71... -
Page 19: Optional Heating
The heater is not necessarily switched on; recommended operation is to activate the heater when there is a risk of dew deposition. In case power is available, many users choose to keep the heater continuously on. NR01 RA01 manual v1710 19/71... -
Page 20: Specifications Of Nr01
Working completely passive, using a thermopile sensor, the sensors generate a small output voltage proportional to these fluxes. Optional measurands include solar albedo and sunshine duration. NR01 can only be used in combination with a suitable measuring system. The instrument should be used in accordance with the recommended practices of ISO, IEC, WMO and ASTM. - Page 21 Table 3.1.1 Specifications of NR01 (continued) NR01 MEASURANDS Measurand all 4 radiometers net radiation Measurand in SI units irradiance in W/m Measurement function / required E* = E ↓ – E ↑ = E ↑ + E ↓ - E ↓...
- Page 22 Attach mounting tube to levelling assembly using a a hex key size 4.0 mm (not included) for bolt size M5. With the NR01 shim, included in NR01’s delivery, a ¾ inch NPS tube may also be used. This tube’s recommended outer diameter equals 26.8 x 10...
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Page 23: Specifications Of Pyranometer Sr01
This quantity, expressed in W/m , is called “hemispherical” solar radiation. NR01, in which 2 x SR01 are incorporated, is typically mounted horizontally. Measuring in the horizontal plane, downward solar radiation is called global solar radiation, upward solar radiation is called reflected solar radiation. Working completely passive, using a thermopile sensor, SR01 generates a small output voltage proportional to this flux. -
Page 24: Specifications Of Pyrgeometer Ir02
, from a 150° field of view angle, which approximates the ideal 180° field of view angle. NR01 contains two IR01's; one facing up, the other facing down. In meteorological terms these IR01's measure downward and upward longwave irradiance. Working completely passive, using a thermopile sensor, IR01 generates a small output voltage proportional to the radiation balance between the instrument and the source it faces. - Page 25 °C CALIBRATION Calibration traceability to WISG Calibration hierarchy from WISG through Hukseflux internal IRC calibration procedure employing a blackbody Calibration method indoor calibration under a blackbody, by comparison reference pyrgeometer traceable to WISG Calibration uncertainty <...
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Page 26: Dimensions Of Nr01
Figure 3.4.1 Dimensions of NR01 in x 10 m. NR01 fits a 1 inch NPS tube (recommended outer tube diameter is 33.4 x 10 m). Alternatively (displayed in grey), NR01 may be mounted on a ¾ inch NPS tube using NR01’s shim. NR01 RA01 manual v1710 26/71... -
Page 27: Standards And Recommended Practices For Use
7.3 measurement of global and diffuse solar radiation Table 4.1.2 Standards for pyrradiometer classification. NOTE: Hukseflux does not use the WMO classification because its specifications are not sufficiently clear. STANDARDS FOR PYRRADIOMETER CLASSIFICATION ISO STANDARD EQUIVALENT... -
Page 28: General Use For Net Radiation Measurement
Table 4.3.1 Standards with recommendations for instrument use in sunshine duration measurement STANDARDS FOR INSTRUMENT USE FOR SUNSHINE DURATION WMO-No. 8; Guide to Meteorological Instruments and Methods of Observation, chapter 8, measurement of sunshine duration, 8.2.2 Pyranometric Method NR01 RA01 manual v1710 28/71... -
Page 29: Specific Use In Meteorology And Climatology
“characteristics of operational pyrradiometers” (table 7.7). For pyranometers, nowadays WMO conforms itself to the ISO classification system. Hukseflux does not use the WMO characteristics of pyrradiometers because its specification is not sufficiently clear. -
Page 30: Installation Of Nr01
Mechanical mounting / thermal insulation a levelling assembly for x- and y axis is included with NR01. NR01 is suitable for mounting on a 1 inch NPS tube and, alternatively, on a ¾ inch NPS tube using the shim included with NR01’s delivery. -
Page 31: Installation Of The Sun Screens
1 inch NPS tube. The recommended outer diameter of such a tube is 33.4 x 10 m. This tube is not included with NR01 deliveries. Use a 4 mm hex key for fixation. Optionally, NR01 may be mounted on a ¾ inch NPS tube. Such a tube is not included with NR01 deliveries. -
Page 32: Electrical Connection Of Nr01
5.4 Electrical connection of NR01 In order to operate, NR01 should be connected to a measurement system, typically a so- called datalogger. NR01 contains passive sensors that do not need any power, however there is an on-board heating resistor in the instrument body, that may be switched on to prevent dew-deposition. - Page 33 Table 5.4.3 Internal connection diagram of NR01 for servicing purposes only. NOTE: internal connections are replaced by non-serviceable flexfoil connectors in the latest models. INTERNAL ELECTRICAL CONNECTION FOR SERVICING (EARLY NRO1 MODELS) PCB04 PCB04 PCB05 PCB05 Polarity connection terminal connection terminal IR01 ↓...
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Page 34: Requirements For Data Acquisition / Amplification
In case programming for similar instruments is available, this can typically also be used. NR01 can usually be treated in the same way as other 4-component net radiometers. Table 5.5.1 Requirements for data acquisition and amplification equipment for NR01 in... -
Page 35: Making A Dependable Measurement
* defined at Hukseflux as all factors outside the instrument that are relevant to the measurement such as the cloud cover (presence or absence of direct radiation), sun position, the local horizon (which may be obstructed) or condition of the ground (when tilted). -
Page 36: Reliability Of The Measurement
(drying the entire sensor) in case the sensor allows this. For non- serviceable sensors like Hukseflux second class pyranometers (for example model SR01 in NR01), this may slowly develop into a defect. For first class and secondary NR01 RA01 manual v1710... -
Page 37: Repair And Maintenance
Dependability is not only a matter of reliability but also involves the reaction to problems; if the processing time of service and repairs is short, this contributes to the dependability. Hukseflux net radiometers are designed to allow easy maintenance and repair. The main maintenance actions are: replacement of desiccant (not applicable for NR01) •... - Page 38 3) A separate estimate has to be entered to allow for estimated uncertainty due to the instrument maintenance level. 4) The calibration uncertainty has to be entered. Please note that Hukseflux calibration uncertainties are lower than those of alternative equipment. These uncertainties are entered in measurement equation (equation is usually Formula 0.1: E = U/S), either as...
- Page 39 Table 6.4.1.1 Preliminary estimates of achievable uncertainties of measurements with pyranometers. For SR01, included in NR01, see the row on “second class” pyranometers. The estimates are based on typical pyranometer properties and calibration uncertainty, for sunny, clear sky days and well maintained stations, without uncertainty loss due to lack of maintenance and due to instrument fouling.
- Page 40 (-100 W/m ) to around 0 W/m . Water deposition at clear nights may largely be avoided by using the on-board heater of NR01. Errors due to solar offset, which is of the order of +15 W/m at 1000 W/m global •...
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Page 41: Maintenance And Trouble Shooting
Maintenance and trouble shooting 7.1 Recommended maintenance and quality assurance NR01 can measure reliably at a low level of maintenance in most locations. Usually unreliable measurements will be detected as unreasonably large or small measured values. As a general rule this means that regular visual inspection combined with a critical review of the measured data, preferably checking against other measurements, is the preferred way to obtain a reliable measurement. -
Page 42: Trouble Shooting
Check the condition of the shielding. variations Check the condition of the sensor cable. Check if the cable is not moving during the measurement The dome Arrange to send the sensor back to Hukseflux for diagnosis. shows internal condensation NR01 RA01 manual v1710 42/71... - Page 43 If the trouble shooting steps were followed and further diagnosis is needed, contact Hukseflux and arrange to send an Excel file containing raw sensor data of a few days of measurement for diagnostics. Include time of day, coordinates, raw voltages and instrument temperature.
- Page 44 1 x 10 Ω. Check the electrical resistance between the wires of the heater and the wires of the sensors; this should be higher than 1 x 10 Ω. NR01 RA01 manual v1710 44/71...
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Page 45: Calibration And Checks In The Field
The applicable standard is ISO 9847 “International Standard- Solar Energy- calibration of field pyranometers by comparison to a reference pyranometer”. At Hukseflux an indoor calibration according to the same standard is used. Hukseflux recommendation for re-calibration: if possible, perform calibration indoor by comparison to an identical reference instrument, under normal incidence conditions. - Page 46 6) for second class radiometers, to correct deviations of more than ± 10 %. Lower deviations should be interpreted as acceptable and should not lead to a revised sensitivity (applicable to pyranometer type SR01 as used in the NR01). 7) for first class pyranometers, to correct deviations of more than ± 5 %. Lower deviations should be interpreted as acceptable and should not lead to a revised sensitivity (not applicable to NR01).
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Page 47: Data Quality Assurance
• The main idea is that one should look out for any unrealistic values. There are programs on the market that can automatically perform data screening. See for more information on such a program http://www.dqms.com. NR01 RA01 manual v1710 47/71... -
Page 48: Ra01 2-Component Radiometer
With the RA01 shim, included in RA01’s delivery, a ¾ inch NPS tube may also be used. Suggested use: • energy balance studies • surface flux measurements • climatological networks Figure 8.1.1 RA01 2-component radiometer NR01 RA01 manual v1710 48/71... -
Page 49: Specifications Of Ra01
ASTM G183 - 05 Standard Practice for Field Use of Pyranometers, Pyrheliometers and UV Radiometers WMO-No. 8, Guide to Meteorological Instruments and Methods of Observation, seventh edition 2008, paragraph 7.4 "measurement of total and long-wave radiation" NR01 RA01 manual v1710 49/71... - Page 50 Measurement function / optional programming according to WMO guide paragraph programming sunshine duration 8.2.2 Measurand Pt100 instrument body temperature T body Measurand in SI units temperature in ° C *required measurand: instrument body temperature. NR01 RA01 manual v1710 50/71...
- Page 51 Cable replacement cable can be removed and installed by the user provided that the cable is sealed at the instrument side against humidity ingress. Consult Hukseflux for instructions or use Hukseflux-supplied parts. Instrument mounting a levelling assembly for x- and y-axis is included. It fits a 1 inch NPS tube (the tube’s recommended outer...
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Page 52: Dimensions Of Ra01
RA01 fits a 1 inch NPS tube (recommended outer tube diameter is 33.4 x 10 m). Alternatively (displayed in grey), RA01 may be mounted on a ¾ inch NPS tube (recommended outer tube diameter is 26.8 x 10 m) using RA01’s shim. NR01 RA01 manual v1710 52/71... - Page 53 Figure 8.3.3 Top view of RA01 fitting a 1 inch tube: levelling assembly for x- and y-axis (2) cables (cable 1 at the left, at pyranometer side, cable 2 at the right, at pyrgeometer side) 1 inch mounting tube (not included) NR01 RA01 manual v1710 53/71...
- Page 54 Figure 8.3.4 Top view of RA01 fitting a ¾ inch NPS tube (alternative mounting method): levelling assembly for x- and y-axis cable (cable 1 at the left, at pyranometer side, cable 2 at the right, at pyrgeometer side) ¾ inch mounting tube (not included) shim, included with RA01 delivery NR01 RA01 manual v1710 54/71...
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Page 55: Electrical Connection Of Ra01
Note 1: the heater is not necessarily connected. In case it is connected, the polarity of the connection is not important. Note 2: signal wires are insulated from ground wire and from the sensor body. Insulation resistance is tested during production and is larger than 1 x 10 Ω. NR01 RA01 manual v1710 55/71... - Page 56 NR01 RA01 manual v1710 56/71...
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Page 57: Appendices
Cable and connection specifications are summarised below. NOTE: the body of NR01 contains connector blocks that can be used for the internal connection of a new cable. See the chapter on electrical connections. Usually it is easier to connect a new extended cable inside the instrument body cable than to make a good (weatherproof) connection to an existing cable. -
Page 58: Appendix On Tools For Nr01
6 mm tooling required for 2-axis levelling assembly hex key 4 mm 9.3 Appendix on spare parts for NR01 NR01 cable (specify length in multiples of 5 m), sealed at one end (2 cables per • instrument) cable gland NR01 •... -
Page 59: Appendix On Standards For Classification And Calibration
WMO-No.-8, Guide to Meteorological Instruments and Methods of Observation, seventh edition 2008, table 7.7 gives 3 levels of performance of pyrradiometers. Hukseflux does not use this classification system because its specifications are not sufficiently clear. -
Page 60: Appendix On Calibration Hierarchy
Group (WSG) which materialises the World Radiometric Reference. http://www.pmodwrc.ch The Hukseflux standard is traceable to an outdoor WRR calibration. Some small corrections are made to transfer this calibration to the Hukseflux standard conditions: irradiance level. During the outdoor calibration the sun is sun at zenith and 1000 W/m typically at 20 to 40 °... - Page 61 (transfer error). The coverage factor must be determined; at Hukseflux we work with a coverage factor k = 2. NR01 RA01 manual v1710...
- Page 62 (transfer error). The coverage factor must be determined; at Hukseflux we work with a coverage factor k = 2. Hukseflux specifies a calibration uncertainty of < 7 % (k = 2).
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Page 63: Appendix On Meteorological Radiation Quantities
In solar energy radiant exposure is often given in W∙h/m Table 9.6.1 Meteorological radiation quantities as recommended by WMO (additional symbols by Hukseflux Thermal Sensor). POA stands for Plane of Array irradiance. The term originates from ASTM and IEC standards. -
Page 64: Appendix On Iso And Wmo Classification Tables
WMO 7.3.2.5: Table 7.5 lists the expected maximum deviation from the true value, excluding calibration errors. ** At Hukseflux we use the expression ± 1 % instead of a range of 2 %. *** an instrument is subject to conformity testing of its specifications. Depending on the classification, conformity compliance can be proven either by group- or individual compliance. -
Page 65: Appendix On Definition Of Pyranometer Specifications
1.6.3 reading. Zero offset a: response to 200 W/m net thermal radiation (ventilated). (200 W/m Hukseflux assumes that unventilated instruments have to specify 9060- thermal the zero-offset in unventilated – worst case – conditions. 1990 radiation ) Zero offsets are a measure of the stability of the zero-point. -
Page 66: Appendix On Terminology / Glossary
The former is the direct component, the latter is the diffuse component of the solar radiation. (ref: WMO, Hukseflux) Hemispherical solar radiation received by a plane surface from a 180 ° field of view angle (solid solar radiation angle of 2 π... - Page 67 1. Surface equivalent blackbody radiative temperature of the surface; i.e. the temperature temperature calculated from pyrgeometer data measuring upwelling longwave radiation, assuming the ground behaves as a blackbody with an emission coefficient of 1. NR01 RA01 manual v1710 67/71...
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Page 68: Appendix On Older Nr01 Models
Earlier NR01’s, with serial numbers up to #2782, either did only fit a ¾ inch NPS tube, or, when manufactured and sold as NR01-C, solely a 1 inch tube. The current model NR01 has a width of 268 mm, wheras the earlier model NR01 had a width of 262 mm, as Table 9.10.1 shows. -
Page 69: Eu Declaration Of Conformity
EN 61326-1 (2006) Immunity: EN 61326-1 (2006) Emission: EN 61000-3-2 (2006) Emission: EN 61000-3-3 (1995) + A1 (2001) + A2 (2005). Report: 08C01340RPT01, 06 January 2009 Kees VAN DEN BOS Director Delft 20 April, 2016 NR01 RA01 manual v1710 69/71... - Page 71 © 2017, Hukseflux Thermal Sensors B.V. www.hukseflux.com Hukseflux Thermal Sensors B.V. reserves the right to change specifications without notice.
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