Hukseflux SR25-D2 User Manual Download

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USER MANUAL

SR25-D2

Digital secondary standard pyranometer
with sapphire outer dome

Summary of Contents for SR25-D2

Page 1: ...Copyright by Hukseflux manual v1603 www huksefluxusa com info huksefluxusa com USER MANUAL SR25 D2 Digital secondary standard pyranometer with sapphire outer dome...

Page 2: ...4 to 20 mA can lead to permanent damage to the sensor For proper instrument grounding use SR25 D2 with its original factory made SR25 D2 cable Using the same Modbus address for more than one device w...

Page 3: ...SR25 D2 s 4 to 20 mA output 24 5 6 Connecting to an RS 485 network 26 5 7 Connecting to a PC 28 6 Communication with SR25 D2 29 6 1 PC communication Sensor Manager software 29 6 2 Network communicatio...

Page 4: ...on tables 65 9 9 Appendix on definition of pyranometer specifications 66 9 10 Appendix on terminology glossary 67 9 11 Appendix on floating point format conversion 68 9 12 Appendix on function codes r...

Page 5: ...C Solar irradiance E W m2 Solar radiant exposure H W h m2 Time in hours h h Temperature coefficient a 1 C Temperature coefficient b 1 C Temperature coefficient c Output of 4 20 mA current loop I A Tr...

Page 6: ...keeping the SR25 D2 outer dome free of dew and frost with help of the internal heater data availability is highly increased over traditional pyranometers whether these are ventilated or not SR25 D2 of...

Page 7: ...cation settings Figure 0 2 User interface of the Sensor Manager SR25 D2 is designed for use in SCADA Supervisory Control And Data Acquisition systems supporting Modbus RTU Remote Terminal Unit protoco...

Page 8: ...taic Non Concentrator System Performance issued end 2011 confirms that a pyranometer is the preferred instrument for PV system performance monitoring SR25 D2 pyranometer complies with the requirements...

Page 9: ...setting is 4 mA at 0 W m2 and 20 mA at 1600 W m2 Specify preferred range setting 1 2 Included items Arriving at the customer the delivery should include pyranometer SR25 D2 sun screen cable of the len...

Page 10: ...tance The signal should read 100 W m2 now Darken the sensor either by putting something over it or switching off the light The instrument irradiance output should go down and within one minute approac...

Page 11: ...1 cable standard length 5 metres optional longer cable 2 fixation of sun screen thumb screw 3 glass inner dome 4 thermal sensor with black coating 5 sapphire outer dome 6 sun screen 7 humidity indicat...

Page 12: ...opile sensor generates a voltage output signal that is proportional to the solar irradiance a high end 24 bit A D converter The analogue thermopile voltage is converted by the instrument electronics t...

Page 13: ...rectional response of a SR25 D2 pyranometer of 4 azimuth angles compared to secondary standard limits 0 0 2 0 4 0 6 0 8 1 1 2 100 1000 10000 relative spectral content response arbitrary units waveleng...

Page 14: ...still complies with the secondary standard requirements The instrument should be used in accordance with the recommended practices of ISO IEC WMO and ASTM Table 3 1 1 Specifications of SR25 D2 continu...

Page 15: ...m Chassis connector M16 panel connector male thread 10 pole Chassis connector type HUMMEL AG 7 840 200 000 panel connector front mounting short version Cable connector M16 straight connector female th...

Page 16: ...n uncertainty evaluation WMO estimate on achievable accuracy for daily sums see appendix for a definition of the measurement conditions 2 WMO estimate on achievable accuracy for hourly sums see append...

Page 17: ...loop 240 x 10 3 W at 12 VDC see chapter on using SR25 D2 s 4 20 mA output BACKWARDS COMPATIBILITY SR25 D2 and SR25 D1 SR25 D2 is the successor of model SR25 D1 SR25 D2 is completely backwards compatib...

Page 18: ...SR25 D2 manual v1603 18 73 3 2 Dimensions of SR25 D2 Figure 3 2 1 Dimensions of SR25 D2 in x 10 3 m 85 M6 M5 2x 150 65...

Page 19: ...s and Methods of Observation chapter 7 measurement of radiation 7 3 measurement of global and diffuse solar radiation 4 2 General use for solar radiation measurement Table 4 2 1 Standards with recomme...

Page 20: ...performance testing STANDARDS ON PV SYSTEM PERFORMANCE TESTING IEC ISO STANDARD EQUIVALENT ASTM STANDARD IEC 61724 Photovoltaic system performance monitoring guidelines for measurement data exchange...

Page 21: ...trument mounting with one bolt 1 x M6 bolt at the centre of the instrument connection from below under the bottom plate of the instrument Performing a representative measurement the pyranometer measur...

Page 22: ...screw can be turned without tools for fixation or loosening of the sun screen as visualised below Once the thumb screw has turned the sun screen loose the screen can be lifted off manually After remov...

Page 23: ...is typically connected to the mounting platform which should be locally connected to ground The shield is not the power supply ground which is at pin 6 VDC Note 2 at the connector end of the cable th...

Page 24: ...The temperature dependence of every individual instrument is tested and supplied as a second degree polynomial The irradiance output provided by SR25 D2 is temperature corrected All temperature correc...

Page 25: ...am of the connection of SR25 D2 to a typical voltmeter or datalogger with the capacity to measure voltage signals Usually a 100 shunt resistor R is used to convert the current to a voltage SR25 D2 ope...

Page 26: ...twork figure adapted from Modbus over serial line specification and implementation guide V1 02 www modbus org The power supply is not shown in this figure After the last nodes in the network on both s...

Page 27: ...25 D2 is powered by an external power supply of 5 to 30 VDC shield common data data RS 485 A A SR25 D2 wire red blue white green pink grey brown yellow black RS 485 B B RS 485 network 12 VDC heater 5...

Page 28: ...other high voltage surges to enter the data lines An external power supply is required to power the SR25 D2 5 to 30 VDC SR25 D2 s internal heater needs 12 VDC An RS 485 to USB converter is usually pow...

Page 29: ...er software is supplied with the instrument on a USB flash drive For available software updates of the Sensor Manager please check www hukseflux com page downloads 6 1 1 Installing the Sensor Manager...

Page 30: ...ss can be entered directly Clicking Connect will establish contact If the instrument address and communication settings are not known the instrument is found by using the Find or Find All function The...

Page 31: ...s Communicating with the instrument is possible after changing the communication settings and Modbus address in the main window to the values of the instrument and then clicking Connect Figure 6 1 3 2...

Page 32: ...Y axis automatically scales to display the full measured range Figure 6 1 4 1 Example of an SR25 D2 irradiance plot in the Sensor Manager 6 1 5 Sensor Manager information about the instrument The main...

Page 33: ...6 Sensor Manager changing Modbus address and communication settings In the Sensor details window the Change settings function opens the Change serial communication settings window as shown in the figu...

Page 34: ...adiance output in W m2 that is 990 whereas the standard indicates it should be 970 The SR25 D2 output is in this example 2 06 too high The original sensitivity of 16 15 x 10 6 V W m2 ought to be chang...

Page 35: ...sters multiple requests should be used If the format of data is a signed or an unsigned 32 bit integer the first register received is the most significant word MSW and the second register is the least...

Page 36: ...sated signal in x 0 01 W m R S32 4 5 Irradiance uncompensated signal Uncompensated signal in x 0 01 W m R S32 6 Sensor body temperature In x 0 01 C R S16 7 Sensor electrical resistance In x 0 1 R U16...

Page 37: ...in 0 01 W m not compensated for temperature dependence The data must be divided by 100 to achieve the value in W m Hukseflux recommends not to use this data MSW and LSW should be read together in one...

Page 38: ...rdware version R U16 Register 32 to 39 Sensor model String of 8 registers This register will return 8 numbers which correspond with ASCII characters Register 40 Sensor serial number Register 41 42 Sen...

Page 39: ...78 Calibration date history 4 See register 65 66 R U32 79 80 Sensor sensitivity history 5 See register 63 64 R Float 81 82 Calibration date history 5 See register 65 66 R U32 Register 63 to 82 Only a...

Page 40: ...6 Register 86 to 95 these registers are for reference purposes Please note that if your data request needs an offset of 1 for each SR25 D2 register number depending on processing by the network master...

Page 41: ...sor will restart If applied a new Modbus address or new serial settings will become effective Coil 2 Check when 0xFF00 is written to this coil the internal electronics will measure the electrical resi...

Page 42: ...the master If the SR25 D2 is not already defined as a standard sensor type on the network contact the supplier of the network equipment to see if a library file for the SR25 D2 is available Typical o...

Page 43: ...5 D2 Normal sensor operation consists of requesting the output of registers 2 3 the temperature compensated solar radiation For quality assurance also the sensor serial number register 40 and the temp...

Page 44: ...216 LSW 100 In this example the result is 216 x 1 31823 100 973 59 W m Request for body temperature register 6 Master Request 40 03 00 06 00 01 6B 1A 40 Modbus Slave address 03 Modbus function 00 06...

Page 45: ...sters 0B 13 CRC Sensor response 40 03 02 0A 29 43 35 40 Modbus Slave address 03 Modbus function 02 Number of bytes 0A 29 Content of register 40 decimal equivalent 2601 43 35 CRC Register 40 represents...

Page 46: ...n case of pyranometers the measurement uncertainty as obtained during outdoor measurements is a function of the instrument class the calibration procedure uncertainty the duration of instrument employ...

Page 47: ...l conditions for instance when installed at a sub optimal measurement location with obstacles in the path of the sun other environmental conditions for instance when assessing PV system performance an...

Page 48: ...meters are designed to allow easy maintenance and repair The main maintenance actions are replacement of desiccant replacement of cabling For optimisation of dependability a user should estimate the e...

Page 49: ...tion uncertainty 5 In uncertainty analysis for pyranometers the location and date of interest is entered The course of the sun is then calculated and the direct and diffuse components are estimated ba...

Page 50: ...9060 season latitude uncertainty minute totals at solar noon uncertainty hourly totals at solar noon uncertainty daily totals secondary standard SR25 D2 summer mid latitude 2 7 2 0 1 9 equator 2 6 1 9...

Page 51: ...me measurements to PV system output Look for any patterns and events that deviate from what is normal or expected 2 2 weeks cleaning use a soft cloth to clean the dome of the instrument persistent sta...

Page 52: ...y replacing the sensor with a spare sensor with the same address Not able to communicate with the sensor Check all physical connections to the sensor and try connecting to the sensor again If communic...

Page 53: ...Calibration and checks in the field Recalibration of field pyranometers is typically done by comparison in the field to a reference pyranometer The applicable standard is ISO 9847 International Standa...

Page 54: ...ss radiometers to correct deviations of more than 10 Lower deviations should be interpreted as acceptable and should not lead to a revised sensitivity 7 for first class pyranometers to correct deviati...

Page 55: ...SR25 D2 manual v1603 55 73...

Page 56: ...nected The combined use of sapphire and internal heating keeps the outer dome dew and frost free This highly increases data availability while maintaining high measurement accuracy Therefore the gener...

Page 57: ...an the other secondary standard pyranometers both when unheated and when heated Figure 9 1 2 2 nighttime offsets of ventilated pyranomers and SR25 versus net longwave radiation SR25 has lower nighttim...

Page 58: ...had no reduction in data availability due to dew SR20 ventilated with VU01 had 1 one dew event The unheated SR25 performs better than SR20 in this dew experiment This can be explained by the better t...

Page 59: ...cable by himself Please note that Hukseflux does not provide support for DIY connector and cable assembly SR25 D2 is equipped with one cable Maximum length of the sensor cable depends on the RS 485 ne...

Page 60: ...ale thread for cable 3 to 6 x 10 3 m special version The shield is electrically connected to the connector Cable 8 wire shielded with copper conductors at Hukseflux 8 wire shielded cable is used of wh...

Page 61: ...ctor specify length in multiples of 5 m O ring SR25 D2 NOTE Outer dome level and sensor of SR25 D2 cannot be supplied as spare parts In case of possible damage to the SR25 D2 after repair the instrume...

Page 62: ...dard Solar energy Methods for testing pyranometer and pyrheliometer characteristics has been announced in ISO 9060 but is not yet implemented not available ISO 9846 1993 Solar energy Calibration of a...

Page 63: ...ometers Method ISO 9846 type 1 outdoor This working standard has an uncertainty uncertainty of standard The working standard has been calibrated under certain test conditions of the standard The worki...

Page 64: ...apparent solar zenith angle W m2 DNI Direct Normal Irradiance E0 solar constant W m2 Eg h global irradiance hemispherical irradiance on a specified in this case horizontal surface Eg E cos h Ed W m2...

Page 65: ...2 4 8 Tilt response 0 to 90 at 1000 W m2 0 5 2 5 ADDITIONAL WMO SPECIFICATIONS WMO CLASS HIGH QUALITY GOOD QUALITY MODERATE QUALITY WMO achievable accuracy for daily sums 2 5 10 WMO achievable accura...

Page 66: ...tivity at 500 W m2 due to the change in irradiance within the range of 100 W m2 to 1000 W m2 Non linearity has an overlap with directional response and therefore should be handled with care in uncerta...

Page 67: ...diation not of solar origin but of terrestrial and atmospheric origin and having longer wavelengths 3 000 to 100 000 x 10 9 m In case of downwelling El also the background radiation from the universe...

Page 68: ...rted to decimal data automatically Example of the calculation of register 41 42 representing a floating point for the sensitivity of the sensor which is 15 14 Data in register 41 16754 MSW Data in reg...

Page 69: ...local master Table 9 12 2 Modbus registers 0 to 99 MODBUS REGISTERS 0 99 REGISTER NUMBER PARAMETER DESCRIPTION OF CONTENT TYPE OF FORMAT OF DATA 0 Modbus address Sensor address in Modbus network defa...

Page 70: ...ormer calibration date of the sensor in YYYYMMDD Default value is 0 R U32 67 68 Sensor sensitivity history 2 See register 63 64 R Float 69 70 Calibration date history 2 See register 65 66 R U32 71 72...

Page 71: ...R U16 99 Humidity temperature In x 0 01 C R S16 Note 1 Up to five 16 bit registers can be requested in one request If requesting six or more registers use multiple requests Please note that if your d...

Page 72: ...ereby declare under our sole responsibility that Product model SR25 D2 Product type Pyranometer has been designed to comply and is in conformity with the relevant sections and applicable requirements...

Page 73: ...2016 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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