IR100/IR120 Infra-red Remote Temperature Sensor
Contents
1. with another sensor Dim IRSensor Volt The Measured Thermopile Voltage Dim IRSensor Volt TC The Measured Thermopile Voltage Temp Compensated Dim IRSensor E Energy Difference Dim IRSensor T4 Black body surface temperature to the power 4 Dim IRSensor T Black body surface temperature in Kelvin Uncorrected Dim IRTFilm T4 Temperature after the film correction to the power 4 Public IRTemp C Corrected Surface Temperature in Celsius DataTable IR100Data 1 1 DataInterval 0 1 Min 10 Average 1 IRTemp _C FP2 False FieldNames AVG Surface Temperature C EndTable Main Program BeginProg Scan 5 Sec 0 0 Measure the IR1x0 Body Temperature Measure the thermistor using a half bridge by applying a negative excitation voltage of 2 5V Note that switching the bridge excitation is set to FALSE 15 IR100 IR120 Infra red Remote Temperature Sensor Uses channel 3 Single ended 20 ms settling time for long cable BrHalf BR_Res 1 mV2500 3 Vx1 1 2500 False 20000 50Hz 1 0 Multiply the ratio of measured voltage by a constant appropriate to the thermistor IRSensor Resis 77020 BR Res 1 BR Res Using Steinhart hart apply the calibration coefficients to arrive at a body temperature in Celsius IRSensorCan Temp 1 Coeff A Coeff B LN IRSensor Resis Coeff C LN IRSensor Resis 3 273 15 Measure the IR1x0 Infrared Temperatur Measure the infrared temperature using a full2. IR120 Example Program Table 1 Program Olds 5 Execution Interval seconds Calibration Data for the IR120 NOTE These values should match those listed on the IR100 Calibration Certificate 1 Z F x 10 n P30 1 2 29176 F 235 n Exponent of 10 3 4 Z Loc Coeff X 16 User Manual 2 Z F x 10 n P30 1 5 17221 F Qi dl n Exponent of 10 die Di Z Loc Coeff Y 3 Z F x 10 n P30 Lig 3 50399 E 2 0 n Exponent of 10 3 6 Z Loc Coeff zZ 4 Z F x 10 n P30 Lis 0 94 F 2 00 n Exponent of 10 3 18 Z Loc Emissiv Measure the IR100 Body Temperature Measure the thermistor using half bridge by applying negative excitation voltage of 2 5V 5 Excite Delay SE P4 dig T Reps Di cd 2500 mV Slow Range Si 3 SE Channel 4 1 Excite all reps w Exchan 1 SZ Delay 0 01 sec units 6 2500 V Excitation Poe T Loc BR Res 8 0004 ultiplier 1 2500 to give the ratio V Vx 9340730 Offset Multiply the ratio of measured voltage by constant appropriate to thermistor 6 BR Transform R X 1 X P59 duro DL Reps 2 7 Loc BR_Res Six TOZO Multiplier Rf Use Steinhart Hart apply calibration coeff to get body temperature in deg C Calibration Data for the IR120 a NOTE These values should match those listed on the IR100 Calibration Certificate 7 Steinhart Hart Equation P200 deal Reps 23 7 Source Loc R
3. IRSensor_E is the resultant measured thermal radiation proportional to the net rate of energy exchange with the target surface and must be combined using Stefan Boltzmann with the radiant energy from the sensor to obtain the measured remote temperature IRSensor T4 IRSensor E 5 67E 8 IRSensorcan temp 273 15 4 IRSensor T IRSensor T4 0 25 273 15 If the target surface were a blackbody then this would suffice and the temperature value obtained would be an accurate representation of actual surface temperature However since nothing in the real environment acts like a blackbody we have to correct this temperature value to account for the emissivity of the target surface Additionally if the sensor is looking through a window from inside an enclosure an additional correction is needed 6 2 Correcting for an enclosure window The following example shows the additional lines of code required to obtain an infrared temperature measurement from the IR100 sensor when installed inside an enclosure that has protective window This correction is not needed for the sensor fitted in an IR SS shield Campbell Scientific uses a thin plastic film that has high IR transmission The signal the sensor sees is mainly from the target but partly about 20 from the window material To correct for this the window temperature has to be known and the IR transmission of the window material A similar equation is used as for emissivity corrections to s
4. temperature of the detector measured by an internal thermistor Ener is determined by the amplified thermocouple voltage inserted into a polynomial equation whose constants were obtained during calibration from a 2 order polynomial fit of sensor voltage and irradiance obtained during calibration Thus The specifications of the thermopile sensor state that the sensitivity decreases by 0 04 per deg C To compensate for this we need to increase the multiplication factor by 0 04 for every degree C above the calibration temperature The following equation takes care of this compensation Temperature_Compensated_x x 1 0004 IRcan_Temp 25 5 4 Correction for Non Blackbody Surfaces The IR100 sensor is calibrated against a blackbody target The proportion of energy it emits to that which it reflects is known as its Emissivity e A black body is said to have an emissivity of 1 In the real environment most surfaces will reflect some radiation from the surroundings and this component should be removed to get an accurate reading Since E oT And E measured E surface 1 E reflected 4 Ra E 1 z NT reflected Hus Lon e E Where is the emissivity of the surface whose value depends on the nature of the surface and always lies between 0 and 1 and T eflected is the temperature of the surrounding surfaces whose energy is in part being reflected by the measured surface For most applications
5. It is the policy of Campbell Scientific to protect the health of its employees and provide a safe working environment in support of this policy a Declaration of Hazardous Material and Decontamination form will be issued for completion When returning equipment the Repair Reference Number must be clearly marked on the outside of the package Complete the Declaration of Hazardous Material and Decontamination form and ensure a completed copy is returned with your goods Please note your Repair may not be processed if you do not include a copy of this form and Campbell Scientific Ltd reserves the right to return goods at the customers expense Note that goods sent air freight are subject to Customs clearance fees which Campbell Scientific will charge to customers In many cases these charges are greater than the cost of the repair x CAMPBELL SCIENTIFIC Campbell Scientific Ltd 80 Hathern Road Shepshed Loughborough LE12 9GX UK Tel 44 0 1509 601141 Fax 44 0 1509 601091 Email support campbellsci co uk www campbellsci co uk PLEASE READ FIRST About this manual Please note that this manual was originally produced by Campbell Scientific Inc primarily for the North American market Some spellings weights and measures may reflect this origin Some useful conversion factors Area 1 in square inch 645 mm Mass 1 oz ounce 28 35 g 1 Ib pound weight 0 454 kg Length 1 in inch 25 4 mm
6. The primary components of the observed radiation are thus reflected radiation from the sky and surrounds radiation emitted by the environmental protective film and the component we are interested in radiation from the road Thus Radobserved A Radgim B Radpoaa C Radsxy D Radpuildings amp trees Since Radiation Energy oT where T is in Kelvin then rearranging and cancelling out the Stephan Boltzman constant we can say that Troad4 Tovserved A Trim T C T sy T D Tbuildingsetrees B The proportion of radiation being transmitted through the radiation film is known as the Transmissivity Thus A 1 Transmissivity The proportion of the observed radiation being emitted by the road is dependent on both the Emissivity of the road surface and the Transmissivity of the film A 1 Thus B Transmissivity x Emissivity The proportion or the sky depends to an extent on the exposure to of the site in question This is known as the Sky View Factor and is the ratio of the area of the surrounding buildings amp trees weighted according to the cosine of their incidence to the surface to the area of exposed sky An open road fully exposed has a Sky View Factor of 1 A road fully enclosed in a tree canopy may have a Sky View Factor as low as 0 It should be borne in mind that whatever the Sky View Factor may be only a portion of the radiation coming from the sky will be reflected by the road 1 Emissivity and on
7. bridge instruction Note that switching the bridge excitation is set to FALSE Use 75 ms settling time to allow amplified signal to settle The multiplier is used to correct the ratiometric output to mV Uses channel 1 differential ExciteV Vx1 2500 0 Delay 0 75 mSec BrFull IRSensor Volt 1 mV250 1 Vx1 1 2500 False False 0 50Hz 2 5 0 Apply temperature compensation IRSensor Volt TC IRSensor Volt 1 0004 IRSensorCan Temp 25 Apply coefficients IRSensor E Coeff X IRSensor Volt _TC 2 Coeff Y IRSensor Volt TC Coeff Z Add difference to absolute energy from the sensor body IRSensor T4 IRSensor E 5 67E 8 IRSensorCan Temp 273 15 4 Resolve for remote surface temperature in Kelvin NOTE this is the UNCORRECTED value IRSensor T IRSensor T4 0 25 273 15 Correct for the effects of the high infrared transmission film Have to assume Airtemp IRsensorcan temp in this example as no air temp measurement Airtemp IRSensorCan Temp IRTFilm T4 IRSensor T4 Airtemp 273 15 4 1 Film Film Combine with the correction for Emissivity and Convert to Celsius IRTemp C IRTFilm T4 Airtemp 273 15 4 1 Emissivity Emissivity 0 25 273 15 Store the results to a table CallTable IR100Data NextScan EndProg 6 5 Edlog CR10X Program Example This example does not include a correction of any enclosure window film CR10X
8. film correction 6 5 Edlog CR10X Program Example Appendices A Correction for Non Blackbody used in Campbell Scientific s Road Temperature Monitoring Equipment cestista aaa A 1 B 1R100 Thermistor resistance B 1 Table 1 IR100 Datalogger Wiring Details ii 2 Figures 1 A picture of the IR SS with IR120 fitted eee cee eeeeeeeeeneel 4 2 A cross sectional diagram of the sensor fitted inside the IR SS shield 5 3 The shield fitted onto the IRIX0 mounting arm iii 6 4 An IR SS fitted to a pole with an optional band clamp fitting 6 5 The arrangement of the nut and washers on the band clamp fitting 7 IR100 IR120 Infra red Remote Temperature Sensor 1 Introduction The IR100 IR120 is an infrared temperature sensor It offers a non contact means of measuring the surface temperature of an object by sensing the infrared radiation given off It can be used in the measurement of leaf canopy and average surface temperature Non contact measurement is often simpler to install does not influence the target temperature and is an effective means of getting a spatial average temperature Two variants of the sensor are available the IR100 has an ultra narrow field of view whilst the IR120 has a narrow field of view see specifications below Throughout the remainder of this manual IR100 is used to represent both versions 2
9. it is commonly assumed that reflected radiation comes from surfaces at the sensor body temperature However in outdoor applications it may be better to use a more appropriate temperature e g air temperature The algorithms used within Campbell Scientific s road temperature monitoring equipment take account of reflected radiation from the sky building and trees in the surrounding area and radiation emitting from the environmental film that IR100 IR120 Infra red Remote Temperature Sensor 10 protects the sensor All the algorithms consist of converting the temperatures assumed or measured into their fourth power in Kelvin and subtracting portions one from the other to arrive at the actual surface temperature Please refer to Section 6 2 and Appendix A for a more detailed explanation 5 5 Getting the best measurements Taking good infra red temperature measurements does require some understanding of the measurement principle and careful use of the sensor especially for field measurements Here are some points you need to take into consideration e The accuracy of the temperature measurement is dependent on knowing the emissivity of the surface being measured The further the emissivity is from one the more critical it is to measure and compensate for the emissivity e Try to take measurements with the sensor pointed directly at the target rather than at acute angles This is because reflection can lead to significant errors and re
10. the thermopile measures the reference body temperature Both results are combined and processed in the logger to output the measured surface temperature The measured resistance of the thermistor varies with temperature using a third order Steinhart Hart thermistor equation L A B In R C In R where A B and C are calibrated constants for individual thermistors The sensor element used in the IR100 is individually calibrated and so the Steinhart Hart must be applied in the program using the sensor calibration coefficients supplied 5 3 The Stefan Boltzmann Law Using the Stefan Boltzmann Law we can determine the temperature of a particular surface based on the amount of thermal energy it radiates Stefan Boltzmann states that the total energy radiated per unit time per unit surface area of a blackbody is proportional to the fourth power of the temperature of the body expressed in Kelvin s i e E oT User Manual where o is a constant of proportionality known as Stefan s constant whose value is 5 67E W m K The rate at which a unit surface area of this blackbody receives radiation from surrounding objects at temperature Tis oT and the rate at which the blackbody at temperature Ty emits radiation in oT thus the net rate of loss of energy by the blackbody is therefore given by Enen where Ene o T To T Zeer o where 7 is the surface temperature observed by the detector and T the
11. 1 ft foot 304 8 mm Pressure 1 psi Ib in 68 95 mb 1 yard 0 914 m 1 mile 1 609 km Volume 1 UK pint 568 3 ml 1 UK gallon 4 546 litres 1 US gallon 3 785 litres In addition while most of the information in the manual is correct for all countries certain information is specific to the North American market and so may not be applicable to European users Differences include the U S standard external power supply details where some information for example the AC transformer input voltage will not be applicable for British European use Please note however that when a power supply adapter is ordered it will be suitable for use in your country Reference to some radio transmitters digital cell phones and aerials may also not be applicable according to your locality Some brackets shields and enclosure options including wiring are not sold as standard items in the European market in some cases alternatives are offered Details of the alternatives will be covered in separate manuals Part numbers prefixed with a symbol are special order parts for use with non EU variants or for special installations Please quote the full part number with the when ordering Recycling information At the end of this product s life it should not be put in commercial or domestic refuse but sent for recycling Any batteries contained within the product or used during the products life should be removed from the product and also
12. IVANVIA JASA CAMPBELL SCIENTIFIC 1R100 IR120 Infra red Remote Temperature Sensor Issued 25 2 15 Copyright 2007 2015 Campbell Scientific Ltd CSL 708 Guarantee This equipment is guaranteed against defects in materials and workmanship This guarantee applies for 24 months from date of delivery We will repair or replace products which prove to be defective during the guarantee period provided they are returned to us prepaid The guarantee will not apply to e Equipment which has been modified or altered in any way without the written permission of Campbell Scientific e Batteries e Any product which has been subjected to misuse neglect acts of God or damage in transit Campbell Scientific will return guaranteed equipment by surface carrier prepaid Campbell Scientific will not reimburse the claimant for costs incurred in removing and or reinstalling equipment This guarantee and the Company s obligation thereunder is in lieu of all other guarantees expressed or implied including those of suitability and fitness for a particular purpose Campbell Scientific is not liable for consequential damage Please inform us before returning equipment and obtain a Repair Reference Number whether the repair is under guarantee or not Please state the faults as clearly as possible and if the product is out of the guarantee period it should be accompanied by a purchase order Quotations for repairs can be given on request
13. Ohms BR _ Res 3 8 Destination Loc Deg C IR Can 4 3 08524 A S38 x 10 n 6 9 95376 B Ti 5 xO a Be Da L77900 9 6 x 10 n Measure the IR100 Infrared Temperatur Measure the infrared temperature using a full bridge Ex Delay Diff Volt instruction Delay of 80ms for settling time Ex Del Diff P8 1 Reps 5 2500 mV Slow Range DIFF Channel Excite all reps w Exchan 1 0 DONI DSWNNL e 8 Delay 0 01 sec units 2500 V Excitation 12 Loc IRs_V 0 Multiplier 17 IR100 IR120 Infra red Remote Temperature Sensor r 9 18 Add difference to absolute energy from sensor body 0 0 Offset Apply Temperature Compensation Z X F P34 8 X Loc IR_Can 25 F 10 Z Loc IR Can Tp Z F x 10 n P30 1 0004 F 00 n Exponent of 10 LL Z Loc IRs_V_TC Z X Y P47 11 X Loc IRs_V_TC 10 Y Loc IR_Can_ Tp sia Z Loc IRs_V_TC Z X Y P36 12 X Loc IRs _ V 11 Y Loc IRs_V_TC LL Z Loc IRs_V_TC Apply Coefficients Z X Y P36 11 X Loc IRs_V_TC 11 Y Loc IRs_V_TC 13 Z Loc IRs_E Z X Y P36 4 X Loc Coeff X 13 Y Loc IRs_E 13 Z Loc IRs_E Z X Y P36 5 X Loc Coeff Y 11 Y Loc IRs_V_TC 14 z Loc IRs Temp Z X Y P33 14 X Loc IRs_ Temp 6 Y Loc Coeff zZ 14 Z Loc IRs_Temp Z X Y P33 13 X Loc IRs_E 14 Y Loc IRs_ Temp 13 Z Loc IRs_E Z X F P34 8 X Loc IR Can 21315 F 14 Z Loc IRs Temp Z F x 10 n
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15. P30 4 F 00 n Exponent of 10 15 Z Loc IR Exp Z X Y P47 14 X Loc IRs Temp 15 Y Loc IR_Exp 14 Z Loc IRs Temp WNErnN WNR EF WNF W Z F x 10 n 5 67 F 8 n T9 Z Z X Y P38 q3 X 15 Y 13 Z Z X Y P33 13 X 14 Y 16 Z Z F x 10 n 025 F 00 n 15 Z Z X Y P47 16 X TS X 17 Z Z X F P34 7 X 2 13 lt L5 E 17 Z Correction fo Z F x 10 n 4 F 00 n 15 Z Z X F P34 8 X 213s L5 F 14 Z Z X Y P47 14 X 15 Y 14 Z Z X F P37 18 X 1 F 19 Z Z X F P34 9 X el F 19 Z Z X Y P36 14 X 19 Y 14 Z Z X Y P35 16 X 14 Y P30 P30 P30 Exponent of 10 Loc IR_Exp Loc IRs_E Loc IR_Exp Loc IRs_E Loc IRs_E Loc IRs_Temp Loc IRs T4 Resolve for remote surface temp in Kelvin Exponent of 10 Loc IR_Exp Loc IRs T4 Loc IR_Exp Loc IRs T Loc IRs T Loc IRs T r Emissivity and convert to deg C Exponent of 10 Loc IR Exp Loc IR Can Loc IRs_ Temp Loc IRs_ Temp Loc IR Exp Loc IRs_ Temp 10C Emissiv 10C EmissivTp 10C EmissivTp 10C EmissivTp Loc IRs_ Temp 10C EmissivTp Loc IRs_ Temp Loc IRs_T4 Loc IRs Temp User Manual 19 IR100 IR120 Infra red Remote Temperature Sensor 3 14 Z Loc IRs_Temp 34 Z X Y P38 1 14 X Loc IRs_ Temp 2z 18 Y Loc Emissiv 3 14 Z Loc IRs_ Temp 35 Z F x 10 n P30 de
16. Program 5 Sec 0 0 easure the IR1x0 Body Temperature asure the thermistor using a half bridge by applying a negative xcitation voltage of 2 5V ote that switching the bridge excitation is set to FALSE ses channel 3 Single ended 20 ms settling time for long cable Half BR_Res 1 mV2500 3 Vx1 1 2500 False 20000 50Hz 1 0 ultiply the ratio of measured voltage by a constant appropriate to the hermistor Sensor Resis 77020 BR Res 1 BR Res sing Steinhart hart apply the calibration coefficients to arrive at a ody temperature in Celsius SensorCan Temp 1 Coeff A Coeff B LN IRSensor Resis Coeff C LN IRSensor Resis 3 273 15 easure the IR1x0 Infrared Temperatur easure the infrared temperature using a full bridge instruction ote that switching the bridge excitation is set to FALSE se 75 ms settling time to allow amplified signal to settle he multiplier is used to correct the ratiometric output to mV ses channel 1 differential ExciteV Vx1 2500 0 Delay 0 75 mSec BrFull IRSensor Volt 1 mV250 1 Vx1 1 2500 False False 0 50Hz 2 5 0 Apply temperature compensation IRSensor Volt_TC IRSensor Volt 1 0004 IRSensorCan Temp 25 Apply coefficients User Manual IRSensor E Coeff X IRSensor Volt _TC 2 Coeff Y IRSensor Volt TC Coeff Z Add difference to absolute energy from the sensor body IRSensor T4 IRSensor E 5 67E 8 IRSensorCan Temp 273 15 4 Re
17. Specifications 2 1 General Specifications Field of View half angle IR100 4 5 IR120 20 Dimensions 92 mm long by 28 mm diameter Mounting holes Response Time 2 x 6 mm thread 5 mm deep min lt 1 second to changes in target temperature Target Output Signal IR100 5 mV per C IR120 20 mV per C difference from sensor body IR100 IR120 Infra red Remote Temperature Sensor Signal Offset Removed by calibration supplied Typical Noise Level as measured by a CS datalogger Calibrated Range Operating Range Accuracy over Calibrated Range Current Consumption Sensor output impedance Thermopile Excitation Voltage Thermistor Excitation Voltage 3 Wiring IR100 0 2 C RMS IR120 0 05 C RMS 25 C below body temperature to 25 C above body temperature 25 C to 60 C 0 2 C against a blackbody source over a 50 C temperature span under laboratory conditions 0 4 mA when excitation applied 0 mA quiescent 320 Ohms 2 to 3 5V 2 5V The IR100 can be used with all Campbell Scientific dataloggers except CR200 and most other dataloggers that support negative voltage excitations Wiring colours and connections between the sensor and datalogger are shown in Table 1 Table 1 IR100 Datalogger Wiring Details Colour Description Wiring SE Wiring Diff Brown Thermistor SE Channel SE Channel Green IR Temperature SE Channel Diff x High White Groun
18. be sent to an appropriate recycling facility Campbell Scientific Ltd can advise on the recycling of the equipment and in some cases arrange collection and the correct disposal of it although charges may apply for some items or territories For further advice or support please contact Campbell Scientific Ltd or your local agent fz CAMPBELL SI SCIENTIFIC Campbell Scientific Ltd Campbell Park 80 Hathern Road Shepshed Loughborough LE12 9GX UK Tel 44 0 1509 601141 Fax 44 0 1509 601091 Email support campbellsci co uk www campbellsci co uk Contents PDF viewers note These page numbers refer to the printed version of this document Use the Adobe Acrobat bookmarks tab for links to specific sections 1 2 3 4 5 7 Maintenance Introduction Specifications 2 1 General Specifications Principles of Measurement 5 1 Thermopile Detector 5 2 Thermistor 5 3 The Stefan Boltzmann Law 5 4 Correction for Non Blackbody Surfaces 5 5 Getting the best measurements Program Examples amp Explanation of Terms 6 1 IR100 Blackbody Infrared Temperature Measurement 6 1 1 Thermistor Measurement Sensor Body Temperature 6 1 2 Thermopile Detector Infrared Radiation Measurement 6 2 Correcting for an enclosure window 6 3 Non Blackbody Infrared Temperature Measurement 6 4 CRBasic CR1000 Program Examples 6 4 1 CRBasic example with Emissivity correction 6 4 2 CRBasic example with Emissivity and Window
19. d IR Temperature AG Diff x Low Red Excitation EX EX Black Ground AG AG Clear Shield The IR100 can be wired either single ended or differentially as detailed in Table 1 3 1 Spectral response Wavelength Range IR120 8 to 14 um See graphs below IR100 effective bandwidth 7 14 um some sensitivity from 2 6 um IR120 Relative Spectral Response 1 0 0 8 IR100 Relative Spectral Response 0 6 0 4 0 2 4 6 8 10 12 0 0 6 7 8 9 10 15 20 Wavelength micrometres Wavelength micrometres Thermistor 30K 25 C Excitation Thermistor Ground Groung Amplifier IR Temp Shield Thermopile IR100 IR120 Infra red Remote Temperature Sensor 4 Installation The IR100 sensor should not be allowed to fill with water Do not point skywards The IR100 can be secured by means of one or two 6 mm screws to fix the sensor to a flat surface such as a metal mounting bracket screws not provided Older units had a 14 20 UNC thread For best precision the body should not be exposed to rapid changes of temperature ideally shielded from direct exposure to wind rain sun and handling Optional housings are available for these sensors which both protect the sensor from the weather and act to dampen rapid temperature changes which can improve measurement accuracy The IR SS Solar Shield is the simple shield recommended for most outdoor installations It protects the sensor from direct solar radiation and othe
20. e shown below in Figure 5 pring washer Figure 5 The arrangement of the nut and washers on the band clamp fitting After mounting the sensor tie the cable to the pole to stop it flexing in the wind When installing the sensor consideration must be taken of the field of view distance to the target and angle of the sensor relative to the main surfaces of the target All of these can affect the accuracy of the measurement The field of view can be calculated thus with a half angle of n degrees see specifications the sensor will observe radiation from a circular area whose radius will be tan n the target distance from sensor If possible the distance to the target should be minimised as visible mist and invisible water vapour or dust in the air between the sensor and target can lead to measurement errors The shorter the distance the smaller this effect It is also desirable for the sensor to point at the surface being measured directly at 90 degrees relative to the surface rather than being at an acute angle This is because many surfaces will have increased reflectivity at low angles of view At acute angles the sensor reading may end up being biased towards the temperature of the reflections rather than the target itself This is similar to trying to look into a pond where you cannot see the bottom of the pond only a reflection at low angles of view IR100 IR120 Infra red Remote Temperature Sensor Both variants of
21. eparate out energy coming from the target Film IR transmission CSL window measured value Const Film 0 79 The correction equation IRTFilm T4 IRSensor T4 Airtemp 273 15 4 1 Film Film The line above uses air temperature as a measure of the window temperature which is a fair assumption as long as the window is shaded from the sun If air temperature is not available the sensor body temperature can be used although this may result in small transient errors due to the different time responses of the window and the sensor body The variable IRTFilm_T4 is the corrected target temperature in Kelvin to the power four It can be converted to Celsius or used in place of IRSensor_T4 in the emissivity correction equation shown in Section 6 3 12 User Manual 6 3 Non Blackbody Infrared Temperature Measurement The following example shows the additional line of code required to obtain an infrared temperature measurement from the IR100 sensor corrected for a target surface emissivity of 0 94 and assuming that the adjacent surfaces are at the sensor temperature Emissivity 0 94 Temp IRSensor T4 IRSensorcan temp 273 15 4 1 Emissivity Emissivity 0 25 273 15 When measuring surface leaf temperature under a tree canopy a measure of air temperature may be more suitable for the adjacent temperature than the sensor can temperature See Appendix A for further examples 13 IR100 IR120 Infra red Re
22. flection increases the more acute the angle Those reflections can be long wave IR and or from reflected sunlight the IR100 is more prone to this as it has a little sensitivity at lower wavelengths e Try to install the sensor relatively close to the surface being measured within a few metres as mist and even high humidity especially in the case of the IR100 will cause the sensor to be influenced by the temperature of the air between it and the target On the other hand do not install the sensor so close that it interferes with the IR exchange with the target and its environment e Try to ensure the sensor body is insulated from rapid changes in temperature as small gradients of temperature around the sensor aperture can lead to large transient measurement errors To do this if the sensor is installed outside the sensor should be shielded from direct exposure to the sun which could be in the form of a shield or added insulation a tube of foam pipe insulation is suitable Alternatively it can be installed in an optional camera style housing with an IR transmissive window e If your readings seem to be always close to the body i e not sensing the target temperature as expected check the sensing aperture of the sensor is not blocked by spiders etc and if using an enclosure that the IR transmissive film is not dirty or wet User Manual 6 Program Examples amp Explanation of Terms 6 1 IR100 Blackbody Infrared Temperature Measu
23. lace at the desired angle When inserting a mounting bolt do not screw it too far such that it hits the sensor body which could lead to damage IR100 IR120 Infra red Remote Temperature Sensor Figure 3 The shield fitted onto the IR1X0 mounting arm Optional band clamp pole mounts are available to allow the IR SS to be mounted on the side of lamp posts and similar structures The band clamps are specified to match a specific range of size of pole Figure 4 An IR SS fitted to a pole with an optional band clamp fitting For this type of bracket the shield must first be attached to the band clamp bracket This is most easily done before mounting the bracket on the pole To do this first put the nut then the two washers onto the bolt of the bracket screwing the nut loosely up to the bracket and leaving the thread of the bolt User Manual free at the end Then screw that bolt into the side of the shield so the bolt is fully screwed into the metal insert in the shield but not so far that the end is not touching the body of the sensor Now mount the bracket on the pole using the band rotating the band so the sensor points in the right direction Next rotate the sensor on the bolt to point at the target and use the lock nut on the bolt to fix the shield at the correct angle Tighten the bolt so the spring washer is compressed Do not overtighten as you risk turning the fitting in the plastic shield The arrangement of the nut and washer ar
24. ly a portion of the resulting reflected radiation will be transmitted through the film Transmissivity thus C Transmissivity x 1 Emissivity x SVF And likewise for the surroundings D Transmissivity x 1 Emissivity x 1 SVF And since the surrounding buildings and trees along with the protective environmental film are all at air temperature we can say that Trim Tpuildings amp trees Tair Thus Troad4 Tobserved C T sky Tair At D B Where A 1 Transmissivity B Transmissivity x Emissivity C Transmissivity x 1 Emissivity x SVF D Transmissivity x 1 Emissivity x 1 SVF Appendix B IR100 Thermistor Resistance Please note tolerance on these figures is 5 Individual calibration for each sensor is included on the calibration certificate Degree C Ohms o 95 3550 E 005 7 605 0 so 8860 4 0 2 818 8 B 1 CAMPBELL SCIENTIFIC COMPANIES Campbell Scientific Inc CSI 815 West 1800 North Logan Utah 84321 UNITED STATES www campbellsci com e info campbellsci com Campbell Scientific Africa Pty Ltd CSAf PO Box 2450 Somerset West 7129 SOUTH AFRICA www csafrica co za e sales csafrica co za Campbell Scientific Australia Pty Ltd CSA PO Box 8108 Garbutt Post Shop QLD 4814 AUSTRALIA www campbellsci com au e info campbellsci com au Campbell Scientific do Brazil Ltda CSB Rua Apinag s nbr 2018 Perdizes CEP 01258 00 S o Paulo S
25. mote Temperature Sensor 14 6 4 CRBasic CR1000 Program Examples 6 4 1 CRBasic example with Emissivity correction CR1000 Program for the IR1x0 with emissivity correction Calibration Data for the IR1x0 NOTE These values should match those listed on the IR100 calibration certificate Const Coeff A 9 355652E 04 Const Coeff B 2 203275E 04 Const Coeff C 1 394681E 07 Const Coeff X 2 748588E 04 Const Coeff Y 1 787100E 00 Const Coeff Z 6 923498E 02 Emissivity should be appropriate for the surface type Const Emissivity 0 94 Dim BR Res The Measured Bridge Resistance Main BeginProg Scan Dim IRSensor Resis Public IRSensorCan Temp Ul e N U Br IR b IR N U dl U a lhermistor Resistance lhermistor Temperature in Celsius Public Airtemp Used in the emissivity correction ideally measured with another sensor Dim IRSensor Volt The Measured Thermopile Voltage Dim IRSensor Volt TC The Measured Thermopile Voltage Temp Compensated Dim IRSensor E Energy Difference Dim IRSensor T4 Black body surface temperature to the power 4 Dim IRSensor T Black body surface temperature in Kelvin Uncorrected Public IRTemp_C Corrected Surface Temperature in Celsius DataTable IR100Data 1 1 DataInterval 0 1 Min 10 Average 1 IRTemp_C FP2 False FieldNames AVG Surface Temperature C EndTable
26. on and at least a75 mS settling time before taking the measurement You need to choose whether to make the measurement differentially or single ended A differential measurement will give the most accurate reading especially for long cable runs but needs a differential channel equivalent to two single ended inputs Therefore the single ended technique is only usually used if there is a shortage of inputs on the datalogger and cables are short lt 10 m Refer to Table 1 above for the difference in wiring The program structure is Singl nded measurement note the positive 2500mV excitation which is turned on first to force a 75mS delay ExciteV Vx1 2500 0 Delay 0 75 mSec BrHalf IRSensor Volt 1 mV250 1 Vx1 1 2500 False 0 50Hz 2500 0 Or Differential measurement note the positive 2500mV excitation which is turned on first to force a 75mS delay ExciteV Vx1 2500 0 Delay 0 75 mSec BrFull IRSensor Volt 1 mV250 1 Vx1 1 2500 False False 0 50Hz 2 5 0 11 IR100 IR120 Infra red Remote Temperature Sensor Then Apply temperature compensation for the IR Sensor IRSensor Volt TC IRSensor Volt 1 0004 IRSensorCan Temp 25 Apply calibration factors IRSensor E IRSensor x IRSensor Volt TC 2 IRSensor y IRSensor Volt TC IRSensor z NOTE The range codes will need to be amended if using a CR3000 datalogger The bridge instructions have multipliers in them to scale the values back to mV
27. r weather which might otherwise lead to rapid changes of body temperature which can lead to transient measurement errors The sensor can be mounted to any suitable structure using the 6 mm threaded hole in the side of the shield for example on Part 009905 the IR1x0 mounting arm that is designed to attach to Campbell Scientific Instrument tripods and towers Figure 1 shows an IR120 mounted inside the shield on the end of a 009905 arm Figure 1 A picture of the IR SS with IR120 fitted To install the sensor inside the IR SS shield two nylon mounting pillars plus 6 mm screws are provided plus spares Refer to Figure 2 below This shows the sensor in place with the mounting holes pointing downwards which is the normal orientation when installed in the field To fit the sensor in the shield lay the main tube of the shield on a desk with the mounting holes facing up Rotate the sensor so the flat side of the sensor faces up too Take one of the nylon mounting pillars and place it on the flat of User Manual the sensor above the hole in the sensor nearest the cable position A so you can see the mounting hole through the centre of the pillar Carefully lift the sensor and insert it inside the shield balancing the pillar on sensor as you do so Move it into alignment with the holes in the shield so you can see the hole in the pillar through the matching hole in the shield the hole nearest to the metal threaded insert Drop one of the 20 mm n
28. rement 6 1 1 Thermistor Measurement Sensor Body Temperature The following CR1000 example shows the code required to obtain the sensor body temperature measurement from the thermistor in the IR100 sensor A 20 ms delay is used to allow adequate settling time for long cable runs BRHalf IRSensor can l mV2500 3 Vx1 1 2500 false 20000 50Hz 1 0 IRSensor resis 77020 IRSensor can 1 IRSensor can IRSensorcan temp 1 IRSensor a IRSensor b LN IRSensor resis IRSensor c LN IRSensor resis 3 273 15 A half bridge measurement is taken to obtain the ratio of the measured voltage divided by the excitation voltage from which the resistance is then calculated This resistance is then entered into the Steinhart Hart equation together with the calibration constants IRSensor_a IRSensor_b and IRSensor_c obtained during the body temperature calibration and supplied with the sensor Each sensor is individually calibrated to return a value in degrees KELVIN Note the use of a negative excitation voltage This is used because the same wire is used to power the Thermopile amplifier see next section by applying a positive voltage 6 1 2 Thermopile Detector Infrared Radiation Measurement The following CR1000 program example shows the code required to obtain a raw infrared radiation measurement from the IR 100 sensor To minimise the effect of noise on the signal the IR100 has an internal amplifier that requires a positive 2500 mV excitati
29. s 80425 F 2 00 n Exponent of 10 St 5 Z Loc IR_Exp 36 Z X Y P47 1 14 X Loc IRs_ Temp 2 AS Y Loc IR_Exp 3 14 Z Loc IRs_Temp 37 Z X F P34 1 14 X Loc IRs_ Temp Di S273 515 CE 3 20 Z Loc IRTemp_C Output array 38 If time is P92 1s 0 Minutes Seconds into a 21 Interval same units as above 33 10 Set Output Flag High Flag 0 39 Set Active Storage Area P80 mea Final Storage Area 1 23 1 Array ID 40 Average P71 dito Reps Dis 20 Loc IRTemp_C 41 Sample P70 TEE Reps 23 20 Loc IRTemp_C 7 Maintenance The sensor contains no serviceable parts When installed outside in the field though the sensor should be checked and cleaned to remove dirt or insects especially within the tube at the free end of the sensor To clean use an air duster and if absolutely necessary due to deposits on the window of the detector a cotton bud dipped in electronics grade alcohol Avoid scratching the silvered window 20 Appendix A Correction for Non Blackbody used in Campbell Scientific s Road Temperature Monitoring Equipment This appendix is added so that those wishing to understand the correction method used in IRIS and other road surface monitoring equipment may do so and to help those wishing to apply similar techniques to other applications The radiation balance model that exists on roads is as follows Radiation Balance Sensor S Radobserved Radguitdings amp trees
30. solve for remote surface temperature in Kelvin NOTE this is the UNCORRECTED value IRSensor T IRSensor T4 0 25 273 15 Combine with the correction for Emissivity and Convert to Celsius Have to assume Airtemp IRsensorcan temp in this example as no air temp measurement Airtemp IRSensorCan Temp IRTemp C IRsensor T4 Airtemp 273 15 4 1 Emissivity Emissivity 0 25 273 15 Store the results to a table CallTable IR100Data NextScan EndProg 6 4 2 CRBasic example with Emissivity and Window film correction CR1000 Program for the IR1x0 with film correction Used when the sensor is installed inside a protective housing with a transmissive film or window Calibration Data for the IR1x0 NOTE These values should match those listed on the IR100 calibration certificate Const Coeff A 9 355652E 04 Const Coeff B 2 203275E 04 Const Coeff C 1 394681E 07 Const Coeff X 2 748588E 04 Const Coeff Y 1 787100E 00 Const Coeff Z 6 923498E 02 Emissivity should be appropriate for the surface type Const Emissivity 0 94 Film IR transmission CSL measured value Const Film 0 79 Dim BR_ Res The Measured Bridge Resistance Dim IRSensor Resis Thermistor Resistance Public IRSensorCan Temp Thermistor Temperature in Celsius q Public Airtemp Used in the emissivity correction ideally measured
31. these sensors limit sensitivity to just the long wave infra red spectrum as required for infra red thermometry The IR100 has some residual sensitivity to radiation below 7 um so care should be taken with that model in particular to make sure shorter wavelength radiation such as that from the sun does not reflect off surfaces with high albedo into the sensor The IR100 will also be more sensitive to moisture in the atmosphere compared to the IR120 so the distance to the target should be minimised Beware that other housings which have a front window do reduce the sensor output and accuracy a little as a result of corrections and assumptions that need to be made to correct the readings of the sensor due to it looking through a window see Appendix A and Section 6 2 5 Principles of Measurement 5 1 Thermopile Detector 5 2 Thermistor The IR100 sensor contains a thermopile which detects the presence of thermal radiation This consists of a number of thermocouples connected in series one set being exposed to the source radiation whilst the other is shielded from it A highly polished metal cone concentrates the radiation onto the exposed junctions which are coated with lamp black to enhance the efficiency with which the radiation is absorbed The thermopile detector outputs a voltage proportional to the thermal energy balance between itself and the surface it is detecting A separate thermistor embedded in the sensor body directly behind
32. ylon screws through the hole in the shield and through the hole in the pillar Turn it gently to pick up the thread in the sensor body Check the pillar is still in place and turn the screw clockwise until it is hand tight With the sensor held by this screw pick up the shield and look into the target end Take the other mounting pillar and slide it down the flat side of the sensor until it is centred on the empty hole in the shield position B Insert the other screw through the shield and pillar and on into the sensor Screw it into the thread in the sensor Then use a screwdriver to tighten both screws without using excessive force TARGET SENSOR BODY EXTERNAL MOUNTING MOUNTING PILLARS HOLE EXTERNAL SCREW HEADS Figure 2 A cross sectional diagram of the sensor fitted inside the IR SS shield With the sensor inside the shield the shield can be mounted on a mounting arm or other rigid structure If possible mount the shield so the sun does not shine directly into the open ends of the shield hitting the sensor inside Do not block the top end of the shield which would restrict natural ventilation Figure 3 shows the shield fitted onto the IR1X0 mounting arm Note that the cable ties should be used to restrict movement of the cable The mounting arm is supplied with a long bolt which should be used with the spring washer and locking nut as shown After screwing the bolt into the shield use the locking nut to lock the shield in p
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