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Appendix A. Filter Bandwidth and Time Delay

A-3

FIGURE A-2. Frequency response comparison of the EC100 10 Hz

bandwidth and a 50 ms moving average

TABLE A-1. Filter Time Delays for Various Bandwidths

Bandwidth (Hz)

Time Delay (ms)

800

400

12.5

317

200

Hertz

0.0001

0.001

0.01

0.1

o U

EC100 10-Hz Bandwidth Filter

10-Hz Bandwidth from a 50-msec Moving Average

EC100 10-Hz Filter Compared to 20-msec Moving Average (Amplitude Responses)

Summary of Contents for IRGASON

Page 1: ...INSTRUCTION MANUAL IRGASON Integrated CO2 H2O Open Path Gas Analyzer and 3D Sonic Anemometer Revision 4 16 C o p y r i g h t 2 0 1 0 2 0 1 6 C a m p b e l l S c i e n t i f i c I n c ...

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Page 3: ...s 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 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 De...

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Page 5: ...s 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 fo...

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Page 7: ...fore beginning work Wear a hardhat and eye protection and take other appropriate safety precautions while working on or around tripods and towers Do not climb tripods or towers at any time and prohibit climbing by other persons Take reasonable precautions to secure tripod and tower sites from trespassers Use only manufacturer recommended parts materials and tools Utility and Electrical You can be ...

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Page 9: ...7 6 2 Mounting 7 6 3 Wiring and Connections 11 7 Settings 15 7 1 Factory Defaults 16 7 2 Bandwidth 16 7 3 SDM Address 16 7 4 Unprompted Output 17 7 5 Unprompted Output Rate 17 7 6 RS 485 Baud Rate 17 7 7 Analog Output 17 7 8 ECMon Update Rate 17 7 9 Temperature Sensor 17 7 10 Fixed Temperature Value 17 7 11 Pressure Sensor 18 7 11 1 Pressure Gain 18 7 11 2 Pressure Offset 18 7 11 3 Fixed Pressure ...

Page 10: ...rences 44 Appendices A Filter Bandwidth and Time Delay A 1 B Equations B 1 C Material Safety Data Sheets MSDS C 1 C 1 Magnesium Perchlorate MSDS C 1 C 2 Decarbite MSDS C 8 Figures 5 1 IRGASON dimensions side view 6 5 2 IRGASON dimensions front view 6 6 1 Exploded view of mounting the IRGASON 9 6 2 EC100 enclosure mounting bracket mounted on a vertical mast left and a tripod leg right 10 6 3 Explod...

Page 11: ... A 1 Frequency and amplitude response of EC100 filter at various bandwidths A 2 A 2 Frequency response comparison of the EC100 10 Hz bandwidth and a 50 ms moving average A 3 Tables 6 1 EC100 SDM Output to a Campbell Scientific CR1000 CR3000 or CR5000 Datalogger 14 7 1 Factory Default Settings 16 8 1 USB and RS 485 Output Elements 23 8 2 Multipliers and Offsets for Analog Outputs 25 9 1 Rain Wick R...

Page 12: ...Table of Contents iv ...

Page 13: ...t contact with the chemicals Ensure your work area is well ventilated and free of reactive compounds including liquid water Store used chemical bottles in a sealed container until disposal Dispose of chemicals and bottles properly Materials Safety Data Sheets MSDS are provided in Appendix C MSDS are updated periodically by chemical manufacturers Obtain current MSDS at www campbellsci com WARNING o...

Page 14: ... carbon dioxide and water vapor while the sonic anemometer measures orthogonal wind components The IRGASON is measured and controlled by the EC100 electronics which synchronizes gas and wind data essential for valid flux calculations using the eddy covariance method The EC100 electronics also uses inputs from an included temperature thermistor probe and a barometer IRGASON and EC100 are often used...

Page 15: ...t bandwidth2 5 10 12 5 or 20 Hz Datalogger prompted output rate 1 to 60 Hz Output rate2 10 25 or 50 Hz Operating temperature 30 to 50 C Gas analyzer Measurement precision1 CO2 density 0 2 mg m 3 0 15 µmol mol 1 H2O density 0 00350 g m 3 0 006 mmol mol 1 Factory calibrated range CO2 0 to 1000 µmol mol 1 H2O 0 mmol mol 1 to 37 C dewpoint Analyzer temp 30 to 50 C Baro pressure 70 to 106 kPa CO2 perfo...

Page 16: ...acy 30 to 0 C 3 7 kPa at 30 C falling linearly to 1 5 kPa at 0 C 0 to 50 C 1 5 kPa Measurement rate 10 Hz Optional enhanced barometer Manufacturer Vaisala Model PTB110 Accuracy 30 to 0 C 0 15 kPa Measurement rate 1 Hz IRGASON temperature sensor Manufacturer BetaTherm Model 100K6A1A Thermistor Accuracy 0 15 C 30 to 50 C 1 noise rms assumes o 25 C o 85 kPa o 14 g m 3 H2O o 597 mg m 3 CO2 o 25 Hz ban...

Page 17: ...2 mVout 102 59 Full scale range 103 to 1829 mg m 3 H2O density equation g m 3 0 00865 mVout 2 26 Full scale range 2 to 41 g m 3 1 Synchronous Device for Measurement A Campbell Scientific Inc proprietary serial interface for datalogger to peripheral and sensor communication See Section 8 1 SDM Output p 22 for details 2 user selectable 5 3 Physical Description Optical path length 15 37 cm 6 05 in So...

Page 18: ...IRGASON Integrated CO2 H2O Open Path Gas Analyzer and 3D Sonic Anemometer 6 FIGURE 5 1 IRGASON dimensions side view FIGURE 5 2 IRGASON dimensions front view ...

Page 19: ...in such as the Campbell Scientific CM202 CM204 or CM206 crossarm The following steps describe the normal mounting procedure Refer to FIGURE 6 1 1 Secure the chosen crossarm to a tripod or other vertical structure using a CM210 Crossarm to Pole Mounting Kit pn 17767 2 Point the horizontal arm into the direction of the prevailing wind and tighten the nuts and bolts Do not carry the IRGASON by the ar...

Page 20: ...ts are found in the mesh pocket inside the EC100 enclosure If the pipe does not run vertically for example if the enclosure is being attached to a leg of a tripod rotate the bracket to the side of the pipe The enclosure must hang upright Make angle adjustments as needed by loosening the four nuts and rotating the bracket plates relative to one another If the necessary angle cannot be achieved in t...

Page 21: ... 3D Sonic Anemometer 9 FIGURE 6 1 Exploded view of mounting the IRGASON Over tightening bolts will damage or deform the mounting hardware WARNING CM250 Leveling Mount pn 26559 IRGASON IRGASON Mounting Bracket pn 27496 CM20X pn 1790X or equivalent crossarm ...

Page 22: ...ted CO2 H2O Open Path Gas Analyzer and 3D Sonic Anemometer 10 FIGURE 6 2 EC100 enclosure mounting bracket mounted on a vertical mast left and a tripod leg right FIGURE 6 3 Exploded view of mounting the EC100 enclosure ...

Page 23: ...enclosure Attach the humidity indicator card to the inside of the enclosure FIGURE 6 4 Mounting the IRGASON Temperature Probe 6 3 Wiring and Connections FIGURE 6 5 FIGURE 6 6 and FIGURE 6 7 show the EC100 electronics panel the bottom of the EC100 enclosure and sensor connections to the EC100 respectively Refer to these figures during wiring and connecting 1 Find the thicker black cable coming from...

Page 24: ...t of the EC100 enclosure Insert the cable entry plug on the cable into the slot and connect the male end to the female connector labeled Sonic Anemometer on the EC100 electronics see FIGURE 6 5 The sonic cable is approximately 3 meters in length FIGURE 6 5 EC100 electronics front panel with enhanced barometer At left as received from Campbell Scientific At right all wiring and connections complete...

Page 25: ...c Anemometer 13 FIGURE 6 6 Base of EC100 enclosure Unique calibration information is stored in the gas and sonic connectors of the IRGASON rather than in the EC100 This means that any IRGASON may be used with any EC100 FIGURE 6 7 Sensor connections to EC100 NOTE ...

Page 26: ...ons signal cable to the EC100 Loosen the nut on one of the cable entry seals Cable 1 or Cable 2 on the base of the EC100 enclosure remove the plastic plug plug may be stored in mesh pocket of enclosure insert the cable and retighten the nut by hand Refer to the sections below on SDM USB RS 485 and Analog communications for information on required signal cable types and connections to the EC100 pan...

Page 27: ...er is applied to the EC100 three status LEDs on the EC100 panel will illuminate The power LED is green and the sonic and gas LEDs are orange until the unit has warmed up and is ready to make measurements at which time the LEDs become green If after several minutes the LEDs turn red a diagnostic flag has been detected Check the individual diagnostic bits to determine the specific fault Diagnostics ...

Page 28: ...o the flux will be lost The factory default bandwidth of the EC100 is 20 Hz which is sufficient for most flux applications Lower bandwidth settings may be used for higher measurement heights which inherently have lower frequency content Refer to Appendix A Filter Bandwidth and Time Delay p A 1 for more information on the digital filter options If a spectral analysis is being done to evaluate the e...

Page 29: ...115200 bps although the user may enter another value 7 7 Analog Output The EC100 has two analog outputs for CO2 and H2O densities see Section 8 3 Analog Outputs p 24 for more information These outputs may be enabled or disabled with this setting The default is for analog output to be disabled Note that the analog output does not include sonic data 7 8 ECMon Update Rate This setting determines the ...

Page 30: ... Normally Pressure Sensor is set to EC100 Basic or EC100 Enhanced and this setting is not used 7 11 3 Fixed Pressure Value If Pressure Sensor is None the EC100 will use the value of this setting for the barometric pressure This mode is intended for troubleshooting only In normal operation this setting is not used 7 12 Pressure Differential Enable This setting should remain disabled It is used only...

Page 31: ...n such as dew and frost and help the analyzer recover more quickly when precipitation has blocked the optical path Use this setting with caution Excessive heating may lead to density fluctuations and subsequent flux measurement errors More information about heater control and specifically using a datalogger for control may be found at the end of Section 10 2 EC100Configure Instruction p 37 7 14 EC...

Page 32: ...ECMon is a useful tool for common tasks such as Monitoring real time data from the IRGASON from the main window Performing manual zero and span of the instrument see Section 9 4 Zero and Span p 28 Troubleshooting and monitoring diagnostics using the Status window FIGURE 7 1 Main window of ECMon software ...

Page 33: ...ientific website www campbellsci com DevConfig requires a USB driver to communicate with the EC100 similar to ECMon See Section 7 14 ECMon p 19 for notes on installing a USB driver After launching DevConfig select EC100 from the list of device types The EC100 electronics should be connected to the PC with the EC100 USB cable pn 26563 and the appropriate USB port selected before connecting Once con...

Page 34: ...CR5000 dataloggers the SDM protocol uses SDM dedicated ports SDM C1 SDM C2 and SDM C3 On CR6 dataloggers the user must assign which set of three ports will be used for SDM This is done in the datalogger program using the SDMBeginPort programming instruction See the CR6 manual for more details Each SDM device on the SDM bus must have a unique address The IRGASON has a factory default SDM address of...

Page 35: ...arriage return and line feed TABLE 8 1 lists the elements in each output array and FIGURE 8 1 shows an example USB data feed in terminal mode TABLE 8 1 USB and RS 485 Output Elements Data Element Description Units comments 1 Ux m s 2 Uy m s 3 Uz m s 4 Sonic Temperature C 5 Sonic Diagnostic Flag 6 CO2 Density mg m 3 7 H2O Density g m 3 8 Gas Diagnostic Flag 9 Air Temperature C 10 Air Pressure kPa 1...

Page 36: ...t match the data should be disregarded Following is an example implementation of Campbell Scientific s signature algorithm in the programming language C To generate the signature of an output array of bytes the seed needs to be initialized to 0xaaaa and a pointer passed to the first byte of the output array The number of bytes in the output array should be entered in as the swath The returned valu...

Page 37: ... instruments are powered Also check the individual diagnostic bits for the specific fault See TABLE 10 2 Bits in the Sonic Diagnostic Flag and TABLE 10 3 Bits in the Gas Diagnostic Flag 9 2 Wick Maintenance 9 2 1 Sonic Wicks The IRGASON cannot measure wind when water droplets completely obscure the face of the sonic transducers If the site experiences frequent rainfall using wicks on the sonic tra...

Page 38: ...proper position The top wick must be flush with the transducer face with the wick tail located at the lowest point of the transducer see FIGURE 9 1 The end of the bottom transducer wick must extend above the transducer face by one half to one mesh line see FIGURE 9 1 Secure the wicks to the transducer with a drop of adhesive which is provided in the CSAT3 Sonic Wick Spares Kit pn 28902 Take care t...

Page 39: ...N WICK TOP The top wick has a short seam which has to be aligned with the short side of the top snout The angled edge of the wick must closely follow the edge of the window without encroaching on the optical path see FIGURE 9 3 Proper location of the sonic top wick and bottom wick The bottom wick is installed in a similar manner except the long seam should be aligned with the long side of the bott...

Page 40: ...ironmental conditions in which the instrument is making measurements Campbell Scientific recommends that a new instrument or an instrument that has been moved to a new location should have a monthly zero and span procedure performed Additionally it is recommended to always zero and span the analyzer after cleaning the windows see Section 9 3 Gas Analyzer Window Cleaning p 28 After the first severa...

Page 41: ...y To check and then set the IRGASON zero and span follow the steps below 1 Remove power from the EC100 2 If not already done clean the windows and snouts with alcohol and a non scratching tissue or cloth Make sure the alcohol and any residual water completely evaporate from the analyzer before proceeding with the zero and span procedure 3 As shown in FIGURE 9 4 position the IRGASON zero and span s...

Page 42: ...w be reporting real time CO2 and H2O concentrations Click Zero Span A graph will appear in the lower half of the zero and span window showing measured CO2 and H2O concentrations see FIGURE 9 5 8 Connect a gas tank of known CO2 concentration to a pressure regulator then to a flow controller and finally to the intake of the shroud Optimally the concentration of span CO2 should be near the concentrat...

Page 43: ...he shroud it may take many minutes for the H2O concentration to stabilize If desired increase the flow rate for the first several minutes to more quickly stabilize the system before returning it to between 0 4 and 0 6 l min to make the H2O measurement Write down the reported H2O concentration 10 Remove the H2O span gas and connect a zero air source no CO2 or H2O to the inlet tube of the shroud As ...

Page 44: ... into the shroud should be close to the recommended rate If the flow is too low the shroud will not be properly flushed if it is too high the air pressure within the shroud will be too high and the analyzer will not be zeroed and spanned properly 13 Remove the zero air source and replace it with the CO2 span gas Allow the gas to flow through the shroud maintaining a flow between 0 4 and 0 6 l min ...

Page 45: ...dizing agents Avoid direct contact with the chemicals inside the bottles Also ensure your work area is well ventilated and free of any reactive compounds including liquid water Store used chemical bottles in a sealed container until disposal The chemical bottles should be disposed of according to local and federal regulations For more information MSDS Material Safety Data Sheets for the chemicals ...

Page 46: ...ind Offset available at www campbellsci com When recalibration is deemed necessary contact Campbell Scientific 10 Datalogger Programming The datalogger is programmed in the CRBasic language which features two instructions for communication with the EC100 via SDM The first instruction is EC100 which reads measurement data from the EC100 The second is the EC100Configure which receives and sends conf...

Page 47: ... values Sonic Diagnostic Flag and Gas Diagnostic Flag The values contain a bit field with each bit representing a monitored condition When a certain condition is detected the corresponding bit is set The value remains set until the event that caused the condition is no longer present TABLE 10 2 and TABLE 10 3 describe the bits in the sonic diagnostic flag and the gas diagnostic flag respectively T...

Page 48: ... powered 9 0x200 512 Chan Err Gas input data out of sync with home pulse 10 0x400 1024 Amb Temp Invalid ambient temperature 11 0x800 2048 Amb Press Invalid ambient pressure 12 0x1000 4096 CO2 I CO2 I exceeds limits 13 0x2000 8192 CO2 Io CO2 Io exceeds limits 14 0x4000 16384 H2O I H2O I exceeds limits 15 0x8000 32768 H2O Io H2O Io exceeds limits 16 0x10000 65536 CO2 Io Var Moving variation in CO2 I...

Page 49: ...nd code 99 can then be sent to the IRGASON The DestSource parameter variable should be set to 2718 to save the settings The reception of this command is acknowledged but since it takes up to a second to complete a successful return code does not mean that all data were successfully written to the appropriate non volatile memory The instruction syntax is EC100Configure Result SDMAddress ConfigCmd D...

Page 50: ...stor 2 EC155 Sample Cell Thermocouple 3 None use fixed value 4 Auto Select 8 108 Fixed Temperature Value 9 109 Unprompted Output Mode 0 Disable 1 USB 2 RS 485 10 110 RS 485 Baud Rate 11 111 Span Zero Control 0 Inactive 1 Zero 2 Span CO2 3 Span H2O see Section 10 2 1 ConfigCmd 11 Zero and span Control p 39 12 112 CO2 Span Concentration 13 113 H2O Span Dewpoint Temperature 14 114 CO2 Zero Coefficien...

Page 51: ...ing the heater voltage ConfigCmd 218 allows EC100Configure to operate in the SDM task thus avoiding skipped scans When using ConfigCmd 218 the command must be a constant and the instruction cannot be placed in a conditional statement The IRGASON includes heaters near the optical windows This setting gives the voltage applied to the heater It can be set to 1 to disable the heater or set it to any v...

Page 52: ...a 5 diag_sonic Alias sonic_irga 6 CO2 Alias sonic_irga 7 H2O Alias sonic_irga 8 diag_irga Alias sonic_irga 9 cell_tmpr Alias sonic_irga 10 cell_press Alias sonic_irga 11 CO2_sig_strgth Alias sonic_irga 12 H2O_sig_strgth Units Ux m s Units Uy m s Units Uz m s Units Ts C Units diag_sonic arb Units CO2 mg m 3 Units H2O g m 3 Units diag_irga arb Units cell_tmpr C Units cell_press kPa Units CO2_sig_str...

Page 53: ...he time of flight of the first signal out is given by t d c u o a 1 and the time of flight of the second signal back is given by t d c u b a 2 where to is the time of flight out along the transducer axis tb is the time of flight back in the opposite direction ua is the wind speed along the transducer axis d is the distance between the transducers and c is the speed of sound The wind speed ua along...

Page 54: ...he total mass of air Kaimal and Gaynor 1991 Wallace and Hobbs 1977 Note that γ is a function of specific humidity It would be convenient if the effects of humidity could be consolidated into one term The specific heats for moist air at constant pressure and volume are given by Cp qC q C pw pd 1 C q pd 1 0 84 7a Cv qC q C vw vd 1 C q vd 1 0 93 7b where Cp and Cv are the specific heats of moist air ...

Page 55: ...ed using interference filters located on a spinning chopper wheel For CO2 light with a wavelength of 4 3 µm is selected as it corresponds to the molecule s asymmetric stretching vibrational band For H2O radiation at 2 7 µm corresponding to water s symmetric stretching vibrational band is used The IRGASON gas analyzer is a dual wavelength single beam analyzer thus rather than using a separate refer...

Page 56: ...J A 1980 An Introduction to Atmospheric Physics Academic Press Inc New York Liu H Peters G and Foken T 2001 New Equations for Sonic Temperature Variance and Buoyancy Heat Flux with an Omnidirectional Sonic Anemometer Boundary Layer Meteorol 100 459 468 Schotanus P Nieuwstadt F T M and de Bruin H A R 1983 Temperature Measurement with a Sonic Anemometer and its Application to Heat and Moisture Fluxe...

Page 57: ...lculations inherently reduce noise and second aliasing does not degrade the accuracy of covariance calculations Therefore the factory default for the EC100 bandwidth 20 Hz is rather wide to preserve the signal variations that transport flux and that bandwidth is suitable for most flux applications Additional bandwidths are available for experimenters desiring to match the EC100 filter bandwidth to...

Page 58: ...ll data acquisition system the EC100 down samples its USB and RS 485 outputs to a user selectable rate of 10 25 or 50 Hz Although the gas and wind data from the EC100 remain synchronized the user must consider the down sampled output interval when synchronizing the EC100 data with other measurements in their system These slower output intervals increase the asynchronicity of EC100 data with other ...

Page 59: ...0 ms moving average TABLE A 1 Filter Time Delays for Various Bandwidths Bandwidth Hz Time Delay ms 5 800 10 400 12 5 317 20 200 1 10 70 Hertz 0 0001 0 001 0 01 0 1 1 10 No Units EC100 10 Hz Bandwidth Filter 10 Hz Bandwidth from a 50 msec Moving Average EC100 10 Hz Filter Compared to 20 msec Moving Average Amplitude Responses ...

Page 60: ...Appendix A Filter Bandwidth and Time Delay A 4 ...

Page 61: ...elative to dry air mmol mol 1 c M Molecular Weight of CO2 44 mg mmol 1 d M Molecular weight of dry air 0 029 g mmol 1 v M Molecular weight of H2O 0 018 g mmol 1 P Ambient Pressure kPa R Universal Gas Constant 8 3143 10 6 kPa m3 K 1 mmol 1 T Ambient Temperature C e Vapor Pressure kPa f Enhancement Factor Arbitrary d T Dew Point Temperature C tmp d T _ Temporary variable for dew point calculation Ar...

Page 62: ...apor Mass Density from Dew Point d d v T T EXP T R f 97 240 502 17 15 273 61121 0 018 0 ρ B 112 Vapor Pressure from Molar Mixing Ratio and Water Vapor Density v v X P X e 1000 B 12 v v M T R e 15 273 ρ B 13 1 Leuning R 2004 Measurements of Trace Gas Fluxes in the Atmosphere Using Eddy Covariance WPL Revisited The Handbook of Micrometeorology 29 119 132 New York Kluwer Academic Publishers Eq 6 23 2...

Page 63: ... are available for chemicals used in IRGASON filters The MSDS samples below are made available for convenience However chemical manufacturers may change MSDS at any time Up to date MSDS are available at www campbellsci com C 1 Magnesium Perchlorate MSDS ...

Page 64: ...Appendix C Material Safety Data Sheets MSDS C 2 ...

Page 65: ...Appendix C Material Safety Data Sheets MSDS C 3 ...

Page 66: ...Appendix C Material Safety Data Sheets MSDS C 4 ...

Page 67: ...Appendix C Material Safety Data Sheets MSDS C 5 ...

Page 68: ...Appendix C Material Safety Data Sheets MSDS C 6 ...

Page 69: ...Appendix C Material Safety Data Sheets MSDS C 7 ...

Page 70: ...Appendix C Material Safety Data Sheets MSDS C 8 C 2 Decarbite MSDS ...

Page 71: ...Appendix C Material Safety Data Sheets MSDS C 9 ...

Page 72: ...Appendix C Material Safety Data Sheets MSDS C 10 ...

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Page 74: ...Rua Apinagés nbr 2018 Perdizes CEP 01258 00 São Paulo SP BRASIL www campbellsci com br vendas campbellsci com br Campbell Scientific Canada Corp 14532 131 Avenue NW Edmonton AB T5L 4X4 CANADA www campbellsci ca dataloggers campbellsci ca Campbell Scientific Centro Caribe S A 300 N Cementerio Edificio Breller Santo Domingo Heredia 40305 COSTA RICA www campbellsci cc info campbellsci cc Campbell Sci...

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