Campbell CSAT3 Instruction Manual Download

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Appendix C. CSAT3 Measurement Theory

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Summary of Contents for CSAT3

Page 1: ...CSAT3 Three Dimensional Sonic Anemometer Revision 9 12 C o p y r i g h t 1 9 9 8 2 0 1 2 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: ...removing reinstalling and shipping defective products to Campbell Campbell will return such products by surface carrier prepaid within the continental United States of America To all other locations Campbell will return such products best way CIP Port of Entry INCOTERM 2010 prepaid This warranty shall not apply to any products which have been subjected to modification misuse neglect improper servi...

Page 4: ...ng container Campbell Scientific s shipping address is CAMPBELL SCIENTIFIC INC RMA _____ 815 West 1800 North Logan Utah 84321 1784 For all returns the customer must fill out a Statement of Product Cleanliness and Decontamination form and comply with the requirements specified in it The form is available from our web site at www campbellsci com repair A completed form must be either emailed to repa...

Page 5: ...M Address 5 4 Installation 5 4 1 Orientation 5 4 2 Mounting 6 4 3 Leveling 8 4 4 Fine Wire Thermocouple 8 5 Wiring 8 6 CSAT3 Outputs 11 6 1 SDM Output 11 6 1 1 CRBasic Dataloggers 12 6 1 2 EDLOG Dataloggers 12 6 1 3 CR9000 12 6 2 RS 232 Output 13 6 3 Analog Output 13 7 Operational Principles 13 7 1 Embedded Code Version 4 13 7 2 Embedded Code Version 3 14 7 3 Effects of Crosswind on the Speed of S...

Page 6: ...ientation A 1 A 2 Online Magnetic Declination Calculator A 3 B Serial Communications with the CSAT3 B 1 B 1 CSAT3 RS 232 Commands B 1 B 2 CSAT3 Binary Data Output Format B 3 B 3 Words 0 through 3 B 4 B 4 Word 4 B 5 B 5 CSAT3 RS 232 Status Format B 5 C CSAT3 Measurement Theory C 1 C 1 Theory of Operation C 1 C 1 1 Wind Speed C 1 C 1 2 Temperature C 1 D SDM Communications and Long Signal Cables D 1 ...

Page 7: ...ng Scheme 5 5 1 CSAT3 Power 9 5 2 CSAT3 SDM Output to a CR3000 CR5000 and CR9000X Datalogger 9 5 3 CSAT3 SDM Output to a CR1000 CR800 850 CR23X and CR10 X Datalogger 9 5 4 CSAT3 SDM Output to a 21X Datalogger 10 5 5 CSAT3 SDM Output to a CR9000 Datalogger 10 5 6 CSAT3 RS 232 Output Pin Out 10 5 7 CSAT3 Analog Output Wiring 10 5 8 FW05 FWC L35 Fine Wire Thermocouple 11 6 1 CSAT3 Outputs 11 6 2 SDM ...

Page 8: ...Table of Contents iv D 1 Data from Example CR3000 SDM Clock Rate Search Program D 2 D 2 Data from Example CR23X SDM Clock Rate Search Program D 3 D 3 SDM Clock Rate Report D 3 ...

Page 9: ...nications and a Campbell Scientific Inc datalogger All Campbell Scientific dataloggers that support the CSAT3 SDM instruction do so without a special operating system with the exception of the 21X and CR10 see TABLE 6 2 for compatible dataloggers The fine wire thermocouple used with the CSAT3 is the FW05 It is a 0 0005 diameter thermocouple mounted on a stainless steel bayonet A FWC L35 cable is r...

Page 10: ...ade of a constant signal The noise is unaffected by the sample rate OPERATING TEMPERATURE RANGE 30 to 50 C standard 40 to 40 C cold shifted ACCURACY 30 to 50 C and 40 to 40 C operating range wind speed 30 m s 1 azimuth angles between 170 Offset Error ux uy 8 cm s 1 uz 4 cm s 1 Gain Error Wind vector within 5 of horizontal 2 percent of reading Wind vector within 10 of horizontal 3 percent of readin...

Page 11: ...m s 1 uz 8 192 m s 1 4 mm s 1 c 300 to 366 m s 1 16 mm s 1 50 to 60 C 0 026 C 2 3 Physical Description MEASUREMENT PATH LENGTH 10 0 cm vertical 5 8 cm horizontal TRANSDUCER PATH ANGLE FROM HORIZONTAL 60 degrees TRANSDUCER 0 64 cm 0 25 in diameter TRANSDUCER MOUNTING ARMS 0 84 cm 0 33 in diameter SUPPORT ARMS 1 59 cm 0 63 in diameter DIMENSIONS Anemometer Head 47 3 cm l x 42 4 cm h 18 6 in x 16 7 i...

Page 12: ...er Source Internal Clock see Section 8 9 and B 1 SDM Address 3 see Section 3 2 6 1 and 10 3 RS 232 baud rate 9600 bps RS 0 see Section 12 and Appendix B Software RTS Off RI 0 see Section 12 and Appendix B Unprompted Output Off 0 see Appendix B The above settings can be changed with a PC running the CSAT3 PC support software CSAT32 EXE and the RS 232 cable A copy of the CSAT3 PC support software is...

Page 13: ...ess F on the CSAT3 s CPU board TABLE 3 1 SDM Addressing Scheme CRBasic Datalogger Address base 10 EDLOG Datalogger Address base 4 CSAT3 Thumb Switch hexadecimal 0 00 0 1 01 1 2 02 2 3 03 3 4 10 4 5 11 5 6 12 6 7 13 7 8 20 8 9 21 9 10 22 A 11 23 B 12 30 C 13 31 D 14 32 E 4 Installation 4 1 Orientation The three components of wind are defined by a right handed orthogonal coordinate system The CSAT3 ...

Page 14: ...te up to a 1 outside diameter pipe Attach the crossover fitting to the vertical pipe and lightly tighten the vertical set screws Insert the horizontal mounting arm into the crossover fitting and lightly tighten the horizontal set screws Point the horizontal arm into the prevailing wind Tighten all the fitting set screws Mount the anemometer head to the horizontal arm Lightly tighten the bolt under...

Page 15: ... S N 102 MADE IN USA 60 o FIGURE 4 2 CSAT3 coordinate system and captive mounting hardware s n 0631 to current 10 00 cm Y Z X Logan Utah CSAT3 3 D SONIC ANEMOMETER S N 102 MADE IN USA 60 o FIGURE 4 3 CSAT3 coordinate system captive mounting hardware and cup washer s n 0107 to 0630 8915 CSAT3 Boom ...

Page 16: ...the side of the anemometer block to measure temperature fluctuations Attach the female connector from the FWC L35 to the side of the anemometer with the short screw 2 56 0 437 p n 3514 that was provided with the thermocouple cover Insert the male connector of the FW05 into the female connector of the FWC L35 Finally attach the thermocouple cover to the anemometer block using the thumb screw so tha...

Page 17: ...rivers independent of the RTS line Spark gaps model 6536 and 6361 may be required to protect against transients when using wire short haul modems Spark gap protection is not needed with fiber optic short haul modems TABLE 5 1 CSAT3 Power Battery Terminal Description Color Pin Positive 12 Vdc Red A Negative Power Reference Black B TABLE 5 2 CSAT3 SDM Output to a CR3000 CR5000 and CR9000X Datalogger...

Page 18: ...ger Description Color Pin 8 SDM Data Green D 7 SDM Clock White C 6 SDM Enable Brown E 2 Digital Ground Black Clear F nc TABLE 5 6 CSAT3 RS 232 Output Pin Out CSAT3 DCE DB9 Pin PC DTE DB9 Pin Color Pin 2 TxD 2 RxD Red B 3 RxD 3 TxD White C 5 gnd 5 gnd Green E 7 CTS 7 RTS Brown G 8 RTS 8 CTS Black H TABLE 5 7 CSAT3 Analog Output Wiring Description Color Pin ux sig high Brown A ux sig low Black E uy ...

Page 19: ...ations has the following advantages lowest CSAT3 current drain best control and diagnostics and highest data resolution TABLE 6 1 CSAT3 Outputs SDM RS 232 Analog Typical Current Drain 10 Hz 51 mA 12 Vdc 89 mA 12 Vdc 99 mA 12 Vdc External Trigger Source yes yes no Output Dynamic Range 19 bit 19 bit 12 bit Diagnostics Available yes yes no 6 1 SDM Output SDM is a Campbell Scientific communication pro...

Page 20: ... measurement and rapid communication between a datalogger and the CSAT3 The CRBasic datalogger instruction CSAT3 is used to communicate with the CSAT3 over the SDM bus 6 1 2 EDLOG Dataloggers SDM is a Campbell Scientific communication protocol used between a Campbell Scientific dataloggers and a smart sensor This protocol uses SDM dedicated control ports CR23X or multipurpose control ports 21X or ...

Page 21: ...65 536 m s 1 These ranges are changed using the support software Low range is adequate to measure wind speeds 32 768 m s 1 TABLE 6 3 gives the multipliers and offset for all the anemometer outputs in m s 1 TABLE 6 3 Calibration for Analog Outputs Slope Low Range m s 1 V 1 Slope High Range m s 1 V 1 Offset m s 1 ux 6 5536 13 1072 0 uy 6 5536 13 1072 0 uz 1 6384 1 6384 0 c 6 5536 6 5536 340 When ana...

Page 22: ...ot use simple threshold detection to determine the ultrasonic times of flight Instead it uses advanced digital signal processing techniques and pattern recognition algorithms which in comparison to other systems results in more accurate lower noise measurements The pattern recognition algorithms allow the system to quickly detect and indicate a degradation of signal quality and system performance ...

Page 23: ...atching it to the trigger frequency are discussed in Section 8 7 3 Effects of Crosswind on the Speed of Sound The speed of sound is found by combining the out and back time of flight measurements see Eq 5 in Appendix C The parallel component of the wind along the sonic axis does not affect the measured speed of sound however the perpendicular component does The effects of the perpendicular compone...

Page 24: ...than or equal to the Execution Parameter This is because as discussed above the Execution Parameter is used to define how much the wind speed could have changed from the previous reading If the anemometer is triggered too slowly under gusty conditions it is possible that the CSAT3 sets its search window to a point in time which misses the ultrasonic pulse This will give erroneous readings Converse...

Page 25: ...pling Modes The CSAT3 can be configured to make measurements in either a single measurement mode or an oversampled mode In the single measurement mode the CSAT3 makes one measurement synchronously with the trigger provided by the CSAT3 internal trigger SDM communications or RS 232 communications In the oversampled mode the CSAT3s internal trigger SDM communications or RS 232 communication trigger ...

Page 26: ...mode the CSAT3 interpolates six minor triggers that are centered on the 10 Hz master trigger In the three times oversample mode the CSAT3 interpolates three minor triggers that are centered on the 20 Hz master trigger For compatibility with the existing single sampled modes the block averaged output data have a fixed delay of two periods of the master trigger 9 Data Pipeline Delay When the CSAT3 i...

Page 27: ...0 3 TABLE 10 2 SDM CSAT3 P107 Instruction Parameters Parameter Number Data Type Default Description 01 2 Reps 02 2 SDM Address 03 2 Option 04 4 Ux Input Location 10 3 Datalogger Instruction Parameters Dest The destination variable to store the first of five data values to a CRBasic datalogger The variable must be declared as a float default with at least five elements The CSAT3 returns the followi...

Page 28: ...logger Command Option 92 Trigger and Get Wind c 340 Data sends a measurement trigger to the CSAT3 whose SDM address is specified in SDMAddress SDM Address parameter The CSAT3 also sends wind speed and the speed of sound minus 340 m s 1 via the SDM bus to the datalogger Command Option 97 Get Wind and c 340 Data After a Group Trigger The CSAT3 specified in SDMAddress SDM Address parameter sends wind...

Page 29: ...r tells the CSAT3 to oversample Section 8 1 2 the wind measurements at a rate of 48 Hz and expect a trigger at a rate of 8 Hz option 51 or 16 Hz option 52 from a CR10 X datalogger TABLE 10 3 CR3000 CR1000 CR5000 CR800 850 CR9000 X CR23X and 21X Execution Interval and CSAT3 Execution Parameter Datalogger Execution Interval seconds Datalogger Execution Frequency Hz CSAT3 Execution Parameter 0 05 20 ...

Page 30: ...6 bits 11 through 6 represent the range the measurements are reported in used by the datalogger and bits 5 through 0 are a counter A detailed description of decoding the diagnostic word is given in Appendix B TABLE 10 5 Diagnostic Word Diagnostic Word b15 b12 b11 b10 b09 b08 b07 b06 b05 b00 diagnostic flags ux range uy range uz range counter The following are four specific Diagnostic Words Base 10...

Page 31: ...gh Description Comment b15 Difference in the speed of sound between the three non orthogonal axes is greater than 2 360 m s 1 4 C 25 C The anemometer path length may have been altered or the anemometer head is broken b14 Poor signal lock There may be an obstruction in the anemometer path or on the transducer face b13 Sonic signal amplitude too high An obstruction in the anemometer path or on the t...

Page 32: ...mpbell Scientific Inc All rights reserved The following sensors are measured CSAT3 three dimensional sonic anemometer The site attendant must load in several constants and calibration values Search for the text string unique to find the locations where unique constants and calibration values are entered PipeLineMode Constants Measurement Rate 10 Hz Const SCAN_INTERVAL 100 100 mSec Output period Co...

Page 33: ... clock speed Variables Online lagged CSAT3 data Public wind 5 Alias wind 1 Ux Alias wind 2 Uy Alias wind 3 Uz Alias wind 4 Ts Alias wind 5 diag_csat Units Ux m s Units Uy m s Units Uz m s Units Ts C Units diag_csat unitless Public diag_bits 4 AS Boolean Warning flags Alias diag_bits 1 del_T_f Delta temperature warning flag Alias diag_bits 2 sig_lck_f Poor signal lock warning flag Alias diag_bits 3...

Page 34: ...umber of samples in the online stats Units n samples Working variables Dim wind_east East wind in compass coordinate system Dim wind_north North wind in compass coordinate system Dim diag_csat_work AS Long Final Output Data Tables Online stats data DataTable stats TRUE 1 DataInterval 0 OUTPUT_INTERVAL Min 10 Average 1 Ts IEEE4 disable_flag_on 1 StdDev 1 Ts IEEE4 disable_flag_on 1 Average 1 Ux IEEE...

Page 35: ...every OUTPUT_INTERVAL minutes DataTable wnd_vec TRUE 1 DataInterval 0 OUTPUT_INTERVAL Min 1 Compute wind direction from CSAT3 data WindVector 1 wind_east wind_north IEEE4 disable_flag_on 1 0 1 2 WindVector 1 Uy Ux IEEE4 disable_flag_on 1 0 1 2 EndTable Program BeginProg n 1 Set all CSAT3 variables to NaN Move Ux 5 NaN 1 Set the SDM clock speed SDMSpeed SDM_PER Scan SCAN_INTERVAL mSec 3 0 CRBasic d...

Page 36: ...gnificant bits of the CSAT3 diagnostics except for the special cases NaN 61502 a Lost Trigger 61440 No Data 61503 an SDM error 61441 or wrong CSAT3 embedded code 61442 If diag_csat_work hf000 Then diag_csat INT diag_csat_work h1000 Compute the online wind vector statistics CallTable wnd_vec If wnd_vec Output 1 1 Then GetRecord wnd_out 1 wnd_vec 1 Compass wind direction will be between 0 and 360 de...

Page 37: ...lear G Power Red 12 Vdc Power Refernece Black G Power Shield Clear G EXAMPLE 2 Measuring the CSAT3 Using the SDM Output and a CR23X Datalogger CR23X 22 April 2001 Copyright c 2001 Campbell Scientific Inc All rights reserved Flags Flag 1 Set low default to configure the CSAT3 Set high after CSAT3 is configured Compass coordinate system Right handed coordinate system theta N x CSAT3 Transducers W y ...

Page 38: ...l seconds Get the data from the CSAT3 1 SDM CSAT3 P107 1 1 Reps 2 3 SDM Address 3 91 Trigger and Get wind Ts data 4 1 Ux Input Location Ux Configure the CSAT3 2 Do P86 1 1 Call Subroutine 1 Change the CSAT3 Ux and Uy to instantaneous compass wind direction 3 Z X P31 1 1 X Loc Ux 2 11 Z Loc Prop_N 4 Z X F P37 1 2 X Loc Uy 2 1 F 3 9 Z Loc Prop_E Copy the CSAT3 Ux and Uy instantaneous wind to compute...

Page 39: ...Storage Area P80 1 3 Input Storage Area 2 13 Loc wnd_spd_a Compute the horizontal wind speed and wind direction in the compass coordinate system and in the CSAT3 right handed orthogonal coordinate system 12 Wind Vector P69 1 2 Reps 2 0 Samples per Sub Interval 3 10 S θ1 σ θ1 Orth 4 9 Wind Speed East Loc Prop_E 5 11 Wind Direction North Loc Prop_N 13 Do P86 1 29 Set Intermed Proc Disable Flag Low F...

Page 40: ...Totalize P72 1 7 Reps 2 20 Loc smpls Table 2 Program 02 0 Execution Interval seconds Table 3 Subroutines Configure CSAT3 1 Beginning of Subroutine P85 1 1 Subroutine 1 Check the diagnostic word for lost trigger condition Set Flag 1 low to reconfigure the CSAT3 if it is in a lost trigger state 2 If X F P89 1 5 X Loc diag 2 1 3 61440 F 4 21 Set Flag 1 Low Configure the CSAT3 This is done the first t...

Page 41: ...F P30 1 16384 F 2 0 Exponent of 10 3 32 Z Loc _4000h 7 Z F P30 1 8192 F 2 0 Exponent of 10 3 33 Z Loc _2000h 8 Z F P30 1 4096 F 2 0 Exponent of 10 3 34 Z Loc _1000h Look for a diag that is not 99999 meaning that the CSAT3 is connected to the CR23X and the two devices are communicating correctly 9 If X F P89 1 5 X Loc diag 2 3 3 0 F 4 30 Then Do Send the configuration command to the CSAT3 only if i...

Page 42: ... values of one or zero 17 Beginning of Subroutine P85 1 2 Subroutine 2 Set the flags low set each flag s input location 0 before recording the number of samples Not a Number NaN or diagnostic flags that were on 18 Block Move P54 1 7 No of Values 2 19 First Source Loc zero 3 1 Source Step 4 20 First Destination Loc smpls 5 1 Destination Step 19 If Flag Port P91 1 19 Do if Flag 9 is High 2 30 Then D...

Page 43: ... Exponent of 10 3 26 Z Loc F03F_f 28 Else P94 Set the delta temp del_T_f tracking track_f amplitude high amp_h_f or amplitude low amp_l_f flag high if the CSAT3 is reporting those flags as set 29 Beginning of Loop P87 1 0 Delay 2 4 Loop Count 30 If X Y P88 1 30 X Loc diag_work 2 3 3 31 Y Loc _8000h 4 30 Then Do 31 Z F P30 1 1 F 2 0 Exponent of 10 3 22 Z Loc del_T_f 32 Z X Y P35 1 30 X Loc diag_wor...

Page 44: ...irection is positive 40 If X F P89 1 14 X Loc cmpss_dir 2 4 3 0 F 4 30 Then Do 41 Z X F P34 1 14 X Loc cmpss_dir 2 360 F 3 14 Z Loc cmpss_dir 42 End P95 Ensure that the compass wind direction cmpss_dir falls between 0 and 360 degrees 43 Z X MOD F P46 1 14 X Loc cmpss_dir 2 360 F 3 14 Z Loc cmpss_dir Ensure that the csat3 wind direction csat_dir falls between between 180 and 180 degrees 44 If X F P...

Page 45: ...______ 28 _________ 29 _________ 30 diag_work 31 _8000h 32 _4000h 33 _2000h 34 _1000h 35 theta 36 diag_abs 11 Maintenance The CSAT3 like other ultrasonic anemometers is unable to measure wind when water droplets completely obscure the face of the transducers The wicks help remove some of the water however under some conditions may not be adequate The CSAT3 will be ready to measure wind as soon as ...

Page 46: ...e point where the transducer face will be obscured The CSAT3 Sonic Wick Spares Kit p n 28902 consists of three top wicks three bottom wicks adhesive and an installation tool see FIGURE 11 2 The installation tool is used by placing a wick over the angled end of the tool placing the straight end of the tool gently against the transducer face and sliding the wick down the tool onto the transducer Whe...

Page 47: ...ons or it will set diagnostic flags under dry conditions with little to no wind and with no obstruction in the ultra sonic paths CSAT3s running embedded code version 4 will develop the offset first and then possibly set diagnostic flags under dry conditions CSAT3s running embedded code version 3 will set diagnostic flags before a wind offset develops 11 2 1 Cold Shifted Calibration A CSAT3 with a ...

Page 48: ...medium 13 gallon kitchen waste bin liner Fold tape or tie closed the opening of the liner to prevent air from moving in and out of the liner Ensure that the liner does not obstruct any of the three CSAT3 sonic paths Connect the CSAT3 power cable to a 12 Vdc power supply Connect the CSAT3 s RS 232 port to the PC s RS 232 port using the RS 232 cable that shipped with the CSAT3 This cable was origina...

Page 49: ...s labels Collect and graph 1 minute of wind data from the CSAT3 while it is in the zero wind environment FIGURE 11 6 The wind offset should be less than 4 cm s 1 0 04 m s 1 for ux and uy and less than 2 cm s 1 0 02 m s 1 for uz If the CSAT3 wind offset is greater than these specifications contact Campbell Scientific Inc for an RMA number to recalibrate the CSAT3 ...

Page 50: ...ecommunications software you will have to issue the T command to enter the terminal mode and the D command to return to the normal operating mode data mode Back door commands will not be accepted by the CSAT3 if it is communicating with a Campbell Scientific datalogger via SDM The SDM communications must first be terminated by shutting down the program turning off the datalogger or disconnecting t...

Page 51: ... n 0 means the CSAT3 will not send the synchronization code and n 1 means the CSAT3 will send the synchronization code at the end of the 10 byte RS 232 output BR n Baud Rate n 0 is 9600 bps and n 1 is 19200 bps RI n Rts Independent n 0 means power the RS 232 drivers if the RTS line is asserted and n 1 means to always power the RS 232 drivers SNnnnn Serial Number of the calibration file stored in E...

Page 52: ...cs box lid is pointing towards the ceiling These instructions reference the location of various components as top bottom left and right The Campbell Scientific logo is in the top left corner of the electronics box lid Loosen the four electronics box cover retaining screws with the large Phillips screw driver Remove the electronics box cover to gain access to the printed circuit board Locate the CS...

Page 53: ...ic declination where the magnetic declination is the number of degrees between True North and Magnetic North Magnetic declination for a specific site can be obtained from a USGS map local airport or through a NOAA web calculator Section A 2 A general map showing magnetic declination for the Conterminous United States in 2004 is shown in FIGURE A 1 FIGURE A 1 Magnetic declination for the contermino...

Page 54: ...s shown in FIGURE A 3 Note that when a negative number is subtracted from a positive number the resulting arithmetic operation is addition For example the declination for Longmont CO 10 June 2006 is 9 67 thus True North is 360 9 67 or 350 33 as read on a compass Likewise the declination for Mc Henry IL 10 June 2006 is 2 68 and True North is 0 2 68 or 2 68 as read on a compass FIGURE A 2 A declinat...

Page 55: ...dels Declination jsp After the web page loads enter the site zip code or longitude and latitude then click on the Compute Declination button FIGURE A 4 FIGURE A 4 USGS web calculator The declination for Logan UT is 12 4 degrees 3 June 2010 As shown in FIGURE A 4 the declination for Utah is positive east of north so true north for this site is 360 12 4 or 347 6 degrees The annual change is 7 minute...

Page 56: ...Appendix A CSAT3 Orientation A 4 ...

Page 57: ...rompted output mode TABLE B 1 complicates anemometer data processing software because the original output format contains no fixed pattern to delimit the CSAT3 s 10 byte output record To configure the CSAT3 to output 12 byte records with the last two bytes being a fixed pattern of AA55 hex send an rs n where n 0 default means no synchronization code and n 1 means send the synchronization code to t...

Page 58: ...timer Turn the analog outputs on with 32 m s 1 full scale range in sync with the next trigger No change H SDM PC or CSAT3 timer Turn the analog outputs on with 64 m s 1 full scale range in sync with the next trigger No change 1 The CSAT3 will ignore this command if a datalogger SDM is triggering the anemometer 2 After the PC takes over as the trigger source it must continue to trigger the CSAT3 at...

Page 59: ...asurements sent the U or P command set timer to zero send the An command to acquire signals until CTS line is high read CTS line set RTS line high FIGURE B 1 PC as the trigger source set RTS line low repeat until finished collecting data process data send W or S command read wind data W or long status S from serial port keep checking until there is data on the serial port check for data serial por...

Page 60: ...Output Resolution b11 b10 mm s 1 0 1 1 ux wind m s 1 word 0 0 001 0 25 0 25 1 1 0 ux wind m s 1 word 0 0 001 0 50 0 50 2 0 1 ux wind m s 1 word 0 0 001 1 00 1 00 3 0 0 ux wind m s 1 word 0 0 001 2 00 2 00 TABLE B 4 Converting uy Wind from Word 1 Range Word 4 Range Code Conversion Output Resolution b09 b08 mm s 1 0 1 1 uy wind m s 1 word 1 0 001 0 25 0 25 1 1 0 uy wind m s 1 word 1 0 001 0 50 0 50 ...

Page 61: ...eter path or on the transducer face was removed b12 Sonic signal amplitude too low There may be an obstruction in the anemometer path or on the transducer face Bits b11 through b06 are used in determining the range of the wind speed reported in words 0 through 2 Bits b05 through b00 are a diagnostic counter This counter increments once per measurement The minimum value is 0 and the maximum is 63 T...

Page 62: ...nd Byte Description Value 0 Trigger Source 0 CSAT3 Timer 1 PC 2 SDM 1 Execution Parameter see TABLE B 1 2 Analog Range 0 Off 1 32 m s 1 2 64 m s 1 3 Data Status 0 Good Data 1 Acquiring Signals 2 Lost Trigger 4 Terminal Mode D Normal Mode T CSI Mode 5 8 CSAT3 Serial Number 9 P or U P Prompted U Unprompted ...

Page 63: ...The wind speed ua along any axis can be found by inverting the above relationships then subtracting Eq 2 from 1 and solving for ua u d t t a o b 2 1 1 3 The wind speed is measured on all three non orthogonal axis to give ua ub and uc where the subscripts a b and c refer to the non orthogonal sonic axis The non orthogonal wind speed components are then transformed into orthogonal wind speed compone...

Page 64: ...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 at constant volume and pressure Cpw and Cvw is the specific heat of water vapor and Cpd and Cvd is the specific heat of dry air respectively Fleagle and Businger 19...

Page 65: ...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 Fluxes Boundary Layer Meteorol...

Page 66: ...Appendix C CSAT3 Measurement Theory C 4 ...

Page 67: ...n until there are no SDM communication errors They then begin to speed up the rate until SDM communications fails The processes of slowing down and speeding up the SDM clock rate around the fail threshold continues for approximately three minutes The CRBasic dataloggers output a single data table called report The fastest SDM clock rate that can be used with a particular system setup can be found ...

Page 68: ...b CR3000 1138 CR3000 Std 05 02 CPU Sdm_cr3kv1_3 cr3 21566 report RECORD SDM_Period All_Fail_Tot CSAT_sig_Tot CSAT_NaN_Tot IRGA_sig_Tot IRGA_NaN_Tot Number_Attempts CSAT3 LI 7500 RN uSec samples samples samples samples samples unitless Smp Smp Smp Smp Smp Smp Smp Smp Smp 0 30 2 0 0 2 0 2984 1 1 1 40 0 0 0 0 0 2 1 1 2 50 0 0 0 0 0 2 1 1 3 60 0 0 0 0 0 2 1 1 From the results in TABLE D 1 the shortest...

Page 69: ...un the SPLIT parameter file SDM PAR to filter out the SDM clock parameters that were not tested 99999 in array 151 This parameter file also creates a report of the SDM clock parameters that were tested and their failure rate as a percent of attempts The following report was created from the above SPLIT parameter file SDM PAR TABLE D 3 SDM Clock Rate Report SDM Param Failures Attmpt Attempts 1 100 ...

Page 70: ...Appendix D SDM Communications and Long Signal Cables D 4 ...

Page 71: ......

Page 72: ...entific Canada Corp CSC 11564 149th Street NW Edmonton Alberta T5M 1W7 CANADA www campbellsci ca dataloggers campbellsci ca Campbell Scientific Centro Caribe S A CSCC 300 N Cementerio Edificio Breller Santo Domingo Heredia 40305 COSTA RICA www campbellsci cc info campbellsci cc Campbell Scientific Ltd CSL Campbell Park 80 Hathern Road Shepshed Loughborough LE12 9GX UNITED KINGDOM www campbellsci c...

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