Campbell CSAT3B Product Manual
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Campbell CSAT3B Product Manual

Three-dimensional sonic anemometer
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CSAT3B
Three-Dimensional
Sonic Anemometer
Revision: 5/19
Copyright © 2015 – 2019
Campbell Scientific, Inc.

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Summary of Contents for Campbell CSAT3B

  • Page 1 CSAT3B Three-Dimensional Sonic Anemometer Revision: 5/19 Copyright © 2015 – 2019 Campbell Scientific, Inc.
  • Page 2 Limited Warranty “Products manufactured by CSI are warranted by CSI to be free from defects in materials and workmanship under normal use and service for twelve months from the date of shipment unless otherwise specified in the corresponding product manual. (Product manuals are available for review online at www.campbellsci.com.) Products not manufactured by CSI, but that are resold by CSI, are warranted only to the limits extended by the original manufacturer.
  • Page 3 Campbell Scientific company serves your country. To obtain a Returned Materials Authorization (RMA) number, contact CAMPBELL SCIENTIFIC, INC., phone (435) 227-9000. Please write the issued RMA number clearly on the outside of the shipping container. Campbell Scientific’s shipping address is: CAMPBELL SCIENTIFIC, INC.
  • Page 4 Periodically (at least yearly) check electrical ground connections. • WHILE EVERY ATTEMPT IS MADE TO EMBODY THE HIGHEST DEGREE OF SAFETY IN ALL CAMPBELL SCIENTIFIC PRODUCTS, THE CUSTOMER ASSUMES ALL RISK FROM ANY INJURY RESULTING FROM IMPROPER INSTALLATION, USE, OR MAINTENANCE OF TRIPODS, TOWERS, OR ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS, CROSSARMS, ENCLOSURES, ANTENNAS, ETC.

  • Page 5: Table Of Contents

    Table of Contents PDF viewers: These page numbers refer to the printed version of this document. Use the PDF reader bookmarks tab for links to specific sections. 1. Introduction..............1 2. Precautions ..............1 3. Initial Inspection ............1 4. QuickStart ..............2 Hardware Connections .................2 Communications Connections ..............4 Factory Settings ..................7...
  • Page 6 Desiccant .................... 60 Calibration ..................62 9.4.1 Test for Wind Offset ..............62 Troubleshooting ................. 64 9.5.1 Sending an OS to the CSAT3B ........... 64 Returning the CSAT3B ..............65 10. Reference and Attributions ........65 10.1 References ..................65 Appendices A.
  • Page 7 CSAT3B shown with coordinate system, with arrows representing positive x, y, and z axes; curved arrows indicate positive rotations of pitch and roll angles ............. 30 7-6. Exploded view of fine-wire thermocouple (TC) with CSAT3B ..31 7-7. CSAT3B with fine-wire thermocouple mounted ....... 32 7-8.
  • Page 8 Table of Contents 7-14. CPI daisy chain (CSAT3B sensor arms and grounding cables not shown) .................... 41 7-15. CPI star topology (CSAT3B sensor arms and grounding cables not shown) ..................42 7-16. RS-485 cable connections ..............44 8-1. Angle θ...

  • Page 9: Introduction

    CAUTION Voltage input must be within range of 9.5 − 32 VDC The CSAT3B head should be handled by holding the block at the back of the sensor. Handling it by the arms or transducers could cause geometric deformation, which degrades the measurements.

  • Page 10: Quickstart

    CSAT3B using SDM or CPI communications with a Campbell Scientific data logger. It is intended primarily as an overview and general reference for setup of a CSAT3B, and is not intended as a replacement for the more detailed information on installation found in Section 7, Installation (p.

  • Page 11: Csat3B Mounting

    FIGURE 4-2. CSAT3B mounting Ground the CSAT3B to the tower by attaching a user-supplied, heavy- gauge wire from the copper grounding lug on the back of the CSAT3B block (FIGURE 4-3). Earth (chassis) ground the other end of the wire to the CSAT3B mounting structure or to a grounding rod.

  • Page 12: Communications Connections

    Connect power and communication cable(s). SDM Communications If using SDM communications, connect a CSAT3BCBL1-L (“L” denotes the cable length in feet) cable to the connector on the back of the CSAT3B block labeled Power/SDM as shown in FIGURE 4-4. CPI Communications...

  • Page 13: Cable Connections For Cpi

    CSAT3BCBL1-L cable to the data logger SDM and power ports according to TABLE 4-1. Refer to FIGURE which shows these connections to a CR6 data logger. TABLE 4-1. Wiring Diagram for CSAT3B with SDM Communications Data Logger Terminal Wire Color 12 V (or other 9.5 to 32 VDC source)

  • Page 14: Sdm And Power Wiring To A Cr6 Data Logger

    CSAT3B Three-Dimensional Sonic Anemometer CSAT3BCBL1 SDM/Power cable from CSAT3B To 12 VDC power supply Wire to power and SDM ports FIGURE 4-6. SDM and power wiring to a CR6 data logger CPI Communications With CPI communications, connect the red and black wires on the end of the CSAT3BCBL2-L-PT to the 12 V and ground terminals of a data logger or to a 9.5 to 32 VDC power supply.

  • Page 15: Factory Settings

    Operating Modes , for more details), the CSAT3B Status (p. 48) light will flash red until a data logger is connected to the CSAT3B and its program is running and sending measurement triggers. FIGURE 4-8. Lit status light on CSAT3B block...

  • Page 16: Overview

    Data Logger Prompted Output Overview The CSAT3B is an ultrasonic anemometer for measuring sonic temperature and wind speed in three dimensions. It is often used for studies of turbulence and flux measurement, where turbulent fluctuations of wind speed and sonic temperature must be measured at high frequencies;...

  • Page 17: Sensor Components

    FIGURE 5-1. CM250 mount 5.2.1.2 USB Data Cable The USB data cable is a 5 m (16 ft) USB cable included with the CSAT3B. One end has a standard type-A male connector to connect to a computer, while the opposite end has a mini-B male connector, which connects to the USB port on the back of the CSAT3B block.

  • Page 18: Resourceusb

    If opting out of the sonic carrying case, the CSAT3B will be shipped in a large cardboard box. The same set of foam inserts used in the sonic carrying case is used in the cardboard box to securely hold the CSAT3B.

  • Page 19: Common Accessories

    Common accessories for the CSAT3B include cables as well as other equipment to make sensible heat flux measurements. A fine-wire thermocouple is an example of an additional sensor often used with a CSAT3B. Descriptions of cables and other common accessories are described in greater detail in the following sections.

  • Page 20: Options For Csat3Bcbl1 Power/Sdm Cable

    FIGURE 5-4. Options for CSAT3BCBL1 Power/SDM cable Power Cable (CSAT3BCBL2) To use CPI, RS-485, or USB communications to collect data from a CSAT3B, the CSAT3BCBL2-L-PT or CSAT3BCBL2-L-MC should be ordered to provide power to the sensor. A second cable to transmit the communications is also required (for example, CSAT3BCBL3 CPI/RS-485 cable for CPI or RS-485, or the 30179 USB data cable).

  • Page 21: Fw05 Thermocouple

    The FW05 is a Type E thermocouple with a 0.0127 mm (0.0005 in) diameter (FIGURE 5-7). The thermocouple measures atmospheric temperature fluctuations and may be used with the CSAT3B to directly calculate sensible heat flux. Larger size fine-wire thermocouples, such as the FW1 and FW3, which are more robust but have slower response times, may also be used with the CSAT3B.

  • Page 22: Thermocouple Cover

    FW/ENC when not in use. It is also recommended to order, at a minimum, a set of four FW05 thermocouples for every CSAT3B as the FW05 will break during normal wear and tear in the field.

  • Page 23: Power/Sdm Splitter

    5.2.4.2 CPI/RS-485 Splitter The CPI/RS-485 splitter (pn 30294) has three 8-pin M16 connectors. The splitter allows connection at the CPI/RS-485 port on the back of the CSAT3B block to two CSAT3BCBL3 cables. The splitter is IP68 rated. It is used for daisy-chaining multiple CSAT3Bs in series that use CPI or RS-485 communications.

  • Page 24: Hub-Sdm8

    The HUB-SDM8 (shown in FIGURE 5-12) allows up to six SDM devices (typically, one data logger and multiple SDM sensors) to be connected together in parallel. In the case of the CSAT3B, up to five CSAT3Bs, or CSAT3B daisy-chains using CSAT3BCBL1 cables, may be connected to the HUB- SDM8.

  • Page 25: Sdm Cable Cable5Cbl-L

    5.2.4.5 HUB-CPI The 8-channel RJ45 HUB-CPI allows up to eight CPI devices to be connected together in parallel. In the case of the CSAT3B, up to seven CSAT3Bs, or CSAT3B daisy-chains using CSAT3BCBL3 cables, may be connected in parallel to the HUB-CPI. The remaining port may be used with a CAT5e or CAT6 Ethernet cable (see Section 5.2.4.4, SDM Cable CABLE5CBL-L...

  • Page 26: Cat6 Ethernet Cable

    CR6. FIGURE 5-14. CAT6 Ethernet cable Specifications The CSAT3B measures wind speed and the speed of sound along the three non-orthogonal sonic axes. The wind speeds are then transformed into the orthogonal wind components u...

  • Page 27: Measurements

    An output prompt may come from the data logger, or in the case of unprompted output mode (such as computer data collection), the output is prompted by the CSAT3B itself. The default operating mode of the CSAT3B is to make measurements when triggered by a data logger (SDM or CPI), which does not apply any low-pass (high-cut) filtering.

  • Page 28: Communications

    CSAT3B Three-Dimensional Sonic Anemometer Internal Monitor Measurements Update Rate: 2 Hz Inclinometer Accuracy: ± 1 ° Relative Humidity Accuracy: ± 3% over 10 − 90% range ± 7% over 0 − 10% range ± 7% over 90 − 100% range Board Temperature Accuracy: ±...

  • Page 29: Physical Description

    CSAT3B Three-Dimensional Sonic Anemometer Physical Description Dimensions Anemometer Overall: 60.7 cm (23.9 in) length 43.0 cm (16.9 in) height 12.2 cm (4.8 in) width Measurement Path: 10.0 cm (3.9 in) vertical 5.8 cm (2.3 in) horizontal Transducer Angle: 60 degrees from horizontal Transducer Diameter: 0.64 cm (0.25 in)

  • Page 30: Installation

    CSAT3B, which is covered in the following sections. If the CSAT3B is to be used in a marine environment, or in an environment where it is exposed to corrosive chemicals (for example, the sulfur-containing compounds in viticulture), attempt to mount the CSAT3B in a way that reduces the exposure of the sonic transducers to saltwater or corrosive chemicals.

  • Page 31: Settings

    Provide power to the CSAT3B by connecting the M16 connector of either a CSAT3BCBL1 or CSAT3BCBL2 to the Power/SDM port on the back of the CSAT3B block. The other end of this cable will have red and black wire leads that should be connected to a 9.5 to 32 VDC power source.

  • Page 32: Connecting Csat3B Using Device Configuration Utility

    Ensure that the appropriate settings are enabled for the communication protocol that will be used. An example subscreen is shown in FIGURE 7-2. TABLE 7-1. CSAT3B Settings and Status Values in Device Configuration Utility Setting or Status Subscreen Value...
  • Page 33 CSAT3B Three-Dimensional Sonic Anemometer TABLE 7-1. CSAT3B Settings and Status Values in Device Configuration Utility Setting or Status Subscreen Value Options Description Internal Temperature inside CSAT3B block Temperature Relative humidity inside CSAT3B block. Internal Relative Change desiccant if greater than 50% (see Humidity Section 9.3, Desiccant...
  • Page 34 CSAT3B Three-Dimensional Sonic Anemometer TABLE 7-1. CSAT3B Settings and Status Values in Device Configuration Utility Setting or Status Subscreen Value Options Description Mode 0: Data logger triggered | No filter | Data logger prompted output Mode 1: Self triggered | Filtered |...

  • Page 35: Orientation

    (p. 29) Mounting The CSAT3B is supplied with mounting hardware to attach it to the end of a horizontal pipe with an outer diameter of 3.33 cm (1.31 in), such as the Campbell Scientific CM202, CM204, or CM206 crossarm (referred to generically as a CM20X crossarm).

  • Page 36: Cm210 Mounting Kit With Cm20X Crossarm

    3/16-in hex socket head wrench. Refer to FIGURE 7-4. Attach the CSAT3B to the leveling mount by inserting the bolt on the mount into the threaded hole on the bottom of the CSAT3B block as shown in FIGURE 7-4.

  • Page 37: Leveling

    Finally, tighten the bolt with a 9/16-in wrench. If an application requires greater accuracy in inclination of the CSAT3B, or if an application requires a measurement that shows if, and when, the inclination...

  • Page 38: Additional Fast-Response Sensors

    CSAT3B wind measurements. The outputs of the CSAT3B integrated inclinometer can be viewed by connecting the USB data cable (pn 30179) to the CSAT3B and a computer computer running Campbell Scientific’s Device Configuration Utility. It can also be output using the CRBasic instruction CSAT3BMonitor. See Section 8.4.1.2, CSAT3BMonitor()

  • Page 39: Exploded View Of Fine-Wire Thermocouple (Tc) With Csat3B

    CSAT3B Three-Dimensional Sonic Anemometer the side of the anemometer with the short screw (#2-56 x 0.437 inch) that was provided with the white thermocouple cover. Insert the male connector of the FW05 into the female connector of the FWC-L. Finally, attach the thermocouple cover to the anemometer block using the thumb screw so that both the FW05 and FWC-L connectors are covered.

  • Page 40: Other Gas Analyzers

    Wiring On the back of the CSAT3B block there is a copper grounding lug (refer to FIGURE 4-3). Use a standard flat-head screwdriver to pinch an 8 AWG to 14 AWG wire between the lug and the lug screw. Campbell Scientific offers a 10 AWG copper wire that is suitable for grounding sensors.

  • Page 41: Communications

    , for information about ordering cables). (p. 11) If the CSAT3B is going to be operated using SDM or CPI communications where the data logger triggers the measurement and the data are unfiltered (see Mode 0 in Section 8.2, Operating Modes ), then the CSAT3B default (p.

  • Page 42: Sdm Communications

    FIGURE 7-8. No other cables are required for SDM communications, as the CSAT3BCBL1 contains both power and SDM wiring. If only one CSAT3B is being measured, the opposite end of the cable will have wire pigtails if connecting directly to the ports on a data logger. Refer to Section 4.2, Communications Connections...

  • Page 43: Sdm/Power Connections

    For applications requiring very long cable lengths, a higher voltage power supply is recommended as voltage drop over long distances will occur and the CSAT3B requires a minimum of 9.5 VDC. CSAT3BCBL1-L-PT Grounding Cable FIGURE 7-8. SDM/Power connections...
  • Page 44 (p. 23) been assigned a unique SDM address. Connect a CSAT3BCBL1 to the Power/SDM port of the terminal CSAT3B. The opposite end will have an M16 connector that mates with one of the split M16 connectors on the Power/SDM splitters (pn 30293). Next, screw the side of the splitter with only one M16 connector to the Power/SDM port of the second CSAT3B.

  • Page 45: Sdm Daisy Chain

    CSAT3B Three-Dimensional Sonic Anemometer 30293 Splitter CSAT3BCBL1-L-MC CSAT3BCBL1-L-MC 30293 Splitter To power supply CSAT3BCBL1-L-PT To power supply FIGURE 7-10. SDM daisy chain (CSAT3B sensor arms and grounding cables not shown)

  • Page 46: Cpi Communications

    Next, connect a CSAT3BCBL3 to the CPI/RS-485 port in the same manner. If only one CSAT3B is being measured, the opposite end of the power cable should have pigtail wire leads which may be wired to the 12 V and G terminals on a data logger or to another 12 to 32 VDC power supply.
  • Page 47 CSAT3B Three-Dimensional Sonic Anemometer CSAT3BCBL2-L-PT Grounding Cable CSAT3BCBL3-L-RJ FIGURE 7-12. Power and CPI cable connections CSAT3BCBL3-L-RJ To power supply CSAT3BCBL2-L-PT FIGURE 7-13. CPI connection to a CR6 data logger...

  • Page 48: Cpi Daisy Chain

    CSAT3BCBL2 cable to each Power/SDM port of each CSAT3B, and connect the other wire leads to the 12 V and G ports of a data logger or to another 12 to 32 VDC power supply (for convenience, it’s possible to use a wiring bus such as the HUB-SDM8 to bring several power...
  • Page 49 CSAT3B Three-Dimensional Sonic Anemometer CSAT3BCBL2-L-MC 30293 Splitter CSAT3BCBL3-L-MC CSAT3BCBL2-L-MC 30294 Splitter 30293 Splitter CSAT3BCBL3-L-MC CSAT3BCBL2-L-PT To power supply 30294 Splitter CSAT3BCBL3-L-RJ To power supply FIGURE 7-14. CPI daisy chain (CSAT3B sensor arms and grounding cables not shown)
  • Page 50 CSAT3B Three-Dimensional Sonic Anemometer CSAT3BCBL2-L-PT CSAT3BCBL3-L-RJ HUB-CPI To power supply CAT6 Cable FIGURE 7-15. CPI star topology (CSAT3B sensor arms and grounding cables not shown)

  • Page 51: Rs-485 Communications

    Next, connect a CSAT3BCBL3 cable to the CPI/RS-485 port in the same manner. If only one CSAT3B is being measured, the opposite end of the power cable should have pigtail wire leads, which may be connected to a 12 to 32 VDC power supply, and the RS-485 cable should have pigtail wire leads for wiring to a connector on a computer (see FIGURE 7-16).

  • Page 52: Usb

    FIGURE 7-16. RS-485 cable connections 7.7.4 USB If data collection from the anemometer is to be done by a computer using USB communications, first connect to the CSAT3B as described in Section 7.1, Settings , to confirm the following three settings: (p.

  • Page 53: Csat3B Cable Wire Assignments

    CSAT3B Three-Dimensional Sonic Anemometer Connect the 5 m (16 ft) USB cable included with the CSAT3B to the USB port in the same way. If only one CSAT3B is being measured, the opposite end of the power cable should have pigtail wire leads, which may be connected to a 12 to 32 VDC power supply, and the USB cable should be connected to a USB port on a computer.

  • Page 54: Operation

    The CSAT3B is able to calculate the wind vector components along each sonic axis using the time difference between an outgoing and return sonic signal, along with the distance between sonic transducers.

  • Page 55: Sonic Transducer Shadow Correction

    Accordingly, an optional wind shadow correction specific to the CSAT3-series transducer diameter and sonic path length has been implemented in the CSAT3B OS versions 1.11 and newer. This shadow correction, known as the Kaimal correction (Kaimal, 1979 and Horst et al, 2015), is applied according to: ����...

  • Page 56: Operating Modes

    The following sections give more information on the measurement trigger, data filters, and data output as a guide to selecting the appropriate mode. Mode 0 is the default operating mode for the CSAT3B and is recommended when fluxes are the primary interest.

  • Page 57: Measurement Settings In Device Configuration Utility

    CSAT3B Three-Dimensional Sonic Anemometer FIGURE 8-2. Measurement settings in Device Configuration Utility TABLE 8-1. Overview of CSAT3B Operating Modes Measurement Trigger Filters Output Prompt Mode Source Rate Enabled Bandwidth (Hz) Source Rate Data logger 1 to 100 Hz Data logger...

  • Page 58: Measurement Trigger

    A measurement trigger is the actual command to initiate a sonic measurement and can be driven by either a data logger or the CSAT3B internal timer. If the trigger is given by a data logger as in Mode 0, then no data filtering is done (bandwidth is wide open) since each trigger will initiate a single new measurement (single-measurement regime).

  • Page 59: Data Output

    CSAT3B OS versions 1.09 and newer. 8.2.3 Data Output After a measurement is triggered and optionally run through a filter, it is stored in the CSAT3B data buffer until it is output to either a data logger or a computer. Mode 0...
  • Page 60 CSAT3B Three-Dimensional Sonic Anemometer Mode 1 In the case where the CSAT3B is self triggered and filtered, the output data can still be collected by a data logger (Mode 1) using CPI communications. In this case, the data logger will prompt the CSAT3B for an output each time it executes the CSAT3B() CRBasic instruction in the program scan.

  • Page 61: Example Of Unprompted Rs-485 Or Usb Output To Computer

    In most situations, a computer computes the signature by reading in the ASCII data and extracting the last four ASCII characters, casting them as Long data type. The signature is then calculated on the data sent from the CSAT3B, and ending with the counter. All the characters after the counter starting with u are not part of the signature.

  • Page 62: Operating Mode Recommendations

    Synchronization with other sensors As there is a delay between the CSAT3B measurement and output to a data logger or computer (see TABLE 8-2), the CSAT3B data will be slightly older than the record’s timestamp (recall that the timestamp is assigned to the record by the data logger or computer).

  • Page 63: Data Logger Programming Using Sdm Or Cpi

    CSAT3B() The CSAT3B() instruction is the primary instruction used to retrieve anemometer data from the CSAT3B. This will set the operating mode of the anemometer and retrieve the wind, sonic temperature, and diagnostic information. The instruction requires four parameters which are further...

  • Page 64: Csat3Bmonitor()

    CSAT3B Three-Dimensional Sonic Anemometer The CSAT3B() instruction should appear in the main scan of the CRBasic program operating in pipeline mode. Destination: This variable will store the values returned by the anemometer. The destination variable must be declared as a float (default) with at least five elements. The CSAT3B returns the following data in response to a measurement trigger: –...

  • Page 65: Diagnostic Word

    CSAT3B. The data logger will display the diagnostic word as a base-10 integer. Viewed in this manner, each of the 32 bits has a different magnitude as a decimal number.

  • Page 66: Sdmtrigger()

    8.4.3 SDMTrigger() The SDMTrigger() is an SDM Input/Output instruction that controls SDM devices that support the group trigger protocol, including the CSAT3B. Up to 15 group-trigger devices can be connected to the SDM bus. All group-trigger devices are triggered for simultaneous measurements with the SDMTrigger.

  • Page 67: Maintenance And Troubleshooting

    CSAT3B Three-Dimensional Sonic Anemometer Maintenance and Troubleshooting General Maintenance With no moving parts, maintenance of the CSAT3B is minimal and limited to the following: • Replacing rain wicks Replacing the desiccant canister • Monitoring diagnostics and measurement offsets to determine when •...

  • Page 68: Desiccant

    As the relative humidity approaches 100%, condensation will begin to form on the internal surfaces. The CSAT3B has a cavity to hold a replaceable desiccant canister that removes water from the air (see FIGURE 9-2). Water molecules will unavoidably ingress into the electronics over time, so the internal humidity of the CSAT3B head should periodically be checked.

  • Page 69: Exploded View Of Csat3B Desiccant Canister

    CSAT3B Three-Dimensional Sonic Anemometer If monitoring shows the internal humidity of the CSAT3B rising above 50%, including during night time cooling cycles, the desiccant should be replaced with canisters that can be purchased from Campbell Scientific. The small canister holds desiccant and is installed on the underside of the anemometer block inside of the brass screw cap (see FIGURE 9-2).

  • Page 70: Calibration

    Because it is difficult to do this in the field, wind offset data from the CSAT3B should be collected in a field office or the lab. A zero-wind environment can be created with a kitchen waste bin liner. The following steps should be taken to test the CSAT3B for wind offset.

  • Page 71: Csat3B Real-Time Data With 1 Sec Update And U

    CSAT3B Three-Dimensional Sonic Anemometer FIGURE 9-3. CSAT3B real-time data with 1 sec update and u and u wind component graphed FIGURE 9-4. CSAT3B real-time data with 1 sec update and u wind component graphed...

  • Page 72: Troubleshooting

    CSAT3B Three-Dimensional Sonic Anemometer Graph 1 minute of wind data from the CSAT3B while it is in the zero wind environment. The wind offset should be less than ± 8 cm·s –1 (0.08 m·s –1 ) for u and u , and less than ±...

  • Page 73: Returning The Csat3B

    CSAT3B Three-Dimensional Sonic Anemometer After connecting to the CSAT3B, click on the Send OS tab at the top of the Device Configuration Utility main screen. Click on the Start button at the bottom of the page, select the .obj file that you downloaded from the Campbell website, and click Open.
  • Page 74 CSAT3B Three-Dimensional Sonic Anemometer Kaimal, J.C.: 1979, “Sonic anemometer measurement of atmospheric turbulence”, Proceeding of the Dynamic Flow Conference, Skovlunde. DISA Electronic A/S, 551 – 565. Horst, T.W., Semmer, S.R., and Maclean, G.: 2015, “Correction of a Non- orthogonal, Three-Component Sonic Anemometer for Flow Distortion by Transducer Shadowing”, Boundary-Layer Meteorol, 155, 371 –...

  • Page 75: Csat3B Orientation

    Appendix A. CSAT3B Orientation A.1 Determining True North and Sensor Orientation The orientation of the CSAT3B negative x-axis is found by reading a magnetic compass and applying the site-specific correction for magnetic declination; where the magnetic declination is the number of degrees between True North and Magnetic North.

  • Page 76: A Declination Angle East Of True North (Positive) Is Subtracted From 360 (0) Degrees To Find True North

    Appendix A. CSAT3B Orientation Declination angles are always subtracted from the compass reading to find True North. A declination angle East of True North is reported as positive a value and is subtracted from 360 (0) degrees to find True North as shown FIGURE A-2.

  • Page 77: Online Magnetic Declination Calculator

    Appendix A. CSAT3B Orientation A.2 Online Magnetic Declination Calculator The magnetic declination calculator web calculator published by NOAA’s Geophysical Data Center is available at the following URL: www.ngdc.noaa.gov/geomag-web/#declination. After the web page loads, enter the zip code, country and city, or latitude and longitude of the site, then click on Calculate to get the declination for that site (FIGURE A-4).
  • Page 78 Appendix A. CSAT3B Orientation FIGURE A-5. NOAA magnetic calculator results The declination for Salt Lake City, UT is 11.7 degrees (4 November, 2014). As shown in FIGURE A-5, the declination for Utah is positive (east of north), so true north for this site is 360 – 11.7, or 348.3 degrees. The annual change is...

  • Page 79: Csat3B Measurement Theory

    Theory B.1 Theory of Operation B.1.1 Wind Speed Each axis of the CSAT3B pulses two ultrasonic signals in opposite directions. The time of flight of the first signal (out) is given by: (B-1) and the time of flight of the second signal (back) is given by:...

  • Page 80: Temperature

    The sonically determined speed of sound is given in Eq. (B-5) and was found from the sum of the inverses of Eq. (B-1) and (B-2). The CSAT3B corrects online for the effect of wind blowing perpendicular to the sonic path. No additional off-line corrections are required as suggested by Liu et al., 2001.

  • Page 81: References

    Appendix B. CSAT3B Measurement Theory and C = specific heat of dry air, respectively (Fleagle and Businger, 1980) Substitute Eq. (B-7a) and (B-7b) into (B-6) and ignore the higher order terms. This yields 1 0 51 γ γ d d s...

  • Page 82: Example Crbasic Data Logger Programs

    Sample (5,CSATVals(1),IEEE4) EndTable DataTable (MonitorData,1,-1) DataInterval (0,5,Sec,10) Sample (4,CSATMonitorVals(1),IEEE4) EndTable '--------------------------------------------- ' Main Program '--------------------------------------------- BeginProg Scan(50,msec,500,0) '20 Hz Scan 'CSAT3B(Destination, Bus, Address, OperatingMode) CSAT3B(CSATVals(),0,SDM_ADDR,0) CallTable(SonicData) NextScan SlowSequence Scan(5,sec,0,0) '5 second scan 'CSAT3BMonitor (Destination, Bus, Address) CSAT3BMonitor(CSATMonitorVals(),0,SDM_ADDR) CallTable(MonitorData) NextScan EndProg...

  • Page 83: Simple Cpi Program

    (SonicData,1,-1) Sample (5,CSATVals(1),IEEE4) EndTable DataTable (MonitorData,1,-1) DataInterval (0,5,Sec,10) Sample (4,CSATMonitorVals(1),IEEE4) EndTable '--------------------------------------------- ' Main Program '--------------------------------------------- BeginProg Scan(50,msec,500,0) '20 Hz Scan 'CSAT3B(Destination, Bus, Address, OperatingMode) CSAT3B(CSATVals(),1,CPI_ADDR,0) CallTable(SonicData) NextScan SlowSequence Scan(5,sec,0,0) '5 second scan 'CSAT3BMonitor(Destination, Bus, Address) CSAT3BMonitor(CSATMonitorVals(),1,CPI_ADDR) CallTable(MonitorData) NextScan EndProg...

  • Page 84: Advanced Cpi Program

    {+y} 'The program computes the compass wind direction, using the constant 'CSAT3B_AZIMUTH, and a CSAT3B wind direction. Good CSAT3B wind directions 'are between -90 to 0 and 0 to 90 degrees, e.g. the wind is blowing into 'the CSAT3B sensor head.
  • Page 85 = Flag_TrigErr 'Trigger Error Flag 'Wind directions and speed. Public wind_out(8) 'Alias wind_out(1) = wind_spd - in compass coord system, same as CSAT3B 'Alias wind_out(2) = result_wind_speed - in compass coord system, same as CSAT3B Alias wind_out(3) = wind_dir_compass...
  • Page 86 (Flag_TrigErr) OR NOT (disable_stats(2))) FieldNames ("Flag_TrigErr_Tot") Average (1,panel_temp,IEEE4,FALSE) Average (1,battery_volt,IEEE4,FALSE) Average (1,board_temp,IEEE4,FALSE) Average (1,board_humidity,IEEE4,FALSE) Average (1,incline_pitch,IEEE4,FALSE) Average (1,incline_roll,IEEE4,FALSE) EndTable '--------------------------------------------- ' Main Program '--------------------------------------------- BeginProg Move (Ux,5,NaN,1) 'Set all CSAT3B variables to NaN CPISpeed (CPI_RATE) 'Set the SDM clock speed...
  • Page 87 'Measure data logger panel temperature Battery (battery_volt) 'Measure battery voltage. 'CSAT3B(Destination, Bus, Address, OperatingMode) CSAT3B(wind(),1,CPI_ADDR,0) 'Copy and convert CSAT3B for compass wind vector computation. wind_east = -1*Uy wind_north = Ux 'Break up the warning flags into separate bits. diag_integer = diag diag_bits(1) = diag_integer &h00000001...
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