Decagon Devices DS-2 Operator's Manual

Decagon Devices DS-2 Operator's Manual

Sonic anemometer

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DS-2
Sonic Anemometer
Operator's Manual
Decagon Devices, Inc.
Version: August 29, 2013 — 16:00:00

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Summary of Contents for Decagon Devices DS-2

  • Page 1 DS-2 Sonic Anemometer Operator’s Manual Decagon Devices, Inc. Version: August 29, 2013 — 16:00:00...
  • Page 2 DS-2 Decagon Devices, Inc. 2365 NE Hopkins Court Pullman WA 99163 Phone: 509-332-5600 Fax: 509-332-5158 Website: www.decagon.com Email: support@decagon.com or sales@decagon.com Trademarks c 2007-2013 Decagon Devices, Inc. All Rights Reserved...
  • Page 3: Table Of Contents

    1.4 Seller’s Liability ..... . 1.5 About DS-2 ......
  • Page 4: Introduction

    Customer Support If you ever need assistance with your DS-2 or have any questions or feedback, there are several ways to contact us. Decagon has customer service representatives available to speak with you Monday through Friday, between 7 am and 5 pm Pacific time.
  • Page 5: Warranty

    About DS-2 Decagon designed the DS-2 Sonic Anemometer to measure wind speed, direction, and even wind gusts. It is a two dimensional ul- trasonic anemometer with no moving parts that provides specified...
  • Page 6: Specifications

    DS-2 1 INTRODUCTION accuracy for long-term installations. It outputs SDI-12, and is com- patible with Decagon’s Em50, Em50R, Em50G, and other loggers like those from Campbell Scientific. Specifications Wind Speed Range: 0 to 30 m/s Wind Speed Resolution: 0.01 m/s Wind Speed Accuracy: 0.30 m/s or <...
  • Page 7: Theory

    2 THEORY DS-2 Theory The theory behind the sonic anemometer comes from Campbell and Unsworth (1979). The speed c(m/s) of sound in still air depends on air temperature T (K), vapor pressure e(kP a) and atmospheric pressure, p(kP a), as seen in equation 1.
  • Page 8 DS-2 2 THEORY This is the basic equation for the anemometer. ∆n is proportional to the phase difference between the forward and reverse sound pulses. The sound comes from a 40 kHz ultrasonic transducer in the head of the anemometer. It is transmitted diagonally across the anemometer, bouncing off...
  • Page 9: Connecting The Anemometer

    Decagon’s support site: http://www.decagon.com/support/. To use the DS-2 with your Em50 data logger, simply plug the stereo plug into one of the five ports on the data logger and use either O Utility, or DataTrac 3 software (see respective manuals) to configure that port for the DS-2 and set the measurement interval.
  • Page 10: Mm Stereo Plug Wiring

    Campbell Scientific or similar logger. 3.5 mm Stereo Plug Wiring DS-2 anemometers, used with Decagon loggers, come with a 3.5 mm stereo plug connector. The stereo plug allows for rapid connection directly to Decagon’s Em50 and Em50G data loggers. Figure 3 shows the wiring configuration for this connector.
  • Page 11: Pigtail End Wiring

    Data Loggers, then you will need to power the sensors from a 12 V or switched 12 V port. If your DS-2 is equipped with the standard 3.5 mm plug, and you wish to connect it to a non Decagon data logger, you have two op-...
  • Page 12 DS-2 3 CONNECTING THE ANEMOMETER tin the wires, and wire it directly into the data logger. This has the advantage of creating a direct connection with no chance of the sensor becoming unplugged; however, it then cannot be easily used in the future with a Decagon data logger.
  • Page 13: Communication

    The SDI-12 protocol requires that all sensors have a unique address. DS-2 anemometers come from the factory with an SDI-12 address of 0. To add more than one SDI-12 sensor to a system, the sensor address must be changed to some value other than zero and all sen- sors on the bus must have unique addresses.
  • Page 14 10 second intervals and retain the gust speeds. Reading the DS-2 anemometer in SDI-12 mode using a CSI data logger requires a function call. An example program from Edlog and CRBasic can be found in the software section of http://www.decagon.com/support/.
  • Page 15: Campbell Scientific Programs

    SDI-12 Recorder command and input the necessary parameters. As mentioned earlier, the sensor outputs three values, so be sure to define your array size as 3 in CRBasic (i.e. Public DS-2(3)) or leave room for two more parameters after your “Loc” call in Edlog. Ex-...
  • Page 16: Installing The

    5 INSTALLING THE DS-2 Installing the DS-2 Attaching and leveling The DS-2 is fitted with a U-bolt, allowing it to be mounted atop most posts, poles, tripods, etc. Depending on the application, the DS-2 should be mounted two to three meters above ground.
  • Page 17: Cleaning And Maintenance

    5 INSTALLING THE DS-2 DS-2 Cleaning and Maintenance Occasionally, the anemometer might become subject to interference from the environment. This could be due to miscellaneous environ- mental, animal or insect made debris. It is a good idea to check the...
  • Page 18: Troubleshooting

    DS-2 6 TROUBLESHOOTING Troubleshooting Problem #1: Sensor not responding: Check power to the sensor Check sensor cable and 3.5 mm plug integrity Check data logger wiring to ensure White - 3.6 to 15 V supply Red - Digital out Bare - Ground If sensor does not respond, use the Pro-Check to make sure it is working satisfactorily.
  • Page 19: Declaration Of Conformity

    DS-2 Year of First Manufacture: 2012 This is to certify that the DS-2 anemometer, manufactured by Decagon Devices, Inc., a corporation based in Pullman, Washington, USA meets or exceeds the standards for CE compliance as per the Coun- cil Directives noted above. All instruments are built at the factory at Decagon and pertinent testing documentation is freely available for verification.
  • Page 20 Cleaning and Maintenance, 14 Communication, 10 SD-12, 10 Connecting Sensors Non-Decagon Logger, 7 Contact Information, 1 CSI Loggers Using DS-2 with, 11 Customer Support, 1 Declaration of Conformity, 16 Email, 1 Installation Leveling, 13 Mounting to Post, 13 Orientation, 13 Seller’s Liability, 2...

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