Anemometers (Wind Speed Sensors) from by pharmphresh33


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Anemometers (Wind Speed Sensors)

      Other Related information:
            Anemometer selection table (and datasheets)
            Additional Anemometer Information

    The A100 series of cup-anemometers all have the same physical outline and basic mechanics. This
arrangement has been used since the introduction of the Porton Anemometer in 1972, and this was preceded
by a similar design in the original CDE Porton anemometer of 1964. The different sensors within the A100
range use differing transducers/technologies within the same physical outline to provide different outputs
optimised for different applications and interface requirments. Transducer technologies and output signal
types include...

      Contact Closure (Switching)
            A100R, magnetic/reed-switch system, low-power, 1 contact closure per 1.25m of wind run
      Opto Electronic (require a source of DC power)
            A100 Porton, analogue output of 0-10v for 0-50 metres/sec windspeed
            A100H Porton, analogue output of 0-7.5v for 0-75 metres/sec windspeed
            A100L2, Low Power (<2mA), analogue output of 0-2.5v for 0-150 knots windspeed and
            frequency output of 10Hz per knot
            A100M, frequency output of 10Hz per metre/sec
            A100K, frequency output of 10Hz per knot

    The 3-cup rotor, common to all A100 series anemometers, consists of three conical cups of weather-
resisting plastics attached to an anodised aluminium alloy hub/arms assembly. Every rotor is individually
calibrated in-house by comparison in our wind tunnel at one airspeed with a 'reference' rotor which is
traceable to UK national standards.

    A unique gravity sensitive fastener secures the rotor to the anemometer spindle. This was developed for
portable applications, but is also an advantage in reducing likelihood of damage during transport and
installation. The design avoids the use of a fixing screw and has therefore no entry point for water, with
reduced susceptibility to corrosion. The rotor fastener is released by inverting the anemometer and pressing
the hub.

    The stainless steel spindle turns on two precision ball races. In the optoelectronic anemometers, this turns
a slotted disc which interrupts a light beam to measure rotation speed. This arrangement results in a low
threshold and allows highly accurate windspeed measurements to be made. Various types of internal
electronic modules convert the light beam signal into the required analogue or pulse output. In the contact-
closure (switching) anemometer, a rotating magnet system operates a mercury-wetted reed switch.

   The standard instrument is designed to withstand all weather conditions; many thousands being in
continuous use at all latitudes around the world. Marine versions are available and heaters can be fitted to
prevent icing of the bearings.

   Mounting is by means of a single screw into the base. If required, a range of standard mounting adaptors
are available to simplify mounting on masts and poles. These include a single mast-top adapter (the preferred
method for accurate wind speed measurement), a single side mounting arm, or the anemometer can be
mounted at one end of mast-top cross arm (the opposite end usually being reserved for the wind direction

   A100 series instruments are fitted with a 3 metre length of cable as standard, but other stock lengths of 6,
10 or 15m (or any custom length) may be specified. For many installations (and particularly when longer
lengths are required) it is advisable to use one of our weatherproof junction boxes and extension cables.                                                                               13.01.2003
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Additional Anemometer Information...
      Other Related information:
            Anemometer selection table
            Lightning Protection for Anemometers
            Safety and Reliability of Anemometers and Systems
            Siting Recommendations when installing Anemometers

The 3-cup R30 series rotors used on the A100 series anemometers responds to wind from all directions in the
horizontal plane, and to ±20° vertically with an approximate cosine law. The response to wind speed is nearly
linear, simplifying the measurement process, however a correction table is provided with each
rotor/anemometer so that even this small non-linearity can be corrected by users if required. The response is
also virtually unaffected by air pressure, temperature or precipitation, provided there is no build-up of ice on
the cups.

Instruments are designed for mounting outside with their axes vertical (although non-vertical mounting has
been used in a few research applications). Consult the siting guide for information about the best place/way to
install an anemometer.

                      1 metre per second = 2.237 miles per hour
                                  1 metre per second = 1.9426 Knots
                                  1 metre per second = 3.60 kilometres per hour
                                  1 Knot             = 0.515 metres per second
                                  1 Knot             = 1.152 miles per hour
                                  1 Knot             = 1.85 kilometres per hour
                                  1 mile per hour    = 0.447 metres per second
                                  1 mile per hour    = 0.868 Knots
                                  1 mile per hour    = 1.61 kilometres per hour

                Calm                            = Force 0     = Less than 1 Knot
                      Light Air                 = Force 1     = 1 to 3 Knots
                      Light Breeze              = Force 2     = 4 to 6 Knots
                      Gentle Breeze             = Force 3     = 7 to 10 Knots
                      Moderate Breeze           = Force 4     = 11 to 16 Knots
                      Fresh Breeze              = Force 5     = 17 to 21 Knots
                      Strong Breeze             = Force 6     = 22 to 27 Knots
                      Near Gale                 = Force 7     = 28 to 33 Knots
                      Gale                      = Force 8     = 34 to 40 Knots
                      Strong Gale               = Force 9     = 41 to 47 Knots
                      Storm                     = Force 10    = 48 to 55 Knots
                      Violent Storm             = Force 11    = 56 to 63 Knots
                      Hurricane                 = Force 12    = More than 64 Knots                                                                              13.01.2003
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Anemometers from

    The table below shows a summary of each sensor's specifications. For detailed information, please refer
to the individual sensor data sheets. To obtain a datasheet for a specific sensor, click the sensor 'Cat No.' in
the leftmost column of the table below. Note: Vector Instruments' policy of continuous development means
that these specifications may be altered without notice, however new product will (wherever possible) remain
compatible with that previously supplied. If any specification parameter is critical to your application, our sales
office will be pleased to confirm the current specification or discuss and advise on suitability of a particular
sensor for your application.

   Wind Speed Sensor Selection Table...

  Cat.                                  Supply Supply Standard
           Description    Calibration                          Mountings              Applications
  No.                                     V      A     Cables
                                                                           Where analogue
                                                                            output with self
                                                              405, 405-1, calibration facility is
            Porton       0-10V for 0- 10 -           6-wire +
  A100                                       <15mA              405-1L,       required, i.e.
          Anemometer        100Kts     30Vdc          screen
                                                                 405E            portable
                                                                          applications or long
            Porton       0-7.5V for 0-
 A100H                                    "     "        "    [as above]             "
          Anemometer         75m/s
                         0-2.5V for 0-
                                                                           Where analogue
           Low Power     150Kts and 6.5-
A100L2                                        <2mA       "    [as above] output is required
          Anemometer       10Hz per 28Vdc
                                                                            for wind speed.
                                                                            General use on
                           10Hz per                                        permanent sites,
          Pulse Output                  10-   30mA 4-wire +
 A100K                        knot                            [as above]    e.g. PLCs (high
          Anemometer                   30Vdc    @     screen
                           (nm/hour)                                       resolution, Knots
                           10 pulses                                         As above, m/s
 A100M          "                         "     "        "    [as above]
                           per metre                                           calibration.
                                                                          As above, electronic
                          1 pulse per
 A100S          "                         "     "        "    [as above] version of Switching
                                                                              Remote sites
           Switching       1 contact                 2-wire +
 A100R                                 1.25m 0-72Vdc          [as above]     (without mains
          Anemometer        closure                   screen

115, Marsh Road, RHYL, Denbighshire, N.Wales, LL18 2AB, United Kingdom.                                                                                 13.01.2003

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