|
The WeatherHawk Series 500 family of weather stations measure and record wind
speed and direction, air temperature and relative humidity, barometric pressure,
solar radiation, and rain. In addition, the system calculates and exports an
evapotranspiration (ET) value that can be used by third party systems for irrigation
control. They are designed for applications where a minimal visual impact, high
reliability, and a long interval between routine servicing are significant factors in the
decision to purchase.
The Series 500 family is fully compatible with all versions of software, data
management, input power and mounting accessories designed for the WeatherHawk
Signature Series. It is also backwards compatible with all third party certified
software drivers.
The principle difference between the Series 500 and Signature Series WeatherHawk
systems is that the Series 500 utilizes solid state sensors, with no moving parts.
Solid state sensors enable a low profile design better suited to high visibility locations
where a traditional weather station would be visually objectionable; they have higher
reliability and a longer interval between routine service and inspection requirements;
they are more robust and less susceptible to damage from wind carried debris; and
they are not impaired by heavy snowfall or freezing conditions that produce rime ice
Models 520/521
These versions of the Series 500 weather station are wireless to a host device (PC or
server) using fully integrated industrial grade 916 MHz spread spectrum RF
communications technology. They also have an RS232 serial data I/O located on the
bottom of the weather station, which can be used as a second serial communications
port, or for programming and testing the system, or for direct data downloads using
a PC or PDA. The Model 521 also incorporates a thermostatically controlled heater
element in the sensor head that keeps the ultrasonic wind sensor elements and the
piezometric precipitation sensor surface free of snow and ice to –52
o C. Optional
configurations of both units enable replacement of the 916 MHz RF components with
922 MHz and 2.4 GHz RF components to comply with local, regional or national radio
frequency licensing requirements.
Sensor Technologies
Series 500 WeatherHawk weather stations employ the latest in weather
measurement sensors. Wind speed and direction use acoustic techniques formerly
available on only the most expensive professional wind velocity measurement
systems. Rain is measured using an impact surface that literally counts the raindrops
and measures their acoustic signature, integrating that information to provide a near
real-time value for rainfall amount and rate. Barometric pressure, relative humidity,
air temperature and solar radiation measurements are made by calibrated scientific
grade sensors typically installed in the finest professional weather measurement and
monitoring systems.
Wind Speed & Direction
is measured by a sensor consisting of three equally spaced
ultrasonic transducers in a horizontal plane. The sensor measures the bi-directional
transit time along the three paths established by the transducer array. This transit
time is dependent on the wind velocity across the ultrasonic path. For zero wind
velocity, both the forward and reverse transit times are identical; with wind, the
upwind transit time increases and the downwind time decreases. The values of any
two array paths will enable computation of both wind speed and direction, and a
signal processing technique enables the measurement to be calculated using the two
array paths of the best quality. If the system is used in a high accuracy application a
factory recalibration is recommended every five years.
Rainfall
is measured with a stainless steel piezometric surface on top of the weather
station. As individual raindrops (or hailstones) impact on the surface they each
provide an acoustic signature that is measured and processed in real-time to give a
value for their volume. The volume is then processed with respect to time to provide
a rainfall rate. This measurement technique eliminates all of the traditional problems
with tipping bucket type rainfall measurement devices, including worn or damaged
bearings, clogged funnels and drip orifices, and damage from wind blown debris.
Air temperature and relative humidity (RH)
sensors are combined in an integrated,
user replaceable unit that requires no calibration. The RH sensor is a thin polymer,
capacitive type sensor that degrades with exposure due to age and airborne
contaminates. It should be user replaced every three years to maintain accuracy,
and at a shorter interval if the location is subject to high levels of air pollution or is
subject to airborne chemical spraying. The air temperature sensor is a capacitive
ceramic sensor that is typically not subject to environmental degradation.
Barometric Pressure
is measured with a capacitive silicon temperature corrected
strain gauge device that is typically not degraded by environmental exposure and
does not require calibration after manufacture.
Solar Radiation
is measured by a silicon pyranometer with a cut filter limiting the
spectral exposure to the 300-1100 nm wavelength. This device typically degrades at
a rate of 2% of the full scale value each year and should be recalibrated, or replaced
every 3-5 years, depending on the application.
Data Transfer Protocols, Software and Data Interface Hardware
All WeatherHawk systems communicate using a proprietary Pakbus protocol. Any
qualified software developer may request a software development kit, at no charge,
to assist in the development of software drivers for third party devices or software.
Software
WeatherHawk offers the following software applications for weather station
management, data acquisition and logging, report generation and data display.
Visual Weather Station – a single host, multi-site professional application
that will communicate with any WeatherHawk weather station, as well as
CR200 Series data loggers from Campbell Scientific, Inc. Visual Weather
Station adapts to any data telemetry scheme including direct connection,
wireless short haul RF (spread spectrum radio), wireless long-haul RF
(VHF/UHF radio), satellite modem, IP modem/server module, or landline
and cellular modems. The application also offers a variety of standard and
user defined reports and export file formats, and it will support the
generation, export and update of a weather data GUI for a website. This
application runs on PC-XP computers.
WeatherHawk-XP/X – a single host, single site consumer application that
will communicate with any WeatherHawk weather station. WeatherHawk-
XP/X connects using a directly to the serial port on the WeatherHawk, or
by wireless short haul RF (spread spectrum radio), or IP modem/server
module, or landline and cellular modems. The application also offers a
three export file formats, and it will support the generation, export and
update of a weather data GUI for a website. This application runs on PCXP
and Macintosh OS-X computers.
Virtual Weather Station – a single host, single site consumer application
that will communicate with any WeatherHawk weather station. Virtual
Weather Station connects directly through the serial port on the
WeatherHawk, or by wireless short haul RF (spread spectrum radio). The
application also offers a two export file formats, and it will support the
generation, export and update of a weather data GUI for a website. This
application runs on IBM compatible computers (INCLUDED).
Weather Display – a single host, single site consumer application that will
communicate with any WeatherHawk weather station. Weather Display
connects directly through to the serial port on the WeatherHawk, or by
wireless short haul RF (spread spectrum), or IP modem/server module.
The application also offers a range of export file formats, and it will
support the generation, export and update of a weather data GUI for a
website. This application runs on PC-XP computers.
Data Interface Hardware
RF4xx spread spectrum RF transceiver is supplied as standard equipment with
every wireless WeatherHawk weather station. The unit comes with an AC power
supply (120 VAC/60 Hz), a 6 foot serial cable and an antenna. Additional RF4xx kits
can be purchased for simultaneous communication with any WeatherHawk wireless
weather station, enabling multiple host computers to use the data from a single
weather station. Typical applications for multiple receiver units are in home
automation where a single weather station may support a whole house control unit,
with touch panel data display units; and a discrete PC, which may act as the server
for a local intranet or internet weather data display website.
WeatherHawk IP server(Optional)
modules are a proprietary web server that is designed to
interface the serial output of any WeatherHawk weather station, or companion RF4xx
transceiver with an Ethernet. Output formats from the IP server module are HTML,
XML and CSV (with headers).
The Model 520 WeatherHawk Wireless Weather Station is complete and includes a solar panel and XP/X software for PC or MAC.
|
