The A70 Wind Azimuth Transmitter monitors the signal from the Model A75-302 precision  Potentiometric Wind Vane. The wind vane is balance to reduce errors should the vane mounting not be perfectly level. It is injection molded from black UV stabilized Lexan. It has proven rugged and reliable in field tests. The vane produces a signal proportional to the azimuth of the wind. See A75-302 data sheet for detailed sensor specifications. 

The transmitter provides constant excitation for the vane. It also scales the signal from the vane to produce the desired output signal. The vane has a 4° dead band centered on North. Ranges of 0 to 360° and 0 to 540° are available. The 360° range is the least expensive and most suitable for electronic data collection systems. The 540 degree range should be used when driving chart recorders with ink pens. The 540° range minimizes the transitions of the recorder pen from zero to full scale that might otherwise paint the entire chart when the wind direction is from the North. Combination speed and direction instruments are available. Sensor operating range is -40 / 60° C. The system is provided with 60 feet of cable, clamps and an S mast for mounting the direction vane.

These units are used in conjunction with electronic data collection systems or for input to control systems. They are readily combined with meter relays to provide custom controls. 

Systems are available with outputs of 0-1 mA, 0-1 V or 4-20 mA. All systems may be powered from either 120 VAC, 230 VAC or 
12 - 24 VDC. Higher performance sensors are available at additional cost.

The instruments are available in a variety of packages including steel JIC boxes meeting NEMA 12 standards, weatherproof fiberglass enclosures meeting NEMA 4X, IP66 and IEC 529 standards and track mounted versions. NEMA 12 enclosures provide protection from dust for indoor applications. NEMA 4X enclosures may be used indoors or outdoors. They provide protection from corrosion, 
wind blown dust and rain and are undamaged by ice. Track mounted versions are intended for 
mounting inside an enclosure provided by the user. Where required, electrical connection to the sensor is via terminal block. A barrier strip is provided for connection to operating power.

Each system is provided with a detailed instruction manual.

Product Specification Sheet:  A70-D Wind Azimuth Transmitter

EPA Meteorological Monitoring Guidance for Regulatory Modeling Applications                          EPA-454/R-99-005

Beaufort Wind Scale - NWS Storm Prediction Center

Federal Meteorological Handbook