Manufacturer: Vaisala
Model: PWD12
Vaisala PWD series of present weather detectors and visibility sensors provide you off-the-shelf accuracy and reliability. They are a sensor family that grows with your needs.
Tens of thousands of Vaisala present weather and visibility sensors are installed around the world, working reliably and accurately in diverse applications and climates. In Vaisala PWD series, you find the mix you require of visibility measurement range (MOR), characterization of reduced visibility, precipitation type identification, precipitation accumulation/intensity measurement, and report formats (WMO, NWS code tables).
Proven measurement principles for present weather
PWD12 identify the precipitation type by accurately estimating the water content of precipitation with a capacitive device (Vaisala RAINCAP® sensor element) and combining this information with optical forward scatter and temperature measurements. These 3 independent measurements are processed through sophisticated algorithms to produce an accurate evaluation of the weather type according to the WMO and NWS code tables.
Accurate visibility measurement
Calibrated with reference to a highly accurate transmissometer, Vaisala PWD series sensors use the proven forwardscatter measurement principle to report meteorological optical range (MOR). The visibility sensor is well-protected against contamination: the optical components point downward and hoods protect the lenses against precipitation, spray, and dust. This weatherproof design of PWD sensors provides accurate measurement results and reduces the need for maintenance. The optional hood heaters are recommended for wintry conditions to prevent ice and snow accumulation.
Easy installation
PWD sensors are less than 1 meter long. All are compact, light-weight, come with a cable and connector for easy installation, and can be mounted in many ways on any existing mast.
PWD12 is ideal for road weather applications.
For sophisticated road weather applications Vaisala Present Weather Detector PWD12 provides accurate visibility and present weather measurement in the road environment, where low visibility is a serious safety hazard and significantly reduces traffic flow rates. With a visibility measurement range of 10–2000 meters, PWD12 is ideal for road weather applications. PWD12 also indicates the cause of reduced visibility to give you a full picture of weather conditions. Its ability to detect precipitation and identify precipitation type gives the road authority valuable information for the short-range planning of road maintenance operations.
| Item | Specification |
|---|---|
| Operating principle | Forward scatter measurement with 45° scattering angle |
| Measurement interval | 15 s |
| Reporting range of MOR (visibility) | 10–2000 m (32–6500 ft) |
| Reporting resolution | 1 m (3 ft) |
| Reporting uncertainty in operational conditions | ±10 % at 10–2000 m (32–6500 ft) |
| Measurement error (instrument consistency) | ±2.5 % |
| Weather type identification |
4 different types of precipitation (rain, drizzle, mixed rain/snow, snow) Precipitation (unknown type) Fog (mist), haze (smoke, sand) or clear |
| Weather type reporting | WMO 4680 (SYNOP) and NWS code tables:39 different codes supported from WMO 4680 code table |
| Precipitation detection sensitivity (threshold) | 0.05 mm/h (0.0020 in/h) or less, within 10 minutes |
| Precipitation reporting resolution | Intensity 0.01 mm/h Accumulation 0.01 mm |
| Precipitation intensity measurement | 0.00–999.99 mm/h (0.00–39.37 in/h) |
| Precipitation amount measurement | 0.00–99.99 mm (0.00–3.94 in) |
| Amount of new snow |
0.00–999 mm (0.00–39.33 in) |
| Item | Specification |
|---|---|
| Power supply | 12–50 V DC (electronics) |
| 24 V AC or 24 V DC for heater option | |
| Average power consumption | 3 W (peak 10 W) |
| With optional luminance sensor: 5 W | |
| With optional hood heaters: 65 W | |
| Outputs | Serial line RS-232 or RS-485 (2-wire) |
| 3 relay controls (open collector) | |
| Analog output current: 0–1 mA or 4–20 mA | |
| 8-m power/data cable (standard) with connector at PWD end |
| Item | Specification |
|---|---|
| Operating temperature | −40 … +60 °C (−40 … +140 °F) |
| Storage temperature | −40 … +60 °C (−40 … +140 °F) |
| Operating humidity | 0–100 %RH |
| Maximum operating wind speed | 60 m/s (134 mph) |
| Sensor orientation | Align receiver to look away from bright lights (sun or flashing beacons) |
| IP rating | IP66 |
| Item | Specification |
|---|---|
| Weight | 3 kg (6.61 lb) |
| Material | Aluminum |
| Dimensions (H × W × L) | 152 × 404 × 695 mm (5.98 × 15.91 × 27.36 in) |
