Manufacturer: Vaisala
Model: PWD20
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).
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.
Wherever visibility measurement is needed
With a measurement range of 10–20 000 meters, PWD20 offers long-range visibility measurement for diverse applications covering harbors, coastal areas, heliports, windmill parks – indeed, any locations or areas where visibility measurement is necessary
| Item | Specification |
|---|---|
| Operating principle | Forward scatter measurement with 45° scattering angle |
| Measurement interval | 15 s |
| Reporting range of MOR (visibility) | 10–20.000 m (32–65.600 ft) |
| Reporting resolution | 1 m (3 ft) |
| Reporting uncertainty in operational conditions |
±10 % at 10–10.000 m (32–32.800 ft) ±15 % at 10–20km (2.6-12mi) |
| Measurement error (instrument consistency) | ±2.5 % |
| 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) | 146 × 404 × 695 mm (5.75 × 15.91 × 27.36 in) |
