Vaisala PWD52 Technical data

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Vaisala Present Weather Detector PWD52

Automated observation networks need to operate with maximum reliability. Maritime and aviation observing systems need to operate in extremely harsh conditions. Meteorological institutes face challenging productivity and performance requirements. The Vaisala Present Weather Detector PWD52 answers these needs with a mixture of robustness, dependability, versatility and reliability. The PWD52 delivers a wide visibility measurement range and dependable present weather reporting.

Accurate Visibility Measurement

Calibrated with reference to a highly accurate transmissometer, the PWD52 uses the proven forwardscatter measurement principle to measure Meteorological Optical Range (MOR). The sensor optics are well-protected against contamination: the optical components point downwards and hoods protect the lenses against precipitation, spray and dust. This weather-proof design helps sustain accurate measurement results.

Proven Measurement Principles

The PWD52 identies precipitation type by accurately estimating the water content of precipitation using the Vaisala RAINCAP sensor element, and combines this information with optical forward scatter and temperature measurement. These three independent measurements are processed through sophisticated algorithms to produce an accurate evaluation of the precipitation type according to the WMO and NWS code tables.

Features/Beneﬁts

Accurate, traceable

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measurement of prevailing visibility

Detects precipitation type

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Measures the intensity and

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accumulation of precipitation

Estimates snow accumulation

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Robust and dependable

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Weather-proof design reduces

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need for maintenance

Easy to install, easy to integrate

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The optional hood heaters prevent the buildup of ice and/or snow in the optical path.

Solid Track Record

Thousands of PWD series sensors have been installed all around the world. They have undergone rigorous test programs. In the eld, PWD sensors have demonstrated very low failure rates. They have proved their robustness in the harshest climates and most demanding conditions, ranging from offshore to desert and from airport to roadside.

Robust and Dependable

Three measurement methods are used in the PWD52 continuously, independently, and simultaneously thus reducing false alarm rates to a minimum. The identication of precipitation type is reliable due to sophisticated algorithmic processing of complementary data from multiple sources. These factors together produce exceptionally dependable data.

The downward-facing sensor hoods protect the optical surfaces from contamination, resulting in low maintenance needs and costs.

Technical Data

Visibility measurement

Operating principle Forward scatter measurement Measurement range (MOR) 10 ... 35000 m Accuracy ±10 %, range 10 m ... 10000 m

±20 %, range 10 km … 35 km

Present weather

Identiﬁes 7 different types of precipitation (rain,

freezing rain, drizzle, freezing drizzle,

mixed rain/snow, snow, ice pellets)

Fog, mist, haze (smoke, sand) or clear

Reports WMO 4680 (SYNOP), 4678 (METAR),

and NWS code tables; 49 different codes

supported from the WMO 4680 code table-

Precipitation measurement

Measures Precipitation type, intensity,

accumulation and amount of

new snow

Precipitation detection sensitivity 0.05 mm/h or less,

within 10 minutes

Electrical

Power supply 12 - 50 VDC (electronics)

24 VAC or 24 VDC for hood heater option Power consumption 6 W Options

luminance sensor 2 W (24 V) hood heaters 65 W (24 V)

Outputs RS-232 or RS-485 (2-wire)

Three programmable relay controls (open

collector), visibility alarm threshold and

delays conﬁgurable, fault alarm relay

0 ... 1 mA, 4 ... 20 mA analog current

Environmental

Operating temperature Operating humidity 0 ... 100 %RH Protection class IP66

-40 ... +60 ˚C(-40 ... +140 ˚F)

Electromagnetic compatibility

CE-compliant Compliance has been veriﬁed according to the following EMC directives

Veriﬁcation subject Standard Radiated emissions CISPR 16-1,16-2

Radiated susceptibility IEC 61000-4-3,10 V/m Conducted emissions CISPR 16-1,16-2 Conducted susceptibility IEC 61000-4-6 EFT immunity IEC 61000-4-4 ESD immunity IEC 61000-4-2 Surge IEC 61000-4-5

Mechanical

Weight 3 kg (6.61 lb.) Dimensions 222 mm (h) x 695 mm (w) x 432 mm (d)

(8.73” (h) x 27.35 “ (w) x 16.99”(d))

The PWD52 is well suited for meteorological and environmental observation networks.

For more information, visit www.vaisala.com or contact us at sales@vaisala.com

Accessories/options

Interface unit with power supplies 115/230VAC Pole Mast Hood heaters for winter conditions Support arm for mast installations Pole clamp kit for mast top installations Luminance sensor PWL111 Calibration set PWA12 Maintenance cable 16385ZZ

RAINCAP® is a registered trademark of Vaisala.

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